RCA Catalog and price list
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BROADCAST
EQUIPMENT
BROADCAST
CATALOG
AUDIO
EQUIPMENT
AM TRANSMITTING
EQIIPMENT
FM TRANSMITTING
AM, FM AND TELEVISION
EQIIPMENT
1948
TELEVISION STUDIO
Price
... One Dollar
EQUIPMENT
TELEVISION FIELD AND
RELAY EQUIPMENT
TELEVISION
TRANSMITTING
EQIIPMENT
TEST AND
MEASURING
EQLPMENT
DATA
SECTION
INDEX
ENGINEERING PRODUCTS DEPARTMENT
RADIO CORPORATION OF AMERICA
RCA VICTOR DIVISION
RCA INTERNATIONAL DIVISION
COPYRIGHTED
PRINTED IN
CAMDEN, N. J.
N. Y. C.
U.
S
5
91
119
145
173
191
201
231
247
FOREWORD
This Broadcast Equipment Catalog is intended to serve as a buying
guide to the user of this type of equipment. An attempt has been made
to present a clear and concise picture covering: features, uses, description
and specifications for each item of broadcast equipment.
RCA manufactures a complete line of broadcast equipment from microphone to antenna inclusive-for FM, AM and Television. This line in-
cludes not only the operating units but also such necessary accessories
as monitoring and test equipment. RCA is equipped to furnish custom
built studio equipment and antenna phasing equipments. RCA designs
and manufactures the components for its broadcast equipment whenever
necessary or desirable to insure maximum performance and reliability.
Major items of such components are tubes, inductance coils, mica capacitors, crystals and transformers.
RCA is the leader in the field of broadcast equipment. This is evidenced
by the fact that for fifteen years RCA equipment has outsold all other
manufactures. This record includes large and small stations-among
them a large proportion of the most notable installations made during
this period. RCA has been and will continue to be an active leader in
FM development. RCA pioneered the development of electronic television.
Twenty-five years of progress in the radio field plus vast wartime ex-
perience has given RCA an engineering background for the production
of the most advanced and highest quality broadcasting apparatus.
Readers of this catalog are invited to communicate with the nearest
RCA Regional Office for additional information or individual bulletins
on the equipment shown herein. Separate catalogs or descriptive bulletins are available on other lines of RCA equipment such as Sound,
Theatre, Aviation, Communications, Electronic Heating, Scientific Instruments, Records and Radio Receivers.
POLICIES AND INFORMATION
Covering the Direct Sale of
BROADCAST EQUIPMENT
Foreword
RCA Broadcast Equipment is sold directly to the station
through RCA's regional offices. Regional representatives are
conveniently located to render service to broadcast stations
and are familiar with broadcast equipment
problems.
products of other manufacturers shall bear only the guarantee
as may he given by the manufacturer. Electron tubes are covered by a separate warranty.
RCA makes no warranties other than those above described.
and broadcast
The following outline is intended to convey to the purchaser
the policies applicable to the sale of RCA Television Equipment. Policies for the sale of tubes and other RCA products
are described on separate sheets. RCA is setting forth this statement so that all purchasers will clearly understand the terms
and conditions of our sales so that transactions may be carried
forward fairly and promptly.
Patent Protection
RCA agrees to defend any suit which may be brought against
purchaser for infringement of United States patents arising
eut of purchaser's use of the equipment for the purposes and
in the manner contemplated by this agreement, and to pay any
judgment for damages or costs which may be finally awarded
in such suit against the purchaser by a court of last resort.
This is upon the condition that the purchaser will give RCA
prompt notice of any such suit and full right and opportunity
to conduct its defense, together with full information and all
reasonable cooperation. The purchaser agrees that this does
not apply to any infringement arising by reason of combination of the equipment with other apparatus. The purchaser also
agrees that RCA shall have the right to substitute for the
equipment or any parts of it which are claimed to infringe
the patent rights of others, other equally suitable apparatus or
parts, without altering the conditions of the sale, or obtain for
the purchaser the right to continue to use such parts, or in the
event RCA is unable to do so, take back the equipment, refunding any sums the purchaser has paid, less a reasonable
allowance for use.
Contracts
RCA Transmitters, Antennas and all custom-built or special
apparatus are sold by means of a standard agreement form.
Prices
All prices are subject to change or withdrawal without notice.
Prices on Broadcast Transmitters, Antennas and Television
equipment are firm prices, subject to the limitations included
in the agreements covering these sales. Broadcast Audio and
Measuring equipment prices are subject to revision to prices
in effect on date of delivery. All prices are net f.o.b. factory
or warehouse. Prices do not include Federal Excise Tax or
any Federal, State or Local taxes based upon or measured by
sales or use.
Installation
RCA's prices do not include installation, unless specifically
mentioned in a letter of quotation. The purchaser assumes
responsibility for installation and operation of the equipment
as well as obtaining all necessary licenses, permits, etc. RCA
maintains a staff of trained factory engineers who are specialists in the tuneup of transmitters. Orders for this engineering service are arranged through the RCA Service Company, Inc.
Terms
Terms of payment are subject to approval of RCA's Credit
Department.
Delivery
Changes
RCA will furnish an estimate of delivery but assumes no responsibility for delays in delivery. Customers are requested
to specify, at the time the order is placed, the method of
transportation desired, such as motor freight, express, consolidated freight, etc. In the absence of any specific shipping
instructions, RCA will use its best judgment in the selection
of the carrier and will generally ship by the method which
results in the lowest transportation cost.
RCA reserves the right to modify the specifications of equipment described in this catalog, without notice and to supply
such equipment providing that the modifications will not materially affect the performance.
Acceptance of Orders
It is requested that all orders be forwarded to RCA's regional
offices. Regional offices will forward orders promptly to RCA's
Camden, N. J. office for acceptance.
Warranty
RCA will repair or replace, at its expense, f.o.b. factory, any
parts of equipment manufactured by RCA or sold under RCA's
name, which parts show defects of workmanship or material
when used in the normal manner under normal conditions, and
when used for the intended purposes. This is provided that, at
RCA's option, such parts are returned to RCA's factory for
inspection, properly packed and all expenses prepaid, within
one year from date of delivery, and providing that inspection
indicates the defects to RCA's reasonable satisfaction. Equipment manufactured by others and listed in this catalog as
Repairs and Returned Apparatus
Write to the nearest regional office for shipping instructions
and identifying number before returning apparatus for repair
or adjustment. This will enable RCA to render you better
service. RCA receives many shipments daily and without proper
identification, delays may occur. RCA can assume no responsibility for unauthorized returns.
3
You Can Locate Your Nearest R C A
Representative from This List of
FIELD OFFICES
36 W. 49th Street
NEW YORK 20, NEW YORK
Telephone: Circle 6-4030
718 Keith Building
CLEVELAND 15, OHIO
Telephone: Cherry 3450
666 N. Lake Shore Drive
CHICAGO 11, ILLINOIS
Telephone: Delaware 0700
502 Citizens and Southern Bank Bldg.
ATLANTA 3, GEORGIA
Telephone: Walnut 5946
1907-11 McKinney Avenue
DALLAS 1, TEXAS
Telephone: Riverside 1371, 72, 73
621 South Hope Street
LOS ANGELES 14, CALIFORNIA
Telephone: Mutual 1 103
1355 Market Street
SAN FRANCISCO 3, CALIFORNIA
Telephone: Hemlock 8-300
221 West 18th Street
KANSAS CITY 8, MISSOURI
Telephone: Victor 6410
1625 K Street, N. W.
WASHINGTON 6, D. C.
Telephone: District 1260
BROADCAST
AUDIO
EQUIPMENT
Page
MICROPHONES
10
CUSTOM BUILT EQUIPMENT
27
CONSOLETTES & SWITCHING
30
AUDIO AMPLIFIERS
37
REMOTE EQUIPMENT
47
RACKS & RACK EQUIPMENT
52
POWER SUPPLIES
68
TURNTABLES
70
RECORDERS
73
LOUDSPEAKERS
85
Recommended Equipment Lists
Item
The following equipment lists have been prepared as an aid
to the selection of broadcast audio equipment required for an
average studio installation and for audio and monitoring equipment required for use with a transmitter at the transmitter
location. These lists should be used only as a guide in the
selection of equipment since the individual requirements of
each station must be considered carefully before the proper
equipment selection can he made.
Equipment listed for the studio will successfully handle an
average installation where not more than two studios are required. For more than two studios consideration should be
given to the more extensive equipment requirements such as
master control switching with individual studio control. RCA
broadcast audio engineers will gladly assist in planning master
control installations when these are required.
Qty.
3
4
Relays for studio lights
11702
4
2
"On Air" lights
11706-1
5
2
"Audition" lights
11706-3
6
1
Speaker relay for announce booth
11703-A
7
2
Type 70-D turntables U/G
11801
2
Type BA -2C booster amplifiers
11226-B
9
2
Tube kits for BA -2C
11287
10
2
Type 44-BX velocity microphones
(one for each studio)
4027-D
Type 77-D polydirectional microphones
(one for each studio)
4045-A
Type 88-A pressure microphone
(one for announce booth)
4048-D
2
12
1
13
1
11
Type KB -2C "Bantam" velocity microphone (for control room)
11001
2
Type 90-A deluxe program stands
11050
15
1
Type KS -1A floor stand
12065
16
1
Type KS -3A boom stand
4094-B
17
1
Type 91-B desk stand
4092-C
18
1
Desk stand for KB -2C
19
6
Microphone connectors
4630-B
20
6
Wall receptacles
4624-A
and FM Studio Equipment
21
1
Type BR -84B cabinet rack
30951-B84
Equipment
22
2
Single trim strip
30566-G84
23
1
Terminal hoard mounting bracket
4570-A
24
1
Power terminal strip
4568
25
1
Audio terminal block
4569
4645-A
ment with RCA BTA-5F, BTA-10F, BTA-50F and BTF-50A
Transmitters.
The equipment lists include:
1. AM or FM Studio Equipment
3. AM and FM Remote
4.
Professional Type Recording Equipment
5.
Standard Type Recording Equipment
or FM Transmitter Audio and Monitoring
Equipment
6. AM
Transmitter and Studio at Same Location
26
2
Type 33-A jack strip
B
Transmitter at Location Remote from Studio
27
1
Double jack mat
11502-A
C
Transmitter at Location Remote from Studio, where
MI -11623 Rack is desired to be used with transmitter control desk.
28
4
2' patch cord
4652-2B
29
1
Type BE-1B variable line equalizer
30
1
Type BA -4C monitor amplifier
(for house speakers)
11223-B
11267
Suggested apparatus list for handling two studios, an announce
booth, control room microphone, two turntables and equalization for remote lines.
Item.
No.
1
Qty.
1
Description
76-B4 consolette and power supply
MI No.
11613-C/
1
Set of tubes for consolette and power
supply
11252
6
4196-B
31
2
Tube kits for BA -4C
32
2
Type LC -1A loudspeaker
11411/11401
33
1
Type BR -2A panel and shelf
11598/11599
34
3
Studio accordion edge speaker
(for talk -back in studios)
12435/13225
Interconnecting cable (Rack wiring)
35
1000'
36
500'
Interconnecting cable (speaker circuits)
64
37
500'
Interconnecting cable (filament circuits)
65
11301-B
2
12066
A
AM or FM Studio Equipment
1.
MI No.
8
11
Transmitter monitoring equipment lists suggest typical equipment for use when the transmitter is located at a point remote
from the studio and for use when the transmitter and studio
are at the same location. An equipment list is given also for
use where MI-11623 transmitter control rack is to be used
with control desks which are supplied as standard equip-
2. AM
Description
No.
63-A
Item
2. AM and FM Studio Equipment
Suggested apparatus for separate programming of AM and FM
channels. The suggested equipment list assumes four studios,
two announce booths, four turntables and equalization for
remote lines.
Item
No.
Qty.
Description
Type 76-C studio consolette
and power supply
2
1
11624
11301-B
and power supply
"1
4
Qty.
34
2
Description
Type LC -1A loudspeaker (for
control rooms)
MI No.
11411/11401
Accordion edge speakers
for talk -back in studios, etc.
12435/13225
35
6
36
2000'
1000'
Interconnecting cable (rack wiring)
Interconnecting cable (speaker circuits)
63-A
37
38
500'
Interconnecting cable (filament circuits)
65
64
Sets of tubes for 76-C consolette
2
2
MI No.
No.
2
11628-B
3. AM and FM Remote Equipment
BCS-2A switching system
11622
Console supervisory kits (one for
each consolette)
11714
"On Air" light
11706.1
"Audition" light
No.
Qty.
11706-3
1
2
Description
Type OP-6 remote amplifiers
11202-A
Suggested equipment for handling average remote requirements.
Item
5
6
6
4
7
10
Relay for studio light
11702
2
2
Tube kits for OP-6 (one each)
11253
8
2
Speaker relays (for announce booth)
11703-A
3
2
VU meter kits for OP-6 (one each)
11251
9
4
Turntables 70-D
11801
4
2
Cover for OP -6
11256
10
4
Type 44-BX velocity microphone
(one for each studio)
5
1
OP-7 portable mixer -preamplifier
11213
6
1
Tube kit for OP -7
11254
7
1
Cover for OP -7
11257
11
12
13
14
4
2
2
4
.
4027-D
Type 77-D polydirectional microphones (one for each studio)
4045-A
Type 88-A pressure microphone
(for announce booth)
4048-D
Type KB -2C "Bantam" velocity microphone (for control rooms)
Type 90-A deluxe program floor stand
15
2
Type KS -1A floor stands
16
1
Type KS-3A boom stand
11001
11050
12065
4094-B
17
1
Type KS -4A Magic Lock Boom Stand
18
2
91-B desk stand
11052
1
Battery box for OP-6 and/or OP -7
11214
1
Cover for battery box
11258
10
3
Type 88-A microphones
4048-D
11
5
Microphone cable plug
4630-B
12
2
59-B
4093-B
4085
13
1
portable microphone stand
Collapsible banquet stand
14
2
Microphone carrying case
16
Stands for KB -2C "Bantam" velocity
19
2
20
12
Microphone connector
4630-B
21
12
Microphone wall receptacles
4624-A
22
1
Type BR -84-B cabinet rack
30951-B84
23
2
Single trim strip
30566.G84
24
1
25
microphone
8
9
15
4092-C
MI No.
100'
2
4095-A
Microphone extension cable
42
Extension cable plugs
4620-B
12066
4.
Professional Type Recording
Equipment
Suggested apparatus for producing high quality recordings
using Type 73-B professional recording equipment.
Item
4570-A
1
Terminal board mounting bracket
Power terminal strip
4568
1
2
26
1
Audio terminal block
4569
2
3
27
2
Type 33-A jack strip
4645-A
3
1
28
1
Double jack mat (for 33-A)
11502-A
4
1
29
8
2' patch cord
4652-2B
30
2
Type BE-1B variable line equalizer
No.
Qty.
5
31
2
Type BA -4C monitoring amplifiers
(for house speakers)
11223-B
32
2
Tube kits for BA -4C
11267
33
2
Type BR-2A panel and shelf
1
11223-B
1
Set of tubes for BA -5 1
11290
1
or
Set of tubes for BA -4C
11267
6
1
7
1
11598/11599
If more than two consolettes are needed, substitute the
BCS-1A switching system.
7
MI No.
11825/11850-C
Sapphire styli
Orthacoustic recording filter
Type BA -5A Recording amplifier
or
Type BA -4C Monitoring amplifier
4196-B
c
Description
Type 73-B professional recorders
4842
4916-A
11227
Type BR -2A panel and shelf (for
BA -4C amplifier if used)
11598/11599
Limiting amplifier Type 86 -Al
(complete with tubes)
11216-C
Item
Item
No.
Qty.
*3
1
MI No.
Description
36-B panel and shelf (for
limiting amplifier)
Qty.
'8
1
4645-A
1
Type 33-A jack strip
10
1
Double jack mat (for 33-A)
11502-A
11
4
2' patch cord
4652-2B
12
1
VU meter panel
11265
13
1
Filament transformer, 6.3 V
for VU meter panel lamp
11606
14
1
Type BR -84-B cabinet rack
30951-B84
15
2
Single trim strip
30566-G84
16
1
Terminal board mounting bracket
4570-A
17
1
Terminal power strip
4568
18
1
Terminal audio block
4569
19
1
Type 57-C switch and fuse panel
4395-B
20
3
Blank panels 8%"
4594-B
21
1
Blank panel 7"
4593-A
22
1
Blank panel
4591-B
23
1
Type RS -1A suction equipment
11857
24
1
Chip collector and hose assembly
11858
25
*2
Automatic equalizer for 73-B recorder
11100
31/2"
MI No.
Description
panel and shelf (for
limiting amplifier)
36-B
4682-B
9
*
No.
4682-B
9
1
Type 33-A jack strip
10
1
Double jack mat (for 33-A)
11502-A
11
4
2' patch cord
4652.2B
12
1
VU meter panel
11265
13
1
Filament transformer, 6.3 V
for VU meter panel lamp
11606
Please refer to recording charts.
*
4645-A
1-f
1
Type BR -84-B cabinet rack
30951-B81
15
2
Single trim strip
30566.G84
16
1
Terminal board mounting bracket
4570-A
17
1
Terminal power strip
4568
18
1
Terminal audio block
4569
19
1
Type 57-C switch and fuse panel
4395-B
20
1
Type RS-1A suction equipment
11857
21
1
Chip collector and hose assembly
11858
22
2
Automatic equalizers for 72-D recorder
11101
23
3
Blank panel 83A"
4594-B
21
1
Blank panel 7"
4593-A
25
1
Blank panel
4591-B
31/1"
Please refer to recording charts.
5. Standard Type Recording
6. AM or FM Transmitter Audio
and Monitoring Equipment
Equipment
Suggested apparatus for making high quality recordings by
using recording attachments for the 70-D transcription turn-
TRANSMITTER AND STUDIO AT SAME LOCATION
Item
MI No.
Description
No.
Qty.
30951-B84
1
BR -84 cabinet rack
1
tables.
Item
No.
1
Qty.
2
2
3
3
1
4
1
5
1
MI No.
Description
Type 72-D recording attachments with
standard recording head
2
2
Single trim strips (cabinet rack)
''*3
1
Type WF-48A frequency monitor (AM)
**4
1
Type WM -43A modulation monitor (AM)
5
1
30566-G84
11901
4812
Sapphire cutting styli
4916-A
*Orthacoustic recording filter
Type BA -5A Recording amplifier or
Type BA -4C Monitoring amplifier
11227
11223-B
Set of tubes for BA -5A
11290
6
1
Type 86 -Al limiting amplifier
(complete with tubes)
11216-C
Type 36-B panel and shelf
(for limiting amplifier)
4682-B
4645-A
or
1
6
7
1
1
Set of tubes for BA -4C
Type BR -2A panel and shelf for
BA -4C amplifier (if used)
Type 86 -Al limiting amplifier
(complete with tubes)
11267
7
2
Type 33-A jack strip
8
1
Double jack mat (for 33-A)
9
2
Blank panel
83/4"
4594-B
10
2
Blank panel
51/4"
4592-B
11502-A
11598/11599
11216-C
8
Item
No.
Qty.
11
1
Description
Blank panel 3t/z"
12
1
Blank panel
13
1
Type 57-C switch and fuse panel
4395-B
L4
1
4570-A
15
1
Terminal block mounting bracket
Terminal power strip
1
Terminal audio block
4569
16
Transmitter Location Remote From
Studio Where MI -11623 Transmitter
MI No.
4591-B
Control rack Is Desired to Be Used
With Control Desk Supplied With RCA
Transmitters BTA-5F, 10-F, 50-F, and
BTF-50A
4590-B
13/4"
4568
1
1
BR -84 cabinet rack
30951-B84
The MI.11623 Transmitter Monitor and Amplifier Cabinet
Rack has been designed to operate with the Control Desks
supplied with the BTA-5F, 10-F, 50-F and BTF-50A Transmitters to provide a complete and flexible system of controls
and monitors.
2
2
Single trim strip (cabinet rack)
30566-G84
Item
1
Type WF-48A frequency monitor (AM)
17
1000'
Interconnecting cable (rack wiring)
63-A
18
1000'
Interconnecting cable (filament circuits)
65
TRANSMITTER AT LOCATION REMOTE FROM STUDIO
*53
*54
1
5
1
6
1
Type 86-Al limiting amplifier
(complete with tubes)
1
11216-C
panel and shelf (for
limiting amplifier)
4682-B
Type BA -4C monitoring amplifier
11223-B
8
1
Set of tubes for BA -4C
11267
2
BA -2C booster amplifiers (for
Type 33-A jack strip complete with mat
1
Type BA -4C monitoring amplifier and tubes
I
Type 86-Al limiting amplifier and tubes
1
1
11226-B
10
2
Sets of tubes for BA -2C
11
2
BR -2A panel and shelf (for monitor
11598/11599
and booster amplifiers)
12
1
Type 33-A jack strip
13
1
Double jack mat (for 33-A)
14
1
Type BE-1B variable line equalizer
15
1
VU meter panel
2
11287
Type 36-B panel and shelf for
limiting amplifier
Type 57-C switch and fuse panel
*'type BR -2A panel and shelf
MOUNTINGS AND WIRING ARE ALSO PROVIDED
FOR THE FOLLOWING ACCESSORY EQUIPMENT:
4645-A
2
Type 56-C fixed line equalizers
11502-A
2
Type 15 -KC high frequency compensators
(to be used in the 56-C)
4196-B
11265
Filament transformer, 6.3 V for
VU meter panel lamp
MI No.
2
36-B
microphone and turntable)
Description
Transmitter monitor and amplifier
cabinet rack
11623
This cabinet rack is supplied with the following equipment:
1
1
Qty.
1
Type WM -43A modulation monitor (AM)
7
16
No.
11606
1
FM pre -emphasis equalizer
4926-A
1
Power reduction panel
4309-B
1
Hum equalizer
7264-E
17
1
Blank panel 7"
4593-A
3
Type BA -1A amplifiers
18
1
Terminal board mounting bracket
4570-A
1
Type BX-1C pre -amplifier power supply 11305-B
19
1
Terminal power strip
4568
1
20
1
Terminal audio block
4569
21
Type 57-C switch and fuse panel
4395-B
1
1
VU meter panel
11265
4652-28
1
Filament transformer (for VU meter)
11606
1
Sola voltage regulator
11280
22
3
2' patch cord
23
1
Type 88-A pressure microphone
4048-D
24
1
Type 91-B desk stand for microphone
4092-B
Notes:
25
1
Microphone cable plug
4630-B
1.
26
1
Microphone wall receptacle
4624-A
27
1
Type 70-D turntable
28
1
Type LC -1A monitoring speaker
11801
1000'
Interconnecting cable (rack wiring)
63-A
30
1000'
Interconnecting cable (filament circuits)
65
Side panels and trim strips for cabinets are available at
the customer's specific requirements.
2.
*
**
Blank panel drilled and tapped for
mounting 3 MI.10253 line transformers
Space and wiring are available at the top of all Mí.11623
racks for mounting the Frequency Monitor WF-48A and Modulation Monitor WM -43A, or combination FM Frequency and
Modulation Monitor Type WF-5A.
11411/11401
29
11218-A
When used for FM, space occupied will be utilized for FM
frequency and modulation monitor Type WF-5A.
9
One shelf contains the BA -4C amplifier and the other is
wired to accommodate 3 BA -1A pre -amplifiers and 1 BX-1C
power supply for the pre -amplifiers.
MICROPHONES
RCA Microphones
Type No.
44-BX
Directional
Characteristic
Bi-directional
Studio
Studio or
77-D
Poly -directional
Output
Level dbm*
Output
Impedance
Ohms
Frequency
Response
-55
50/250
30.15,000
-57
50/250/600
50.15,000
-118
Satin Chrome
and
Umber Gray
-56
50/250
60-10,000
-109
Satin Chrome
and
Umber Gray
-56
30/150/250
80-8,000
-108
Satin Chrome
Effective
Use
Stage
88-A
Non -directional
Remotes
KB -2C
Bi-directional
Studio
cps
Hum
Pick-up
Level db**
--112
Finish
Satin Chrome
and
Umber Gray
1
irrinz
1/2,,
pipe
Thread
%" pipe
Thread
1/2"
Pipe
Thread
%"-27
Thread
74-B
Bi-directional
MI.6203-C
Poly -directional
MI.6206-G
Non -directional
KN -1A
Non -directional
-56
50/250/15,000
50-9000
-100
Satin Chrome
and
Umber Gray
-58
50/250/600
70-10,000
-111
Umber Gray
Talkback
-56
250
80-8000
-109
Umber Grayy
Talkback
-57
250
100-8000
-109
Satin Chrome
and
Umber Gray
Studio
Stage or
Studio
',4" Pipe
Thread
%" Pipe
Thread
1/a"
*
See "Microphones General. Reference level is one milli watt and a sound pressure of 10 dynes/cm2.
referred to a hum field of 10-3 gauss.
** Level
10
Pipe
Thread
s/8-27
Thread
MICROPHONES
Microphones General Information
RCA Microphones are the product of years of intensive research and development by outstanding engineers. Several types
of microphones are available, some having wide fields of application and some for specific services.
The frequency response curves for all microphones listed in
this catalogue were taken with the microphone working into
an unloaded input transformer of a preamplifier and it is
recommended that the microphones be so operated in practice.
High Quality Broadcast Microphones
Effective Output Level
Broadcast Type Microphones, such as the Types 44-BX, 77-D
and 88-A have characteristics which suit them for high quality
pickup work. They have good frequency response curves, well
shielded output transformers to prevent hum pickup, and are
very well shock mounted to reduce low frequency noises caused
by building rumble. The 44-BX and 77-D Microphones are
particularly suitable for high quality indoor pickups while the
88-A is recommended for outside pickups where rough handling
and wind may be experienced.
When a microphone is effectively working into an open circuit its output cannot be expressed in terms of dbm power level
as no appreciable power is consumed by the open circuit
termination. As a result of this condition the microphone
output ratings are given as Effective Output Level. The effective level is so calculated that when the amplifier gain in db
is added to the microphone output level in db the correct
output level from the amplifier will be obtained. To do this
the effective output level rating is based upon the assumption
that the microphone works into a load impedance which is
equal to its own rated output impedance. The voltage corresponding to this effective output level is actually 6 decibels
below that which is obtained when the microphone is worked
into an "open circuit" preamplifier input. This 6 db difference
is brought about by the fact that the high input impedance
of a preamplifier does not offer a load to the output of the
microphone. Thus the 6 db apparent increase in gain is a'
function of the preamplifier input termination and not of the
microphone itself. The "gain" ratings of preamplifiers takes
into account this 6 db increase in gain so that it becomes
necessary to rate the microphone output at its effective level
for purposes of computing the overall gain of the system as
noted above. The term dbm means the power level expressed
in db resulting from a single frequency sine wave voltage,
referred to 1 milliwatt. For the same peak voltage this will be
about 10 db higher than the indication obtained with a normal
signal of complex wave shape.
Public Address Microphones for Broadcast Use
Public address types of microphones such as the Types KB -2C
and 74-B Velocity Microphone, and the MI-6203-C Varacoustic
Microphones have been designed as economy microphones for
public address and industrial sound use. These microphones,
however, are suitable for use in broadcast applications within
their limitations. The 74-B may be used in place of the 44-BX
in applications where the frequency response, shielding and
shock mounting of the 44-BX is not required. Likewise the
MI -6203-C may be used in place of the 77-D for pickups where
the frequency response, transformer shielding and shock
mounting of the 77-D are not required. Where an extremely
small microphone is desired, the Type KB-2C will give excellent results.
Unloaded Transformer Input
RCA Broadcast Microphones are designed to work into a
microphone preamplifier whose input transformer is unloaded.
Under this condition of operation the full generated voltage
of the microphone appears at the grid of
the first tube resulting
in a gain in signal to
noise ratio of between
RC
No.
1620
1 Input Channel of OP.7 Portable
Preamplifier showing unloaded
transformer input
3
and
6
Hum Pick-up Level
An arbitrary standard a -c field of 10-3 gauss has been established as the reference level. It is representative of fields measured at typical microphone locations in an average studio. The
sound pressure reference is the standard microphone sound
pressure of 10 dynes/cm2. The hum pick-up level is given
for all microphones which permits comparison between an
available unit as compared with other types.
db depending
on whether the major
source of noise is in
the microphone amplifier or in the input resistance of the
Microphones Shipped Less Plug
RCA Microphones are supplied less microphone plugs. Although Cannon Type "P" plugs and receptacles are recommended, and stocked by RCA, many stations use other types
of plugs and prefer to supply their own. For this reason, RCA
supplies the microphone with cord, and, if the Cannon Plug
is desired, it should be ordered as an accessory.
microphone.
Microphone Resistance Loading
Microphones which are relatively inefficient or in which there
is a great deal of damping associated with the moving system
will in general have their frequency response characteristics
little changed by loading. The 88-A and 77-D (in the pressure
position) are examples of this.
Why W" Pipe Thread
RCA has standardized on the rugged t/z" pipe thread for microphone mounting. A recent questionnaire which we sent to
broacasting stations indicated that the 1/z" pipe thread was by
far the most popular microphone thread size. This size pipe
thread makes it easy to add microphone stand extensions,
booms, etc. for they may be easily made up locally from
standard 1/Z" pipe and fittings.
Highly efficient microphones, particularly those in which the
moving system is mass controlled usually show impedance variations for a constant generated voltage. Such microphones will
have their response characteristics adversely affected by resistance loading because the mechanical constants of the moving system will be disturbed by the reflected resistance load.
The Type 44-BX, and 77-D (in the bi-directional and unidirectional positions) are examples of this. Resistance loading
will generally result in a loss in low frequency response.
Suitable microphone stands and adapters are available and
shown in this catalogue for all RCA Microphones.
11
MICROPHONES
Polydirectional Microphone Type 77-D
Description
The 77-D is similar in appearance to the previous Type 77-C1
Microphone but differs in operating principle. The 77-D consists of a single ribbon placed in the air gap formed by the
pole pieces of a permanent magnet, a variable acoustic network,
a well-shielded matching transformer with low hum pickup
and a perforated metal case housing. Effective shock -mounting
is used between the microphone and stand to reduce building
rumble.
One side of the microphone ribbon is completely closed by a
connector tube which in turn is coupled to a damped pipe or
labyrinth. An aperture, placed in the connector tube directly
behind the ribbon, is made variable in size by a rotating
shutter. The directional characteristics of the microphone
are controlled by varying the area of the aperture in the labyrinth connector. When the aperture is so large that the back
of the ribbon is effectively open to the atmosphere, as in a
velocity microphone, the acoustic impedance is zero and a bidirectional characteristic pattern is obtained. When the aperture
is completely closed, the acoustic impedance is infinite and the
characteristic pattern is non -directional which is typical of a
pressure operated microphone. As the area of the aperture is
varied,
a critical value introduces a phase shift which results
in a uni -directional characteristic. Other positions of the
shutter result in patterns varying between bi-directional and
non-directional.
On the back side of the 77-D wind screen (upper shell) is a
slotted shaft control adjustment which is brought out flush with
a designation plate mounted on the screen. The plate is marked
"U", "N", and "B", as designations for the uni-directional,
non-directional and bi-directional response curves. A special
uni -directional plate, marked with a large "U", is provided
with the microphone. When fastened over the designation
plate, it fixes the directional pattern control shaft in the unidirectional position; thereby identifying the microphone as a
uni -directional microphone, when this plate is attached.
The lower half of the case contains the acoustical labyrinth,
output transformer and a selector switch for voice or music.
This switch will attenuate the low frequencies below 300 cycles
for voice pickup and has three positions designated as "M",
"V," and "V2". The switch is operated by a screw driver and
is accessible from the bottom of the lower cylindrical shell.
A protective cloth bag is shipped with each Type 77-D Microphone. The bag can also be used with Type 77-D and 77-C
Microphones and ordered separately as MI -4087.
Features
High fidelity.
Adjustable directional characteristic, continuously variable,
provides non -directional, bi-directional or uni -directional
operation.
Three position "voice -music" switch allows selection of best
operating characteristic for voice or music.
Well shielded output transformer assures low hum pick-up.
Reduced reverberation pick-up through selection of proper
directional characteristic.
Efficient shock mounting reduces building vibrations.
Small size-light weight.
Attractive appearance.
Specifications
Directional Characteristic (adjustable)
Bi-directional, uni -directional and non -directional
Output Impedances (tapped transformer) -50/250/600 ohms
-57 dbm*
Effective Output Level
Hum Pickup Level
-118 dbm**
Frequency Response
See curves
Finish
Satin chrome and umber gray
3/4" pipe thread
Mounting
Dimensions, overall
111/2"
Height
33/4"
Width
21/z"
Depth
3 lbs.
Weight (unpacked including mountings)
30' less plug
Cable (MI -43 3 conductor shielded)
MI.4045-A
Stock Identification
-
Uses
The RCA 77-D is a high-fidelity microphone for use in
broadcast studios. With this one microphone a variety of
directional patterns may be obtained by operating a screwdriver adjustment which is conveniently located on the back
of the microphone. The 77-D combines the best features of the
velocity and pressure microphones. The polydirectional characteristics of this microphone aid materially in obtaining a
better balance, clarity, naturalness and selectivity in studio
pickups. It is also of considerable value where difficulties are
encountered in reverberant locations since the undesired sound
reflections may be reduced by a choice of the proper directional pattern.
Accessories
MI-4630-B
MI.4087
Microphone Plug
Protective Cloth Bag
Referred to one milliwatt and
dynes/cm2.
** Level referred to a hum field of
*
12
a
1
sound pressure of
x
10-3 gauss.
10
MICROPHONES
Directional Response Patterns
Frequency Response Curves
OPEN CIRCUIT FREQUENCY RESPONSE
OF A TYPICAL
TYPE 77-D MICROPHONE
VI
V2
POSITION
UNIDIRECTIONAL
15
il
50
II
I
10000 15,000
1,000
100
FREQUENCY
IN
CYCLES PER SECOND
Uni -Directional Position
OPEN CIRCUIT FREQUENCY RESPONSE
OF A TYPICAL
a
TYPE 77-D MICROPHONE
+5
M
O
7VI
V2
BIDIRECTIONAL
POSITION
-20
0
10000 I5
WOO
10O
FREQUENCY
Bi-Directional Position
IN
0
CYCLES PER SECOND
OPEN CIRCUIT FREQUENCY RESPONSE
OF A TYPICAL
TYPE 77-D MICROPHONE
+5
M
O
N
J
W
m
c
VI
5
V2
10
C
15
NONDIRECTIONAL POSITION
20
I
50
00
FREQUENCY
Non -Directional Position
13
I
1,000
IN
CYCLES PER SECOND
IO,000 15,000
MICROPHONES
Velocity Microphone Type 44-BX
Features
Sensitive ribbon element for faithful reproduction.
Free from cavity or diaphragm resonance and pressure
doubling.
Uniform and smooth reproduction over the entire audio
range.
Response adjustment to provide the best possible frequency
characteristics for either vocal or musical pickup.
Bi-directional "figure eight" type pattern which allows placing of artists on both sides of the microphone and greatly
reduces reflection pickup from side walls.
Unaffected by temperature, humidity or changes in air
pressure.
Ruggedly built for hard usage.
Shock mounted.
Attractive in appearance.
Uses
The 44-BX is primarily intended for studio use where a microphone of the highest quality of reproduction is desired. It can
be used with practically any audio facilities system and lends
itself readily to unusual or difficult studio problems. The 44-BX
is also well suited for high quality remote work. The 44-BX is
found in almost all of the leading studios in the country and
has become a recognized symbol of broadcasting.
Description
The bi-directional pattern of the Type 44BX Microphone is
of the familiar "figure eight" type. Unlike other types of
microphones, it has no diaphragm-the moving element being,
instead, a thin metallic ribbon so suspended as to be able to
vibrate freely between the poles of a permanent magnet. Be.
cause of its lightness, the motion of this ribbon corresponds
exactly to the velocity of the air particles and the voltage generated in it is, therefore, an exact reproduction of the sound
waves which traverse it. Moreover, since it has no diaphragm
and is open in construction so that air flows freely through it,
the Type 44-BX Velocity Microphone is free from the effects of
cavity resonance, diaphragm resonance and pressure doubling,
which cause undesirable peaks in the response of all pressure
type microphones.
The 44-BX is attractively designed in satin chromium and
umber gray to harmonize with practically any modern studio
interior. The yoke mounting permits a wide range of tilting
angles. The shock mounting reduces undesirable pick-up from
floor vibrations, etc.
Directional characteristic of a
typical 44-BX Velocity Microphone
Specifications
-----
Directional Characteristic
Bi-directional
Output Impedances (tapped transformer)
50/250 ohms
Effective Output Level
-55 dbm"
Hum Pickup
-112 dbm**
Frequency Response (see curves)
30-15,000 cycles
Finish
Umber gray and satin chromium
Mounting
t/Z" pipe thread
Dimensions, overall
Height (including cushion mounting)
12"
Width
43/4"
Depth
33/s"
Weight (unpacked, including mountings)
81/2 lbs.
Cable (MI.62 2 conductor, shielded)
30' less plug
Stock Identification
MI.4027-D
Level_
Referred to one milliwatt and
dynes /cm2.
** Level referred to a hum field of
*
a
1
sound pressure of
x
10,000 cps
6,000 cps
1,000 cps
FREQUENCY RESPONSE
OF A TYPICAL
VELOCITY MICROPHONE
OPEN CIRCUIT
44.R%
+10
+
DR
u JSIQ
CyvNPCT7ON
5
o
s
VO/C
10
-
CON NEC
rl
ON
15
20
10
ri
10-3 gauss.
14
00
PRCOUCNCY-CYCLES PER
a0o
SECOND
oboes 15600
MICROPHONES
Pressure Microphone Type 88-A
Features
Good frequency response.
Light weight.
Small size.
Rugged construction.
Low cost.
Minimum effects from wind and moisture.
High output providing unusually good signal-to-noise ratio.
Adaptable for use with any stand or may be carried in the
hand for street interview programs.
Output cord protected by spring.
Uses
The Type 88-A is the ideal microphone for general remote
pickup use. It has been specially designed to provide small
size, light weight, good frequency response and relative freedom
from the effects of wind and moisture. In spite of its light
weight and small size, it is extremely rugged and well -suited
to stand the hard usage to which a remote microphone is put.
The characteristics of the 88-A also make it adaptable for many
types of studio use where a non -directional microphone is
desired.
Description
The Type 88-A Microphone is of the pressure -actuated type.
The moving system consists of a thin molded diaphragm to
which an annular coil assembly is attached. Coupled to the
diaphragm is an acoustic circuit so proportioned that the diaphragm velocity will remain essentially constant for a constant
sound pressure over the frequency range of 60-10,000 cycles.
The coil is placed in the air gap of a magnetic structure and
the ends connected to a transformer which provides output
impedances of 50 or 250 ohms.
This microphone is styled and finished in umber gray and
satin chrome to present a very pleasing appearance. A ball and
socket joint with a thumbscrew clamp permits operation in
either a vertical or horizontal position.
Specifications
Directional characteristic of a
typical 88-A Pressure Microphone
Non -directional
Directional Characteristics
50/250 ohms
Output Impedances (tapped transformer)
-56 dbm*
Effective Output Level
-109 dbm**
Hum Pickup Level
60-10,000 cycles
Frequency Response (see curves)
Umber gray and satin chrome
Finish
1/2" pipe thread
Mounting
Dimensions, overall
Height (including mounting)
Diameter
Length
Weight (unpacked)
Cable (MI -43 three conductor shielded)
Stock Identification
Referred to one milliwatt and
dynes/cm2.
** Level referred to a hunt field of
*
a
O'EN CIRCUIT
FREQUENCY RESPONSE
TYPE
PRESSURE
HO
4%"
71/8"
v.
33/s"
co
J
lb.
30' less plug
1
5
o
-5
-lo
MI.4048-D
sound pressure of
10
80
1
x
88-A
MICROPHONE
10-3 gauss.
lOO
1.000
FREQUENCY IN CYCLES
15
PER SECOND
10.000
rl.60]40
MICROPHONES
"Bantam" Velocity Microphone
Type KB-2C
Features
Miniature size, ideal for remote uses.
Cable disconnect at microphone, permits easy storing in
carrying cases for remote pick-ups.
Smooth frequency response.
Figure eight directional pattern over wide frequency range.
Shock mounted.
Low hum pick-up as a result of correct transformer design.
Low cost.
Uses
The type KB -2C microphone is a miniature velocity microphone which may be used for either remote applications or
studios. The microphone is so small that it may readily be
carried in a coat pocket if desired. Pressure microphones such
as the type 88-A are recommended for outdoor remote uses
where wind noise may be objectionable, but the type KB -2C
will give quality performance for inside pick ups.
The type KB -2C microphone may be used for announce positions, talk back, secondary studios or any application where
the superior performance of the type 44-BX is not required.
Description
Small size is obtained by making the magnet structure a part
of the case. The use of new and highly efficient magnet materials has permitted a further reduction of size while retaining
an output level comparable to other microphones. The cable
may be disconnected from the microphone by lifting a plate
at the back of the stem. An XL type male plug insert is used
in the microphone. A female plug, MI -11090, engages the insert and is enclosed within the microphone stem. Only the plug
at the microphone end is supplied as a part of the cables
listed under accessories. An output impedance of 150 ohms is
included to meet proposed RMA output impedance standards.
The microphone may be titled forward or backward through
an angle of approximately 30°. On one side below the pivot
is a screw driver type switch for selecting the bass response
for voice or music. The voice position is useful for performers
who must work close to the microphone or in studios with
long reverberation periods at the low frequencies.
5
o
;
flUSIC
S
W
to
15
-20
/I
/
VOICE
OPEN CIRCUIT FREQUENCY RESPONSE
OF A TYPICAL
KR2C VELOCITY MICROPHONE
1,000
FREQUENCY
IN CYCLES
PER
10,000 15,000
SECOND
Specifications
Directional Characteristics
Ri -directional
Output Impedances
30/150/250 ohms
Effective Output Level
-56 dbm
Hum Pick-up Level
-108 dbm
Frequency Response (see curve)
50.10.000 cycles
Finish
Satin chrome
Dimensions (overall including stand fitting) :
Length
87/a"
Width
1%a"
Depth
1"
Weight Less Cable (unpacked)
12 oz.
Mounting
%"-27 fixture thread
Stock Identification
MI -11001
(Includes 30 feet MI -43 3 conductor shielded cable)
For desk positions, the KS -2A low -height stand is recommended for use with the KB -2C. Any standard floor stand or
collapsible stand may be used for other applications.
Accessories
Adaptor (%"-27 microphone thread to t/2" pipe thread on
stand)
MI-12053
Cable Only (three conductor shielded) _
MI -43
Desk Stand (umber gray metalustre)
MI -12066
Desk Stand (black)
MI -12066-A
Cannon Microphone Plug-Type P (male)
MI -4630B
Cannon Microphone Plug-Type XL (male)_MI.11089
Referred to one milliwatt and
dynes/cm2.
Level referred to a hunt field of
Directional Characteristics of a Typical K8 -2C
Velocity Microphone
16
a
1
sound pressure of 10
x
10-3
pun.
MICROPHONES
Junior Velocity Microphone Type 74-B
Features
Free from objectional peaks or dips from
70
to 8,000 cycles.
Bi-directional "figure eight" type pattern which allows placing of artists on both sides of the microphone and greatly
reduces reflection pickup from side walls.
Light weight, small size.
Attractive appearance.
Uses
The 74-B has been widely used by broadcasters for years. It
offers the smooth bi-directional response of the 44-BX in an
inexpensive, small and light -weight model. The 74-B is particularly recommended for applications where the extended
frequency response and more elaborate shielding and shock
mounting of the 44-BX are unnecessary. It is, therefore, a very
useful microphone for audition studios, announce positions,
talk back and for small and occasionally used studios. It may
also be used for remote pickups where the frequency response
is limited by lines and other factors. While the 74-B is particularly useful for pickups from inside remote points, the
Type 88-A Microphone is especially suited for general remote
use. The 88-A is designed to give the greatest freedom from
the effects of wind, shock and moisture.
Description
In design the Type 74-B is similar to the larger 44-BX Microphone, but lacks the latter's shock mounting and transformer
shielding. The transformer output impedance taps are for 50,
250 and 15.000 ohms. The windscreen is finished in satin
chromium and the hase is umber gray. Attached to the base
is a ball and socket joint which permits rotation or tilting at
any desired angle.
Specifications
Directional Characteristics
Bi-directional
Output Impedances (tapped transformer) -50/250/15,000 ohms
Effective Output Level
-56 dbm*
Hum Pickup Level
-100 dbm*
Frequency Response (see curves)
50-9,000 cycles
Finish
Umber gray and satin chromium
Dimensions (overall)
Length
73/4"
Width
23/4"
Depth
2t/2"
Weight (unpacked)
21/2 lbs.
Mounting
t/2" pipe thread
Cable (Mí.42 2 conductor, shielded)
30' less plug
Stock Identification
MI.4036-AA
*
Directional characteristic of a
typical 74-B Junior Velocity
Microphone.
1000 cps
300 cps
-----3000
N +5
Q
5
lo
15
Level referred to one milliwatt and a sound pressure of
dynes/cm2.
Level referred to
10
*
a
hum field of
1
x
cps
60
10-3 gauss.
100
1900
FREQUENCY IN CYCLES PER SECOND
17
0000
MICROPHONES
Microphones
MI -6203-C, MI -6206-G, KN -1A
Varacoustic MI -6203-C
Aeropressure MI -6206-G
Uses
The Varacoustic Microphone is ideally suited for public address
use under high reverberatory conditions and for stage pickups
where auditorium noises are to be kept to a minimum. As an
economy microphone it may also be used for similar broadcast applications when shock mounting is not required and
the ruggedness of broadcast types is not required. Compared
to the original MI.6203, the MI.6203-C has an improved transformer, and impedances of 50, 250 and 600 ohms. 1/2" pipe
thread fitting is also used.
Uses
The MI.6206-G offers outstanding performance as a public address microphone. Its relatively wide frequency response, high
sensitivity and attractive appearance also readily adapt it for
use as a "talk back microphone in broadcast studios. It is well
suited to the requirements of a program director's microphone
or it may be used for emergency announce purposes.
Description
Like other pressure operated microphones, the MI.6206-G is relatively non directional at the lower frequencies and
directional at the higher frequencies.
The reversible paracoustic baffle supplied with this microphone will change
the high frequency directional characteristics. This baffle either sharpens or
broadens the directional characteristic,
depending upon whether its concave
surface faces toward or away from the
microphone grille. This microphone is
supplied with a devis mounting bracket
and a short six inch cable and female
plug, or as indicated.
Description
This microphone is of entirely new
design. A slide adjustment which
changes the physical characteristics
of the labyrinth permits a choice of
non -directional, bi-directional or unidirectional operation. In addition,
three variations between the unidirectional and bi-directional pattern
may be obtained.
Features
Features
Low cost.
Good frequency response.
Low cost.
Good frequency response.
Baffle for directional or non -directional application.
Reduced reverberation pickup.
Adjustable directional characteristics.
Specifications
Specifications
Directional
Non -directional
Directional Characteristics
950 ohms
Output Impedance
--56 dbm*
Effective Output Level
109 dbm**
Hum Pick-up Level
80-8,000 cycles
Frequency Response
Two tone umber gray
Finish
i/s" pipe thread
Mounting
(Supplied with adaptor t/$" to %"-27 fixture thread.
Mí.12051 Adaptor required for t/" pipe thread.)
Dimensions, overall
Length
5"
"
Diameter
lbs.
21/2
Weight (unpacked)
Stock Identification:
MI.6206-G
With 6 in. Cable and Female Plug
MI -12077-B
With 15 ft. Cable and Male Plug
MI.12077-C
With 30 ft. Cable and Male Plug
for non -directional,
bi-directional or uni -directional
CharacteristicsAdjustable
50/250/600 ohms
Output Impedance
-58 dbm
Effective Output Level
111 dbm*
Hum Pick-up Level
70-10,000 cycles
Frequency ResponseUmber gray
Finish
1/2" pipe thread
Mounting
(Supplied with adapter 1/2" to %"-27 fixture thread)
Dimensions, overall
/s
Length
2%
Width
Depth
31/2 lbs.
Weight (unpacked)
30' less plug
Cable (MI.42 two conductor shielded)
MI -6203-C
Stock Identification
61
Announce Microphone, Type KN -1A
109 dbm**
Hum Pick-up Level
100-8,000 cycles
Frequency Response
30/150/250 ohms
Output Impedance
Umber gray
Finish
Dimensions:
Length
93/4"
11/2"
Width
9"
Depth
9
lbs.
Weight Less Cable (unpacked)
%"-27 fixture thread
Mounting
Stock Identification:
MI.12081-B
With 15' CableMI.12081-C
With 30' Cable
Uses
The KN -1A is an excellent microphone of the dynamic
pressure type, ideally suited for announcing and
"talkback" purposes in broadcasting.
Description
This microphone is of an entirely new design with
modernistic lines. The shank fitting is a standard
%"-27 thread for public address use. %"-27 to V2"
adaptor, MI.12053, is used to attach it to the broadcast standard V2" pipe thread stand fitting. The
microphone is mounted on the adjustable swivel and
may be moved through an arc of 80° in the vertical
plane. The shank accommodates the cable with the
new type "XL" female plug which is inserted in
the microphone male plug. A hinge cover protecting the connectors is snapped closed.
Accessories
Cable Only (2 conductor)
Desk Stand (gray metalustre)
Desk Stand (black)
Referred to one milliwatt and a sound pressure
10 dynes/cm2.
** Level referred to a hum field of 1 x 10-3 gauss.
Specifications
Directional Characteristic
Effective Output Level
MI.42
MI.12066
MI.12066-A
*
Semi -directional
-57 dbm*
18
MICROPHONES
Microphone Plugs and Receptacles
RCA Microphones are sold without plugs in order that the
purchaser may use any type desired. The Cannon Type "P"
Series are recommended for their reliability and ruggedness.
This series of Cannon Plugs is used in all RCA remote amplifiers. The Cannon Type "P" Plugs and Receptacles stocked
by RCA have steel jackets, which are preferred to the die cast
type, for their increased ruggedness. All fittings are finished
in satin chrome.
miniature size plug was developed to obtain a cable connection that could be housed in the stern of the KB-2C Microphone. This size of microphone plug is identified in the
Cannon XL -3 Series. The versions stocked by RCA for broadcast use have satin chrome finish and use steel jackets to
reduce possible mechanical damage. A split gland type of
cable clamp will accommodate cable diameters up to 1/4 inch.
Although features preferred by broadcasters have been incorporated into this plug, its smaller size and restricted space
for making connections to the contact pins may make it less
acceptable than the larger Cannon "P" Series for general use.
The XL -3 Series of Plugs and Receptacles has been accepted
by RMS as standard for public address use.
A
MI -4624-A Wall Receptacle
CANNON "P" SERIES OF PLUGS
Cannon
RCA Stock
Description
Stock No.
Identification
MI.4630-B
Male Plug for Microphone Cords P3 -CG -12S
MI-4624-A
Wall Receptacle for Above Plug P3.35
Note: The MI.4624-A Receptacle will fit in
a standard a -c outlet box.
MI.4620-B
Extension Cord-Female Connector P3 -CG -11S
MI -11090
Cord Connector
CANNON "XL" SERIES OF PLUGS
RCA Stock
Cannon
Stock No. Identification
Description
MI.11089
Male Plug for Microphone Cords XL-3-12SC
MI-11090
Female Connectors-Extension Cord XL-3.11SC
Wall Receptacle for Microphone
None
MI-11096
Plug
MI.11088
Female Receptacle-for Amplifiers XL -3.13N
MI -11089
Microphone Plug
MI -4630-B Microphone Plug
M1.11096 Wall Receptacle
MI-4620-B Cord Connector
19
MICROPHONES
Microphone Stands
Banquet Stand MI -4095-A
Desk Stand
Features
Features
Type 91-B
Small size.
Heavy base with felt covered bottom.
Compact and convenient for portable use.
Rugged construction.
Easy to assemble or take apart.
Attractive finish.
Adjustable height.
Attractive appearance.
Uses
This newly designed stand is the ideal for banquets or
other occasions where a sturdy, attractive and truly portable
stand is required.
Uses
The 91-B is a heavy -based desk stand
designed especially for studio or announce use. It is attractive in appearance and easily mounts the heaviest of
studio microphones.
Description
The MI.4095-A is of novel construction in
that its base forms a compact carrying
case for the entire stand. The hollow under
side of the base casting accommodates the
stand's three telescoping tubular sections
and two fin type legs fold into the base
sides. When unfolded the legs extend 51/4"
from center of the vertical rod. The bottom of the base is covered with felt.
Specifications
Height-Adjustable 103/" to
Description
The 91-B is finished in the new RCA
umber gray metalustre with polished
chromium trim. The base is felt covered to prevent marring the table or
desk on which it may be placed.
The stand has a base size of 41/2" and is provided with a
choice of two mounting fittings. The shorter one with a 3/"
extension is intended for use with the 77-D, 44-BX, and 74-B
microphones. The longer extension with a 13/" extension is
intended for use with the 88-A microphone.
243/4"
Base Dimensions 3%"x101/2"xl%"
Microphone Mounting
Specifications
%" pipe thread
5 lbs.
Weight
Finish-Umber gray and chromium
MI -4095-A
Stock Identification
Desk Stand
pipe thread
6%" x 3/"
Umber gray with polished chromium trim
Microphone Mounting
Base
Dimensions.-
Finish
Weight
Stock Identification
1/2"
41/2" x
4 lbs.
MI -4092-C
Type KS -5A
The desk stand, Type KS -5A, is a
neatly designed stand primarily for
use with the KB -2C and KN -1A
microphones. It is of cast metal and
attractively finished in two glossy
finishes, gray metalustre or black. The
microphone is held rigidly in position
by %"-27 thread bolt. The bottom
is cushioned by a strip of rubber,
giving adequate protection to any
finely finished surface.
Announce Stand Type 91-A
For 44-BX Only
The 91-A is a simple but attractive
desk stand for 44-BX Microphones.
It is finished in dark umber gray
metalustre and its base rests on three
felt buttons. Height of the 44-BX
Center above desk is 8%". Base diameter, 7". Use only with Type 44-BX
Microphone.
Specifications
Dimensions:
41/2"
Length
5%"
Width
3/4"
Height
Weight
Fitting Size (of mike extension)
Stock Identification:
Gray Metalustre
Glossy Black
11/4
lbs.
%"-27 thread
Specifications
Weight (unpacked)
Stock Identification
MI.12066
MI.12066-A
20
31/2
lbs.
MI.4058-C
MICROPHONES
Announce Stand
Desk Stand MI -12063
MI -4096
The MI.12063 is a special light weight
6" desk stand with a %"-27 pipe thread
fitting. It is especially suited for use with
the RCA Aeropressure and Aerodynamic
Microphones. It is attractively finished
in dark umber gray metallustre and has
a heavy 6" felted base.
Weight (unpacked) _ _ _
P/
This attractively-designed announce stand is adjustable from
8 to 101/2", making it ideal for
use on a desk or table. It is
finished in chromium and black
and features a 71/2" base. The
microphone mounting is for a
standard 1/2" pipe thread.
lbs.
Weight (unpacked)
4
lbs.
Pushmike Stand MI -6427
This smartly designed table stand features a built-in microphone switch and
is suitable for use with all RCA pressure type microphones. The switch is
of the D.P.D.T. long leaf anti -capacity
type and permits turning the microphone on and off right at the microphone stand. It may also be used for
`push -to -talk" operation or lock -in
"Talk" position.
Pushmike Adaptor MI -6425
An adaptor with a built-in microphone switch
of the D.P.D.T. long leaf anti -capacity type.
The switch permits "push -to -talk" operation or
locked -in "talk" position and may be used
with any floor or table stand having %"-27
fixture threads. The adaptor is an extremely
light compact unit finished in chromium. It
is 4%" long, 1ik" in diameter and weight is
3/4 lbs. unpacked.
The stand is 43/4" high with 53/" base
and is attractively finished in chromium.
The microphone mounting is for a
%"-27 male or female thread. Stock
#33543 Adaptor is available on separate order for microphone with 1/2"
pipe thread.
Weight (unpacked)
Stock Identification
Fitting
Top
Bottom %"-27 fixture thread (female)
%"-27 fixture dread (female) with added
%"-27 thread, male nipple
Weight (unpacked)
Stock Identification
lbs.
MI.6427
11/8"
3/4 lb.
MI -6425
(Includes MI.6425 Stand and MI.6426 Base)
Microphone Adaptors
RCA offers a comprehensive stock of microphone adaptors
suitable for microphones and stands, etc., used in the broadcast field. A recent questionnaire confirmed that for its simplicity in procurement and availability, the 1%" standard pipe
Stand
Thread
1/s" pipe thread
1/2" pipe thread
1/2" pipe thread
1/2" pipe thread
%"--24 (W.E.)
%"-27
%"-27
Microphone
Thread
1/Z" pipe thread
1/8" pipe thread
%"-27
%"-24 (W.E.)
1/2"
1/8"
1/2"
pipe thread
pipe thread
pipe thread
thread was infinitely more popular than any other pipe size.
For this reason, RCA has standardized on the 1/2" standard
pipe thread, and avails broadcasters of adaptors to suit any
application.
Stock
Identification
Stock No. 32212
MI.12051
MI-12053
MI.12057
MI.12057-A
Mí.6229
Stock No. 33543
Stock
#33543
21
Mí.12051
MI -6229
MICROPHONES
Program Stand Type 90-A
Floor Stand Type KS -1A
Uses
The 90-A Program Stand is the standard unit at leading Station
and Network Studios. With its attractive finish and sturdy construction this stand will improve the appearance and operation
of any studio set-up. It may be used with all RCA Broadcast
Type microphones or with any other microphone which may
he adapted to a 1/2" pipe thread mounting. The t/Z" fitting
may be removed to expose a %"--27 thread.
Uses
The KS -1A is an attractive light -weight floor stand specially
designed to provide the superior qualities of the Type 90-A
Program Stand in a light -weight model. This stand may be used
with all RCA microphones and is particularly recommended
for applications where the heavier construction of the 90-A
Stand is not required.
Description
Description
The 90-A floor stand is equipped with
a simple clamping device which permits height adjustments to be made
easily and quietly without operating
any release mechanism. The up and
down operation is smooth and the
locking operation positive. The patented clamp is mechanically simple
and is ruggedly constructed to give
years of service. The weighted base
of the 90-A is equipped with equalizing projections to assure a firm position on an uneven floor. The stand is
finished in satin chrome to harmonize
with any studio decoration. Cable
guides are included to hold the microphone cord in proper position.
The KS -1A, like all RCA Floor Stands,
features the patented clamping device
that permits smooth height adjustment
without the operation of any release
mechanism. The clamping arrangement is positive in operation and is
ruggedly constructed to give years of
trouble -free service. The telescoping
tube sections are stainless steel and
the weighted base is finished in dark
umber gray wrinkle. A cable clamp
is provided in the base to hold the
cable in position.
Features
Suitable for use with all RCA
Microphones.
Low price.
Features
Hundreds giving excellent performance in leading broadcast studios.
Smooth operation with automatic
clamping and release device.
Suitable for use with all RCA
Microphones.
Light weight.
Heavy ten inch base.
Large heavy base with equalizing
projections assure sturdy support
of microphone.
Simple non slide,
clamping device.
Attractively
chrome.
Sturdy construction.
Attractively finished.
trouble free
finished
in
Specifications
satin
Height of Stand
Microphone Mounting
Diameter of Lower Tube
Diameter of Base
Weight (unpacked)
Finish
Base
Stand
Stock Identification
Specifications
Adjustable from 3'8" to 6'2"
Height of Stand
Standard 1/2" or %"-27 pipe thread
Microphone Mounting
121/x"
Diameter of Base
33 lbs.
Weight (unpacked)
S'itin Chrome
Finish
MI.11050
Stock Identification
MI.11099
Accessory Item-Cable Hook
Adjustable from 3' 2" to 5'51/2"
1/2" pipe thread
I"
11"
14
lbs.
Dark umher gray
Satin chrome
MI -12065
Cable Hook Ml -11099
Features
Uses
Can he attached or removed in a few seconds.
Attached to the 90-A or any other 11/4" round tube
stand the MI -11099 provides a convenient method of
holding the cable when it is not in use.
Saves wear on the cable.
Keeps cable out of the way when not in use.
Description
Specifications
The Cable Hook is simple to install, and may be easily
adjusted to the proper height. Merely tightening a
smooth locking nut bolds it in position.
Weight
Finish
Hole Diameter
22
15 oz.
Satin chromium
1%"
MICROPHONES
Boom Stand Type KS -3A
Three -section Microphone Stand
MI -6208
Description
The KS -3A is a studio type stand which is especially suited for
piano pickups and arrangements where it is desirable to locate
a microphone close to the source of sound. It is also ideal
for picking up large orchestra groups where the microphone
must be elevated above the height attained with a Type 90-A
Stand.
Description
The MI -6208 is a convenient and attractive
stand for floor or banquet use. It is especially suitable for portable use since it may
be taken apart into three sections for easy
packing or carrying. The stand has a heavy
ten -inch gray crackle base which is trimmed
with satin -silver stripes. The stand finish is
chromium.
Adjustments are easily made with large knurled and polished
handwheels. The boom is adjustable and counterbalanced.
Smooth -rolling, rubber-tired casters eliminate noise and facilitate movement. Foot operated locks are located on all casters.
The boom stand is finished in satin aluminum and umber gray
wrinkle. Cable supports are provided for the microphone cord.
Features
Utility stand for floor or banquet use.
Three sections for easy packaging or
carrying.
Heavy ten -inch base.
Attractive appearance.
Features
Sturdy construcstruction, strong
tubing and casting.
Specifications
Large hase with
rubber tired
Height (for floor use-3 sections)
Adjustable from 3' 11" to 5'
Height (for banquet use -2 sections)
Adjustable from l' 6" to 2' 7"
Microphone Mounting
1/2" pipe thread
Finish
Stand
Polished chromium
Base
Gun metal crackle with
satin -silver stripes
Weight (unpacked)
11 lbs.
Stock Identification
MI -6208
casters.
Easily adjusted
over wide range
of heights and
boom length.
Positive locking
adjustments.
Air
cushion
lowering brake.
Specifications
Floor Stand
Height of Stand
Adjustable from 41/2' to 8'
Horizontal Arm Adjustment
4' 11" to 7' 6"
Microphone Mounting
Standard 1/2" pipe thread
Weight (unpacked)
62 lbs.
Finish_Satin aluminum and black
Stock Identification
MI -4094-B
MI -4068-D
Description
The MI.4068-D is a lightweight microphone
floor stand with a twelve -inch base. It may
be used with any RCA Microphone where
a stand of heavier structure is not required.
Portable Stand
Type 59-B
Features
Description
The 59-B is a collapsible, lightweight and rugged stand which is
unexcelled for field use. It features a
tripod base and a patented clutch
arrangement which permits height
adjustments to be quickly made without the operation of a mechanical
release.
Heavy twelve -inch base.
Modern appearance.
Finish harmonizes with all colors.
Specifications
Height
Adjustable from 2' 11" to 5' 7"
Microphone Mounting -%"-27 pipe thread
fitted with 1/2" pipe thread adaptor. (For
microphones with 1/" pipe thread use
Mí.6229 Adaptor.)
Finish
Chromium and black
Weight (unpacked)
141/ lbs.
Stock Identification
MI-4068-D
Specifications
Height
Adjustatble from 3' to 5'
31/2 lbs.
Weight (unpacked)
Finish
Satin chrome
Microphone Mounting 1/2" pipe thread
MI -4093-B
Stock Identification.
23
MICROPHONES
"Magic Lock"Boom Stand Type
KS -4-A
shaft of the stand utilizes one main "magic lock" which constitutes an instantaneous and positive action in the vertical
plane. The securing screw brake controls and locks the boom
movement in azimuth.
Features
Remarkable dimensional flexibility --a 13' arc extending to
21' high.
One arm universal action.
The boom, with two telescoping 4' sections, has a controllable
arc of approximately 180° by virtue of another "magic lock".
The microphone may be elevated and rotated in azimuth to
any point by a one arm operation of counter balance. The base
has a radius of 26", giving it great mobility, and allowing it
to pass through any standard door. The stand and base are
supported by three large, heavy-duty ball bearing casters, rubber covered to insure a smooth and silent operation. The
microphone cable is guided at six locations and thus eliminates
any possibility of fouling apparatus or instruments. If desired,
the boom's vertical shaft may be removed from the housing
and used on a catwalk or a wall fitting bracket.
"Magic Lock", insuring positive and instantaneous action.
Microphonic noises reduced to a minimum.
Mobility-base will pass through any door.
All steel construction-satin chrome finish.
Low operating expense-no maintenance required.
Suitable for catwalks, etc., with mounting bracket.
Uses
The "Magic Lock" Boom Stand is another addition to the
series of microphone stands employing the "magic lock" prin.
ciple. The ingenuity of this patented device is unexcelled by
any other type of mechanism produced. It allows a one hand
movement of the boom without operation of screws or release
mechanisms and will retain a positive position without any
possibility of slipping.
The stand's flexibility embraces a wide variety of positions
with various types of microphones, and presents a boom stand
of universal action that will find an infinite number of applications in any broadcast or television studio.
Specifications
Dimensions:
Height
Radius of Arc
Weight of Microphone
21'
13'
1 lb.
17'
9'
4 lbs.
14'
6'
8 lbs.
2' from center yoke
Counter Balance
5' radius
Boom When Closed
6' to 9'
Adjustable Height Above Floor
Satin chrome
Finish
Approx 200 lbs.
Weight
-Standard %"-27 with adaptor to t/2"
Microphone Thread
MI.11052
Stock Identification_
Description
The "Magic Lock" Boom Stand is of all steel construction
with a satin chrome finish throughout except for the low
gravity cast iron base, which is dark umber gray. The main
24
MICROPHONES
Microphone Boom & Perambulator MI -26574
Features
Boom and perambulator can he passed through narrow
doorways.
hand wheel, the elevating column raises the boom from a
height of 6 feet, 5 inches to 9 feet, 5 inches. The operating
platform raises with the boom. The wheel tread of the perambulator can be narrowed to 27 inches and the leaf portions
of the table can he lowered to permit passing the perambulator
through a 30 -inch door.
Duraluminum tubing for boom assures rigidity and light
weight.
"Gunning" device revolves directional microphones through
280°.
Radius of boom can be extended to
7 feet, 4 inches.
17 feet --retracted to
hand crank governs extension and retraction of the boom,
and a hand rail controls elevation and horizontal traversal.
As the boom is retracted, the microphone cable is received on
take-up sheaves. The movement of the telescoping member is
counterbalanced by weights which can be adjusted to properly
balance different microphones. Since many microphones are
directional, the boom is fitted with a "microphone gunning"
device which revolves the microphone through 280°.
A
Boom fitted with adjustable counterbalance for different
microphones.
Quiet in operation.
Use
The MI -26574 Microphone Boom and Perambulator is designed
for use in broadcast or television studios. It enables the operator to quickly place the microphone with respect to the sound
source. He can closely follow the sound, or move from one
source of sound to another easily and quietly.
Specifications
Dimensions:
Maximum Height (with boom pedestal elevated)
Maximum Height (with pedestal lowered)
Length of Boom:
Extended
Retracted
Description
The perambulator is constructed of steel tubing with drop -rim
type wheels and pneumatic tires. The steering wheel swivels
180° and can be clamped to hold a given radius. The tiller
when pushed back operates a toggle brake on the steering
wheel. It is also provided with steps which aid the operator
in mounting the platform when it is elevated. Operated by a
Weight:
Boom (with gunning device)
Counterweights for Boom
Perambulator
25
9' 5"
6' 5"
17'
7' 41/2"
663/ lbs.
351/4 lbs.
421 lbs.
MICROPHONES
Microphone Cables
Cable MI -41
Cable MI -43
High impedance microphone cable
Use
Single conductor stranded equiv. #25 AWG
Type
Special rubber compound
Insulation
Tinned copper
Shield
Special durable black rubber compound
Outer Covering
Approximately 0.245"
Overall Diameter
Does not exceed 26 mmf per ft. at 1000 cycles
Capacity
MI.41
Stock Identification (specify length in feet)
Use
Low impedance microphone cable
77 Series KB -2C
For Use with Microphones
Type
Stranded three -conductor shielded equiv. #20 AWG
Special rubber compound
Insulation.
Tinned copper
Shield
Special durable black rubber compound
Outer CoveringApproximately 0.280"
Overall DiameterMI-43
Stock Identification (specify length in feet)
-
Cable MI -62
Low impedance microphone cable
For Use with Microphones
44-BX
(Extra flexible lightweight construction for portable use)
Type
Twisted two -conductor shielded, 41 strands #34 wire
Equiv. #18 AWG
Special rubber compound
Insulation
Tinned copper
Shield
Outer Covering
Special durable black rubber compound
Approximately 0.285"
Overall Diameter
MI -62
Stock Identification (specify length in feet)
Use
Cable MI -42
-
Low impedance microphone cable
74-B, 88-A, MI -6203-C
For Use with Microphones
Stranded two -conductor shielded equiv. #20 AWG
Type_
Special rubber compound
Insulation
Use
_
Tinned copper
Shield
Outer Covering_Special durable black rubber compound
Approximately 0.280"
Overall Diameter
MI -42
Stock Identification (specify length in feet)
-
Interconnecting Cables
The majority of cables required to interconnect the various
components of a broadcast audio assembly are of a special type
and cannot be readily purchased from the local electrical dealer.
In order to avoid unnecessary installation delays, RCA carries
in stock five of the generally used special type cables.
Solid Conductor Cable MI -63-A
General purpose audio transmission line
Twisted two -conductor, solid copper, shielded,
tinned #19 AWG
Insulation-Varnished cambric covered with a serving of cotton
Tinned copper braid
Shield
Overall Diameter
Approx 0 25"
Red and black
Color Code
600 volts
Rating
MI.63-A
Stock Identification (stocked in 1000' rolls)
Use
Type
Stranded Conductor Cable MI -49
Especially recommended for audio circuits
and general rack wiring
Type Shielded, twisted pair, stranded, composed of 10 .010
tinned copper conductors equivalent to #16 AWG
Outside covering of cotton braid.
Insulation-_Varnished cambric covered with a serving of cotton
Tinned copper braid
Shield
Approx. 0.25"
Overall Diameter
Red and black
Color Code
600 volts
Rating
MI.49
Stock Identification (stocked in 1000' rolls)
Use
Stranded Conductor Cable MI -64
Use
extra flexibility is required
Shielded, twisted pair, stranded, composed of 10 .010
tinned copper conductors equivalent to #19 AWG
Insulation-Varnished cambric covered with a serving of cotton
Tinned copper braid
Shield
Approx. 0.28"
Overall DiameterRed and black
Color Code
600 volts
Rating
MI -64
Stock Identification (stocked in 1000' rolls)
Type
Stranded Conductor Cable MI -65
Solid Conductor Cable MI -63
Use
-
-General
-Recommended for power circuits particularly where
Especially recommended for 110 volt supply
and filament circuits
Type-Shielded, twisted pair, stranded, composed of 26 .010
tinned copper conductors equivalent to #16 AWG
Insulation_Varnished cambric covered with a serving of cotton
Tinned copper braid
Shield
Approx. 0.275"
Overall Diameter
Red and black
Color Code
600 volts
Rating
-MI.65
Stock Identification (stocked in 1000' rolls)
Use
rack wiring
_Shielded, twisted pair, solid copper #19 AWG
Silk wrapping and cotton braid
InsulationTinned copper braid
Shield
Approx. 0.24"
Overall Diameter
Red and black
Color Code
600 volts
Bating
MI -63
Stock Identification (stocked in 1000 ft. rolls)
Type
26
CUSTOM BUILT
CUSTOM
BUILT
EQUIPMENT
RCA "Custom -Built" equipments are complete speech input
RCA "Custom -Built" equipments can be furnished to meet
systems designed according to the requirements and specifica-
them.
tions of individual stations. RCA engineers have worked closely
Moreover, the "Custom -Built" service means more than just
with the country's leading broadcast and network engineers in
so many racks or pieces of
the design, production and installation of many such equip-
the services of the whole RCA engineering organization. In
the accompanying
some cases, for instance, the station or network engineers may
ments, a few of which are shown in
photographs.
equipment,-it includes, in fact,
wish to lay out the system themselves, complete with specifica-
No two broadcast studio layouts are just alike, and never,
except perhaps in the smaller stations, are the equipment
tions. In such instances, RCA engineers will assemble standard
units and, where necessary, specially -built units to meet these
specifications in every detail. On the other hand, where sta-
requirements exactly the same. Moreover, the larger the in-
tions so desire, RCA engineers will study the requirements
stallation, the more specialized the equipment problem. But,
of the station, make overall and detailed layouts, and draw up
however large or however modern may be the requirements,
specifications for the needed equipment.
A
completely RCA equipped master control console and associated audio equipment installed at WFAA, Dallas, Texas.
27
CUSTOM BUILT
Master control console installed at WCAO,
Baltimore, Md.
View of a studio control console at WNEW,
New York City.
Deluxe, custom-built installation, completely RCA equipped, at WNEW, Neu:
York City.
28
CUSTOM BUILT
ai.s....ew.4.1.0Lablegi
control console designed especially for installation at WIBP, Baton
Rouge, La.
A studio
-
-..
"(s
A partial vie« of the master control installation
ct WCAO, ditimore, Md., showing the rack mounted audio equipment. This is companion
equipment ta ;hat shown on the oppes$e page
top view.
Master control desk, transcription turntable, and associated audio racks as in.
stalled at WISH, Indianapolis, Ind.
1
.i.
.
4Y
29
-
4
444
r
n
e
CONSOLETTES
Studio Consolette Type 76-B4
Features
locked push -keys connected to the remaining two. The output
of each mixer connects to lever keys so it may be switched to
the input of the program amplifier for broadcasting or to the
monitor amplifier for auditioning. These key switches are interlocked to disconnect the studio loudspeakers and operate "On
Air" light relays. A three position key switch in the input of
the fourth pre -amplifier permits it to operate from a microphone in the studio, announce booth, or local control room.
The push -keys on the fifth and sixth mixer positions allow
any one of six remote lines and two turntables to be instantly
connected to the input of either of the two mixers. Additional
push -key sets provide circuits for feeding cue to remote lines
and for bringing in monitoring circuits such as transmitter or
master control outputs. A monitoring headset jack is supplied
and the headphones may be connected to the output of the
program channel, the remote line push -keys, or the incoming
network by means of a three -position lever switch. Lever keys permit using monitoring amplifier for program amplifier
in emergencies. Talkback facilities are included and separate
push -keys permit talking back to either of the two studios or
to the remote lines. The talk -back circuits are interlocked to
prevent feed-back or program interruption.
An "Over -ride -Record" switch is provided which permits the
remote operator to call in on any of the six remote lines and
over-ride the progam on the control room speaker. The
"Record" position of the switch furnishes a signal source for
Complete high fidelity speech input system for two studios,
announce booth, turntables and remotes.
Excellent frequency response-low distortion for FM or AM.
No broadcast time lost from amplifier or power supply failures. Duplicate equipment may be quickly connected by
means of switches.
8 -watt monitoring and audition amplifier with interlocked
relay circuits for three loudspeakers.
Full facilities for simultaneous audition and broadcast.
Push button selector switches-six channel mixer.
Large vu meter connected to rotary selector switch permits
accurate program monitoring and checks plate currents of
all tubes in pogram channel.
Talk -back system independent of program channel-interlocked switching prevents feed-back.
Easy access for maintenance.
Heavy duty power supply for external bunting allows
space for full-sized components in small sized console.
Uses
The 76-B4 provides a completely flexible and high quality
speech input system for FM as well as standard broadcasting.
The new design supersedes the type 76-B2 and is advantageous
L" its increased flexibility in the switching of the 4th mixer
position from Studio B to the Announce Booth or control
room. This model also uses push button switches of an improved design.
The 76-B4 provides all the amplifying control and monitoring
equipment required to handle successfully two studios, an
announce booth microphone, a control-room announce microphone, two transcription turntables and six remote lines. Full
facilities are provided for simultaneously auditioning and
broadcasting from any combination of the studios, turntables or
remote lines.
Description
All the amplifying and control equipment is mounted in
single metal console and the power supplies are located in
a
a
metal box designed for wall mounting.
The standardized, illuminated volume indicator meter is furnished calibrated in "vu's." This meter is also used to measure
the plate current of all the tubes in the program channel. The
meter is switched to the various tubes by means of the rotary
switch which is mounted to the left of the meter. An adjustable
attenuator at the right of the meter allows the 100% mark on
the scale to be calibrated for +4, +8, +12, and +16 vu.
The console contains four pre-amplifiers, one high -gain program amplifier and one high-gain 8 -watt monitoring amplifier.
A six position mixer is utilized wth the pre -amplifiers conected to four of the mixers and banks of mechanically inter-
aececemcc
CeGTc09ce
76-B4
30
with top raised
CONSOLETTES
an external recording amplifier. Two remote line repeating
coils and attenuator pads are provided.
The console is constructed of metal with wooden style plates
on each end. A lid is provided for access to tubes, etc. from
the top and is equipped with sturdy concealed hinges. The
entire console chassis is hinged across the back to permit
quick and easy access to every component and all the wiring.
Handles on the front panel facilitate opening the chassis fun
inspection. When the chassis is
opened, all the mixers are made
accessible for servicing.
Transcription Input to Line
81 db
Frequency Response (to line or speaker) ±2 db 30-15,000 cycles
Noise Level (below +18 db output, 68 db gain)__ -68 db
Power Input: 105/125 volts, 50/60 cycles
225 watts
Dimensions
Consolette Power Supply
Length
39"
15"
Height
101/"
15"
17
Depth
8"
Finish
Two-tone Umber Grey Dark Umber Grey
Weight, unpacked (less tubes)
135 lbs.
60 lbs.
Sock Identification
MI.11613-C
MI.1130I-B
The metal power supply box is
equipped with a hinged front door
and a hinged chassis. Two separate
rectifier and filter units provide
power for the program amplifierpreamplifiers, monitoring amplifier,
three speaker interlocking relays
and up to 4 external 12 volt relays
for studio signal lights. A switch
permits feeding the preamplifiers
from the monitor supply in emergencies.
Accessories
BA -2C Booster Amplifier (one required for each
70-D turntable)
MI.11226-B
Tube Kit (complete tube complement for 76-B4)_MI.11252-E
RCA -1620
1 RCA-5R4GT
RCA -1621
2 RCA -1622
1
RCA-5R4GT
Emergency Tube Kit (complete tube complement) MI -11252-D
11 RCA -6J7
1 RCA-5R4GT
2 RCA -6F6
2 RCA -6L6
1 RCA-5Y3G
On -Air Light Relay (one required for each
studio on air or audition light)
MI.11702
Speaker Relay (not required unless an interlocked speaker is desired in Announce Booth)_MI.11703-A
11
2
Wall Mounting
Power Supply
Specifications
Source Impedance
Microphones
Remote Lines
30/50 or 250
150, 300 or 600
250
20,000
Components Easily
Accessible with this
Hinged Feature
ohms
ohms
ohms
ohms
Turntables
Monitor Cue
Load Impedance
Line
500/600 ohms
Speaker (total of four speakers)
each 15 ohms
OUTPUT LEVEL
Line (distortion less than 0.5% 50.7500 cycles)__ +18 dbm
Maximum Line Output LeveL
+26 dbm
(With 1.0% rms distortion at frequencies 50-7,000 cycles)
Speaker (distortion less than 3% 50-7500 cycles)
8 watts
Gain (maximum microphone to line)
112 db
---
250.,
MIAERS
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ALL STUDIO LIGHTS a RELAYS
ARE EXTRA AND OPTIONAL
AUDITION
ON AIR
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5.,
Simplified block diagram of 76-B4 Consolette
31
NET
RECORDXT
ING
AMPLIFIER
MONITOR
PRONE
F
AR
N
C6MS6MTES
Studio Consolette Type 76-C
Features
Complete AM, FM studio system for large and small
stations.
Six microphone inputs, six mixers, six pre -amplifiers, eight
watt monitoring and auditioning facilities.
Offers maximum flexibility for large or small stations.
Uses
The 76-C Studio Consolette offers a complete and flexible control system for AM and FM broadcasting. This new design has
resulted from a desire expressed by many broadcasters for a
consolette possessing six pre -amplifiers and additional flexibility
on the fifth and sixth mixer positions. The consolette is versatile in operation and is admirably suited for single studioa
use in a large station or as a complete control unit for
small station.
Specifications
Source Impedance:
Microphones
Remote Lines
The 76-C provides all the amplifying control and monitoring
equipment required to operate efficiently a control room, two
studios and announce booth, two transcription turntables, four
remote lines and five cue circuits. The consolette contains six
pre -amplifiers, six mixer positions, a high gain program amplifier and eight watt monitoring amplifier which may be utilized
to feed an external recording amplifier terminals -67 db gain.
All amplifier inputs and outputs are terminated in terminal
strips, thereby allowing intermediate jack facilities for patching, etc. The fifth and sixth mixer positions are flexible and
may be used as microphone inputs (giving each channel a
112 db gain) or switched to serve four remote lines and two
turntables. Turntables 1 and 2 have their respective cueing
keys which allow cueing signal to be fed to an external amplifier. Full facilities are provided for simultaneously auditioning and broadcasting for any combination of studios,
turntables, or remote lines. Monitoring facilities are provided
for all auditioning channels, turntables, remote and cue lines.
The 76-C is attractively finished and in all respects similar to
the 76-B series consolettes. The chassis is hinged at the rear,
permitting ready accessibility for maintenance. The MI -11301-B
power supply contains two separate rectifiers and filter units
supplying power for the amplifiers, speaker relays and four
studio signal lights.
-
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ohms
ohms
ohms
ohms
Turntables
Monitor Cue
Load Impedance:
500/600 ohms
Line
Each 15 ohms
Speaker (total of three speakers)
2 to 5000 ohms
Headphone Output
Output Level:
Line (distortion less than 0.5% 50 to 7500 cycles)-+18 db
Maximum Line Output Level
(distortion less than 1% at 50 to 7500 cycles)-+26 dbm
Speaker (distortion less than 3%, 50 to 7500 cycles)_8 watts
112 db
Gain (maximum microphone to line output)
81 db
Transcription Inputs Line to Line Output
Frequency Response
+2 db 30 to 15,000 kc
(to line or speaker)
-68 db
Noise Level (68 db gain, +18 dbm output)
125 watts
Power Input (105/125 volts, 50/60 cycles)
Dimensions:
Power
Supply
Consolette,
15 inches
39 inches
Length
15 inches
101/2 inches
Height
8 inches
17 inches
Depth
60 lbs.
140 lbs.
Weight
Dark U/G
Two-tone U/G
Finish
MI -11301-B
MI-11624
Stock Identification
Description
D
30/50 or 250
150, 300 or 600
250
20,000
T
TO
32
MOM. 1cmm.a
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AUD
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Insu4
CONSOLETTES
Switching System Type BCS-2A
Features
Economically priced.
Control of two consolettes for two outgoing lines.
Independent or simultaneous switching of inputs to outgoing channels.
Attractive styling blends with all RCA consolettes and
equipments.
AM, FM, or other desired outgoing channel combinations.
Nine possible combinations of switching.
Mechanically interlocked.
Uses
The BCS-2A switching console has been developed to meet
the demands of many stations now operating both AM and FM
transmitters, or one transmitter and a utility channel for feeding network, recording studio, etc. The addition of this extra
channel adds many complications to programming, unless a
switching system is evolved providing adequate flexibility and
protection from erroneous switching. This is accomplished in
the design of the BCS-2A.
560 0
0
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,, .,,,
Description
The BCS-2A switching console is used in conjunction with
the 76 series or any general consolette, and enables two console outputs to be switched independently to either of the two
outgoing lines such as AM and FM or other combinations
including recording, audition, and network feed. If desired,
either of the two consolettes will feed both outgoing lines
simultaneously, however, push button switches are mechanically
interlocked and prevent both consolettes feeding the same
outgoing line. If the program necessitates material from two
different studios, this may be accomplished through the originating consolette's remote facilities. Switch contacts are provided to operate signal lights that may be located on or near
the input consolettes to indicate if outgoing channel A or B
or both are being fed. The 76 series consolettes have holes
with plug buttons in place on either side of the VU meter
in which the signal lights may be located. Signal light kits
are available as MI.1]714. Power for the signal lights is obtainable from 6.3 volt filament supply.
Cu
000N,
Simplified schematic diagram of BCS-2A
Specifications
Dimensions:
Length v.,
Height
Depth
Weight
Finish_
Stock Identification
10%"
10í/a"
17"
Approx. 30 lbs.
Two tone umber gray
MI -11622
Accessories
BCS-2A with 76-134 Consolerte
Console Signal Light Kit
MI.11714
CONSOLETTES
Switching System Type BCS-1A
Features
Facilities comparable with custom-built equipment.
Control of
5
consolettes to
3
outgoing lines.
Attractive styling blends with all RCA consolettes and
equipment.
Eliminates any possibility of
going line.
2
programs feeding one out-
AM, FM and utility, or any desired combination.
Monitoring facilities for all channels, networks, etc.
Master Switching Console
Uses
The BCS-1A switching system has evolved after numerous requests from broadcasters to develop a "fool-proof" system of
flexible switching for stations operating several studios to more
than one outgoing channel. With the addition of FM to many
stations, it has become apparent that a separate system for
AM and FM transmitter channels is desirable. This feature
decreases the possibility of inadvertent switching and also
enables the operator to satisfactorily adhere to switching functions as assigned.
toring amplifier input selector switch is placed on the left of
the center VU meter to provide a cue check on monitoring
of programs on any of the three outgoing lines, anyone of
the five originating consolettes and two spare positions for
user's choice, such as networks, remotes and recording, etc.
A step-by-step bridging type volume control on the right hand
side controls the level of the monitoring amplifiers.
The Studio Switching Console (see photograph) has three
vertical rows of lights and switches, each vertical being associated with an outgoing channel. Reading from top to bottom, the horizontal rows are the "On -Air" lights which light
only in the program originating control room and indicate
which outgoing channel or channels the originating control
room is feeding. The next row is "In Use". These are operated
when the originating studio, or any other studio, is feeding
program to the channel. The "On" switch which controls each
channel is on the next row. The "Off" switch and the "Studio
Control" lights are the bottom two rows.
Description
The BCS-1A is a relay operated system consisting of a master
switching console, usually installed in the main control room,
and a studio console for each control room. The complete
system provides the master switching console with handling
capacity for one to five studio consoles, with each studio console handling two studios and one announce booth. This
system will switch the output of five consoles to three outgoing
lines. The unique design of the relay interlocking feature
prevents the feeding of more than one program to an outgoing line, or lines, although supporting program material may
be handled as remotes by the originating studio.
The Master Switching Console (see photograph) has three
groups of lights and switches and an associated VU meter for
each of the three outgoing channels. In each group the top
row of lights indicates which of the five studio switching
consoles is feeding the outgoing channel. The associated
switches for each studio are immediately below the lights. A
studio release switch for each outgoing channel is on the next
row. "Studio Controls" are on the lower two rows. A moni-
Some operating features are as follows:
a. The master control switching unit can put any studio on
or off the air at any time. It is the only unit which has
unqualified control.
b. The master switching control can extend control to any
studio control and any outgoing bus or buses that are desired.
This is accomplished by the operation of the studio control
switch on the master switching console, the status of this
control is indicated by the lower signal light row on each
control box.
c. The studio control feature prevents unauthorized switching
from occurring in control rooms not in use.
d. A studio control set up for the next program as indicated
by the studio control light cannot interrupt the originating
studio using the channel. Only the studio feeding or the
master control can release the channel. This is a very important feature. The new originating studio is advised of
the channel availability by the extinguishing of the "In Use"
signal light for that channel. When the "On" button is depressed the studio is placed on the air and the "In Use" and
"On Air" lights are lighted to indicate that the studio is
feeding the channel.
e. The system can be operated as a "roving" control if an
operator is not stationed at the master control. The studio
control switches for all studios and channels that will be
used can be turned on and control can be handled at the
studio controls without benefit of the master control
operator.
All relays and main terminal blocks are located in the base
of the master switching unit and readily accessible by raising
the top and front portion of the case which are hinged at the
rear. With the minimum of channel switching, the minimum
power required for the operation of the complete system
(master and studio consoles) exceeds 1 amp. The MI.1.1304
Studio Switching Console
34
CONSOLETTES
Relay Power Supply (maximum output
5 amps.) is therefore
recommended.
The master switching console is the common point for all
control wire connections. 19 conductors are required from this
console to each studio console if all three outgoing channels
are used. No jumpers are required at any terminal blocks in
case the maximum number of control boxes are not used.
MI -61 shielded, 15 -pair (twisted) cable is available for wiring
between the Master Switching Console and the Studio Switch-
3 OUTGOING CHANNELS
FM
AM
UTILITY
MAIN CONTROL ROOM
r
ing Consoles.
Specifications
L
Dimensions:
Master Switching Console
Length
24"
Height
101/2"
Depth
17"
Weight
(approx.) 80 lbs.
Studio Switching Console
Length
101/2"
Height
101/2"
Depth
17"
Weight
(approx.) 30 lbs.
Stock Identification:
BCS-1A Master Switching Console
Mí.11625
BCS-1A Studio Switching Console (each unit)-MI.11625-A
CONTROL ROOM
CONTROL ROOM
STUDIO
I
]STaDIO
ANN.
CONTROL ROOM
Accessories
Relay Power Supply
MI -11304
BA -3C Program Amplifier (Carbon Control)
MI -11224-E
BA -3C Program Amplifier
(Step -by step Control, Daven)
MI -11224-F
BA -4C Monitoring Amplifier
MI -11223-B
BR -2A Panel and Shelf
MI.11598/11599
LC -1A Loudspeaker (Umber Gray)
MI.11401/11411
LC -1A Loudspeaker (Walnut)
MI -11401A/11411
Line Transformers, 250.600/250-600 ohms
MI -10253-A
Pads, 6 db, 600/600 ohms
-MI.4171.29
15 Pair Twisted Cable (per foot)
MI.61
CONTROL ROOM
s.wo ,
WOO
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OUT
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r
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000
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Schematic diagram of BCS-IA Switching System
35
H
CONSOLETTES
Studio Warning Lights, MI -11706 Series
Outer case removed showing Lumiline
illuminating lamp
Features
Modern styling.
Satin chrome finish.
Available in five types.
Uniform illumination.
Easily mounted.
Uses
The MI-11706 series of warning lights is another new product
to supplement the RCA line of modernistically designed studio
equipment. These lights have been developed after many requests from broadcasters to furnish a studio warning light that
has bold and uniformly illuminated lettering with an external
design that would enhance the appearance of any studio.
The interior or mounting base, containing the lamp, sockets
and terminal strip for the a -c supply, is of separate metal
construction and insures adequate protection from wires shortcircuiting. The complete interior is a wall mounting fixture
and allows a new lamp to be replaced quickly by simply removing the outer case by two screws. The warning light is
available with five signs as indicated below.
Description
The lights are constructed of satin finish cast aluminum with
trimmed etchings and tastefully styled for all studio furnishings. The sign is an opaque black glass with frosted translucent
2" letters, using a 40 watt 12" lumiline lamp for a light source.
Specifications
Dimensions: (overall of case)
Length
Width
Depth
(Glass Sign Aperture)
Length
Width
Weight (unpacked)
Stock Identification:
"ON-AIR"
"REHEARSAL"
"AUDITION"
"STANDBY"
"SILENCE"
Back view showing simplicity of construction and
outer case mounting screws
36
14"
3%"
2/1"
93/4
93/4"
3% lbs.
MI -11706-1
MI -11706.2
MI.11706.3
MI.11706-4
MI.11706.5
AMPLIFIERS
RCA Broadcast
Amplifiers
unsurpassed service and nothing has been omitted which would
contribute to their usefulness and reliability.
Attention is invited to gain and level references in this catalog.
db-refers to gain.
dbm-sine wave power measurement referred to one milliwatt.
VU-refers to average program level as read on a standard
VU meter. This value is subject to considerable variation
from dbm but is generally considered 10 db below peaks.
Allowance must be made for program peaks to avoid amplifier
overloading, for exaple, a pre-amplifier rated at + 10 dbm
should not be operated at more than 0 VU.
The RCA line of high fidelity Speech Input Amplifiers has
been designed to provide stations with studio, recording and
portable remote amplifiers which will offer the maximum in
fidelity, flexibility, convenience and reliability. All amplifiers
are suitable for FM having a uniform response to 15,000 cycles.
Distortion and noise levels have been reduced to a very low
value through careful engineering design and construction.
While the apparatus is unexcelled in performance and appearance, it is very economical considering the many features
which are offered. The amplifiers have been designed to give
Summary of RCA Broadcast Amplifier Characteristics
Type
Usage
Preamplifier
Max.
Gain
db
Max.
Max.
dbm*
Output
dbm*
Matching
Matching
Input
Ohms
Load
Impedance in
Ohms
Source
Impedance
-30
+10
30/250
250/600
Chassi
or
Rack
Bridging
+30
+10
10,000
250/600
Chassis
or
Rack
50
-25
-2
30/250
250/600
Chassis
or
Rack
Matching
40
BA -1A
Isolation
Type
Mounting
Bridging
Amp.7
BA -2C
Mic. Preamp.
or Turntable
Preamplifier
Program Amp.
Line Amp.
Isolation Amp.
Monitor. Amp.
Matching
BA -3C
105
BA -4C
Monitoring or
Recording
Amplifier
BA5A
Recording
Amplifier
65
+11
Bridging
Bridging
27
with
rem. v.c.
70
Matching
80
Bridging
+33
2
600 /250
Watts
600 /250 / 150 /15
7.5
and
5
+40
30/250
(10,000 ohms
40.8
-25
12
-15
amp. input
rem. v.c.)
Watts
+48
50
Watts
600/250/15
7.5
and
5
Chassis
or
Rack
Chassis
or
Rack
150/600
7.5/15/150
Chassis
or
Rack
47
Monitoring
Amplifier
85
-25
+ 10
100,000
40,000
250
15
Chassis
86.A1
Limiting
Amplifier
60
At verge
of Limiting
+30
600/250
600/250
Chassis
or
Rack
76-B4
Studio
Consolette
110
-30
+26
30 /50/250
300 /600
600 Pgm.
Console
112
-30
+26
92.5
-30
+20
30/150/250
150/600
8
-27
-24
30/250
30/250
-24
+19
30/250
600/150
MI -12236
76-C
Studio
Consolette
BN -2A
Portable
Remote
Amplifier
OP -7
Portable
Pre -amp.
Mixer
OP6
*
Portable
t
Amplifier
90
+ 10
Reference level one milliwatt.
37
30/50/150
250 /300 /600
'
15
Monitor
600 Pgm.
15
Monitor
Console
Portable
Carrying
Case
Portable
Carrying
Case
Portable
Carrying
Case
AMPLIFIERS
Two Stage Preamplifier and Isolation Amplifier
Type BA -1A
Features
Excellent frequency response
Description
±1
db 30 to 15,000 cycles.
The BA -1A has been designed to obtain the maximum gain from
two pentode -connected RCA 1620 low noise tubes. The tubes
are mounted vertically and the first stage is shock mounted
to prevent microphonics. The circuit is conventional with unloaded transformer input, resistance -capacitance coupling between stages and transformer output. The distortion and hum
level has been reduced to a very low value through proper
circuit design and through the use of stabilized feedback.
Cross talk between units is -75 dbm, 50 to 15,000 cycles
when mounted side by side and operated from the BX-1C
Power Supply.
Two stages. Ample gain for any preamplifier application.
May be used as an isolation amplifier providing 80 db
isolation.
Low distortion and hum level.
Compact. Six units may be mounted in a single BR -2A
Panel and Shelf Assembly.
As supplied the BA -1A has an essentially flat frequency response
from 30 to 15,000 cycles. However, if desired to help compensate for deficient frequency response of other components of
the system, or long input and output connections, a change can
he made in one or both of two capacitors to provide either a
1 db boost at 30 cycles, a 1 db boost at 15,000 cycles or a 1 db
boost at both 30 and 15,000 cycles. With the addition of the
MI -11274-A or MI.11274-B volume control kit to provide a
10,000 ohm input, the BA -1A may also be used as an isolation
amplifier. The MI -11274-B kit can be mounted on the BA -1A
chassis. The MI.11274-A is intended for panel mounting remote
from the amplifier. As an isolation amplifier, the BA -1A has a
maximum of 7 db of gain with the volume control at minimum
loss position. Approximately 80 db of isolation between output
and input is obtained with the amplifier operating as an isolation amplifier. A switch is provided for metering a portion
of the cathode voltage of each tube when connected to a high
resistance voltmeter such as the Type BI-1A. The switch is
"off" in the center position. The unit is designed to operate
from the BX-1C Power Supply or its equivalent. The power
requirements are 6.3 volts a -c or d-c at 0.6 amperes and 250
volts d-c at 3.4 ma.
Hermetically sealed output transformer.
Uses
The BA -1A is a compact, two stage high fidelity preamplifier.
Its high gain (40 db), extremely low noise level and low
distortion makes it an ideal unit for use as a microphone preamplifier, turntable preamplifier or booster amplifier. It may
also be used as a low level isolation amplifier operating from
a zero to + 30 vu feeder bus by the simple addition of an
MI.11274-B bridging volume control. The BA -1A has a plug-in
type chassis using multi -conductor plugs. The small size of the
BA -1A gives it a great deal of mounting flexibility. It may be
placed directly in a control console, control desk or transcription turntable cabinet. Where cabinet rack mounting is desired, one to six of these units may be installed in a single
BR -2A Panel and Shelf Assembly.
38
AMPLIFIERS
.2
0
1
0
I
``-
220
'
FREQUENCY RESPONSE TYPICAL
I
OW FREQUENCY
COMPENSATION
100
601A
AMPLIFIER
NIGH F EQU NCI
COMPENSATION
\i
3
NORMAL
1000
FREQUENCY M CYCLES PER SECOND
10000
.
20000
15,000
Noise Level
(+10 db, output full gain) below full output
-90 db
-120 db
Equivalent Input Noise
Plate Power Supply
250 volts d-c at 3.4 ma
Filament Supply
6 3 volts a -c or d-c at 0.6 amps
Dimensions, overall-Length 113/4", width 2 c", height 4%FR
Finish
Umber gray
Weight (unpacked)
4% lbs.
Stock Identification (less tubes)
MI -11218-A
Side view of BA -1A used as an isolation amplifier showing
MI-11274-B bridging input control mounted in place
Specifications
BA -1A as Preamplifier:
Source Impedance
Accessories
Tube Kit #1 (complete tube complement)
30/250 ohms
Input Impedance (unloaded input transformer)
Substantially above source impedance
Load Impedance (balanced)
250/600 ohms
Maximum Input Level (less than 0.5 rms dist. 50-7500 cps)
-
Two RCA 1620
Two RCA 6J7
MI-11288-A
NOTE: 6J7 may be used when maximum uniformity of
characteristics and minimum of microphonics, hum and
distortion are not required.
MI -11274-B
Volume Control Kit (Chassis Mounting)
MI -11274-A
Volume Control Kit (Remote Panel Mounting)
Filament Transformer
MI.11606
BX-1C Preamplifier Power Supply (furnishes filament and plate
MI-11305-B
power for 1 to 6 BA -1A Preamplifiers)
Type BI-1A Meter Panel (Black MI.4388B-U/G-MI-4388-C
BR -2A Panel and Shelf Assembly
(required when cabinet rack mounting is desired)
MI.11598/11599
Umber Gray
MI -11598-A /11599-A
Black
-30 dbm
Maximum Output
+10 dbm
Maximum Gain (250 ohm source to 250 ohm load)
db
BA -1A as Isolation Amplifier (with MI -11274 Volume Control)
Source Impedance (Input Impedance 10,000 ohms)
30 to 600 ohms
Load Impedance (balanced)
950/600 ohms
Maximum Input Level, Volume Control at:
Maximum
0 dbm
Minimum
+40 dbm
Maximum Output Level
+10 dbm
Maximum Gain
+7 db
BA -1A as either Preamplifier or Isolation Amplifier Frequency
±1 db 30-15,000 cps
Response
Level-
MI -11288
Tube Kit #2 (emergency tube complement)
-40
Remote Volume Control MI -11274-A, MI -11274-B
Description
Specifications
The MI.11274-A and MI -11274-B Volume Controls are designed
to provide a high resistance bridging input circuit for connections between any low impedance source and the 250 ohm
input terminals of an amplifier. The use of one
of these units makes it possible to pick up
program material conveniently from a program
buss or any low impedance terminated line
without disturbing the operation characteristics
of the buss or the line. Any line of +40 dbm
or below may be bridged. The MI -11274-B Volume Control is designed to be mounted on
the chassis of an amplifier (Le., BA -1A preamplifier). The MI -11274-A Volume Control is
designed for rear panel mounting with the shaft
MI.11274-B extending through the panel.
Input Impedance
10,000 ohms
(approx.)
250 ohms
Output Impedance
Insertion Loss (bridging a 600 ohm line
and operating into a 250 ohm amplifier input)
32 db
Control at maximum position
+40 dbm
Maximum Input Level
Overall Dimension (including shaft) :
Height
Width
Depth
Weight
39
MI.11274-A
%"
1%"
9
11/2"
:41/ ozs.
AMPLIFIERS
Booster Amplifier Type BA -2C
specially shielded power and audio transformers. Connecttions are provided from each cathode circuit to terminals on
the male plug at the rear of the chassis. Corresponding terminals on the receptacle permit metering of tube condition
when connected to a high resistance voltmeter such as the
Type BI -1A. Input, output and a -c connections are also brought
out to the male plug. The unit is equipped with a power switch
and fuse and is provided with a base cover plate for shielding
when used in turntable installations. A mating receptacle is
supplied for the male chassis plug.
Specifications
Source Impedance
Load Impedance (tapped transformer)
30 /250
ohms
ohms
Input Impedance
Substantially above source impedance
Distortion (at normal output level of -15 dbm measured at any
frequency between 40 and 15,000 cycles)
less than 0.75% rms
Maximum Input Level (less than 1% distortion 40-15,000
-25 dbm
cycles)
Maximum Output Level (less than 1% distortion 40-15.000
dbm
cycles)
Frequency Response (see curve)- ±1.5 db 30 to 15,000 cycles
50 db
Gain (250 or 30 ohm source to 600 or 250 ohm load)
70 db
Noise Level (below --2 db* output, maximum gain)
13 watts
A -c Power Input 105/125 volts, 50/60 cycles
Dimension
Overall
Chassis
_-____250/600
-2
Height
Width
Length
Weight (unpacked)
Finish
Stock Identification (less tubes)
BA -2C Amplifier--Front View
Features
High gain
-
Two stages
-
Excellent frequency response
Self contained power supply.
-
lbs.
Umber gray
MI-11226-B
Accessories
Tube Kit (complete tube complement)
MI -11287
2 RCA 1620, 1 RCA 6X5GT/G
Emergency Tube Kit (complete tube complement)
MI.11287-A
2 RCA 6J7, 1 RCA 6X5GT/G
Note: 6J7's may be used when maximum uniformity of
characteristics and minimum of microphonics, hum and
distortion are not required.
MI-11598 /11599
BR -2A Shelf and Panel
Plug-in chassis-Simplified servicing.
-
113/4"
11
Low distortion.
Low noise level. Specially shielded transformers.
Compact
Shelf.
2t/2"
8"
6t/z"
8"
14"
two BA-2C's may be mounted on one BR -2A
May be mounted inside turntable cabinet.
Provision for tube plate current check.
Economically priced.
Reference level one milliwatt.
Uses
The RCA BA -2C Amplifier is a high fidelity two stage unit
for use as a microphone preamplifier, a booster amplifier for
transcription turntables or as an isolation amplifier when used
with suitable bridging resistors. It is also useful at transmitter
installations where a high gain amplifier is required between
the announce microphone and the limiting amplifier. When
used as a transcription pickup amplifier, the BA -2C may be
mounted inside the turntable cabinet. For rack mounting, two
BA -2C Amplifiers may be mounted on one BR -2A Panel and
Shelf Assembly.
Amplifier-Rear view.
Plug-in chassis permits easy
removal of amplifier for
servicing
BA -2C
Description
.]
The BA -2C circuit is conventional and utilizes two RCA 1620
tubes operated as triodes. The first stage tube is shock mounted
to reduce microphonic noises. An interstage gain control, which
is a continuously variable potentiometer with a logarithmic
taper, is provided for adjusting the output level. The amplifier is designed to work into a balanced load of 600/250 ohms.
-1
FREQUENCY RESPONSE OF TYPICAL BA -SA AMPLIFIER
o
The amplifier is complete with built in a -c power supply which
eliminates the need for external rectifiers. The hum and noise
level bas been kept to a very low value through the use of
30
100
000
FREQUENCY IN CYC ES PER SECOND
Frequency Response of a Typical BA -2C Amplifier
40
15.000
AMPLIFIERS
Program Amplifier Type BA -3C
by changing one resistor and one capacitor. Low Frequency
compensation is effected by changing two resistors and adding
two capacitors.
All external connections to the BA -3C are made through the
ten-prong male plugs which engage with two mating pockets
supplied with the amplifier. Connections are provided front
each cathode circuit through a selector switch to ilruiinal on
p1r
the plug in the back of the amplifier. These r
mit metering of tube conditions by means of a bieb rra-t:ul
voltmeter such as the RCA Type BI-lA and Type BI -2A.
r
The amplifier is complete with built-in
rectifier used is 1 RCA-SY3GT/G.
a -c
power supply. The
Specifications
Source Impedance
250/600 ohms
Input Impedance (balanced-center lap grounded
250/600 ohms
a. Matching (50-15,000 cps)
b. Bridging (50-15,000 cps
20,000 ohms (approx.)
Maximum Input Level
(a) Bridging (less than 1.0% rms distortion 30 to 15,000
+40 dbm"
cycles)
(b) Matching (with less than 1.0% rms distortion 30 to
+11 dbm
15,000 cycles)
Load Impedance (tapped transformer)
5/75/18/150/600 ohms
Features
Excellent frequency response-for FM and television.
High gain-low distortion-low noise level.
Provision for cathode metering.
May be mounted in cabinet or panel and shelf.
Economical in price.
Output Level
Less than 0.5% rms distortion 30-15,000 cycles_+25 dbm
Less than 1% rms distortion 30-15,000 cycles_+30 dbm
Less than 1% rms distortion 50-15,000 cycles (2 watts)
+33 dim
Gain Maximum
(a) Matching Input (600 ohm line to 600 ohm load)_65 db
(b) Bridging Input (600 ohm terminated line to 600 ohm
27 db
load)
+1 db
Frequency Response (30 to 15,000 cps)
-82 db
Noise Level (for +30 dbm output, max. gain)
55 watts
A -c Power Input, 100 to 130 volts, 50/60 cycles
Dimensions, overall
Length, 13%"; width 8"; height 71/2"
Light umber gray
Finish
171/2 lbs.
Weight (unpacked)
Stock Identification (with carbon volume control)-MI.11224-E
MI -11224-F
(with step-by-step control)
Uses
The BA -3C is one of the most versatile high fidelity broadcast
amplifiers available. Its high gain and low distortion makes it
ideal for use as:
1. Program or Line Amplifier.
2. Bridging Amplifier.
3. Isolation Amplifier.
4. Cueing Amplifier or Monitoring Amplifier with approximately 2 watts output.
The BA -3C is a plug-in type amplifier which has been designed
for use with the BR -2A Panel and Shelf. This shelf permits
quick and easy removal for servicing or interchanging units.
An adaptor kit, furnished with each unit, permits mounting
the amplifier in the Type 36-B Panel and Shelf. The Type
BR -2A or the Type 36-B Shelf assemblies provide mounting
space for the two Type BA -3C Amplifiers.
Accessories
Tube Kit (complete tube complement)
MI.11266
2 RCA -1620, 1 RCA -1622, 1 RCA-5Y3GT/G
Alternate Tube Kit
MI-11266-A
2 RCA -6J7, 1 RCA -6L6 /G, 1 RCA-5Y3GT/G
BR -2A Panel and Shelf Assembly
/11599
(Black MI.11598A/11599A) U
Type BI-lA Meter Panel (Black MI.4388-B) U/G-MI.4388-C
Description
The BA -3C is a three stage amplifier employing one RCA 1620
pentode first stage, one RCA 1620 pentode second stage and
one RCA 1622 beam power output tube. Excellent frequency
response, high gain and low distortion have been provided in
the design of this amplifier by use of resistance -capacitance
interstage coupling and stabilized feedback. The noise level
has been kept extremely low by the use of a dual volume control which simultaneously controls the gain of the first and
second stages. When a step type control is required an
MI-11224-F amplifier should he ordered.
A special design feature of the BA -3C permits a boost of the
low, the high or the low and high frequencies as shown in the
accompanying frequency response curve. This feature aids in
obtaining an overall system flat response since compensation
may be added to overcome high frequency losses in the interconnecting lines or inadequate low frequency response of associated equipment. High frequency compensation is easily made
"
dbm = db referred to one milliwatt when single frequency
tone modulation is used.
FREQUENCY 11150015E TYPICAL SA -00 AMPLIFIER
,qM ."rañ
r 43E
Dl
i
0
_
b
000
100
FREQUENCY
Frequency response of
41
IN CYCLED
a
Ott
M000
DECONO
typical BA -3C amplifier
40000
1E000
AMPLIFIERS
Monitoring Amplifier Type BA -4C
ing input impedance of 10,000 ohms and may be placed on
the side of a speaker cabinet, on a console panel, or at any
other point within two or three hundred feet of the amplifier.
Where the normal flat frequency response is not desired by
the customer, a boost of the low and high frequencies may be
made by connecting additional resistors and capacitors which
are supplied with the amplifier. A +5.0 db boost at 60 cycles
is accomplished by adding a resistance capacity network into
the plate circuit of the second stage. A +6.0 db boost at
15,000 cycles is accomplished by adding a resistance capacity
network into the cathode circuit of the third stage.
The amplifier is complete with a heavy-duty built-in power
supply. The hum level has been kept to a low value through
the use of a multiple -case shielded input transformer. The
amplifier is designed to supply a nominal low -distortion output of 12 watts.
Specifications
Source Impedance (unloaded transformer input) -250/30 ohms
Bridging Impedance (when used with remote volume
control)
10,000 ohms
Load Impedance
600/250/15/7.5/5 ohms
Audio Power Output (rated output with less than 3% total rms
distortion 50-7500 cycles)
12 watts
+40.8 dbm*
Maximum Input Level
(a) Matching (less than 1% rms distortion)
-27 dbm
(b) Bridging (less than 1% rms distortion)
+40 dbm
Maximum Gain
(a) Overall from 250 ohm source to a 15 ohm load
105 ±2 db
(b) With bridging volume control 600 ohm terminated line
to 15 ohm or 600 ohm
73 db
Frequency Response (see curve) 250 ohm source to 15 ohm
±2 db, 30-15,000 cycles
load
Noise Level (for +40.8 dbm output, max. gain)
-60.8 db
A -c Power Input (105-125 volts, 50-60 cycles)
105 watts
Dimensions, overall
Width
103/4"
Depth
113/ori
7%"
Height
Finish
Light umber gray
Weight (unpacked)
91t/ lbs.
Stock Identification
MI.11223-B
Features
Excellent frequency response to 15,000 cycles.
12 watts output with low distortion-uses feedback.
Suitable for emergency use as program amplifier.
Ideal for recording and playback applications.
Sufficient gain for direct operation of a speaker from turntable output.
High gain-Used directly in talk back circuits, without
preamplifier.
Heavy-duty components. Will operate continuous duty with
ambients up to 120°F.
Suitable for cabinet or panel mounting.
Compensator Kit supplied for boosting response at 60 and
load-
15,000 cycles.
Economical in price.
Uses
The BA -4C is a high fidelity, high gain flexible 12 watt amplifier suitable for monitoring, audition, recording, and talk back
applications or it may be used in emergencies as a program or
line amplifier. It is ideal for transcription playback booths
since its 105 db gain is sufficient to operate an LC -1A or 64-B
Speaker directly from the output of a 70-C2 or 70-D Turntable.
The high gain feature also allows its use directly in studio talk
hack circuits without an intervening preamplifier. The BA -4C
is an excellent recording amplifier being suitable for both
high quality recording and playback applications. It may be
mounted in a type BR -2A or 36-B Panel and Shelf Assembly.
The BA -4C has a plus-in type chassis using multi -conductor
plugs.
Accessories
Stock
Identification
U/G
MI -11598/Mí-11599
MI.11598A /11599A
9 RCA -1620,
Tube Kit (complete tube complement)
MI -11267
1 RCA-6SN7-GT, 2 RCA -1622, 1 RCA-5U4G
Alternate Tube Kit (complete tube complement) 2 RCA -677,
1 RCA-6SN7-GT, 2 RCA-6L6/G, 1 RCA-5U4G_MI-11267-A
Note: 6J7's may be substituted for RCA -1620's and 6L6's for
RCA -1622's when maximum uniformity of characteristics
and minimum of microphonics, hum and distortion are
BR -2A Panel and Shelf,
Black
not required.
Description
*
Employing metal tubes in the audio circuits, this amplifier has
four stages consisting of: (1) RCA -1620 single stage, (2) RCA 1620 single stage, (3) single stage with RCA-6SN7-GT phase
inverter, and (4) 2 RCA -1622's in push-pull. Feedback is used
around the phase inverter and output tubes to reduce noise
and distortion. Gain adjustment is provided through the use
of an interstage control in the grid circuit of the second RCA 1620 tube and through an additional remote volume control.
The remote volume control is a potentiometer and resistance
network which is used when the BA-4C input is to be bridged
across a 600/250 ohm line. This control provides for a bridg-
Reference level one milliwatt.
100
1000
Frequency in Cycles per Second
42
AMPLIFIERS
Recording Amplifier Type BA -5A
Features
Output of 50 watts with 1.5% distortion 50 to 15,000 cycles.
Adequate power to drive two recorder heads.
Response
±1
db 30 to 15,000 cycles (without equalization).
Provides switchable equalization for four recording characteristics.
Plug-in capacitors-reduction in servicing time.
Completely self-contained with power supply.
Bridging facilities for all monitoring applications.
Uses
The BA -5A 50 Watt Recording Amplifier is another development by RCA in high fidelity amplifier design. This amplifier has been primarily designed as a high quality, high
power unit, with a variable equalizer incorporated in the circuit to provide compensation for the various Standard recording characteristics. The BA -5A with its large power handling
capacity provides adequate power to drive two recorders with
negligible distortion. A four -position rotary switch introduces
the necessary equalization to produce recording characteristics
as illustrated. In addition to recording facilities, this amplifier
may also be used for any application where high power is
required. Sufficient power to drive eight to twelve house monitoring speakers or several RCA LC -1A speakers is available.
A bridging resistor network and an unloaded input transformer allows the BA -5A to bridge any high impedance line
or any normal 0 to +8 VU bus monitoring purpose.
This unit is constructed as a self-contained amplifier complete
with power supply for mounting in the BR -84 series cabinet,
9 -AX or any 19" standard rack.
meter, such as the BI -1A or BI-2A. The hinged front panel
permits ready accessibility for tube and capacitor replacement.
The BA -5A is complete with a heavy-duty power supply employing (2) RCA 5R4GY tpbes connected in parallel with
the power switchable from the inside of the panel. All audio
and power connections are terminated at the rear of the chassis.
Specifications
Source Impedance (unloaded transformer input)
150/600 ohms
(Approx.) 20,000 ohms
Bridging Impedance
Load Impedance
7 5/15/150 ohms
Audio Power Output (rated output with less than
1.75% distortion) -50-15,000 cycles, 50 watts (+48 dbm)
Maximum Gain (overall from 150 or 600 ohm source
80 dh
to 150 or 15 ohms level) Matching
47 db
Bridging (to 15/150 ohm load)
Frequency Response (see curves):
1. ±1 db, 30 to 15,000 cycles
2. +6 db at 30 cycles, +16 db at 15,000 cycles for Standard NAB Orthacoustic response
3. +6 db at 30 cycles, +15 db at 15,000 cycles
4.
+6 db at 30 cycles, +13 db at 15,000 cycles
-80 db
Noise Level (for +48 dbm output max. gain)
105-125 volts, 50-60 cycles, 225 watts
A -c Power Input
Dimensions (overall) :
12t/a"
Height
19"
Width (for rack mounting)
13t/s"
Depth Behind Panel (overall)
42 lbs.
Weight (unpacked)
Light umber gray
Finish
MI -11227
Stock Identification (less tubes)
.
Description
The BA -5A is a four-stage, all push-pull amplifier, using the
highest grade input and output transformers. The circuit is a
new four -stage design, employing resistance -capacitance inter,tage coupling with a stabilized feedback circuit over two stages.
The first stage consists of (2) RCA 1620's triode connected
in push-pull, with the interstage containing a variable compensating network for the response curves (see curves). The
second stage with (2) RCA 1620's pentode connected work
into (1) RCA 6SN7GT, operating as a dual triode. The last
stage utilizes (4) RCA 807's connected in push-pull parallel
to deliver 50 watts of power. Feedback is taken from the
primary of the output transformer to the cathode of the second
stage, maintaining an excellent frequency response with a
negligible distortion. A four -position rotary switch introduces
various equalization curves. Position (1)-a desirable flat
curve with a response of ±1 db, 30 to 15,000 cps., (2)-conforming to NAB Standards (Orthacoustic), (3)-75 microsecond tip -up, and Position (4)-a 50 microsecond tip -up.
Plug-in capacitors are used to simplify servicing and to reduce
the time loss involved in capacitor failures. A small pilot lamp
located in the center of the control panel gives a visual indication that the amplifier is in operation. Metering facilities are
provided by a twelve -position rotary switch located on the
front panel. This allows all tubes to be metered in the cathode
circuit for a normal reading of 1 volt from an external volt -
Accessories
MI -11290
Tube Kit for BA -5A
4
RCA -1620,
1
RCA-6SN7-GT, 4 RCA -807
0
S
0
0
11
0
20
00
w
O
1000
FREQUENCY
20
00
1000
FREQUENCY
IN
10000
20000
---
CYCLES PER SECOND
FREQUENCY RESPONSE OF A TYPICAL BA -5A
AMPLIFIER WITHOUT COMPENSATION
IN
CYCLES PER SECOND
SELECTOR SWITCH POSITION 2
SELECTOR SWITCH POSITION 3
SELECTOR SWITCH POSITION 4
FREQUENCY RESPONSE CURVES OF A TYPICAL
BA -SA AMPLIFIER WITH COMPENSATION
43
10000
20000
AMPLIFIERS
Limiting Amplifier Type 86 -Al
86 -Al Mounted on 36.B Shelf
Features
There are no audible "thumps" even though a large compression is suddenly applied. Compression timing constants have
been chosen which have proved most desirable in actual broadcast service. The fast pick-up time of one millisecond restricts
over -modulation surges which might cause transmitter outages.
The return time is slow enough to prevent distorting low frequency times, but fast enough to prevent noticeable level
reduction after loud volume peaks.
Excellent frequency response --suitable for FM.
High compression with low distortion.
Low noise level.
Prevents distortion and adjacent channel interference caused
by overmodulation of transmitters.
Provides for a more effective use of transmitter power by
raising the average modulation percentage.
Meter with rotary selector switch shows gain reduction,
checks plate current of all tubes, and checks overall voltage
supply.
Economical in price.
The circuit of the 86 -Al is straight forward and push-pull
stages are used throughout. The a-c power supply is self contained and utilizes one RCA 5T4 rectifier tube. New plug-in
type electrolytic capacitors are used to simplify servicing the
equipment. The hum and noise level is maintained to a low
value through special transformer shielding. When used in
conjunction with a two stage pre-amplifier, the 86 -Al has
sufficient maximum gain (60 db) for making local announcements. The push-pull output stage and efficient circuit design
provide a maximum power output of 1 watt (+30 VU) with
less than 0.75% total me distortion measured at 400 cycles with
a compression of 18 db. The distortion is less than 1.8% rms
when measured at any frequency between 50 and 7500 cycles.
Uses
The 86-A1 Limiting Amplifier has been designed for use in the
speech input channels of FM and AM broadcast transmitters.
It serves to limit the audio signal peaks to a certain pre -determined level thereby preventing over modulation with its consequent distortion and adjacent channel interference. This amplifier also provides for a more effective use of transmitter power
by raising the average percentage modulation level several
db without appreciably increasing the harmonic distortion. The
limiting characteristics of the 86 -Al also readily adapt it for
use in recording applications. For this use, it prevents over cutting of the recording disc on heavy passages of music or
speech and permits a marked improvement in the signal to
noise ratio.
All the components are mounted on a single metal chassis. A
meter is provided for (1) indicating gain reduction directly in
db, (2) dynamic match indicator for input tubes, (3) measurement of all tube plate currents, and (4) measurement of plate
voltage. A switch on the front of the chassis selects the desired meter function.
Step-by-step input and output volume controls are provided.
These controls are equipped with "vu" scales to indicate input
and output levels at the verge of compression. Auxiliary adjustable controls are (1) hum balance, (2) zero adjustment of
gain reduction meter scale, (3) vernier control for close adjustment of level at which limiting action takes place, and
(4) switch (on front) which makes limiter function inoperative. A power switch and fuse are provided. For rack mounting
the Type 36-B Shelf should be used. A special umber-grey
36-B door panel with meter cut-out is supplied with the 86 -Al
Amplifier.
Description
The 86-A1 Limiting Amplifier uses push-pull vacuum tubes
(RCA 6K7) in the variable -gain stage. The design is such that
a uniform frequency response and a remarkably low distortion
is maintained with large compression ratios as much as 18 db.
Moreover, low distortion is maintained at all modulating frequencies in the normal audio band.
44
AMPLIFIERS
Specifications
[ii
600 or 250 ohms
Input Source Impedance
Output Load Impedance
Frequency Response
600 or 250 ohms
±2db 30.15,000 cycles
(At any setting of gain controls-with or without compression)
Input Level
+10 dbm
Maximum (at limiting verge)
+30 dbm
Maximum (with 18 db gain reduction)
-30 dbm
Minimum (at limiting verge)
Output Level:
Less than 1.8% rms distortion with 18 db compression at any
+30 dbm
frequency between 50 and 7500 cycles
Less than 0.75% rms distortion at 400 cycles with 18 db
+30 dbm
gain reduction
Less than 0.4% rms distortion at 400 cycles with no gain
+ 10 dbm
reduction
Gain (with maximum volume control setting and signal below
60 db
limiting level)
-85 db
Noise Level: below +30 dbm output
-77 db
below + 10 dbm output
Output Range (at verge of limiting)- +10 dbm to +30 dbm
Time Constants
0 001
Seconds for complete action of gain reduction
Seconds for 90% recovery of gain after signal drops below
9 0
limiting level (when connected as furnished)
Note: may be varied from .26 sec. to 5.2 sec. by changing
one resistor.
70 watts
Power Input (105-125 volts, 50.60 cycles)
Width 16", depth 13", height 71/2"
Dimensions
30 lbs.
Weight (unpacked)
-11216-C
Stock Identification: Umber grey
Black-
86 -Al LIM TING AMPLIFIER
LIMITING CHARACTERISTIC
TYPE
I
I
I
i
POINT OF 3.0 DB
GAIN REDUCTION
1
'
I
Ì
re
-
1
1
I
r,
7ITED1EVEL..CONTROT
0.1DB GR. WITH
10 VU INPUT
+8
o
+8
+10
+12
+16
+14
INPUT LEVEL
+18
+20
FREQUENCY RESPONSE OF A TYPICAL 86
10 D8. OUTPUT LEEB
+I
MIN.
+22
+24
WITH INPUT CONTROL AT
-AI
+26
+28
+30
+10 VU)
AMPLIFIER
GAI
_MI
MI.11216-B
Complete with one set of tubes and special 36-B door panel
but less 36-B shelf.
m.
IO DI UMITOG
Accessories
1 OF
Tube Kit (complete tube complement)
DLNIO ARION
MID
MI -11286
l0
RCA -6K7, 1 RCA -6N7, 2 RCA -1621, 1 RCA -6R7,
1 RCA -5T4
Tube Kit (set of two matched 6K7 tubes only)_1II-11250
60 cycles MI.11280
Voltage Regulating Transformer
50 cycles MI.11280-A
(Not required unless line voltage variation exceeds 5%)
MI -4682-B
36-B Panel and Shelf Assembly: Umber gray
MI.4682
Black
2
ARION___
GAI
1000
100
FREQUENCY IN CYCLES PER SECOND
*
Reference level one milliwatt.
The 86.A1, as shipped, includes the Amplifier and small accessories as
shown at right plus the special door panel shown in photograph at left
45
10000
I3000
AMPLIFIERS
6 Watt Monitoring Amplifier MI -12236
Description
Features
The amplifier is supplied with or without a cover and may
be fitted within a 70-C or 70-D series turntable. The circuit
employs two RCA 6J7's and one RCA 6L6 beam power tube in
the output stage. The potentiometer is connected in the input
with a master gain control in the second stage. 14 db of inverse feedback insures a flat response with a low distortion
factor. The low impedance input allows a high impedance
microphone or pick up to be used with excellent results.
Excellent frequency response.
Provision for mixing microphone and turntable inputs.
Microphone volume control, master control and tone control.
Variable load impedance -4 to 30 ohms.
Both high and low impedance input.
Uses
The MI-12236 amplifier is an ideal medium output unit, admirably suited for use as a cueing amplifier with transcription
turntables. The unbalanced input enables it to be used for
bridging an unbalanced line for monitoring applications, or
listening circuits such as offices, laboratories, etc.
... .
r
a
rso...
Specifications
.
db 40-10,000 cps
High Impedance Microphone
i ow Impedance Turntable
High Impedance Pickup
68 db
68 db
100,000 ohm Source to 15 ohm load
40,000 ohm Source to 15 ohm load
,
IM.IM.
±3
Frequency Response
Inputs:
(General Microphones)
(Turntables)
(Crystal Pickups)
Gain-High Impedance:
41.1.W.MN
Gain-Low Impedance:
-norm%
*mummy
-
6
db
watts
15
ohms
250 ohm Source to 15 ohm load
.....M.
Power Output (with
71/2%
85
distortion)
4,
Output Impedance
71/2
and
Dimensions:
Length
Width
Height
111/2"
7
71/
111/2
Weight (unpacked)
Power Supply
Stock Identification:
(Without Cover)
(With Cover)
M1.12237 showing cover in place
46
115
volts, 50 to 60 cycles,
75
lbs.
watts
MI -12236
Mí.12237
REMOTE
Remote Amplifier Type BN -2A
Features
High level mixing -15 to 20 db reduction in noise level.
Portable, compact and completely self-contained for a -c
operation.
Excellent frequency response +1 db 30 to 15,000 cycles.
Low distortion-less than 1% for complete range.
Complete range facilities for feeding PA amplifier and program channel simultaneously.
Suitable for battery operation with the MI -11214 battery box.
Uses
The BN -2A is a light weight, three channel amplifier comp;etely self-contained for a -c operation, requiring no additional equipment whatsoever. Battery operation may be used
by simply removing the power connection and plugging in
the cord of the Mí.11214 battery box used with the OP -6
and OP-7 amplifiers. The three amplifier channels use RCA
1620 indirectly-heated tubes, shock mounted to insure low
microphonics and maximum protection from vibration often
experienced during remote broadcasts. Each channel offers
an overall gain of 92.5 db, more than adequate for any
application. High level mixing is used throughout, reducing
microphonics and general noise level by at least 15 to 20 db.
It has capacity for four microphone inputs, the third and fourth
switchable to channel 3, making possible a total of six microphones. Program may be fed to the output channel and the
PA amplifier simultaneously. Also, the cue circuit may be
switched to isolate the remote amplifier and feed PA direct.
Monitoring facilities in both circuits are provided.
External connections located in the rear of the chassis include
four, Cannon 3-connector microphone receptacles and the 12 connector plug for either a -c or battery operation. The power
supply is built into the amplifier and employs one RCA 6X5GT
full -wave rectifier tube.
Specifications
Source Impedance
30/150/250 ohm.
Load Impedance
150/600 ohms
Normal Output Level
+8 VU
Distortion (+18 db output 50 to 15,000 cycles)
Less than 1% rms
Maximum Output Level (less than 1% rms distortion)
+18 dbm
Maximum Gain (150 ohm source to 600 ohm load)
92.5 db
±1
Frequency Response
db 30 to 15,000 cycles
Noise Level (for +18 dbin output max. gain)
-70 db
A.c Power Input
105-125 volts, 50/60 cycles, 25 watts
Battery Operation:
"A" Supply_6 3 volts (nominal) 2.1 amps. (incl. VU lamp)
"B" Supply
270 volts (nominal) 10 MA
Dimensions:
Length
19"
Depth (with cover)
9t/z
Height
10"
Weight
29 lbs. (complete with a -c cable and spare tubes)
Finish
Umber gray wrinkle
Stock Identification (less tubes)
Mí.11230
Description
The BN-2A consists of a three stage, resistance -capacitance
coupled amplifier combined with three individual input channels for each mixing stage. Each input channel uses a high
quality balanced transformer with electrostatic shielding, operating into a non-microphonic RCA 1620 tube. These tubes are
connected with each mixer in parallel to feed the first stage
of the main amplifier. This stage employs another RCA 1620
pentode connected with feedback from the master gain control, which is a high grade step-by-step potentiometer. The
unique design of this arrangement produces maximum feedback with minimum gain, a feature which reduces any inadvertent overloading of the first stage by announcers "blasting" the microphone or by excessive background noise. The
second and third stages each utilize a 6J7 pentode connected
to the output transformer. Further feedback is taken from the
plate of the last stage to the second stage cathode, resulting
in an excellent frequency response with exceptionally low
distortion. A three -position rotary switch selects either "Cue"
when the PA amplifier is feeding the cueing circuit, "Off"
with the PA and cueing circuit isolated from the program
line, and the "Amp" position when the output channel is
feeding the program line and the PA amplifier simultaneously.
The front panel is attractively styled and arranged to give
centralized control of all circuits. The standard size VU meter
is provided for measuring tube voltages in the cathode circuit
and output level. A switch position for feeding +8 VU to
line when the meter is reading 0 is also provided.
The steel case is ruggedly constructed with the front cover
easily removed for quick operation. Accommodation for carrying spare tubes and fuses is provided within the case.
Accessories
Tube Kit (complete tube complement)
MI -11269
RCA -6J7, 1 RCA-6X5GT
Receiver Type Tube Kit (complete tube
complement) 6 RCA -6J7, 1 RCA-6X5GT
MI -11269-A
Battery Box complete with cord connector
MI -11214
Kit of Batteries
MI -11255
Waterproof Cover for BN -2A
MI -11277
4
z
.2
RCA -1620,
2
10
i º
w r
a
O
SO
20
00
10000
1000
20000
FREQUENCY
FREQUENCY IN CYCLES PER SECOND
FREQUENCY
RESPONSE
OF A TYPICAL
55-20
1000
100
IN
CYCLES PER SECOND
15TOPTION CHARACTERISTICS OF A TYPICAL TYPE
UN -2A REMOTE AMPLIFIER WITH OUTPUT OF ISDEIM.
REMOTE AMPLIFIER
47
10000 15000
REMOTE
Remote Pickup Amplifier Type OP -6
Features
Excellent frequency response.
High maximum output level with low distortion.
Low noise and hum levelHigh overall gain permits use with high quality microphones under adverse conditions.
Small size and light weight_
A -c power supply built in. No external supply required.
Two input positions and transfer key.
Tapped input transformer accommodates any type of microphone.
Ruggedly built with high quality components.
Description
The OP -6 is a three stage resistance coupled amplifier using
RCA 1620 low noise; non microphonic tubes. The three stages
afford a gain of 88 db which is more than ample for any required application. One RCA 6X5GT/G is used in the rectifier.
Since only two tube types are used, the stocking of spares is
simplified. The amplifier circuit is unique in that it utilizes
two feedback loops. One loop is around the first stage and is
varied with the main gain control thus maintaining a maximum
feedback consistent with required gain. This arrangement prevents overloading the first tube by high output microphones.
The gain control is located between the first and second stage
and is a high quality step by step device equipped with a
large knob. The second feedback loop is fixed and is connected around the second and third stages. Two inputs are
provided and either may be selected by means of a turn key
switch. One input is brought to shielded screw terminals and
the other to a standard Cannon microphone receptacle. The
output terminates on insulated binding posts which are located
on the front panel for greater accessibility. The power input
receptacle has a number of contacts which are used for altering
the circuit for a -c or battery operation. An a -c power cord is
furnished with the amplifier and the d -c battery cord is supplied with the MI.11214 Battery Box. Located on the front
panel are the power switch, fuse and monitoring headset jack.
The complete amplifier and power supply is enclosed in a
steel case which has removable cover, rubber feet, and steel reinforced handle. The handle lies flat when not in use. A
leather shoulder strap facilitates transporting the unit and
leaves the hands free to carry microphones, etc. The chassis
and front panel may be easily slipped from the case by removing four thumb -screws. The unit is furnished less meter,
thereby avoiding additional expense for those applications
where a meter is unnecessary.
Specifications
30/250 ohms
150/600 ohms
+8 dbm
Distortion (+8db* output, 50-7500 cycles) _Less than 0.5% rms
Maximum Output Level (less than 1% rms distortion between
+ 18 db
50 and 7500 cycles)
±2 db 30 to 15,000 cycles
Frequency Response
±1 db 40 to 10,000 cycles
88 db
Overall Gain
-70 db
Noise Level (for -j-18 dbm output, 68 db gain)
Dimensions, overall
Height
91/2
Width
12%"
Depth
71/2"
Grey wrinkle
Finish
201/2 lbs.
Weight (unpacked but including 8' power cord)
18 watts
A -c Power Input, 105.125 volts, 50 to 60 cycles
-MI -11202-A
Stock Identification (shipped less tubes)
Source Impedance
Load Impedance_
Normal Output Level
2
OP 6 FREQUENCY RESPONSE
8
o
_I
-q
30
moo
100
FREQUENCY IN CYCLES
VU Meter and Attenuator Kit
Weatherproof Fabric Cover
Battery Box
Kit of Batteries
Accessories
Tube Kit (complete tube complement)
Three RCA 1620 and one RCA 6X5GT/G-MI.11253
Emergency Tube Kit (complete tube complement)
Three RCA 617 and one RCA 6X5GT/G_MI.11253-A
Cannon Microphone Plug
Mixer Amplifier, Type OP-7
48
PER
0.000
I3,000
SECOND
Mí.11251
-MI.11256
MI -11214
MI.11255
MI.4630-B
MI.11213
REMOTE
Mixer Preamplifier Type OP -7
Features
Excellent frequency response to 15,000 cycles.
High level mixing reduces noise to a minimum.
Provides unloaded transformer input and high level mixing
for one to four microphones.
Self contained a -c power supply or may be battery operated.
May be used with any program amplifier having a gain of
80 db.
Description
The OP -7 is a high fidelity, c pact and lightweight portable
unit. It provides unloaded transformer input and high level
mixing for as many as four microphones. It may be used with
the OP -6 Portable Amplifier or with any other program amplifier which has a gain of at least 80 db.
The front panel contains the power receptacle, "on-off" power
switch, a-c fuse, four mixer knobs and shielded output terminals. A front panel cover held by two snap type clasps
protects the equipment and provides space for carrying cables.
Four Cannon Type "P" Microphone Receptacles are assembled
on the rear of the amplifier chassis. A fifth receptacle. with
male contacts, provides a cable output connection. This type
of receptacle safeguards the battery from short-circuits that
might occur using a male plug.
The OP -7 is equipped with long life carbon type mixing controls. In addition, the MI-11276 Modification Kit containing
four Daven step-by-step attenuators with the necessary accessory equipment for modification, is available for modifying
the MI -11213. The OP-7 is complete with built-in power supply
or it may be operated from the MI.11214 Battery Box without
circuit changes. A suitable OP -6 interconnection cable, equipped
with Cannon Plugs, is furnished with the OP -7.
OP -7 with front panel cover
removed. Covers of OP -7 and
OP -6 provide space for carrying interconnecting cables.
Specifications
30/250 ohms
Source Impedance
30/250 ohms
Load Impedance
-55 dbm
Normal Output Level
Distortion (-55 dbm output, 50-7500 cycles)-less than 0.5% rms
Maximum Output Level (less than 1% rms distortion measured
dbm
at any frequency between 50 and 7500 cycles)
8 db
Gain (maximum, 250 ohm source to 250 ohm load)
Frequency Response
±2 db 30 to 15,000 cycles
±1 db 40 to 10,000 cycles
-88 db
Noise Level (-24 dbm output for 8 db gain)
Dimensions
91/2"
Height
123/4"
Width
9"
Depth
Gray wrinkle
Finish
93 lbs.
Weight (unpacked but with cables)
20 watts
A -c Power Input, 105-125 volts, 50 to 60 cycles
Mí-11213
Stock Identification
MI -11257 Fabric Cover
for OP -7. Similar covers, listed as accessories, are available
for OP-6 and for the
MI -11214 Battery Box.
--24
OP -7 chassis, rear view.
Four microphone receptacles and output
receptacle are provided.
Accessories
Tube Kit (complete tube complement)
4 RCA 1620, 1 RCA 6X5GT/G
Alternate Tube Kit (complete complement)
4 RCA 6J7, 1 RCA 6X5GT/G
Weatherproof Fabric Cover"
Battery Box
Kit of Batteries
Cannon Microphone Plugs
OP -6 Amplifier (shipped less tubes)
MI -11254
MI -11254-A
Mí.11257
MI -11214
MI -11255
MI -4630-B
MI -11202-A
+2
057
SO
100
FREQUENCY RESPONSE
1000
10.000
15.000
FREQUENCY IN CYCLES PER SECOND
49
REMOTE
Remote Pickup Equipment OP-6/OP-7
Uses
The OP -6/0P-7 is a high quality, light weight portable pickup
equipment providing four microphone inputs with high level
mixing and separate preamplifiers, built in a -c power supply
and full sized vu meter. Small sized cases furnished with
shoulder straps provide a maximum of convenience in carrying these units. Battery operation may be used at any time
by plugging in the cord of the MI -11214 Battery Box. No circuit changes are required. The mixer and amplifier units may
be used side by side or the amplifier may be mounted on
top of the mixer. An outstanding value at an economical price,
the OP -6/0P-7 combination provides the broadcaster with a
field pickup equipment having studio quality performance.
scription as well as features and specifications will be found
on the OP-7 Mixer Preamplifier catalogue sheet.
The OP -6, companion unit to the OP -7, is a high quality, high
gain, three stage resistance coupled amplifier using three
RCA 1620 Pentode -Connected tubes. A more complete description as well as features and specifications will be found on the
catalogue sheet for the OP -6 Amplifier.
Stock Identification OP -6 and OP -7
MI.11202-A/11213
Complete as shown in photograph but less tubes, vu
meter and microphone plug. Complete listing for accessories will be found under the catalogue listing for the
individual OP-6 /OP-7 units.
Description
2
The OP-7 Mixer Preamplifier comprises four unloaded transformer input circuits each working into an RCA -1620 triode
connected tube. Its source impedance is for 30 or 250 ohm
microphones and the load impedance is 250 ohms. While primarily designed for use with the OP -6 Amplifier, the OP -7 may
be operated with any amplifier having a 250 ohm source impedance and a gain of 80 db or more. A more complete de-
FREQUENCY RESPONSE OP-6/0P7
OP -7 AT UNITY GAIN
+I
ç
o
_2
30
loo
1000
FREQUENCY IN CYCLES PER SECOND
10000
15,000
Battery Box MI -11214
The MI -11214 Battery Box has been designed especially for
use with the OP -6 and OP -7 Remote Amplifiers. It is equipped
with two interconnection cords so that it may be used with
both amplifiers simultaneously. The box is constructed of steel
with durable gray wrinkle finish and is equipped with a large
steel reinforced handle and rubber feet. The cables are stored
in the cover when not in use.
Specifications
Finish (matches OP-6/0P-7)
Dimensions
Height
12í/z"
Width
131"
Depth
83/4"
Weight (unpacked)
151/2 lbs.
Weight (including batteries)
Approximate Battery Life in hours for average amplifier operation of six hours per day.
Burgess
OP -6
OP-6
RCA
Type
1 RCA 1620
OP -7 and
OP -6
Type QuartOP-7
No. 3 RCA 1620 2 RCA 6W7G
tity
No.
7.5
34
50
26
VS 004 (15) 4F "A"
16
24
12
3.5
VS 004 (10) 4F "A"
VS 012
(6)
B-30
`B"
270
270
240
44 lbs.
Stock Identification
MI.11214
Accessories
Weather Proof Cover, MI.11258
MI -11255
RCA Battery Kir
95
50
Grey wrinkle
REMOTE
Radio -Microphone Type BTP-1A
Features
Light, compact and completely self contained.
Excellent frequency response-low distortion.
Crystal controlled transmitter for stability.
Automatic gain control to prevent overload and distortion.
Permits broadcasting from otherwise inaccessible places.
Uses
The BTP-1A Radio -Microphone is a crystal controlled portable
UHF transmitter and microphone. It is especially adapted
to broadcasts by announcers mingling with crowds on the
street, at conventions, large stores, golf matches or other loca.
tions, where wire connections are difficult or impractical.
The maximum satisfactory range of the BTP-1A is determined
largely by the interference level at the receiver location.
Under ideal conditions, several miles may be covered; however, building structures or other media which produce signal
attenuation will limit the working range. Overall transmitted quality is comparable to the direct output of a good
microphone.
Description
The BTP-IA Radio -Microphone with its battery power pack is
housed in an attractively styled aluminum case measuring
10 x 41/2 x 31/2 inches. Total weight of the unit with batteries
is 6 pounds, 5 ounces. A 20 inch removable whip antenna
projects from the top of the case during operation.
The transmitter portion of the Radio -Microphone is crystal
controlled and is designed to operate at any specified frequency
between 25 and 28 mc. Maximum power output from the r -f
amplifier is approximately 0.25 watt. This carrier is amplitude
modulated by a Class A audio stage to assure low distortion.
Automatic gain control is incorporated in the audio amplifier in order to insure proper modulation and prevent overloading over a wide range of sound intensity.
The micophone consists of three crystal units operated in
series to give high output with excellent quality. Shock and
wind noise from the microphone is very low.
Power for operating the transmitter is supplied by a battery
pack which will give up to 10 hours service under normal
operating conditions. A "high -low" battery switch is provided
to insure uniform quality and power output throughout the
life of the battery.
Battery life (approx.) :
Continuous Service
Intermittent Service
Dimensions
The BTP-1A is shipped complete with antenna, battery, crystal
and one set of tubes.
Tube Complement:
AF
AF
RF
RF
Weight (total)
Stock Identification
Specifications
Frequency Range
25 to 28 mc.
Power Output
-Approx. 0.25 watt
Carrier Frequency Stability
± 02% deviation
Modulation Capability
100%
Audio Frequency Response (including microphone)
±4 db 80 to 6000 cycles
Audio Distortion (90% modulation)
Less than 5%
Crystal Frequency (specify operating frequency
when ordering)
1/3 transmitter output frequency
5
10
hours
hours
Height 10"; Width 41/2"; Depth 31/2"
(Not including handles or antenna)
1
1
RCA -1L4 Voltage Amplifier
1 RCA -3A4 Modulator
RCA -3A5 Oscillator and Tripler
1 RCA -3A4 RF Amplifier
6 lbs. 5 oz.
Mf-28923
Accessories
Spare Crystals Type RC -2A (specify operating
frequency desired)
Replacement Battery
51
MI.7681
MI.28291
RACK EQUIP.
Standard Cabinet Racks
BR -84B
BR -84A
BR -84C
Description
Features
The five combinations of cabinets and accessories offer a
versatile system for accommodating the user's immediate requirements with maximum accessibility for any future growth
of the installation. Each rack may be mounted singly or, where
desired, tandem together to facilitate the grouping of any
number of cabinets. The cabinet is of sturdy metal construction, welded and bolted in one standard height and width.
The ventilated top with slotted edges provides complete ventilation but protects the equipment from falling articles and
dust. Vertical panel mounting angles have tapped holes at
RMA standard locations to provide 77" of standard 19" panel
mounting space. These angles may be installed to mount equipment within the cabinet, where doors are used, or flush with
the front. When the latter method is desired, trim strips
of neat design for panel mounting and clip fitting provide
the finished appearance. The front and rear doors are of the
universal type and may be hinged on the right or left side,
to rotate in an arc of 180°. Electrical side shields are available in two sizes -21" for the center section, and 28" for the
top and bottom sections. If found necessary after assembly,
they may be fitted between racks of equipment. Terminal
board mounting angles facilitate the mounting of power and
audio blocks in a vertical or horizontal position. Additional
terminal board mounting angles (MI -30527-G29) 'are available
as accessories.
Units placed adjacently may be rigidly bolted together to produce a secure assembly. Locks may be fitted later by virtue
of the "knock outs" provided. The cabinets are finished in a
two-tone umber gray, with dimensional characteristics artistically blending with all RCA FM transmitters.
Cabinets with same styling and height as RCA FM transmitters.
Total panel space 77".
Available in many combinations to suit all studio applications.
Drilled and tapped for standard 19" panels.
Attractively styled to blend witli all control room installations.
Suitable for fitting in
wall.
Accommodates
studio use.
BR -84 Series
a
flush position to
the heaviest
equipment
a
side or rear
encountered
in
Provides flexibility for future expansion.
Uses
The BR -84 series cabinet rack program is another of the new
feature lines of RCA. The cabinet program is presented after
years of practical experience in finally developing a flexible
scheme for accommodating broadcast equipment.
52
RACK EQUIP.
BLANK PANELS
MI -4590 SERIES
SIDE PANEL
MI -3054 I -G84
SHELF MI-11599
SINGLE TRIM STRIP
MI -30566-084
ELECTRICAL SIDE
SHIELD MI -30546-G21
TERMINAL BOARD
MOUNTING ANGLE
MI-30527-029
POWER STRIP
MI-4568
AUDIO BLOCK
MI -4569
MOUNTING BRACKET
MI -4570-A
BR -84D
Specifications
BR -84E with Accessories
Panel Width
19"
Panel Mounting Space (height)
77"
Clearance for Door Swing
23"
Weight (BR -84A)
225 lbs.
Finish
Two-tone umher gray enamel except for the
base which is black
Dimensions:
Height
84"
Width--BR-84A, -B (with side panels)
98"
BR -84C, -D, -FWidth of Frame
Depth of Frame
Depth (including doors and handles)
One electrical shield (for mid-section of rack)
one per side
MI.30546-G21
One only single trim strip for one cabinet where
panels are fitted without door
MI.30566-G84
One only double trim strip used where two or
more cabinets are placed together
MI -30568G84
One lock
MI -30591
One terminal board mounting bracket
MI -4570-A
Blank panels
MI.4590 Series
One audio terminal
MI -4569
One power terminal strip
Mí.4568
One panel and shelf assembly
MI-11598/11599'
22"
22"
18"
block_
241/4"
Stock Identification
Type BR -84A consisting of one frame, one base, one
top cover, one front door (non -ventilated), one
rear door (ventilated), one pair of side panels,
one set of terminal board mounting angles and
one set of panel mounting angles and instruction
book
MI-30951-A84
Type BR -84B, same as BR -84A,
less front door only
MI -30951-B84
Type BR -84C, same as BR -84A,
less side panels only
MI.30951-C84
Type BR -84D, same as BR -84A,
less side panels and front door
MI.30951-D84
Type BR -84E, same as BR -84A,
MI -30951-E84
less side panels, front and rear doors
*
When ordering for cabinet with door, order MI -11599 shelf
only.
is
Accessories
One front door (non -ventilated)
MI.30531-G84
One side panel
MI -30541-G84
One electrical shield (for top and bottom sections)
two per side
MI -30546-G28
T
Layout and dimensions of cabinet base.
53
Cabinet Rack Type 9 -AX
Uses
The Type 9 -AX is a heavy-duty Broadcast Audio Cabinet Rack
which is widely used in control room and transmitter installations. It provides 77" of panel space for mounting amplifiers,
jack panels., switch panels, oscillators, measuring equipment or
other panel -mounted equipment of standard 19" width. The
9 -AX completely shields and protects all the equipment on
the rack, while at the same time, largely dispensing with individual shield covers.
are used with the 9 -AX Cabinet Racks to give them a finished
appearance when the equipment is assembled on the racks.
These strips, which mount along the side of the cabinet and
cover the panel slots and mounting screws, are easily installed
by means of clips and screws which are supplied with the
strips. "U" Strips are used to dress up an assembly of cabinet
racks when they are mounted side by side. Angle strips 8"
long are mounted inside cabinet (see dimension drawing) as a
support for the terminal block mounting bracket.
The bracket will accommodate as many as three W.E. 100-B
(RCA Stock Identification, MI4569) Audio Terminal Blocks
and two General Electric 16EB1B3 (RCA Stock Identification,
MI-4568) A -C Terminal Strips. The cable supports provide a
convenient means for holding the cabling in place. They are
mounted by means of the same screws which hold the front
panels.
Included with each 9 -AX Cabinet Rack is a quantity of 90
12-24 x 1/2" round head machine screws for mounting the
panels.
Description
This rack is of sheet metal construction with an open front
and a hinged ventilated door on the rear. A metal plate placed
approximately one inch below a rectangular opening in the
cabinet top provides complete ventilation, but protects equipment from falling articles and dust. The plate may be removed
completely, if desired. The rack is drilled and tapped, as shown
on the Dimension Drawing, for standard 19" panels and has an
overall height of 6' 107s". It is shipped with supporting rods
to insure accurate alignment.
Accessories for the Type 9 -AX Rack include "J" Strips, "U"
Strips, Terminal Block Mounting Brackets, A -C Terminal
Blocks, Audio Terminal Blocks and Cable Supports. "J" Strips
=' -n
x
alMI--al
er
ME
,
PI
ii
-If
-
N
I1
-
.316
69 HOLES
I1-24
TAP. SPACED AS
SHOWN.
17i
.
roi
r
1
--1316-I
REAR DOOR OPENING
77
Is*
eNOTE :-
-13
e.--132e.--132,--1-1
1
t
-w
-In
WALL.
-TI r41 -1
4
I
1
I
t
i
`
<
----
^13
-- --i
-
JIa
L-144, '-.-1
I
20 g
MINIMUM OF 20" FROM
REAR OF RACK TO
SIDE VIEW
FRONT VIEW
VIEW OF BASE SHOWING
MOUNTING HOLES
7}
Front View Type
Cabinet Rack
9 -AX
7i
OUTLINE DIMENSIONS OF 9AX CABINET RACK
Rear View Type 9 -AX
Cabinet Rack
Outline Dimensions of 9 -AX Cabinet Rack
54
RACK EQUIP.
Specifications
Dimensions, overall
Height
Width
Depth
Panel Size
Mounting Space
Weight (unpacked)
Stock Identification
Black
Light Umber Grey
827/8"
20h"
14h"
19"
77"
1901bs.
MI -4519-C
MI.4519-E
Accessories
"J" Strip
Audio Terminal Block MI.4569
MI -4537-A
Black
MI.4537-D
Dark Umber Grey
"U" Strip
MI -4524-A
Black
MI.4524-D
Dark Umber Grey
Mí-4570
Terminal Block Mounting Bracket
W.E. 100-B, 80 Terminal (4 rows of 20 each) Block_MIh569
MI.4568
G.E. A -C Terminal Strip (12 terminals)
MI.4571
Cable Support
Cable Support MI -4571
Blank Panels
complete line of 19" blank panels are carried in stock for
filling spaces on racks and cabinets not occupied by equipment
panels. These blanks are also suitable for applications where
equalizers, transformers, switches or other items must be panel
mounted by the user. The stock of panels includes all standard
widths from 13/" to 13 31/32". They are e" sheet steel and
are finished and drilled to match the standard equipment panels.
The 33-A and 33-B Jack Panel heights are not standard multiples of 13/ ". Therefore when these jack panels are mounted
in the Type BR -84 series Cabinet Racks or the Type 9 -AX Rack
it is often necessary to use either a 2t/s" or 2%" blank panel
so that the summation of all panel heights will equal 77".
A
Terminal Block Mounting Bracket MI -4570
Terminal Block Mounting Bracket with Terminal Blocks
in Position
ei
til
ilk
if er,
w'
tt
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is
MU
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.:
WaL
Panel Width
1 23/32" Blank Panel, Black
"
Umber Grey
1/8"
"
"
2
3/8"
"ii
"
3
3/32"
3
15/32"
5
7/32"
6
31/32"
8
23/32"
10
15/32"
12
7/32"
13
31/32"
2
"
.
liii: Ws:
if
"
"
ii
"
"
"
"
"
66""
"
"
ii
"
66
"
Powder
Terminal Block MI -4568
66
"
"
"
5$
"
"
"
"
"
"
"
"
"
Black
Umber
Black
Umber
Black
Umber
Black
Umber
Black
Umber
Black
Umber
Black
Umber
Black
Umber
Black
Umber
Black
Umber
Grey
Grey
Grey
Grey
Grey
Grey
Grey
Grey
Grey
Grey
Mí.4590
MI-4590-A
MI.4598
MI -4598-A
MI -4599
MI.4599-A
MI -4589
MI.4589-A
MI -4591
MI -4591-B
MI -4592
MI.4592-B
MI -4593
MI-4593-A
MI -4594
MI -4594-B
MI.4595
MI -4595-B
MI.4596
MI -4596-A
MI.4597
MI -4597-A
RACK EQUIP.
Wall Mounting Cabinet MI -11500
Features
Provides mounting space for equalizer and jack panels.
May be mounted at any convenient wall location.
Sturdy steel construction.
Hinged door permits easy access for servicing.
Drilled and tapped for standard 19" panels.
Attractive appearance.
Uses
The MI-11500 Cabinet has been designed especially to mount
a combination of line equalizers (Type 56-D or 56-E) and
jack panels (Type 33-A or 33-B). It will be found particularly
useful for terminating remote lines in installations using the
76 Series Consolettes. Sample combinations for this cabinet
are given below:
1-56-E Equalizer and 4-33-A Jack Strips.
2. 1-56-E Equalizer, 3-33-A Jack Strips, 1-MI-4590 (13/ ")
blank panel and 1-MI.11503 (7") Jack Mat.
3, 1-56-E Equalizer, 2--33-A Jack Strips, 1-MI-1591 (31/2")
1.
blank panel and 1 MI -11502 (51%") Jack Mat.
1-56-E Equalizer, 1-33-A Jack Strips, 2-MI-4598 (21/s")
blank panels and 1-Mí-4599 (2%") blank panel.
5. 1-56-E Equalizer, 1-33-A Jack Strip, 1-Mí.11501 (3'/2")
Jack Mat and 1--MI-4592 (51/4") blank panel.
6. 2-56-E Equalizers, 2-33-A Jack Strips and 1-MI-1150.2
(5%") Jack Mat.
7, 1-56-D Equalizer, 1-33-A Jack Strip and 1-MI-11501
(3%") Jack Mat.
4.
Description
The cabinet is constructed of steel and is equipped with a
hinged door on which the panels may be mounted. Drilling
and tapping has been provided for standard 19" panels which
are attached by means of the machine screws supplied. A lefthand and a right-hand "J" strip are furnished to cover the
mounting screws. Five knockouts are provided in the bottons
of the cabinet, and five in the top, for conduit connections.
Five terminal blocks may be mounted inside the cabinet on
the brackets provided. Mats are available for improving the
appearance of the jack strips.
TOP VIEW
7 INA. NNOCNOUTS
III DIA. CONDUIT
S EACH IN
FOR
TOP A BOTTOM
STRIPS SHOWN IN THIS VIEW ONLY
21
404 SLOTS
QJO
e
roR
MOUNTING
FRONT VIEW
O
IIPP
I
STERMINAL BLOCH BRAG
1
S
I
IY
Specifications
.
REPEATI
IS
.
12
3T3-e-3-i--3
Dimensions Overall
21" wide, 191/4" high, 10%" deep
Weight (unpacked, less panels)
36 lbs.
Finish
Dark Umber -Grey
Panel Mounting Space
19" wide, 121/" high
Terminal Mounting Space
Maximum -five Standard W.E.
Cat. No. 100-B, 80 terminal (4 rows of 20 each)
blocks which are 21-H" wide by 6-116" long
Stock Identification
MI -11500
3%
56
RACK EQUIP.
Panel and Shelf Type BR -2A
Features
High quality panel mounting for chassis type units.
Quick access to tubes.
Easy insertion and removal of units.
Provision for control shafts on front panel.
Units installed from front of rack.
Uses
The BR -2A Panel and Shelf was designed for use in a broadcasting station audio system primarily to hold the new RCA
plug-in units. It may also be used, however, for amplifiers
with terminal board connections. The shelf is capable of
mounting the following quantities of specific equipments.
6-BA-1
2-BA-3
2-BA-2
2-BX-1
Pre -amplifiers.
Program amplifiers.
Booster amplifiers.
Power supplies.
Monitor amplifier plus 2-BA-1A Pre -amplifiers.
The opening in the front of the shelf is covered by a matching panel. This panel is hinged across the center so that the
top half may he opened to gain access to the vacuum tubes
of the amplifiers. The bottom half has five shaft holes to provide for any controls which the amplifiers may have. When not
in use, these holes are covered by small removable buttons.
The bottom of the shelf has several round holes for ventilation, and also a number of square holes into which fit the
amplifier insertion levers.
This shelf will mount in either the 9AX or the BR -84 series
of racks, or in any other standard nineteen -inch rack. It
occupies eight and three-quarters inches of panel space. Since
the RCA plug-in amplifiers have a standard dimension in
depth, they all fit perfectly in this shelf. They are slid into
the shelf from the front and the connection plugs pushed into
the receptacles at the rear. Guide bars fitting between the
amplifiers assist in guiding them into position. All the plug-in
amplifiers are equipped with levers which serve either to
force them into position or to eject the plugs when dismounting them. The receptacles are mounted on individual U-shaped
brackets. secured to the chassis of the shelf. They fit in such
a manner that a small amount of free movement is permitted
in all directions. This eases the alignment of the plugs and
receptacles when the amplifiers are pushed into position. The
brackets are constructed with a small protruding stop on the
lower, front edge, preventing the amplifier from being forced
to the point where it would exert undue pressure on the receptacle. Provision is made for holding six of these receptacles.
The holes in the chassis which are provided for fastening the
brackets are slightly oversize to permit perfect alignment
during initial installation. The wiring in back of the receptacles is protected by a steel cover which is fastened in place
by two machine screws.
The shelf may be obtained separately, if desired, or the shelf
and panel together, as appropriate. It is supplied complete
with mounting brackets, guide bars, and receptacle cover. The
receptacles themselves are supplied with the amplifiers, and
therefore need not accompany the shelf.
Series
Series
Series
Series
I-BA-4 Series
Description
Specifications
Dimensions, overall:
Width
Height
Depth
Inside
19"
834"
1234"
Width-
167R"
Weight, unpacked:
Shelf
Panel
19
3
lbs.
lbs.
Stock Identification:
Shelf:
Umber Gray
Black
Panel:
Umber Gray
Black
Panel removed showing guide bars and receptacles
MI-11599
MI -11599A
MI -11598
MI -11598A
Panel open showing two BA -3A amplifiers
57
RACK EQUIP.
er_r-rr-,
0
Jack Panels Types 33-A and 33-B
,.
O0iOOiOO OOipOipO 0OI0OfOO100i0'010O
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£?i.O
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t
33.A Jack Panel
A
Rear View of the 33.A Jack Panel
Specifications
Jack Panels, with their associated patch cords, are used with
broadcast speech input systems to improve the overall operating flexibility. In addition to providing a convenient termination for program and order wire telephone circuits, closedcircuit jacks may be connected to provide "patch cord" access
to the input and output circuits of individual units of the
speech assembly. When connected for this purpose, the regular
circuits are continuous through the jacks until a patch cord is
inserted to make an external connection. With properly connected jacks, patch cords may be freely used in emergencies
or for test purposes to interchange or transfer telephone lines.
amplifiers, mixers, microphones, or other equipment items.
The 33-A consists of two rows of twelve double jacks mounted
on thick black bakelite and furnished with designation card
holders. The 33-B is similar to the 33-A but has only one row
of twelve double jacks. The jack sleeves of the 33-A and 33-B
are chromium plated; the sleeves of the 33-AW and 33 -BW
are brass.
Number of Jack Pairs
24
33-A
33-B
Type of Jacks
Dimensions
33-A
12
_
Double jacks of standard closed circuit type
2%a" x 19"
33-B
1t/a" x 19"
:33-B
3
Weight (unpacked)
33-A
5t/z
lbs.
Stock Identification
33-A (RCA Standard)
33-AW (W. E. Jacks)
33-B (RCA Standard)
33 -BW (W. E. Jacks)
lbs.
MI -4645-A
MI -4536-B
MI.4646-A
MI -1534-C
mummilmoundommusig immoduommeliimmid ammod.immmi awned monad
{>IC)
C)I0
C)l0 0l() C)IC3
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3.3-R
Jack Panel
Patch Cords
Jack Mats
RCA maintains a stock of patch cords for the convenience of
broadcasting stations. The W.E. Cord is the standard telephone
type using two W.E. 241-A Double Plugs. The Audio Development Co. Cord is shielded and uses two of their Type PJ-1
Plugs which are interchangeable with the W.E. Type 241-A
Plug. Three sizes of patch cords are available as listed below:
Jack Mats are available for covering 1, 2, 3, or 4 type 3:3-A
Double Jack Strips. When ordering specify finish desired.
Specifications
Single 33-A Jack Strip Mat, overall size
3 15/32"
MI-11501 MI -11501-B
19" x 5 7/32"
MI.11502-A
MI.11502-B
19" x 6 31/32"
MI -11503
MI.11503-A
19" x 10 15/32"
Mí.11504
MI.11504-A
19" x
U/G
Black
Double 33-A Jack Strip Mat, overall size
U/ G
Black
Triple 33-A Jack Strip Mat, overall size
U/G
Black
Quadruple 33-A Jack Strip Mat, overall size
U/G
Black
Two Foot Cord Length
Four Foot Cord Length
Six Foot Cord Length
Western
Electric Co.
Audio
Development Co.
ML4652-2A
MI.4652-4A
MI-4652.6A
MI -4652-2B
MI-4652.4B
MI11652-6B
sasd3+wtwrteltee>.lrwa 1emrttasitlnisetitrJmwI.bitetM-ts
:0i00t00i00:0Oi0O 00100 00i00100 0G
,'D0'00100100100100100100,00.00,00 0o,
r,rrj,
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J.11R*r
:0100100100:00i0010010010000000'
"j^1",^iOCiQO,OO.00 n0:00,00 001000C,
Western Electric Telephone
Type Patch Cord
58
Audio Development Co.
Shielded Type Patch Cord
RACK EQUIP.
Switch and Fuse Panel Type 57-C
Features
Dimensions, overall (panel thickness je")
Height
Width
Depth
Weight (unpacked)
Stock Identification
Black
Light Umber Grey
Provides master switch and fuses for rack -mounted equipment.
Subpanel drilled and tapped for mounting 6 MI.11606 Filament Transformers.
Pilot lamp glows when equipment is on.
Removable door permits front panel access to fuses and
pilot lamp.
7/32"
5
19"
31/2"
81/2
lbs.
MI-4395-A
MI.4395-B
Uses
The Type 57-C Switch and Fuse Panel is designed for use as a
master input control of the a -c power supply. Ordinarily one
such panel is used with each rack or channel of speech input
units. The mounting is for a BR84 Series Standard cabinet
rack or a 9AX Rack.
Description
On this panel are mounted and wired an indicator lamp with
red cap, two single fuse blocks óf the screw -plug type and a
double-pole single -throw power switch. In addition there is a
Subpanel which is drilled to provide a mounting for six of
the standard MI -11606 Filament Transformers. This panel is
ordinarily located near the bottom of the rack to keep the
Front View
transformers well away from low-level amplifier circuits. A
removable door permits front panel access to fuses and pilot
lamp.
Specifications
Switch
Fuses
D P S T., 250 volts, 30 amperes
Screw -plug type (rating depends upon equipment
to be protected)
Rear View
Ringdown Panel MI -11710
Uses
The MI -11710 Ringdown Panel is a twelve position telephone
panel designed for use in control rooms and transmitter installations. The panel provides complete facilities for receiving
incoming calla, listening, talking and ringing on any of the
twelve telephone lines. A two position turn -key introduces
emergency ringing power should the normal supply fail. An
additional feature of feeding cue signal to anyone, or all the
lines simultaneously is provided.
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Description
`:t:
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CUE
R1N4POWN
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The panel contains twelve "ring -talk" keys with an associated
"cue and off" turn -key for each circuit. For normal incoming
calls, ringing current from line operates a ringdown relay and
gives visual and audible indication of the appropriate calling
circuit. A call buzzer is common to all circuits and may be
rendered inoperative by a turn -key. This allows the circuit to
be used in any location where an audible call is undesirable.
Cue signal may be fed from any external bridging transformer
to the cue input, thereby providing cue signal switchable to
any one or all twelve lines. All connections are terminated on
the two terminal boards mounted on the rear of the panel
assembly.
JW./Cm
-
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Specifications
Clot
fuvR`
Dimensions:
Height
Width
Depth
Sed,C.
r ,. .fr
Weight
Stock Identification
59
7"
19"
10%"
lbs.
15
MI -11710
RACK EQUIP.
Meter Panel Type BI-lA
Description
Features
The BI-lA consists essentially of a meter and switch mounted
on a standard 31/2", ,fi" thick steel panel. The meter is a
3.0 volt d-c voltmeter having a resistance of 20,000 ohms per
volt. The double section switch has eleven positions including
the "off" position with the switch arms connected to the
meter terminals. All connections to the panel are made to the
witch contacts.
Provides meter and switch for measuring cathode voltage
of amplifier tubes.
Gives plate current indication of operating condition of
tubes and circuits.
Up to 10 circuits may be metered by rotary selector switch.
Designed for cabinet rack mounting.
Specifications
Uses
D -c Voltmeter
Meter Panel Type
10
Height
Width
Depth
3
15/32"
19"
21/2"
Weight (unpacked)
Stock Identification
Light Umber Grey
Black
41/2
lbs.
MI.4388-C
MI.4388-B
BI -2A
Description
Features
Provides metering for
34
A
circuits by operation of rotary
0-3
high grade rotary switch with
17
positions and four banks
of contacts is used in conjunction with a three position switch
to effect the metering of 34 circuits. The precision built 0 to
3 volt meter possessing an internal resistance of 20,000 ohms
per volt is mounted on a 31/2" steel panel of standard 19"
width. The hinged portion of the meter panel encloses a card
index providing a convenient means of logging maintenance
routine tests. The mounting is for a BR -84 Series Standard
Cabinet Rack or a 9 -AX Rack.
switches.
Precision
volts, 20,000 ohm per volt
position and "off," double pole
0-3 0
-
Metering Switch
Dimensions (overall)
The BI-IA Meter Panel provides a convenient means for checking the cathode bias voltages of amplifier tubes and thereby
furnishes an indication of the operating conditions of amplifier
tubes and circuits. Metering terminals are provided on the
BA -1, BA -2 and BA -3 Series Amplifiers for use with this panel.
The mounting is for a BR84 Series Standard cabinet rack or
a 9AX Rack.
volt voltmeter -20,000 ohms per volt.
May he mounted in any standard 19" rack.
Card index to log maintenance routine checks.
High grade rotary switches.
Specifications
Uses
D -C Voltmeter
Metering Switches
The BI.2A Meter Panel has been developed after numerous
requests from broadcasters to supply a larger version of the
BI.1A Meter Panel. The switching system provides for an instantaneous check of tubes and circuit conditions for 34 circuits and is ideal for use where a large number of circuits
are required to be metered from a central point. The meter
is suitable for use with all RCA standard equipment.
Dimensions (overall)
Height
Width
Depth (behind panel)
Weight (unpacked)
Stock Identification:
Umber Gray
Black
0.3 volts, 20,000 ohms per volt
One 17 position, one 3 position,
giving a total of 34 positions
:
60
3t/z
19"
3%"
6 lbs.
MI -11275
MI -11275-A
RACK EQUIP.
V. U. Meter Panel MI -11265
Features
Measures audio volume levels from +4 to +40 db.
Ten point selector switch permits rapid connection to any
number of circuits up to ten.
Calibration curve supplied for loads other than 600 ohms.
Large vu meter lessens eye strain and fatigue.
The meter and attenuator are calibrated for use with a 600 ohm
line, however, a calibration correction curve furnished with the
instrument permits its use with loads other than 600 ohms.
The ten point selector switch may be connected to any ten
lines (or circuits). If one or more switch positions are connected to a jack strip, the number of circuits that may be
monitored is unlimited. The meter is provided with the 6.3 volt
lamp for illuminating the meter scale. If the 6.3 volt source is
not available, MI -11606 filament transformer will be necessary.
Uses
The MI.11265 employs the industry standardized Weston Type
30 VU Meter which embodies closely controlled electrical and
dynamic characteristics combined with deliberate pointer action,
moderate pointer speed, and small pointer overswing. It is intended as an audio level indicator for broadcasting, recording
or wherever it is desired to read the level of one or more
audio circuits with a rack mounting type of instrument.
Specifications
Input Impedance (except on 1 milliwatt step)
7500 ohms
Attenuator steps
milliwatt position, +4 to +40 db in 2db
steps and off position
No. of lines that may be measured
1 to 10 inclusive
Mounting
Standard Cabinet Rack
Dimensions
51/
Height
Width
19"
Depth
3sß "
Finish
Light Umber Grey
Weight (unpacked)
7t/2 lbs.
Stock Identification
Umber Grey
MI -11265
-1
Description
The volume indicator panel assembly includes the vu meter,
a two circuit ten point selector switch, a variable step-by-step
attenuator (4 to 40 db attenuation), and a vernier control
for making a fine adjustment of the level reading over a
range of ±0.5 db. The attenuator has a 1 milliwatt reference
position which enables a level reading of zero vu.
The vu meter scale is arranged with percent volts in black
figures from "0" to "100" as the principal scale above the arc,
and "vu" levels from "-20" to "0" to "+3" as supplementary
figures in red below the arc.
Black
VU Meter and Attenuator Kit MI -11251
The MI-11251 Meter and Attenuator Kit is used for indicating
audio volume levels when installed in the OP -6 Portable Amplifier or the OR -IA Portable Recorder. It uses a Weston Type 30
VU Meter whose scale reads in percent voltage and in vu's.
'l'he meter has an impedance of 3900 ohms and is designed to
be used in series with the furnished resistance of approximately 3600 ohms to effect the required ballistic characteristics.
The circuit of the MI.11251 Kit employs the Type 30 Meter
connected first to a 3900/3900 ohm constant impedance pad
and then in series with 3200 ohm and tapped 800 ohm resistors
across the amplifier's output. The 3900/3900 ohm pad has
solder type terminals which permit attenuation adjustments
for any value between 1 and 27 db in one db steps, while
vernier adjustments in steps of 0.1 db, if required, are provided
by the tapped 800 ohm resistor which is normally connected
for 400 ohms. By changing the pad or resistor tap connections
the "0" vu setting of the meter may be made to indicate any
value from +4 to +31 db in steps of 1 db or 0.1 db.
61
MI.11265-D
RACK EQUIP.
Variable Line Equalizer Type
Features
BE -1B
Equalization Range_-ISee attenuation characteristic curves)
BR -84 series and 9AX racks
Mounting
Dimensions
5h"
Height
19"
Width
8"
Depth behind panel
9t/a"
Overall including knobs
7 lbs.
Weight (unpacked)
Stock Identification
MI -4196-B
Light Umber Grey
MI.4196-C
Black
Provides a line response ±1 db 30 to 15,000 cycles for FM.
Frequency boost circuit permits up to 14 db boost at 15,000
cycles.
Toggle switch permits 10 kc or 15 kc cut-off.
20 step attenuator affords variable output control.
Line and Isolation transformers built in.
Rack mounting panel-easy installation.
Uses
The BE -1B is an ideal unit for equalizing unloaded telephone lines up to ten miles in length to a frequency response
within +1 db, 30 to 15,000 cycles. In addition to the conventional parallel resonant circuits this equalizer has additional
tuned networks providing a variable frequency boost of 2 to 14
decibels (2 db steps) at 15,000 cycles. This feature aids materially in obtaining an overall flat frequency response to 15,000
cycles. More than 1,000 different attenuation vs frequency
curves are available through adjustment of the front panel
controls.
o
ATTENUATION VS. FREQUENCY CURVES
FOR MI -4196 LINE EQUALIZER
Maximum Boost
10
20
Description
The BE-1B consists of a tuned equalizing circuit, isloating
transformer, attenuating pad, 15,000 cycle booster circuit and
another isolating transformer in the output.
A two -position input switch selects an impedance of 150 or
600 ohms for terminating lines offering 150 or 600 ohms impedance. A three -position switch prepares the circuit for equalization up to 10,000 cycles or 15,000 cycles. The center position
of the toggle switch removes thg attenuator from the circuit,
leaving lines connected with a foss of 1.5 db at 1,000 cycles.
A 20 step (3 db per step, last step infinity) attenuator is inserted in the circuit to permit control of the output level. The
15,000 cycle booster circuit is controlled by an 8 position
switch which will vary the boost from 0 to 14 db in 2 db steps.
Attenuation vs Frequency curves are shown for extreme boost
control settings of "Boost out" and "14 db boost." Intermediate attenuation values will be obtained for intermediate
settings of the boost control. The output transformer has variable taps for a load impedance of 150, 250 and 600 ohms.
The BE-1B is built on a standard 19" panel and is supplied with
a dust cover. A hinged door on the front panel permits easy
access for cleaning or servicing the equipment. A terminal
strip, mounted on the rear of the unit, has five screw -type
terminals for input, output and ground connections.
30
c
R- 10 A
38
-n-
.1
A
40
50
3
Equalixot'on: 5 KC.
Attenuntor:
0 db.
n
Boost:
600
600
10I
60
zo
100
14
Source
Load
1000
10000
20000
FREQUENCY IN CYCLES PER SECOND
o
ATTENUATION VS. FREQUENCY CURVES
FOR MI -4196 LINE EQUALIZER
Boost Out
10
R-110
20
.
30
Specifications
Source Impedance (balanced or unbalanced) -150/600 ohms
Load Impedance
150/250/600 ohms
Equalization Frequency Limit
15,000 cycles
Insertion Loss (attenuator at zero)
For 15 kc equalization
Min 65 db; Max. 59 db
For 10 kc equalization
Min 3 5 db; Max. 42.5 db
Note: With equalization and boost out the minimum loss
at 1000 cycles is 1.5 db.
.á
o
3
A
38.
40
14
A
3.
OA
'-
Equalixot on:
Attenuator:
50
60
600
600
20
100
1000
FREQUENCY IN CYCLES PER SECOND
62
5 KC.
0 db.
Out
Boost:
Source
Load
10000
20000
Dual Line Equalizer Type 56-E
Equalizer Type 56-C
The 56-C Equalizer is a semi -fixed unit which is particularly
useful in connection with permanent lines. Its applications are
similar to those of the Type 56-E described elsewhere on this
page. It is a single unit with reactor, capacitor and all necessary
resistors mounted in a metal case to reduce space requirements.
The resistance terminals are brought out to soldering lugs on
the top of the case where connections may be made for obtaining any resistance value between 1 and 111 ohms in 1 ohm steps.
Features
Provides line equalization to 10,000 cycles or to 15,000 cycles
when used with MI.4925-A Compensator.
Equalization variable in steps of 3 db.
Facilities for equalizing two lines.
Rack mounting panel-easy installation.
Uses
The 56-E has been designed to equalize the non-linear fre
quency characteristics of either one or two non -loaded telephone lines up to ten miles in length. It consists of two separate
and complete variable equalizers mounted on a single panel.
The 56-E is suitable for 15,000 cycle FM applications when
used with the RCA MI -4925-A High Frequency Compensator.
Without this compensator the cut-off frequency is 10,000 cycles.
Specifications
Source Impedance
Equalization Frequency Limit
with MI.4925-A Compensator
Insertion Loss (minilntuu at 1000 cycles)
Depth2t/Z"
Parallel resonant circuits are used in the two equalizers. Each
unit consists of a capacitor, a reactor, a series of resistors and
a rotary selector switch for selecting different resistance values.
Varying amounts of equalization may be obtained in steps of
3 db by rotation of the selector switch to the proper position. The 56-E does not include line transformers or master
attenuators.
Weight (un-
packed) 7 lbs.
Stock Identifica-
tion_MI.4168
Accessory
High Frequency
Specifications
Compensator
-
(one only required if 56-C is to be converted for 15,000
cycle use)
MI -4925 A
600 ohms
10,000 cycles
15,000 cycles
Equalization Frequency Limit
with MI -4925-A Compensator
7 db
Insertion Loss (minimum at 1000 cycles)
Equalization Range (see attenuation characteristic curve)
1.5
Mounting
Dimensions
Width
Height
Depth
Weight (unpacked)
Stock Identification
Black
limber Grey
Accessory
115 db
Equalization
Range (see
attenuation
characteristic
curves)
13 to40db
Dimensions
Width
3%"
Height
33/4"
Description
Source Impedance
600 ohms
10,000 cycles
15,000 cycles
TYPICAL ATTENUATION VS. FREQUENCY CURVES'
2
FOR
to 40 db
56.0 AND 56-E LINE EQUALIZERS
RL
Standard 19" panel
a
lo
7
19"
3t/2"
IZ
43/41'
l6
lbs.
la
R2
4
R3
20
MI.4162
MI -4162-A
22
24
R4
26
Accessories
28
RS
30
High Frequency Compensator (2 units required if 56-E is
MI -4925-A
to be converted for 15,000 cycle use)
MI.10253
Line Transformer _
32
1019
FREQUENCY IN CYCLES PER SECOND
High Frequency Compensator MI -4925-A
o
The MI4925-A is a constant impedance bridged "T" type compensator network to extend the range of the 56-C or 56-E
Equalizers to 15,000 cycles. The necessary reactors and condensers are mounted inside a round metal can, on the side
of which is mounted a terminal board and two groups of resistors. Compensation can be varied by shifting the resistor
connections which are connected by means of solder type
terminals.
ó
6
O
8
Specifications
z
Source Impedance
FREQUElkY'R.E PON5E OF M1 -4925-A
15000 CYCLE COMPENSATOR
2
4
º
600 ohms
15,000 cycles
4 8 db
7 to 17.4 db
2 DB. Equalization
4 DB. Equalization
6 DB. Equalization
lo
ce
I
8 DB.
Equalization Frequency Limit
Insertion Loss (minimum at 1000 cycles)
1
Equalization Range (see curves)
Four-hole flange mounting
Mounting
Dimensions
Width
4%"
Height
43/48,
33/ "
Depth
23/
lbs.
Weight (unpacked)
MI.4925A
Stock Identification
Z
I-
-
--.
I
Equalization
12
I
10 DB.
14
I
I
I
Equalization
I
I
12 DB.
Equalization
14 DB.
Equalization
16
18
100
1003
FREQUENCY IN CYCLES PER SECOND
63
lauoR
15A00
»OM
RACK EQUIP.
Variable Sound Effects Filter MI -4917-A
NIGH FREQUENCY
LON FREQUENCY
CUT-OFF
CUT-OFF
INC
500
250
alto
25C
5
3KC
t00
250
4KC
OFF
100
5KC
,
//'
i(
35C
4KC
5KC
\
OUT
IN
Features
characteristics and insert it in the circuit instantly when
required.
The 600 ohm input and output impedances of the filter enables it to be connected in any 600 ohm circuit or it may be
used in a 250 ohm circuit with only a slight change in response
characteristics.
Permits control of audio bandwidth to permit a variety of
sound effects.
Two front panel selector switches permit easy and quick
change to desired sound effect.
Uses
The MI -4917-A furnishes a desirable means for producing a
variety of special or unusual sound effects through control of
the audio bandwidth of the transmitted program. It is especially useful in the production of dramatic plays for making
programs sound "bassy" or "tinny" or for simulating the sound
of telephone conversations, short wave radio communications or
midget radios.
Specifications
600 ohms
Source Impedance (unbalanced)
600 ohms
Load Impedance
-60 to -i-!3 db*
Input Level
+23 dlt*
Output Level (maximum)
see curves
Frequency Response
Insertion Loss_1 db or less al frequencies remote from cut-off
Dimensions, overall
Height
51/4"
Width
19"
Depth
5"
15 lbs.
Weight (unpacked)
MI -4917
Stock Identification-Black
MI -1917-A
Light Umber Grey
Description
The MI.4917-A consists of high and low pass filters assembled
on a panel with two selector panel switches. The switches have
nine positions each and are calibrated for high and low cut-off
frequencies of 100, 250, 500, 1,000, 2000, 3000, 4000, and 5000
cycles. There is also an "off" position on each switch. A key
switch is provided for removing the filter from the circuit
thus making it possible to preset the filter for the desired
MI -4917
*
Reference level one milliwatt.
VARIABLE SOUND EFFECTS FILTER (800.ra)
0
.
-4
-8
-18
m
o
Arr
ó'\\0,,,óó
/I12 / %1
liflhilliil
O, 111ó i 1llIHlflhI
/IIIIIIIIaI
vgIiil J
IIOIUUV
- 12
IIó
I
,111
-20
-24 IJdlhI
- 28
- 32
- 38
111
,11
--HIGH
=LOW
2
`\
`.
!111
r
30
2
o
b
FREQUENCY CUT-OFF
FREQUENCY CUT-OFF
1000
100
FREQUENCY IN CYCLES PER SECOND
61
00
RACK EQUIP.
Line, Mixing and Bridging Transformers
The following standard RCA transformers arc stocked as a convenience to broadcasting stations. These transformers are of
the highest quality design having
within ±1 db, from
a
frequency response which
They are provided
with electrostatic shields between primary and secondary and
are furnished with heavily shielded cases. Cores are of special
high permeability steel. Terminals are at the top and diagrams
of the connections are stenciled on the side of the case. Broadcasting stations may employ the RCA terminal transformers
between units with assurance that the overall fidelity of the
system will be maintained.
is
30 to 15,000 cycles.
Line Transformer MI -10253
The core structure, frequency characteristics and shielding of
this transformer makes it an ideal unit for isolating line circuits. Its large number of taps provide several combinations
of available impedances. One to two of these transformers are
very useful items to have around any broadcast station. The
impedance combinations are:
Primary Impedances
ohms
Secondary Impedances
125
125
250
300
600
250
ohms
300
600
Stock Identification
MI.10253
Bridging Transformer MI -4901-A
'[he MI -4901-A transformer may be used as an input transformer
for a bridging line amplifier or a monitoring amplifier. It may
also be satisfactorily used where it is desired to bridge a pro gram line to feed programs to other mixing or outgoing cir
cuits such as normally employed in a master control room line
distribution system. The impedance combinations are:
Primary Impedances
ohms
Secondary Impedances
ohms
20,000
250
600
Stock Identification
MI.4901-A
Mixing Transformer MI -4902
Primary Impedances
ohms
Those contemplating the design of their own, or special microphone mixing circuits, will find this transformer ideal for a
76.5
90
109
134
large number of mixer combinations. The impedance combine lions are:
Secondary Impedances
153
187
ohms
250
600
237
320
Stock Identification
MI.4902
General Specifications for MI -10253, MI -4901-A and MI -4902
Frequency Response
Dimensions, overall for cases:
Height
±1
db, 30 to 15,000 cycles
43/e"
Diameter
Baseplate
Mounting
Weight
Finish
3"
3t/" z
3%
65
Four holes with center lines 23/" x 23/"
2
lbs.
14 ozs.
Aluminum gray
RACK EQUIP.
Pads - Fixed, Bridging, Network
RCA offers a comprehensive selection of attenuator pads,
bridging pads and dividing networks. The pads and networks
are well constructed and insulated with precision wound resisters, assuring no internal reflection. The terminals are accessible and securely mounted with the connections stenciled in
an appropriate place. The fixed balanced "H" type is available
in two types, one introducing a loss of 6 db, the other 10 db.
The dividing networks are also available in two types, unbalanced and balanced "H" type, as tabulated below.
FIXED PADS-BALANCED "H" TYPE
Input Impedance
Output Impedance
Insertion Loss
Stock Identification
FIXED PADS-BALANCED "H" TYPE
Input Impedance
Output Impedance
Insertion Loss
Stock Identification
600 ohms
600 ohms
6 db
MI -4171.29
600 ohms
600 ohms
10 db
MI.4171-30
MI-11704-A
I
DIVIDING NETWORKS
Balanced Two-way, 600 ohms
Insertion Loss
Stock Identification
Balanced Three-way, 600 ohms
Insertion Loss
Stock Identification
Balanced Four-way, 600 ohms
Insertion Loss_
Stock Identification
Balanced Six-way, 600 ohms
Insertion Loss
Stock Identification
Balanced Eight -way, 600 ohms
Insertion Loss
Stock Identification
Unbalanced Two-way, 600 ohms
Unbalanced Three-way, 600 ohms
Unbalanced Four-way, 600 ohms
Insertion Loss
Stock Identification
Unbalanced Six -way, 600 ohms
Insertion Loss
Stock Identification
Unbalanced Eight -way, 600 ohms
Insertion Loss
Stock Identification
MI -4171-29
MI-4171-30
BRIDGING PAD
Input Impedance
Insertion Loss
Stock Identification
6 db
MI -11704
9 5 db
MI.11704-A
12
db
-MI-11704-B
600 ohms to two 600 ohm
15 6 db
MI.11704-D
181 db
MI -11704-E
12 db
MI -11704-J
15.6 db
MI.11704L
181 db
MI.11704-M
lines-isola-
tion between lines about
45 db
10 db
MI -11705
Filament Transformer MI -11606
The MI -11606 Filament Transformer furnishes filament voltage
to a maximum of three BA -1A Preamplifiers. It has primary
taps for 110 and 120 volts a-c 50/60 cycles. A variable potentiometer is connected across the secondary and is screw driver
operated for obtaining minimum hum. This transformer is
also used to provide voltage for the Mí11265 VU Meter Panel.
Specifications
Output
Dimensions, overall
Height
Base
63
volts, a -c, 1.8 amperes max.
Four .199" mounting holes are located on
2h" x 1%" center line
9 lbs.
Weight (unpacked)
Stock Identification
MI -11606
Mounting
4"
9I-1" x 2%"
66
AM-FM Radio Tuner MI -6784, MI -6785
Features
Broadcast, shortwave and frequency modulation reception.
Bass, treble tone controls.
Good selectivity.
Incorporates new ratio detector for FM.
Compact and light in weight.
Excellent sensitivity.
Description
The AM -FM radio tuner is presented for broadcasters who
desire a first-class tuner unit for monitoring and listening purposes. This unit may be mounted in a standard 19" cabinet
or any desired location. The M1.6784 tuner is essentially the
radio unit of the RCA "Crestwood" receiver. It is an eight
tube mechanism on a single chassis, equipped to cover the
standard broadcast, shortwave and FM bands.
MI -6784
Specifications
Frequency Coverage -535-1620 kc (Standard Broadcast Band)
9.2-16.25 me (Shortwave Band)
84.5-108.5 me (Frequency Mod.)
3 5 microvolts at 1000 kc
Sensitivity (Absolute)
2.7 microvolts at 11.7 me
4.6 microvolts at 100 me
The receiver is designed to operate from an external power
pack and will supply low level, high impedance audio current to any amplifier with a 250,000 ohm or more source
impedance. The AM portion of the receiver is a superhetrodyne circuit incorporating one stage of RF pre-selection on
both standard and shortwave broadcast bands. It is equipped
with automatic volume control to hold the audio voltage constant over the wide range of input signal voltage.
Image Attenuation__
The FM portion of the receiver is also a superhetrodyne circuit, consisting of many outstanding features, including a
stage of RF pre -selection, a high intermediate frequency for
good signal reflection and the new RCA ratio -detector. This
new detector is only sensitive to a frequency modulated
signal, thus eliminating costly dual and triple limiter circuits.
This also guarantees satisfactory reception of FM signals that
may be weak in signal strength or variable due to fading.
The Mí.6784 tuner utilizes an open -front, slide -rule type of
dial with uniform illumination for the appropriate scale in
use. The front panel with escutcheon, press buttons, knobs, etc.,
is not included in the MI.6784. This allows the user to construct his own panel, if desired. The MI -6785, however, employs a front panel with a slope of 17° and is complete with
press buttons and knobs. Both units may be accommodated
by the MI -12380 panel and shelf, which may be mounted in
any standard 19" rack. The panel controls consist of tuning,
volume, low frequency tone control, high frequency tone control and range switch. The range switch provides connections
for future accommodation of a television audio channel output
and the receiver's audio output jack. The MI-12502 power
supply available for this tuner is an a-c operated full -wave
rectifier and filter unit associated with a suitable transformer
to supply filament plate and bias voltages for receivers using
6.3 volt filament supply. The power supply connections are
made by nine -prong male receptacles on the rear of the chassis.
Coaxial connectors are provided for television audio and audio
transcription inputs, in addition to the receiver's audio output.
7500 at 1000 kc
165X at 1L7 me
Bandwidth at 2 db down
Intermediate Frequencies
Load Impedance
Control
Tube Complement.-_6BA6
6BA6
6BE6
6BA6
6AU6
6AT6
6AL5
500X at FM Frequencies
7 5 kc at 1000 kc
Standard Broadcast
and Shortwave Bands
10.7 me on FM Bands
950,000 ohms or more
Tuning, Volume, Range Switch
Bass, Treble Tone Controls
RF Preslector
Mixer
High Frequency Oscillator
First IF Amplifier
Second IF and Phono Amplifier
Detector-AVC-Audio Amplifier
Ratio Detector
455 kc on
Dimensions:
Length
173/4"
Depth
9+*"
Height
6"
9 lbe.
Weight (unpacked)
Stock Identification:
AM/FM Radio Tuner (Less Escutcheon, Press
MI -6784
Buttons, Knobs)
MI -6785
AM/FM Radio Tuner (Complete)
250 volts d -c at 50 ma
Power Supply Required
100 volts d -c at 15 ma
-24 volts d-c bias
6.3 volts a -c at 2.5 amperes
117 V.A.C. (full load) 64 watts
Power Required
3 amperes
3
AG
Fuse Type
Dimensions:
9"
Length
53/4"
Width
63/4"
Height
RCA
5Y3GT
One
Tube (complement)
6 lbs.
Weight (unpacked)
Stock Identification:
MI -12502
Power Supply 105/125 v. 50/60 cycles
MI.12505
105 /250 v. 25/60 cycles.
-
MI -6785
67
POWER SUPPLIES
Preamplifier Power Supply Type
BX-1C
Features
Exceptionally low hum level.
Compactly designed.
Plugs into BR -2A Shelf Assembly.
Simple design-minimum of parts.
High capacity filter.
Filament supply hum balancing potentiometer.
Voltage variable 180 to 250 volts.
Uses
The Type BX-1C Preamplifier Power Supply is designed to
provide d-c plate and a -c heater power for preamplifiers in
which the hum level must be kept to a minimum. It is intended especially for use as a power supply for preamplifiers
and isolation amplifiers such as the BA -1A.
of filter capacitance, the d-c output is exceptionally free from
hum. The voltage is variable, by means of a screw driver
adjustment, between 180 and 250 volts. The voltage output is
very stable with any load up to fifty milliamperes. A hum
balancing potentiometer, likewise a screw driver adjustment,
is connected across the filament supply circuit.
The BX-1C is designed for operation on any a -c line voltage
between 100 and 130 volts, 50 to 60 cycles. A one ampere,
glass -enclosed, time -delay fuse is mounted on the front of the
chassis. This fuse is unaffected by high transient currents.
Description
The BX-1C is a plug-in unit designed primarily for mounting
in the RCA Shelf Assembly Type BR -2A. This type of mounting is the most convenient for the operator, since the unit may
be easily slid into the shelf for installation or easily removed
for maintenance. If desired, it may also be mounted in the
Type 36-B Shelf Assembly. Two of these power supplies can
be installed in either the BR -2A or the 36-B. If neither of these
shelves is available, the BX-1C may be mounted in any convenient location. Connection to the terminals is made through
a quickly removable, multi -contact connector which fastens to
the plug at the rear of the chassis.
Specifications
Power Supply Required
100 to 130 volts, 50 to 60 cycles,
65 watts
Fuse
Power Output
The power supply circuit is a full -wave, high -vacuum tube rectifier with a choke -input filter. With a total of 260 microfarads
1
D -c
A -c
Output Hum Level
Connections
ampere, Type MDL
180 to 250 volts, up to 50 ma
6 3 volts, up to 3.6 amperes
Approximately -134 db (below 50 ma
d -c load at 250 volts d-c)
One 10-prong plug-in connection at the rear
of the chassis
Dimensions and Weight:
Length
12%"
Width
Height
7"
Weight
151/2 lbs.
Mounting
Shelf mounting in the Type BR -2A or
Type 36-B Shelf Assemblies
Stock Identification (less tube)
MI -11305-B
Accessories
Tube Complement, 1 RCA-5Y3GT/G
Panel and Shelf Type BR -2A:
Umber Gray
Black
Back view showing multi-contact
connection plug
68
MI.11262
MI -11598/11599
MI.11598-A /11599-A
POWER SUPPLIES
Relay Power Supply MI -11303
Specifications
Features
Output (adjustable for loads from 0.2 to 1.0 ampere)
maximum 12 volts 1 amp.
Ripple Voltage (at maximum output of 1 amp.) _0.4 volts rms
Ac Power Input, 105 to 125 volts, 60 cycles
(maximum at rated output) 34 watts
Rectifier
Copper-Sulphide magnesium full wave type
Supplies 12 volts filtered d -c at 1 ampere.
Rotary switch permits varying output voltage in 1/2 volt
steps.
Long life full wave copper sulphide magnesium rectifier.
Housed in an attractive wall mounting cabinet with hinged
door
Uses
Dimensions
Height
Width
Depth
The MI -11303 Relay Power Supply is a complete unit capable
of supplying filtered d -c power to a number of relays and pilot
lights if the total load current at 12 volts does not exceed
one ampere.
Description
Mounting
Finish
Weight (unpacked)
Stock Identification
The power supply is built in an attractive wall -mounting box.
The electrical circuit consists of a power transformer, copper sulfide magnesium full wave rectifier, and a resistance -capacity
filter system with three 1000 mfd. eletrolytic plug-in capacitors.
The power transformer primary is tapped at 105, 115, and 125
volts to provide line voltage adjustment. The secondary of the
power transformer is tapped and connected to a six position
rotary switch which permits a variation in output voltage of
approximately 1/ volt per step.
99
6"
Wall mounted by four mounting slots
Two tone umber grey
14 5 lbs.
Mí.11303
The chassis is bolted in the enclosure with a snap -off cover.
The chassis, inside of the mounting box and the terminal board
cover are finished in silver grey. The outside of the box is
finished in light umber grey with a 4 inch dark umber grey
stripe through the middle of the cover.
Heavy Duty Relay Power Supply MI -11304
Features
Supplies 12 volts filtered d -c at 5 amperes.
Output voltage substantially constant from no-load to full load output.
Full wave Selenium Type Rectifier.
Housed in an attractive wall -mounting box.
Mounting
Finish
Uses
The MI.11304 Relay Power Supply is a complete unit capable
of supplying filtered d -c power to a number of relays and
pilot lights if the total load current at 12 volts does not exceed
5 amperes.
Description
The power supply is built into an attractive cabinet for wall
mounting. The electrical circuit consists of a power transformer, line and load voltage regulating and shunt reactors,
full wave selenium rectifier, filter reactors and capacitors,
variable resistors, and terminal board and fuses. Regulation of
the d -c output voltage is accomplished by use of a saturable
reactor which maintains the output voltage substantially constant from no-load to full -load output.
Specifications
Output (substantially constant from no-load to full -load
output)
maximum, 12 volts 5 amps.
Ripple Voltage (at full load)
01 volt rms
Ac Power Input, 105 to 125 volts, 60 cycles
maximum at rated output) 165 watts
full wave Selenium type
Rectifier
Dimensions
163/8"
Height
1514"
Width
Depth
81/4
69
Wall mounted by four mounting slots
light umber grey
Weight (unpacked)
80 lbs.
Stock Identification
MI -11304
TURNTABLES
Transcription Turntable Type 70-D
Description
The complete equipment is housed in a metal cabinet of modern design. The cabinet is finished in two tones of umber grey
and trimmed in chromium. A large hinged door is located on
the front of the cabinet so as to permit ready access to the
motor and filter circuits. A heat resistant, "Micarta" top is used.
All filters are securely mounted within the cabinet and arranged for minimum hum pickup. There is also sufficient
space within the cabinet for a booster amplifier (such as the
RCA BA -2 Series) where additional output level is required.
If the user desires to raise the height of the cabinet from
28 to 30 inches, the MI.11803 mounting base complete with
hardware is available for the purpose.
Terminal boards are provided for a -c and the audio connections and are accessible from the front of the cabinet. Mounted
on top of the 70-D cabinet are the tone arm, tone arm rest
and filter selector switch. The tone arm is of the counter
weight balance type and provisions are made for accurately
setting the stylus for one ounce weight on a record. The pickup
head is unexcelled and designed to impart high fidelity characteristics for both vertical and lateral recordings. It is of a
moving conductor type in which two ribbons are free to move
in a vertical or lateral magnetic field. Possible damage to the
pickup stylus is prevented by adjustable horizontal and vertical tone arm stops. The horizontal stop prevents the pickup
stylus from reaching the small diameter on which the record
driving holes are placed. The vertical stop can be adjusted
so that the stylus just touches the top of the record platter.
The pickup and filter reproduce the various types of records,
Orthacoustic, RCA -Victor, Columbia, World and others, with
a response characteristic that produces an ideal playback response. The filter unit is designed so that this may be accomplished by merely turning a switch to one of the following
six positions:
Features
High fidelity reproduction of vertical and lateral recordings.
Universal lightweight pickup with long wear diamond
point stylus.
LATERAL
Heavy duty constant speed synchronous motor with ample
driving power for recording or reproducing.
1.
Transcriptions-NAB Lateral.
Home records with 500 cycle crossover frequency (Victor).
Home records with 300 cycle crossover frequency.
4. Test records and special recordings (wide open at high
frequencies) .
2.
3.
Provision for RCA Recording Attachment.
Quiet operation. Cushion-mounted motor with silent on-off
switch.
VERTICAL
1.
Speed change lever in rim of turntable permits change without removing record.
2.
Transcriptions-NAB Standard Vertical.
Transcriptions (worn).
Two vacant positions are available on the switch to permit additional filters or compensators to be added if required.
Ruggedly built to give years of satisfactory service.
The motor is a high torque synchronous type, cushion -mounted
on the bottom shelf of the equipment, thus isolating motor
noise from the cabinet. In order to insure the faithful reproduction of high fidelity records, the turntable platter has associated with it a separate specially designed flywheel. This flywheel is approximately 12" in diameter and is located within
the cabinet itself. The turntable platter and flywheel assembly
is completely isolated from the motor through a series of
mechanical filters and a spring clutch arrangement. The combination insures excellent speed regulation and, with the
cushion mounting of the motor, prevents noise and vibration
Uses
The Type 70-D Transcription Turntable has been developed
to meet the continued demand for higher and higher quality in
the reproduction of broadcast transcriptions. It is the latest
edition to the popular 70 SERIES of transcription equipments,
of which more than 3000 are now in use. It has all the exclusive features of the former models, plus the newly designed
universal pickup head and adjustable filter unit. The 70-D
provides high fidelity reproduction of all vertical or lateral
cut records.
70
A -C
PICKUP
TURNT AILE
POWER SWITCH
SFLFC TOR -FINER SWITCH
+5
PICKUP LIFT
Aide
L4
PICKUP
L1
-5
L-2,
1,
L3
L-4
KISSING ANO SPIRO
r
REDUCTION MOUSING
\
L
1
L-2<`
`\
TYPICAL LATERAL RESPONSE
COUPLING
OF AN MI -4875-G
-25
STABILIZER
(FLYWHEEL)
PICK UP
AND
1111
FILTER
-30
50
OVER -RUNNING
COUPE»
I
FREQUENCY IN CYCLES
MECHANICAL FILTER
----
..
MOTOR
MOTOR
MOUNTING
L-1.
TRANSCRIPTIONS N.A.B.
L-2,
HOME
L-3.
HOME
L-4.
FLAT
500 c.p. s.
300
SECOND
LATERAL
CROSS OVER FREQUENCY
c.p.s.
RESPONSE
PER
CROSS OVER FREQUENCY
(OPEN AT HIGHER FREQUENCIES)
Level -63 dbm Ll
position at 1,000 cycles T-2485
test record
-68 dbm (.001 watt reference) V1 position
at 1,000 cycles-TRV-104 test record
Noise Level (below 1 milliwatt reference level)._ -120 dbm
50-10,000 cycles
Frequency Response (see curves)
24 db at 1,000 cycles at each
Transmission Loss of Filter
of the 6 switch positions
Polished diamond
Stylus
16"
Turntable Diameter
(Will handle records up to 18" in diameter)
33í/s-78 rpm
Turntable Speed
0 2°ío rms at 331/2 rpm
Speed Regulation (wows)
0.09% rms at 78 rpm
Dimensions, overall
983/8"
Height (overall)
30%"
Height (overall with MI.11803)
Width
251/"
Depth
941/4"
Two tone umber grey with chromium trim
Finish
155 lbs.
Weight (unpacked)
105.125 volts, 50 or 60 cycles
Power Supply
35 watts
Power Consumption
Stock Identification
MI -11801
Umber Grey, 60 Cycles
MI -11802
Umber Grey, 50 Cycles
Output
Outline photo of the Type 70-D showing its outstanding
mechanical features, simplicity of design and ruggedness.
-
from being transmitted to the tone arm, a feature which is
highly important when attempting to reproduce high fidelity
records satisfactorily.
A silent type of power switch, located on top of the machine,
permits the turntable to be operated near a microphone.
The RCA Type 72D/72DX Recording Attachments are available for use with the 70-D Turntable. Mounting holes are
provided for easy and quick installation.
Specifications
Pickup Impedance
Load Impedance
10,000
1000
100
CLUTCH
950 ohms
Output of compensator should be connected to the unloaded input transformer of an amplifier designed to operate from a 250 ohm source such as
BA -1A or BA-2 series.
Black, 60 Cycles
MI -11802-A
Accessories
MI.11226-B
BA -2C Booster Amplifier
72 -D/72 -DX Recording Attachment_MI-11901 or MI -11900
MI.11803
Mounting Base
+5
o
V-1
5
-10
V2
o
15
\
-20
TYPICAL VERTICAL RESPONSE
OF AN MI -4875-G
25
PICK UP AND FILTER
-30
50
100
10,000
1000
FREQUENCY IN CYCLES
--
PER
SECOND
V-1. N.A.B. Standard Vertical
V-2. Transcriptions (worn)
70-D
71
Turntable with 72-D Recording Attachment
in position
TURNTABLES
Universal Pickup Kit MI -4875-G
Features
High fidelity reproduction of vertical and lateral recordings.
Adjustable weight pickup head.
Low moving mass.
Adjustable vertical and lateral stops.
No stylus breakages.
Uses
The Universal Pickup Kit has been designed to give an
ideal playback response for all vertical and lateral recordings.
This unit has a versatile mounting attachment and may be
fitted to most turntables.
dial plate and filter kit with cable and terminal board. All
the necessary accessories are provided for use on the 70-C
series transcription turntables. For a more complete description and response curves, refer to the catalog page which
features the 70-D turntable. The pickup compensator will operate satisfactorily into a BA -1A pre -amplifier, BA -3C program
amplifier or any amplifier designed with an unloading input
transformer for operation from a 250 ohm source impedance.
Description
The pickup head is a high quality moving conductor type, in
which two ribbons are free to move in a vertical and lateral
field. The head used in conjunction with a carefully designed
compensator, produces ideal curves for all the various types
of records. The compensator uses a series resonant circuit.
variably tuned and shunted by merely turning a switch to one
of six positions. Each kit consists of a Universal Pickup Head
with an attractively styled tone -arm complete with finger lift,
tone -arm rest position, six position compensator switch with
Weight (unpacked)
Stock Identification
Reproducing Filter MI -4975
The MI.4975 Filter is a newly designed unit and is an integral
part of the 70-C2 and 70-D Turntables and the MI.4875-G
Universal Pickup Kit. This kit is made available for the user
who wishes to convert the superseded 70-C and 70-C1 Turntables and the MI-4875-C Pickup and take advantage of the
considerable improvement in this filter design. The high frequency response for the Associated records is very much improved and the overall response characteristics for lateral
records now conform to an ideal curve. The kit consists of
compensator complete with cable, terminal board and a six position compensator switch.
The changes are effected by merely transferring five wires on
the terminal board. For the new response characteristics produced, reference is made to the 70-D Turntable catalog page,
where these curves are shown.
Weight
Stock Identification
5 lbs.
MI -4975
72
12
lbs.
MI.4875-G
RECORDERS
RECORDING INSTALLATIONS
Studio recording installation at KUTA.
Salt Lake Cty, Utah, showing two
bench-mounted RCA 73-B Professional
Recorders.
An ideal recording installation at
KECA, Los Angeles, Calif., showing
two of the four RCA 73-B Professional
Recorders. Note the conveniently located overhead lighting, the large size
auction duct, and .relatively short
length of hose for chip removal.
RECORDERS
Recording Equipment
RCA offers a complete line of high fidelity recording equipment featuring outstanding
performance characteristics, simplicity of operation and many other exclusive features which
are described on the following pages. For professional recording studios, broadcasting stations, educational institutions or wherever high quality discs are to be cut, these recorders
are unexcelled.
Type
Usage
73-B
Recording Pitch
Lines per InchInside out or
Outside in
Recording
Speed
rpm
Professional
AM -FM Broad-
331/2
cast Studios
78
Co961ío
or
Frequency
Response
cps
Max.
Dia.
Blank
±2
Approx.
db
1
152
18t/a"
50-10,000
With 70 Ser.
Turntables
331/2 or 78
96,112,136
18%"
50-10,000
With 70 Ser.
Turntables
331/2 or 78
96,112,136
181/4"
Educational
*
72 -DX
AM-FM Broadcast Studios
72-D
AM -FM Broadcast Studios
For
**For
Educational
Educational
6.3 cm/sec stylus
6.1 cm /sec stylus
±2
+3
Required
Audio
Power
Watt*
Approx.
db
1
Watt
Approx.
db
50-7,500
1
Watt**
velocity at 1000 cps.
velocity at 1000 cps.
For example, some engineers prefer to introduce compensation prior to the limiting amplifier, while others prefer
to record "flat" with automatic equalization to compensate for
the changes in cutting diameter.
Lions.
The following diagrams bave been designed to assist the user
in determining the equipment required for a recording channel.
Since there is considerable difference in recording technique,
these illustrations must only be regarded as suggested installaLIMITING
RECORDING
AMPLIFIER
AMPLIFIER
VU. METER
IMI -11265
1
rm.1-4916-n
NAB FILTER'
SEE NOTE
BA -4C
I
OIE
BA -5q
MI -11550-C OR
-I
MI -11653
RECORDING HEAD
Fig. 1. This diagram illustrates a recording technique using
the orthacoustic filter only.
PROGRAM
EG -AI
LIMITING
RECORDING
SOURCE
\NPLIFIER
LIMITING
AMPLIFIER
AMPLIFIER
V U.
METER
róö5r"
-
`
BA -ac ex
BA -SA
RECORDING
PosITwN.zJ
I
Ica
MI- 11265
MI -11100 OR
MI -11101
MI
-11850-C
OR
AUTOMATIC
MI -11653
RECORDING
RECORDING FILTER
FILTER
Fig. 2. This diagram illustrates a recording technique using
the automatic recording filter only (or "flat").
RECORDING
LIMITING
AMPLIFIER
vvVl..S
This diagram illustrates a recording installation which will
handle recording techniques shown in Figures 1 and 2.
AMPLIFIER
MI -11100 ORI
MI -11101
AUTOMATIC
r14l-49117-A1
LJA8 FILTER,
Note 1. The MI.4916-A recording filter is not required when
the BA -5A recording amplifier is used. The compensating network is incorporated within this amplifier.
SEE NOTE -I
RECORDING
FILTER
Fig. 3. This arrangement is included for recordists who choose
to use both "automatic" and NAB orthacoustic compensation.
74
RECORDERS
Recording Attachment Type 72 -D/72 -DX
Features
Produces high quality recordings on any 70 -Series Turntable.
Records at 331/2 or 78 rpm at 96, 112 and 136 lines per
inch. Outside -in or inside -out recording is accomplished
without changing feedscrews or gears.
Timing scales indicate remaining recording time.
Improved lowering device avoids stylus or record damage.
Convenient adjustment of stylus angle and depth of cut.
Hand crank for spiralling grooves.
Convenient adjustment for horizontal alignment.
Lead screw protected by cylindrical tube housing.
Provision made for installing automatic equalizer.
Uses
The 72-D Recording Attachment may be easily and quickly
installed on any of the RCA 70 -Series Turntables to provide
an unusually high quality instantaneous recording equipment
at an economical price. It is a newly designed and much improved version of the widely used Type 72-C. Broadcast stations will find many uses for this item such as recording
rehearsals and controversial broadcasts, making records for use
by the time salesmen and recording programs for delayed
broadcasts. It may also be satisfactorily used for making
masters for processing.
Type 72-D Recording Attachment
The 72-D is furnished complete with Standard recorder head,
MI-11853-A mounting base and rest post. However, if a high
fidelity response is required, the type 72 -DX with the MI.11850-C
recorder head is available. This high quality head is maintained at a constant temperature while operating by selfcontained heater and thermostat. The power for the heater operation is obtained from an MI -11855-A heater and compensator
kit as an accessory item. The MI -11854 base attachment is
available for mounting the 72 -D/72 -DX on all 70 series turntables. Additional base attachment kits are available if the
recorder is to be used on more than one turntable.
An MI.4910-A conversion kit, which consists of a replacement
turntable felt, cement, support assembly and template, may be
ordered when the 72-D attachment is to be used with a 70-A
or 70-B turntable.
A suction nozzle is provided to facilitate the use of RCA
suction equipment, Mí.11857/MI.11858.
Description
The 72-D is equipped with a sturdy frame containing a screw
mechanism for driving the cutter carriage across a record
blank. Power coupling is made to the center of the turntable
by means of a vertical shaft spiral gear and loosely coupled
three pin driving flange which eliminates slippage and "knocks."
Precision leveling adjustments are made by a swivel support
with an accurate vertical adjustment. The mechanism is made
so that it will swing clear when not in use or it may be
easily removed from the transcription turntable if desired.
An improved lowering device permits the operator to gently
lower the cutter on to the record, thus avoiding stylus breakage or deep cuts from sudden dropping. The angle of the
stylus and the depth of cut may be conveniently adjusted
even during operation. A spiralling hand crank permits spacing
between musical selections without breaking the continuity of
the groove. It is useful also for cutting starting and finishing
spirals. The 72-D will record at either 331/2 or 78 rpm outside-in
or inside -out at 96, 112 and 136 lines per inch. Selection of
direction and pitch is made easily and quickly without changing
lead screws or gears. Two interchangeable spring released hexagon timing scales are provided for giving an accurate indication of the remaining recording time. The scales are calibrated to cover all combinations of turntable speed and groove
spacing. The cutter carriage does not ride on the feedscrew,
but is supported on a metal tube in which the feedscrew is
enclosed and is guided on another tube which is designed to
house an automatic equalizer. This feature eliminates "grouping" of grooves, increases the life of the feedscrew and protects the feedscrew from dust. A lip has been turned on the
driving spindle to catch the threads and prevent their climbing
into the gears or bearings.
Specifications
Input Impedance to Cutter
Frequency Response:
Type 72-D
15
ohms nominal
±3 db, 50-7500 cps
±2 db, 30-10,000 cps
Type 72 -DX
Sensitivity:
Type 72-D [groove velocity 6.1 cm/sec., .00079" (peak to
+28 dbm
peak) at 1000 cps]
Type 72 -DX [groove velocity 6.3 cm/sec., .00079" (peak to
peak) at 1000 cps]
+30.dbm
Recording Direction (adjustable)_Inside-out and outside -in
Recording Pitch (adjustable)_96, 112, and 136 lines per inch
Drive
Platter of an RCA 70-C series or OR-1A Turntable
Dimensions, overall
Height
53/a
15%"
Length
Depth
61/2"
8% lbs.
Weight (unpacked
Finish
Two tone umber -grey, wrinkle
MI.11901
Stock Identification (as normally shipped)
(Includes MI -11852 Attachment, MI.11853 Recorder Head,
and MI -11854 Mounting Base)
MI -11900
Stock Identification (Type 72 -DX)(Includes MI -11852 Attachment, MI.11850-C High Fidelity
Recorder Head, MI -11854 Mounting Base, and MI -11855-A
Heater and Compensator Kit)
Accessories
Automatic Equalizer
Fixed Orthacoustic Equalizer
Heater and Compensator Accessory Kit
Recording Suction Equipment (less hose)
Chip Remover and Hose Assembly
(for suction equipment)
BA -4C Recording Amplifier
Sapphire Stylus
Type 72-D Recorder Mounted on
a
6_
Kit__
Steel Stylus, package of
Additional Mounting Base
Type 70-C1 Turntable
75
MI.11101
MI.4916-A
MI -11855-A
MI -11857
90°
70°
MI.11858
MI.11223-B
MI.4878-D
MI -4842
MI -4879-A
MI -11854
RECORDERS
Professional Recorder Type 73-B
Description
Features
Complete shock mounting and special motors reduce vibration and rumble to a minimum.
High fidelity recording head handles full power with low
distortion.
Two motor drive. Each motor has its own rubber idler
wheel providing high torque and excellent regulation.
Can be adjusted, while recording, for 96 to 152 lines per
inch inside -out or outside -in cut without changing lend screw
or gears.
Large platter with rubber mat takes blanks up to 181/4 inches.
One driving pin enables any type blank to be used. Pin is
held up by spring and sinks into platter if record without
driving holes is used.
Cutter angle and depth of cut can be easily adjusted while
recording.
Dropping mechanism can be operated with one hand;
lowers cutter on record slowly to prevent stylus damage.
Lathe type construction ensures accurate alignment and permits rapid record changing.
Equipped with high grade microscope and illuminating
lamp for accurately checking grooves on any portion of
record.
The 73-B Recording Equipment consists of a high fidelity
MI -11850-C Recording Head with its associated carriage and
lead screw mechanism, a turntable assembly which includes a
dual motor with rim drive mechanism, a turntable platter with
rubber mat, a microscope and microscope lamp and a suction
nozzle (less the suction generating and hose connecting equipment) for removing acetate shavings from the record.
The MI -11850-C Recording Head is a high quality, precision
built, magnetic type unit with a frequency response which does
not depart from an ideal response curve by more than two
decibels between 30 and 10,000 cycles per second. Any discrepancies created by temperature variation are eliminated by
the self-contained heater and thermostat. A visual indicator
controlled by a switch on the base indicates when the heater
is in circuit. Its flat type mechanical construction eliminates
flutter without the use of special damping mechanisms. The
recorder head rides on a smooth metal tube which encloses
the feed screw and is guided on another tube which is designed
to house an MI -11100 automatic equalizer. This arrangement
eliminates "grouping" of grooves, increases the life of the feed
screw and protects the feed screw from dust and dirt particles.
An improved cam -operated lowering device permits the head
to be lowered gently with decreasing acceleration as the head
approaches the record. This feature prevents stylus breakage
or deep cuts from sudden dropping of the recorder head. The
angle of the stylus, the depth of the cut and the number of
lines per inch may be conveniently adjusted even while
Uses
The 73-B Recorder is an outstanding professional type unit
which has been designed to include almost every known device
for making high quality recordings. Recording studios will
acclaim the 73-B as the ideal recorder for making masters
from which any number of pressings may he made. Broadcasting stations will find it unsurpassed for recording programs
for use on delayed broadcasts, commercial accounts, rehearsals,
auditions or the reference file.
recording.
The turntable is rim driven through rubber idler rollers from
two hysteresis type synchronous motors. These motors were
chosen because of their quiet operation and accurate speed.
The two motors and turntable drive wheels are both controlled by one "on -off" switch and both mechanisms are controlled by one "speed-change" switch. When the motor switch
76
RECORDERS
turned "off", the driving rollers are disengaged and a brake
applied to the rim of the turntable, bringing it quickly to a
stop. The motors are doubly rubber shock -mounted from the
motor board to avoid motor rumble in the recordings.
The feed screw is driven by a planetary-drive mechanism
using a rubber -tired roller on a vertical shaft and a flat driving disc on the end of the horizontally mounted feed screw. The
driving roller may be adjusted to various vertical positions
accts- the driving disc, the speed and direction of rotation of
the feed screw being determined by the roller's position with
re -pees to the center of the drive disc. The roller is automatically disengaged from the driving disc whenever the cutter
head carriage is raised to the rest position. The number of
cutting lines per inch is indicated by an illuminated scale in
the drive housing. Four spring -released interchangeable time
scales are provided to cover all combinations of turntable
is
ment. Also available is the advance ball kit (MI.11851) for
use with the MI.11850-C Recording Head when making wax
recordings.
is
Provision has been made for convenient installation of the
MI.11100 Automatic Equalizer. This was designed to compensate for the variations in recording level, resulting from
changes in the surface speed of the record.
The MI.11827 Recorder Base Cabinet has been specifically designed to offer an attractive and practical base cabinet to
accommodate the 73-B Recorder. The recording cabinet is substantially constructed with a robust adjustable interior shelf
for accommodating transcriptions, recordings, etc. The top icomposed of 1" solid wood with no possibility of introducing
rumble. The door and top at-e finished in dark umber gray
with the sides in light umber gray to blend with all other
RCA broadcast equipnt+nt.
-peed and groove spacings.
A separate motor, controlled by a push button on the recorder
base, is used for motor driven spiralling, overdriving the lead
screw to provide start and finishing spirals. The spiralling pitch
is 6 lines per inch when the recorder is set for 96 lines per
inch and the turntable speed is 78 rpm. For a turntable speed
of 331 rpm, the spiralling pitch will be reduced in proportion
to the speed change.
A high quality, 36 power, Spencer microscope is furnished for
observing the grooves. The microscope has a calibrated eyepiece having 50 divisions of .001 inch and is mounted on an
adjustable arm which permits it to be moved to any part of
the record. On the same arm is mounted a small shielded lamp
which is independently adjustable so as to illuminate the
grooves under observation.
Playback provisions are made by a removable plate on the
recorder base for mounting an MI.11871 Universal pickup
and arm. A receptacle in the base is already connected to
the terminal board. The entire recording mechanism is isolated
from room vibration by rubber mounts. A removable plate,
placed over the pulleys on the left side of the machine, permits ready access to the driver pulleys and driver motors
for servicing. Terminal boards are provided on the front and
on the rear of the recorder base for a -c and audio connections
respectively. The entire mechanism is furnished with an attractive and substantial wooden apron.
The 73-B is supplied with adjustable suction nozzle attached
to the cariage mechanism. The newly designed suction pump
(MI.11857) and accompanying chip collector and hose
(MI -11858) are available as accessories. For a complete and
detailed description, refer to the catalog page for this equip -
Specifications
Recorder Head Impedance (MI -11850-C High Fidelity Head)
15 ohms nominal
Frequency Response
±2 db, 30-10,000 cps
Sensitivity: (Groove velocity 6.3 cm/sec., .00079"
(peak to peak) at 1000 cps)
+30 dbm (1.0 watt)
Stylus
Sapphire or steel
Turntable Diameter (handles blanks up to 181/" dia. and up
to %" thick)
171/2"
Turntable Drive
Rim driven through rubber idler rollers
from two hysteresis synchronous motors
Turntable Speed (accuracy ±1/2%)
331/2 or 78 rpm
Speed Regulation (wows)
014% rms at 331/2 rpm
0.07% rms at 78 rpm
Recording Direction (adjustable)-Inside-out and Outside -in
Recording Pitch
Continuously variable 96 to 152 lines per
inch with detents provided in steps of 8 lines per inch
Dimensions, overall
With Cabinet
Less Apron
Height
20"
20"
Width
31%"
30"
Depth
Height to Top of Base
10110"
í/Z'
,s "
Weight (unpacked)
289 lbs.
Finish_Light umber grey wrinkle with dark umber grey trim.
Apron finished with smooth dark umber grey. All control
knobs and levers are polished nickel.
A -c Power Supply, 115 volts 50-60 cyclesTurntable drive motors
80 watts
Pilot Light
5 watts
Spiralling Motor (when operating)
145 watts
Stock Identification
60 cycles, MI -11825/11850-C
50 cycles, MI -11826/11850-C
SPECIFICATIONS FOR MI -11827 BASE CABINET
Dimensions:
Height (overall)
2' 81/2"
Width
2' 9"
Depth
1' 111/2
Thickness of Top
1"
Weight
85 lbs.
Stock Identification
Mí.11827
Accessories
Automatic Equalizer
Othacoustic Equalizer
Suction Equipment
Spare Chip Collector and Hose Assembly
Sapphire Stylus
MI-11100
MI -4916-A
MI -11857
MI.11858
90° MI.4878-D
70° MI.4842
Steel Stylus
MI -4879-A
Amplifier (BA4C)
MI -11223-B
Universal Pick-up Kit (for 73-B Recorder)
MI -11871
Additional High Fidelity Recording Head
MI -11850-C
Standard Cutter Head
MI.11853
Advance Ball Kit for MI.11850-C Recording Head MI.11851
M1.11827 Recorder Base Cabinet with 73-B Recorder
77
Portable Recording Equipment OR-1A
Features
accommodate any sized record up to 16 inches and the playback apparatus will reproduce all types of lateral and vertical
records with a uniform frequency response between 30 and
Complete high quality portable recording and reproducing
system.
Records at 331 or 78 rpm at 96, 112 and 136 lines per
inch outside-in or inside -out.
10,000 cycles.
When required the turntable, amplifier and speaker units may
be used, less the recording attachment, as a high fidelity record
player for demonstration and sales purposes or, with a microphone, as a 12 watt P. A. system. The amplifier, turntable and
speaker units may be ordered separately for this purpose. If
desired, for a permanent installation, the turntable motor board
may be removed from the carrying case and mounted in a desk
or console.
All exclusive features of the 72-D Recorder such as three
pin drive, inside -out or outside -in recording without changing feed screws or gears, spiralling hand crank and timing
scales.
High quality shock -mounted hysteresis type motor and two
rubber -tired driver wheels provides minimum slippage and
eliminates wows.
High fidelity universal pickup with long wear diamond
point reproduces all lateral or vertical cut records.
High fidelity amplifier (±2 db 30 to 15,000 cycles) with
bridging and matching inputs provides 110 db gain and
12 watts rated output ample for any recording or reproducing requirement.
Description
The OR-1A consists of a 16" MI.11212-B Turntable, a Type
72-D Recording Attachment, Universal Pickup and Arm Assembly, a 12 watt amplifier MI -11212 with dual loudspeaker
unit.
Amplifier includes "playback -record" switch, two external
input terminations, monitoring headphone jack, power
switch and fuse.
Uses
The recording mechanism (Type 72-D attachment) supplied
with an MI.11853 recording head meets all requirements for
producing high quality recordings. If, however, a higher fidelity
characteristic is desired, the MI -11850-C recording head is supplied with the complete recorder, or may be obtained as an
accessory item. High fidelity reproduction of both lateral and
vertical cut records is accomplished by use of the newly designed MI-4875-G universal pickup which is essentially the
same as that used on the 70-D Turntables.
The OR-1A Portable Recording Equipment is a high quality
reasonably priced assembly which includes all the equipment
necessary for cutting high quality instantaneous recordings in
the studio or at remote locations. It is a complete' recording
channel, less microphone, and will record at either 78 or
334 rpm at 96, 112 or 136 lines per inch. The turntable will
The MI -11212 Amplifier has an overall gain of approximately
110 db. This gain remains approximately the same when the
MI.11212 is used with the Orthacoustic Recording Filter or
with the Automatic Recording Equalizer since a compensating
pad is removed when either of these units is connected to
Low control panel includes necessary switches and controls
while permitting good visibility of subject being recorded.
Sloping mounting panel for installation of large volume
meter.
Two "accordion cone" speaker units mounted in carrying
case with removable lid provide a total output of 6 watts.
78
RECORDERS
the amplifier. The amplifier includes a built-in a -c rectifier,
has a frequency response of ±2 db from 30 to 15,000 cycles,
a low noise level, and a distortion content of less than 3%
rms at full output when measured at any frequency between
50 and 7500 cycles. A complete single stage preamplifier with
input and output transformers is included as a part of the
amplifier. This provides a 250 ohm circuit following the preamplifier for the insertion of equalizers, if desired.
Specifications
RECORDING MECHANISM TYPE 72-D
Recorder Head
MI-11850-C or MI -11853
Frequency Response
±4db 50 to 7500 cycles
Recording Direction (adjustable)_Inside-out or outside -in
Recording Pitch_Adjustable, 96, 112, or 136 lines per inch
Finish
Two tone umber grey wrinkle
PORTABLE TURNTABLE (60 cycles)
MI.11211-B
Turntable Diameter (for 12", 14" or 16" records)
16"
Turntable Speeds
331/2
78 rpm
Turntable Drive_Rim driven through rubber idler rollers
by heavy duty synchronous motor
Speed Regulation (wows)
0 15% rms max. at 331/2 rpm
0.1% rms max. at 78 rpm
Power Supply (105-125 volts, 50-60 cycles)
120 watts
Dimensions Overall for Turntable Carrying Case
Height
12%"
Width
24"
Depth
21"
Weight (unpacked, but including 72-D Attachment)
lbs.
AMPLIFIER AND SPEAKER ASSEMBLY
MI -11212
Source Impedance (unloaded transformer input)._ -_250 ohms
Source (Bridging) Impedance
600 ohms
Input Bridging Impedance
90,000 ohms
Load Impedance
Cutter Head Terminals
15 ohms
Speaker Terminals
7 5 ohms
Preamplifier Output (to external filters)
250 ohms
Audio Power Output (less than 3% rms distortion 50 to
7500 cycles)
(40.8 db*) 12 watts
Frequency Response (250 ohm source to 15 ohm load)
±2 db 30 to 15,000 cycles
Maximum Gain
Overall from 250 ohm Microphone to 15 ohm cutter
110 db ±2.0 db
Overall from 250 ohm Pickup to 7.5 ohm Speakers
110 db ±2.0 db
Bridging 20,00 ohms Input
500 ohm line to 7.5
or 15 ohm load approximately 30 db
Noise Level (40.8 db* output, maximum
db
A -c Power Supply (105-125 volts, 50-60 cycles)
120 watts
Dimensions, Overall for Amplifier -Speaker Carrying Case
Height
14"
181/
Width
Depth
231/2
Weight (unpacked-for Amplifier and Speakers)
63 lbs.
Finish
Two tone umber grey
Stock Identification
Complete Recorder, less tubes with Mí.11853 Recorder
Head
MI-11210-E
Complete Recorder, less tubes with High Fidelity Recorder
Head Type MI -11850-C and MI -11855-A Heater and Compensator Kit
MI.11210-D
-
"playback -record" switch is mounted on the front panel and
transfers both the input and output circuits of the amplifier.
When thrown to the "playback" position, the input of the
amplifier is connected to the pickup and the output to the loudspeakers. When the switch is in the "record" position, the
input of the amplifier is connected to the input selector switch
and the output to the recorder head. Two external input terminals are provided; one is a Cannon microphone receptacle
for a 30 to 250 ohm microphone and the other is on insulated
binding posts for bridging a 600 ohm line. The gain control
is a high quality step-by-step potentiometer. A cut-out is provided in the front panel for the installation of an Mí-11251
VU Meter Kit for monitoring the recording level, if desired.
A monitoring headphone jack, a power switch and a fuse are
also located on the front panel for ready accessibility. Mounted
in the removable lid of the amplifier are two RCA "Accordion
Cone" Speaker Units which are enclosed in a sealed compartment for proper cone loading and low frequency response. The
unit is furnished with an a -c power cord and with a turntable
interconnecting cable which is equipped with a Cannon plug
to fit the receptable in the MI -11211B Turntable.
A
-56
gain)_S2
Showing method of Mounting Recording Attachment
while transporting unit.
Accessories
Tube Kit (complete tube complement)
5 RCA 1620, 2 RCA 1622, 1 RCA 5R4GT_MI-11259
Emergency Tube Kit (complete tube complement)
5 RCA 6J7's, 2 RCA 6L6's, 1 RCA 5R4GT-MI-11259-A
High Fidelity Recorder Head
MI -11850-C
VU Meter and Attenuator Kit
MI -11251
Orthacoustic Recording Filter
-MI -4916-A
Automatic Recording Equalizer
Mí-11101
Microphones
RCA 44-BX, 77-D, 74-B, or 88-A
Sapphire Stylus
90° MI.4878-D
70°
Steel Styli, Package of
The complete OR -1A Equipment ready for transporting.
6
Reference level one milliwatt.
79
MI.4842
MI -4879-A
RECORDERS
High Fidelity Recording Head MI -11850-C
Features
Meets all high fidelity requirements.
Does not depart from an "ideal response" by more
±2 db 50-10,000 cps.
Response independent of ambient temperat ures.
t
han
Precision built.
Self-contained heater.
Uses
The MI.11850-C High Fidelity Recording Head has been specially designed for the user who demands high fidelity recordings. It was primarily produced for use with the 72 -DX
Recording Attachment, 73-B Professional Recorder and the
OR -1A Portable Recorder.
lie in a lateral plane, thus eliminating flutter without the need
for special dampening mechanism. Connections are made
through a four -pin plug. Any discrepancies that might be
created by temperature variations are eliminated by a selfcontained heater and thermostat. The power for the heater
operation is obtained from an MI.11855-A Heater and Compensator Kit. A small screwdriver is provided to fit the stylus
setscrew.
Description
The High Fidelity Head is a high quality professionally built
and accurately adjusted unit of the magnetic type. Physically,
the head consists of a cobalt -alloy permanent magnetic, laminated pole pieces, a driving coil, an armature, and dampening
material assembled in an attractive case. The armature is supported on knife-edge bearings and held in position by a steel
centering spring. Its flat type construction allows the head to
Specifications
15 ohms
Input Impedance (with compensator)
±2 db 50 to 10,000 cps
Frequency Response
Sensitivity [groove velocity 6.3 cm/sec., .00079" (peak to peak)
+30 dbm (1.0 watt)
at 1000 cps]
Sapphire or steel
Stylus
Dimensions:
Height
1%"
Width
2"
Length
33/a"
10t/2
oz.
Weight
Light umber gray
Finish
MI.11850-C
Stock Identification_
e
-S
.
-IR
Accessories
20
So
FREQUENCY
IN
MI.11855-A
MI.4878-D
MI-4842
MI-4879
Heater and Compensator Kit
Stylus Sapphire 90°
Sapphire 70°
Steel (packet of 6)
IOOo
IOU
CYCLES PCR SECOND
EMI-IIC50-C RECORDING HEAD
Heater and Compensator Kit MI -11855-A
This kit was specifically design for use with an MI -11850-C
High Fidelity Recording Head. This maintains the operating
temperature at a constant value, rendering the response of the
recorder head independent of ambient temperature. The temperature is held at approximately 95° F. by means of a
thermostatically controlled heater mounted in the recorder
head. The kit consists of the following components: heater
transformer, pilot light assembly complete with bulb, 3 position switch, a 7 ohm 5 watt resistor, a dial plate reading
"High", "Low" and "Off", and a Cannon X-4-13 Receptacle.
Connections are made through this receptacle.
1
15_c-,
AUDIO SOURCE
MI -11850-C
10,
RECORDING
HEAD-.-
110 V.A.C.
_J
o
Mounting facilities are provided for 70-C and 70-D series of
turntables and OR -1A portable recording equipment.
LOW
This kit is an integral part of the MI.11850-C Recording Head
and should be ordered as an accessory except when used with
Type 73-B Recorders, where this kit is self-contained.
MI -11855-A
80
HIGH
HEATER &
THERMOSTAT
HEATER & COMPENSATOR
RECORDERS
Standard Recording Head MI -11853-A
The MI -11853-A Recording Head is available to broadcasters
who demand a good quality, low priced recording head for
applications where the high fidelity response of the MI.11850-C
is not required.
The physical construction of this head is similar to the
MI-11850-C, possessing the feature of eliminating flutter without using special dampening material. The MI.11853-A is
standard equipment with the 72-D Recording Attachment, the
OR -1A Portable Recorder and may also be used with the 73-B
professional recorder. The case is composed of durable, molded
"Urea" with screws for mounting on all RCA type recording
attachments. A 28" two wire, "Vinylite" insulated cable is provided for external connections.
Stylus
Sapphire or
Method of External Connection
Two -wire "Vinylite" insulated 28"
Dimensions
Height
Width
Length
Specifications
Frequency Response
±3 db, 50 to 7500 cycles
Input Impedance (recording head and compensating
resistor)
15 ohms nominal
Sensitivity [Groove velocity of 6J cm/sec. for a stylus excursion of .00077" (peak to peak) at 1000 cps]
+28 dbm
Finish
Weight
Stock Identification
steel
long
I1/4"
9"
97/s"
Dark umber gray
73/ ozs.
MI.11853.A
Advance Ball Kit MI -11851
The Ml -11851 Advance Ball Kit has been designed for use
in conjunction with the MI.11850-C Recorder Head. It serves
to control accurately the depth of groove when the cutter
head is used with soft recording materials. The Advance Ball
Kit is essential when recording on wax and some operators
find it convenient for use with lacquer recordings when
mechanical vibration is present.
The Advance Ball is a sapphire cylinder with a tip that has
been highly polished to a spherical shape and mounted in
a Duralumin shank. The Ball rests on the unrecorded portion
of the record surface, supporting the head at a constant height
above the record, so that the depth and width of the groove
will remain constant. An adjusting knob on top of the head
adjusts the vertical position of the Advance Ball to regulate
the depth of cut. Provision is made for moving the Advance
Ball to either side of the stylus to accommodate outside -in
or inside -out cuts as desired.
Specifications
Dimensions, overall, approximate
Height
Width
Depth
Weight, approximate
Finish
Stock Identification
t/4 "
It/Z"
1"
10
grams
White nickel
\ MI.11851
Cutting Styli
The MI4842 Sapphire Stylus with 70° angle and short shank is
recommended for use with RCA recorders when cutting lacquer blanks for immediate playback and cutting masters for
processing. The 90° stylus is recommended only for use in
cutting masters from which 10" and 12" commercial pressings
are to be made. Long shank styli are no longer stocked by
RCA since their use impairs the recorder frequency response
beyond 8000 c.p.s. and a rather severe peak may develop in
this region.
important tests or for cuttings being made by inexperienced
personnel. In general, steel cutters are not recommended for
high fidelity work because they may produce a higher noise
level, a reduced frequency range and their life is relatively
short. Both sapphire and steel cutting needles are carried in
The use of a sapphire stylus is recommended for all recordings except unimportant tests. Initial cost is reasonable and
the moderate charge for sharpening brings the cost per minute
MI.4842
MI.4878-D
MI.4879-A
of recording equal to or below that for steel cutting points.
Steel cutting points may be used with RCA recorders for un-
stock by RCA.
Stock Identification
70° Sapphire Stylus (short shank)
90° Sapphire Stylus (short shank)
Steel Styli (package of 6)
81
RECORDERS
Recording Filter MI -4916-A
(Orthacoustic)
The MI -4916-A recording filter was designed to provide the
most desirable reproduction characteristic for turntables as
set forth by NAB standards for lateral transcriptions. This
filter was primarily designed for use with an MI -11850-C and
MI-4887 high fidelity recording head to give this orthacoustic
response characteristic.
The filter may also be employed with the MI.11853 standard
recording heads with an excellent frequency response. However, with the MI.11853 recording head, the frequency response
about 7500 cps will be slightly lower due to the lower frequency response of this head. This unit may be mounted on
a BR -2A or 36-B panel and shelf assembly.
Specifications
950/600 ohms
Input Impedance (unbalanced)
Output Impedance (unbalanced)
250/600 ohms
Insertion Loss
(Operating from a 600 ohm source into a 250 ohm load
16 db
at 400 cps)
(Operating from a 600 ohm source into a 600 ohm load
10.5 db
at 400 cps)
Maximum Input Level
+20 dbm
Hum Pickup Level (when placed 6" or more from a power
Less than -120 dbm
transformer)
Dimensions:
+20
.15
.10
.5
o
Height
Width
Length
Weight (unpacked)
Stock Identification
10
IS
-20
-
50
---
IOO
1000
10000
FREQUENCY IN CYCLES PER SECOND
OVERALL FREQUENCY RESPONSE OBTAINED USING MI -4910-A
FILTER WITH MI -11B50 -C RECORDING HEAD.
43/4"
3tá"
12%"
6% lbs.
MI.4916-A
NAB STANDARD LATERAL RESPONSE
Automatic Recording Equalizer
MI -11100, M1-11101
Description
The automatic recording equalizer is another addition to RCA
equipment developed to contribute toward raising the standards
of producing records and transcriptions. The equalizer is designed to compensate for the variation in recording level due
to changes in surface speed of the recorder blank relative to
the stylus. Without this compensation, the recording level due
to the speed change would be of a lower level at the higher
frequencies near the center of the record than they would
near the periphery. The MI.11100 is for use with type 73-B
professional recorders and the MI-11101 is for use with the
72D/72DX recording attachments. Fundamentally the two
equalizers have the same equalization characteristics and differ
only in the mounting facilities and the external connections.
The equalizer consists of fixed capacitors, introduced by a
switch, and a series of ten resistors, varied by a spring -tipped
contact pin, riding with the recorder head carriage. The
equalizers both contain a five -position switch to select the
desired degree of equalization. Suitable hardware is included.
Specifications
Impedances:
Source
Input
Load
Output
600 ohms
Approx 600 ohms
(depending on compensation and frequency)
Unloaded transformer
Approx. 600 ohms
(depending on compensation and frequency)
Insertion Loss (at low frequencies)
Operating Level
Weight (unpacked, less cords and plugs)
82
12 db
-40 db to +
20 db
12 ozs.
RECORDERS
Wire Recorder MI -12775
Features
Good frequency range-80 to 4500 cycles.
Portable-light weight and compact.
Recording time
15
or 30 minutes.
Plug-in type cartridge-no wire threading.
Will playback from a self-contained speaker.
Audio level indicator.
Extremely low noise level.
Uses
The wire recorder is offered to broadcasters as a recording
unit that is portable and completely self-contained with playback facilities for direct programming or listening purposes.
The wire recorder is ideal for field events, excerpts from
speeches, spot announcements, audition, etc., with a playback
response for musical programming comparable to network
quality. Due to its compactness and portability, it is highly
suitable for remotes, merely requiring an a -c supply. Recording is accomplished by simply inserting a cartridge and switching to "record". This method eliminates any wire threading
or any inadvertent breakage of wire. Each cartridge offers 15
to 30 minutes of recording time. When recording for a 30
minute period, a slight interruption of one or two seconds is
introduced after 15 minutes. The unit is modernistically styled
and embraces all the latest electrical and mechanical achievements in wire recording design.
channel of a consolette. A revolutionary feature of the RCA
wire recorder is the plug-in cartridge. This cartridge automatically assumes the correct alignment with the head assembly
when inserted, thereby eliminating any wire threading or
breakages. Each cartridge contains two lengths of wire and
two reels for each wire length. The two sets of wire and reels
are arranged to function in opposite directions so that when
one is being wound on the take-up reel, the other is being
rewound on the supply reel. This method offers 15 or 30 minutes of recording time. A calibrated dial on the front of each
cartridge readily indicates the number of recording or playback minutes elapsed.
Description
All operating controls are located on the front panel. The tone
control, which operates only when the selector switch is in the
playback position, has ten positions for progressively attenuating the high frequencies. The center switch selects the play record and rewind position with the last switch controlling
the volume of the amplifier. A green pilot lamp in the upper
left corner of the speaker grill is in circuit with the power
supply, and a neon lamp in the opposite corner serves as a
volume indicator. The power supply is orthodox and employs
a 5Y3GT full-wave rectifier, supplying power for the amplifier
and oscillator.
The magnetic wire recorder is a device for recording and
reproducing sound using wire of high magnetic retentivity as
a recording medium. The wire will retain its impressed magnetic influence for an indefinite period and the signal may
subsequently be reproduced an infinite number of times without losing its original characteristics. The complete recording
equipment includes the recorder -amplifier unit, wire cartridge
and a low impedance dynamic microphone complete with desk
stand. The recorder-amplifier contains two sets of recording,
playback and erase head assemblies, a motor for driving and
rewinding the spools, a 25 kc oscillator and a 3 stage audio
amplifier. The 25 kc oscillator has two functions-to insure
complete erasure of signal from the wire prior to recording
and as a supersonic bias when recording. The audio section
is a conventional resistance -capacitance coupled amplifier with
a low impedance input operating into an RCA 6J7 voltage
amplifier with a 500,000 ohm interstage potentiometer controlling the input to the following RCA 6SJ7 voltage amplifier.
Specifications
Frequency Range
804500 cycles
Amplifier Output
3 watts
Source Impedance
950 ohms
Load Impedance
6 ohms
Tubes
RCA -6J7, 2 RCA-6SJ7, 1 RCA-6V6GT, 1 RCA-5Y3GT
Power Requirements
115 volts, 60 cycles, 100 watts
Wire Speed
Constant, 2 ft./sec.
Wire Diameter
0 0046 in.
Dimensions:
Width
10"
Height
1014"
Depth
121/ "
Net Weight Complete
Approx 25 lbs.
Stock Identification
-._III-12775
-1
The output utilizes an RCA 6V6GT power amplifier with
(approximately) 14 db of feedback taken from the plate to
the cathode of the 6SJ7 to effect a smooth response with
minimum distortion and noise. The output is switchable for
either driving the recorder head to impress signal upon the
traversing wire or for amplifying the signal induced to
the playback head. When the switch is in the playback position, the output feeds a 5" permanent magnet speaker with
terminals for an additional speaker or high impedance headphones for monitoring purposes. For broadcasting applications,
the output may be slightly modified for matching the input
-
Accessories
Spare Cartridge
83
MI -12877
RECORDERS
Recording Suction Equipment Type
RS -1A
Features
recorders.
1/4 h.p motor-insuring adequate suction for two
Reduces fire risk to a minimum.
Motor maintains constant temperature.
Chip collector eliminating pump failure.
Motor may be isolated from recording room.
Description
This equipment is a new development by RCA and has been
designed to use the most efficient method of removing acetate
shavings from the record surface during the cutting of recordings. The suction apparatus is a high grade, rotary vane type
pump, driven by a 1/4 HP. Repulsion Start, Single Phase Motor.
The unit is ruggedly constructed and mounted on shock dampening rubber cushions. A 10 foot length of tubing with a "Y"
connector provides the suction outlet for one or two recorders.
The chip filter and water jar insure that all chips removed
are absorbed in the water and cannot foul the suction pump.
This equipment is a combination of the following:
MI-17857
One Suction Equipment
One 10' Length of Black Rubber Tubing 1" ID
One "Y" Branch Connector
Two Couplings and Caps
One Reducer Bushing
MI.11858
One Chip Collector and Hose Assembly
Two 6' Lengths of Black Rubber Tubing %" ID
If the user desires to place the suction apparatus remote from
the recorder, 1" tubing which introduces a negligible loss of
suction is recommended. As the majority of loss occurs in
the %" diameter house, the length of this link should be kept
to a minimum. When the apparatus is used with two recorders,
an additional MI -11858 chip collector and hose assembly is
necessary.
130-160°F.
Normal operating temperature
8" mercury
Maximum vacuum for continuous operation
Stock Identification:
RS-1A Equipment (complete for use with one recorder)
MI.11857 /11858
Specifications
115 volts, 50/60 cycles, approx. 450 watts
Power Supply
Dimensions (overall of suction equipment) :
15"
Length
16"
Width
Height
10%
75 lbs.
Weight
Accessory
Extra Chip Collector and Hose Assembly
(For use with two recorders)
Microscope MI -4928
Finish:
The MI -4928 is a high quality, 36 power Spencer Microscope
and Arm Attachment for recorders. It permits close examination of the cutting needle to determine its condition and allows
inspection of individual recording grooves for determining the
noise level, quality and depth of cut.
The microscope has a calibrated eyepiece having 50 divisions
of .001 inch and is mounted on an adjustable arm which permits it to be moved to any part of the record. On the same
arm is mounted a small shielded lamp which is independently
adjustable so as to illuminate the grooves under observation.
The microscope is shipped complete with lens tube assembly,
transformer for the microscope lamp, necessary mounting
screws and installation instructions.
Microscope
Finished instrument black
Light umher gray
Arm
Weight (unpacked less transformer)
7t/z lbs.
Transformer
1 lb
Stock Identification MI.4928
Specifications
Microscope
Unmounted
Overall with
Microscope
Mounted on
Arm
73/4rr
9"
Dimensions:
Height
Width
Depth
3"
3"
25/e"
2%"
Microscope
Light
Transformer
2 7/16"
2 5/16"
2 7/32"
84
MI-11858
LOUDSPEAKERS
RCA
LOUDSPEAKERS
RCA offers to broadcasters a complete line of studio
and station monitoring loudspeakers for use in monitor-
In order to serve the vast multitude of miscellaneous
needs for loudspeakers around broadcasting stations,
there is also included in this line a choice of three
permanent -magnet loudspeaker mechanisms. These mechanisms are intended to be mounted in one of the wall mounting speaker housings, MI -13225, MI -6381, or
MI -6382. The three loudspeaker impedance matching
transformers, MI-12370, MI -12371, and MI -12373 are
designed for use in conjunction with these loudspeaker
mechanisms, or for coupling any of a wide variety of
outputs to these and many other types of loudspeakers.
The quick -selection chart given below provides for design engineers a quick, convenient reference by means
of which they can select the RCA loudspeakers best
suited to their particular requirement.
ing and auditioning booths, hallway installations, talk back applications, elevators and executives' offices. All
RCA loudspeakers are designed to handle adequate
power for the particular application for which they
are designed. The LC -1A, representing the greatest advance in loudspeaker fidelity, is obtainable in a choice
of cabinet styles and finishes, thereby making it possible to conform to any of several interior decorating
schemes. In addition, the LC -1A speaker mechanism may
be obtained by itself for those applications where it
is desirable to use a special type, or custom-made,
mounting.
For those applications requiring a high fidelity loudspeaker not necessarily having quite the same wide frequency range as the LC -1A, RCA offers the MI-12449.
LOUDSPEAKER DATA
Voice Coil
Identification
LC-] A
Impedance
(ohms)
15
Power
Handling
Capacity
(watts)
Weight
(lbs.)
20
21 (mechanism
Cone Dia.
(inches)
15;4
Bolt Circle
Dia.
(inches)
16/
Freq. Range
(CPS)
50-15000
only)
MI -1.2449
15
20
80 (in cabinet)
MI -12422
15
10
3/
MI -12435
6
5
2/
MI -6333-C
6
25
63
85
50-]3000
117
50-6500
5/
6/
70-7000
0 3/32
9g
60-7000
12
]
LOUDSPEAKERS
Monitoring Speaker Type
LC -1A
Features
Excellent frequency response, uniform 50.15,000 cps.
Wide angle sound radiation of all frequencies.
Tastefully styled cabinet.
Low non-linear distortion.
Ideal for monitoring AM -FM television programs.
High grade Alnico V magnets.
Uses
The LC -1A is a high fidelity loudspeaker with a low distortion, wide angle distribution, of extended frequency range,
and specifically designed for the broadcaster and recording
studios.
The fundamental principles are based upon extensive loudspeaker research and development performed by Dr. Olson
at RCA Laboratories (Princeton).
For applications where it is desired to mount the mechanism
on a wall baffle, ceiling, etc., the speaker may be used with
assurance that the entire frequency range will be realized.
The speaker's outstanding performance makes it ideal for the
full frequency range of FM. The LC -1A is also being used
with RCA's new "Festival" series of high quality custom-built
home receivers.
Description
frequency unit to limit the current flowing at the low frequencies. When program material containing a large distortion
factor is prevalent, such as worn records, etc., an MI.11707
high frequency compensator producing curves with a "roll -off"
at 5, 10 and 15 kc, is available to restrict the high frequency
range. The LC -1A is supplied with or without cabinet and is
ideally suited for mounting in the wall or ceiling of the control room, giving a uniform response of 50 to 15,000 cycles.
The cabinet was specifically designed for this speaker and is
attractively styled in two finishes-two-tone umber gray with
a satin chrome trim to blend with all RCA studio equipment,
and a rich walnut veneer for use in finely finished listening
booths. This cabinet is particularly designed for high fidelity
loudspeakers and is constructed with a fixed port to give
maximum response in the low frequencies. Accommodation
for the BA -4 series of monitoring amplifiers is provided. A
brushed -chrome panel on the side of the cabinet will accommodate a volume control, 5/10/15 kc high frequency compensator, 10 channel selector switch, an "off -on" amplifier
switch with a visual indicator.
The LC -1A is a duo-cone speaker mechanism of the direct
radiated type, consisting of high and low frequency units
mounted co -axially together. The 2" high frequency cone and
the aluminum wound voice coil has a low mass utilizing the
wide angle of the shallow, low frequency cone, to effect its
remarkable directional pattern (see curve). An equilibrium
has been reached between the electrical and mechanical design
to impart a high frequency radiation of 120° arc with a loss
of approximately 6 db at 15,000 cps. This eliminates the conventional "beam effect" usually experienced at this frequency.
The low frequency cone employs a 15" diaphragm with a
high mass voice coil and produces the most desirable directional pattern with a handling capacity of 20 watts. Low distortion has been accomplished by a carefully designed compromise of many contributing factors. Distortion usually
experienced when handling large power in the 100-1,000 cycles
range is eliminated by using a high mass coil and a massive
rigid cone, coupled with a low fundamental frequency peak
of 35 cycles. Above this frequency, the reluctance due to the
suspension system of the cone does not appreciably affect the
velocity and, therefore, minimizes distortion.
With an MI.11708, 15 ohm attenuator, the speaker will operate
from a speaker buss, or with an internal amplifier and selector
switch, will function as an independent unit and will bridge
any of ten speaker channels. The desired ordering arrangement
is obtained by consulting the stock identification accessories.
The cross -over network utilizes the physical disposition of the
cones to mutually vibrate in unison over the cross -over frequency region and merely employs one capacitor in the high
86
LOUDSPEAKERS
4
\`
o
60
1000
IOO
10000
FREQUENCY IN CYCLES PER SECOND
HARMONIC DISTORTION OF A TYPICAL LC -IA
SPEAKER IN CABINET
-10
- ---
WATTS
2 WATTS
WATT
I
Accessories
Speaker Filter Unit
Mí.11707
(This item is included in both cabinets, MI.11401
and MI-11401-A, but is necessary if a high frequency filter is desired when the speaker only is
ordered. This unit includes a filter switch and an
escutcheon plate reading 5 kc, 10 kc, and 15 kc.)
Speaker Power Attenuator, 15 ohms
MI -11708
(This is necessary when the audio source is fed
externally through a buss bar, etc. This is mounted
on the speaker cabinet escutcheon.)
Speaker Accessory Kit
MI.11711
(This kit contains a 10 position channel selector
switch, "on -off" switch with visual indicator and
necessary hardware for mounting BA -4C amplifier.)
LC -1A Speaker Mechanism
Specifications
LC -1A SPEAKER MECHANISM
Impedance (nominal)
15 ohms
Frequency Response (see curve)
50.15,000 cps
Directional Characteristic
See curve
90 watts
Power Handling Capacity
Non-linear Distortion (for 10 watt output, 50-15,000 cycles)
Less than 4% at 60 cycles
Weight (unpacked)
91 lbs.
Dimensions:
Diameter (cone)
15,A"
161/4"
Diameter (bolt fixing circle)
Diameter (overall frame)
17"
LC -1A CABINET
Dimensions:
Height
Width
Depth
Weight
40%"
271/e"
15"
Approx 50 lbs.
Close-up of control panel of LC-1A showing controls for
MI -11707, MI -11708, and MI -11711
Stock Identification
LC-1A Speaker, cabinet complete with BA -4C monitor ampli-
fier, volume control, high frequency filter unit 5 kc, 10 kc,
and 15 kc, 10-position channel selector switch, and an
on -off switch with a visual indicator (lees tubes for
amplifier)
Mí.11411 /11401
MI-11711 /11223-B
MI -11411 /11401
LC -1A Speaker and Cabinet
LC -1A Duo-cone Loudspeaker Mechanism only-MI.11411
LC -1A Speaker Console Cabinet Only
MI -11401
(Umber Gray)
LC -1A Speaker Console Cabinet Only
MI.11401-A
(Walnut)
/
o
s
10
IS
f'
15
KC
Ve
10
KC\
DIRECTIONAL CHARACTERISTICS
OF A TYPICAL LC -IA
SPEAKER IN CABINET
roc
V
20
50
1000
100
10000 15000
FREQUENCY IN CYCLES PER SECOND
FREQUENCY
-----MOW
---
1000 CYCLES
7000 CYCLES
RESPONSE OF A TYPICAL LC -IA
SPEAKER IN CABINET
81
CYCLES
LOUDSPEAKERS
Monitoring Loudspeaker MI -12449
The MI -12449 loudspeaker is another new high fidelity speaker
recently designed by RCA. This speaker has an excellent
frequency response and is admirably suited for use in listening booths where faithful reproduction is desired. The Mí.12449
consists of a distinctively styled wooden cabinet finished in
two tone umber gray, containing a low frequency speaker, high
frequency horn driver with the high frequency horn an integral part of the cabinet. This assembly produces an unusually wide frequency range and directional pattern, with a
low distortion power handling capacity of 20 watts.
Specifications
Frequency Range
Power Handling Capacity
Voice Coil Impedance
Axial Sensitivity
95 db at
Distribution (coverage angle)
Cabinet Dimension (overall)
Height
Width
Depth
Finish
Weight (unpacked)
Stock Identification
50.13,000 cycles
90 watts
ohms nominal
feet with 1 watt input
100° at 1000 cycles
15
4
:
37í/s"
941/"
201/2"
Two tone umber gray
80 lbs. (approx.)
Mí.12449
Wall Speaker Housing MI -13225
Molded Speaker Housings MI -6381
and MI -6382
The MI.13225 wall speaker housing is
constructed of special molded material,
with excellent acoustical properties. The
exterior has an attractive appearance
of rich brown Morocco-grain leather.
The sloping front provides for maximum radiation in all directions.
Mounting bolts in the housing facilitate a secure and easy speaker
installation. This speaker housing was
specifically designed to accommodate
the MI -6234-B accordion speaker with
adequate space for the MI.12371 or MI-12373 transformer.
Mounting hardware and terminal strip for the speaker leads
are provided.
These speaker housings are available
for use with the MI -6333-C and
MI-12422 speakers respectively. These
molded fiber wall baffles are particularly suitable for all internal installations and are handsomely finished in
dark umber gray hammeroid with a
gray and silver grill cloth. The front
of the housing has a 10° slope, giving
good sound radiation characteristics.
The baffle board attached to the housing permits the speaker to be securely
installed and eliminates vibration. Speaker mounting bolts for
either speaker render speaker installation an easy operation.
Wall mounting brackets and associated hardware complement
each housing.
Specifications
Dimensions (exterior)
Specifications
Height
Width
Depth
Stock Identification
MI.6381
for 10" PM Speaker MI.6333-C
17"
MI.6382
for 12" PM Speaker MI-12422
13"
Dimensions:
Length
Width
Depth
:
61/2"
maximum
MI -13225
88
23"
173/4"
8" (top)
LOUDSPEAKERS
Permanent Magnet Loudspeaker
Mechanisms
Speaker Mechanism MI -12422
Description
The MI.12422 is a 12" permanent magnet type speaker using
an Alnico magnet and suitable for all general purpose applications. The cone is constructed in one piece, effecting a superior
response to the lapped type of cone. The voice coil assembly
is supported by an adjustable centering device. The speaker
gives a good frequency response and has a power handling
capacity of 10 watts. The Mí.6382 speaker housing is recommended for use with this speaker. MI -12370 and MI-12373
transformers are available as matching transformers.
Specifications
Frequency Range.__
Power Handling Capacity
Voice Coil Impedance
Finish
Weight (unpacked)
Stock Identification
50-6500 cycles
10 watts
_15 ohms nominal
Umber gray
3% lbs.
MI -12422
Accordion Edge Speaker Mechanism
MI -12435
The MI.12435 is a 7" permanent magnet type loudspeaker
with folded edge (accordion) cone. This type of cone is particularly suited for applications where an undistorted low
frequency response is demanded. The cone is virtually freely
suspended and allows the low frequencies to vibrate the
maximum length and are not impeded by the reluctance of
the conventional type suspension system. The permanent field
is produced by Alnico magnet insuring a maximum and stable
field. To derive maximum benefit from this type of speaker,
an enclosed type of housing, such as the MI.13225 which was
specifically designed for this speaker, is recommended.
Specifications
Frequency Range.-
Voice Coil Impedance
Finish
Weight
Stock Identification
6
ohms nominal
Umber gray
21/ lbs.
MI -12435
70.7000 cycles
_5
Power Handling Capacity
watts
Speaker Mechanism MI -6333-C
The MI.6333-C is a high quality 10" general purpose, permanent
magnet speaker suitable for wall baffle or ceiling mounting.
The cone is of single piece construction and moisture resistant,
giving it great ruggedness and a handling capacity of 25 watts
of power.
The speaker uses Alnico II metal for the permanent magnets,
insuring high efficiency and sensitivity with an unusually good
frequency response. The MI.6381 molded speaker housing was
designed and is recommended for use with this speaker.
MI.12370 and MI -12371 transformers are recommended.
Specifications
Frequency Range
Power Handling Capacity (maximum)
Voice Coil Impedance
Cone Diameter
Depth of Speaker
Weight (unpacked)
Stock Identification
60-7000 cycles
25
6
watts
ohms nominal
89
101/"
6
"
63/"
MI -6333-C
LOUDSPEAKERS
Speaker Transformer MI -12370
Specifications
MI
Impedance: (primary connected to 500/600 ohm source)
12370
1.2
Impedance
500/600 ohms
3.4
33
3-5
3-6
3-7
66
132
264
6
32
106
10.6
63
22
Terminals
(Primary)
4.5
4.6
4.7
5-6
5-7
6-7
The MI -12370 is an ideal speaker matching transformer for use
where a large power handling capacity is required. The secondary has three taps which, for a given source impedance
provide ten different output impedances for matching to the
load. All taps are connected to lugs on a bakelite terminal
cover to which the load may be attached by either a screw
or solder connection. The transformer is enclosed in a metal
case which is finished in aluminum gray. The terminal arrangement, voltage ratios, and a schematic diagram of the windings
are stenciled on the side of the case. Four holes through the
two bottom flanges provide for mounting the unit.
Frequency Response
Power Handling Capacity
Distortion
Maximum Primary Voltage
Dimensions
Finish
Weight (unpacked)
Stock Identification
fir
"
"
"
"
±1
db, 30 to 10,000 cycles
40 watts
Less than 1% 100-8000 cycles
125 volts rms
4%" x 41/4" x 5"
Aluminum gray
7 lbs.
MI-12370
-
Speaker Transformer MI -12371
The MI.12371 speaker transformer is a good quality unit with
several taps on the primary winding, giving a wide impedance
range of 1000 to 16,000 ohms. The secondary winding has a
variable tap for three speaker voice coil impedances. It is
designed for bracket mounting with 8" connection leads. This
transformer is suitable for use with the MI -6234-B, MI.6333-C
and the MI -12422 RCA speakers.
The MI-12372 is identical to the MI -12371 except that it is
hermetically sealed.
MI -12371 123Y{
kIi
Specifications
2h"
Length
Width
Height
Weight
+2 db 100-6500 cycles
Frequency Response
than 1% 100-6500 cycles on 2000 ohm tap
Distortion
10 watts
Power Handling Capacity
-Less
9"
11/4
9%"
lbs.
Speaker Transformer MI -12373
connection leads. The same transformer, hermetically sealed
for tropical use, is available as MI -12374.
MI -12 373
Specifications
+1 db 100-12,000 cycles
Frequency Response
than 2% between 100 and 8000 cycles
Distortion
5 watts
Power Handling Capacity
125 volts
Maximum Primary Voltage
Height
v"
9'A"
Length
11"
Width
1a"
Mounting Centers
10" leads
Connections
s/ lbs.
Net Weight
--Less
This transformer is ideal for operating a number of medium
power speakers with a voice coil having 6 or 2 ohms impedance. The primary winding has three taps for 4000, 8000 and
16,000 ohms. It is designed for bracket mounting and has 10"
90
AM
TRANSMITTING
EQUIPMENT
Page
AM TRANSMITTERS
92
PHASING EQUIPMENT
106
TUNERS & ANTENNA ACCESSORIES
112
At the power control section of the five kilowatt transmitter, Type BTA-5F, at KOOL, Phoenix, Ariz.
Fifty kilowatt transmitter, Type BTA-50F, with control
console and extension cabinets containing phasing equipment, at K.MPC, Hollywood, Cal.
At the controls of the one kilowatt transmitter, Type
BTA-IL, at WSBA, York, Pa.
Installatiei
of five kilowatt
transmitter, Type bTA.5F, at
KGKL. San Angeio, Texas.
View shows left and right wing
extension cabinets which contain brocicast audio and antenna ¡Iutsing equipment.
3
riroadMIM'
77_
e.
Control room at WMRN, Mc.rion, Ohia,. showing 250
watt transmitter turntables. aorerol console, and associated audio ana test equipment.
Transmitter roaen at KRIM, Colorado iiprings, Col.,
showing 250 watt transmi.te., Type BTA250L, and
associated audio aid test equipment.
AM TRANSMITTERS
Broadcast Transmitter Type BTA-250L
Description
The Type BTA-250L Broadcast Transmitter is a complete selfcontained unit that will provide reliable, high fidelity operation at any frequency within the range of 540 to 1600 kc.
Encompassing the latest developments in broadcast transmitters, the RCA BTA-250L has been designed to fill every need
of the 250 watt broadcasting station.
The BTA-250L is housed in a modern, attractive, steel cabinet
finished in two tone umber gray and trimmed with strips of
satin chrome. There are ten instruments conveniently located
at eye level on the front panel. All controls are grouped together on a central control panel which is photo -etched and
indirectly illuminated. The tuning controls are provided with
indicators so that their positions may be accurately logged.
The BTA-250L uses the RCA vertical chassis type of construction, whereby the equipment is mounted in such a manner
that each item may be easily removed by one man in the
shortest possible time. The variable elements are placed where
they are functionally needed and where connection leads to
other circuit components may be kept relatively short. This
vertical type of construction provides a high degree of mechanical rigidity, adds considerably to the accessibility of the components, and greatly increases the normal circulation of air
within the cabinet.
The BTA-250L employs a very simple basic circuit arrangement consisting of a crystal oscillator followed by a buffer
amplifier and claps "C" power amplifier.
Two RCA low temperature coefficient quartz crystals mounted
in RCA Type TMV-129-B temperature controlled holders are
provided. The oscillator stage has an extra crystal socket in
which the spare crystal may be continuously maintained at the
correct operating temperature. These crystals provide excellent
frequency stability with no greater deviation than ±10 cycles
from the assigned frequency.
The BTA-250L uses no variable capacitors. Continuously variable inductors are employed as tuning elements throughout,
thus eliminating the possibility of flashovers sometimes occurring in variable capacitors.
The modulation system is high-level with a class "B" modulator.
High fidelity is materially aided by the use of approximately
20 decibels of audio feedback over the audio system.
In order to insure low maintenance cost, the BTA-250L uses
a minimum number of tubes, all inexpensive. There are only
eleven tubes, altogether, and only six tube types. A single high
voltage power supply provides plate voltage for all tubes. This
power supply makes use of two RCA 8008 mercury vapor
rectifier tubes, which are known for their long life and unexcelled performance. Bias voltage for the modulators is provided by a separate power supply using a single RCA 5Y3 -GT.
The power control circuits of the BTA-250L were designed
with an eye to simplicity while also providing adequate protection to the equipment and operating personnel. This transmitter features a relay which eliminates any necessity for re-
Features
Low installation cost.
Low maintenance
cost-only devez tubes,
six types.
Completely self-contained.
Simple and efficient in operation.
Vertical chassis construction
fo:r
accessibility and ventilation.
94
AM TRANSMITTERS
cycling of the time delay relay when momentary power failures
or interruptions occur. Overall protection is provided by the
use of magnetic circuit breakers, serving also as switches, and
completely eliminating fuses from any power circuits.
Carrier Noise and Hum Level
60 db
(unweighted below 100% modulation)
Audio Frequency Response (30 to 10,000 cycles)- ±1.5 db
+16 dbm
Audio Input Level for 100% Modulation
Audio Frequency Harmonic Distortion (50 to 7500 cycles,
0 to 95% modulation)
Not to exceed 3% rms
R -f Load Impedance (unbalanced transmission line or antenna)
A matching network is provided between the output tank cir-
cuit and the output terminals of the transmitter, which includes
series inductive elements and shunt capacitances resulting in
20 to 250 ohms
1-807, 2-810, 2-6J7, 3-828,
2-8008, 1-5Y3GT
Tube Complement
very complete radio frequency harmonic attenuation. Output
terminals are provided at the top of the cabinet for connecting
to an unbalanced open wire transmission line or an antenna
lead-in. A concentric transmission line may be connected
through either the base or the top of the transmitter.
Dimensions, overall
Width Depth
Height
Weight (unpacked)
(packed)
Stock Identification
401/2"
201/ "
847/8"
1360 lbs.
1635 lb..
MI.7242-C
Specifications
Carrier Frequency Range
Carrier Frequency Stability
540 to 1600 kcs
±10
Carrier Power Output
Carrier Frequency Harmonics
A -c
cycles
Accessories
950 watts
Below .05%
Power Input (105 to 115 volts, 50/60 cycles, single phase)
Average Program at 250 Watts Output
-
Carrier Shift (zero to 100% modulation)
-
1625 watts
Type BPA-1 Antenna Tuning Unit
MI -28901-A
Remote Metering Kit for Antenna Current
MI.19404-B
Tube Kit (one complete tube complement)
MI -7245-B
dbm = no. of db above one milliwatt when single frequency
tone modulation is used.
ess than 5%
RESONANCE
NEUTRALIZING
TEMPERATURE
CONTROLLED
CRYSTAL
CHAMBER
HIGH O
INDUCTANCE
TUNING
VERNIER
FREQUENCY
CONTROL
RCA
807
RCA
UNTUNED
,
828
PLATE
CIRCUIT TC
INSURE
RELIABILITY
NO NEUTRALIZING
RCA
LOW DRIFT
CRYSTALS
REQUIRED
HIGH EFFICIENCY
BEAM POWER
AMPLIFIER
PENTODE
OSCILLATO
CIRCUIT
FOR STABILITY
p
MATCHING
NETWORK
CONSERVATIVELY
OPERATED OUT UT
AMPLIFIER FOR LONG
TUBE LIFE
LOW MICROPHONIC
FOR
1
BEAM POWER
HIGH EFFICIENCY
TUBES
AMPLIFIERS
RCA
617
MATCHING
NETWORK
HIGH O
INDUCTANCE
TUNING
4
LOW LOSSES
10 KC CUTOFF FILTER
TO PREVENT ADJACENT
CHANNEL INTERFERENCE
RCA
RCA
828
BOOB
RCA
5Y3 -GT
1.
AUDIO
FF
INPUT
WELL
SH RULED
INPUT
TRANSFORMER
AUDIO
LEVEL
FEEDBACK
LOOP FOR LOW
DISTORTION
RCA
ELECTRICAL FEATURES
L CIRCUIT
OF BTA-250
F LTERED
SUPPLY
FOR LOW HUM
PLATE
617
HIGH GAIN
AUDIO
AMPLIFIER
95
TO BLEEDER FOR
HIGH LEVEL
CLASS
B
MODULATOR
LOW VOLTAGE
SUPPUES
OVERSIZE
RECTIFIERS
AM TRANSMITTERS
Broadcast Transmitter Type BTA-1L
Features
The BTA-1L provides reliable, high-fidelity operation at any
frequency between 540 and 1600 kc. Efficient high level modulation is employed. Only inexpensive tubes are used throughout and the number of tube types is kept to a minimum.
Two RCA low temperature coefficient quartz crystals mounted
in RCA Type TMV-129-B temperature controlled holders are
provided. The oscillator stage has an extra crystal socket in
which the spare crystal may be continuously maintained at the
correct temperature. These crystals provide excellent frequency
stability with no greater deviation than ±10 cycles from the
assigned frequency. A control is provided in the oscillator circuit for precise adjustment of the crystal frequency.
The Type BTA-1L will deliver rated power into a 20 to 250
ohm transmission line or into any type of antenna normally
used by broadcast stations. A matching network is provided
between the output tank circuit and the output terminals of
the transmitter which includes series inductors and shunt
capacitors, resulting in excellent radio frequency harmonic
attenuation. Output terminals are provided at the top of the
cabinet for connections to an unbalanced open wire transmission line or antenna lead-in. A concentric transmission line
may be connected through either the top or the base of the
transmitter. Should the BTA-1L be coupled into either a con
centric line or to a single ended line, the RCA Type BPA-1
(MI.28901) Antenna Tuner may be used. In such cases, a
remote metering kit MI.19404-B is available to replace the
r -f ammeter in the transmitter.
Terminals are provided on the BTA-1L for modulation indication by means of a pickup coil coupled to the tank coil of
the output stage. Excitation for r-f frequency monitoring is
Low installation and maintenance costs.
Completely self-contained.
Simple and efficient operation.
Vertical chassis construction for accessibility and ventilation.
1000 watt, 500 watt, 500/1000 watt, 250/1000 watt and
250/500 watt operation.
Adaptable to 500 or 250 watt operation.
Low tube cost.
Description
The BTA-1L is a one kilowatt transmitter designed to meet
the most exacting demands of the modern broadcasting station.
Essentially, the BTA-1L is composed of an RCA BTA-250L
transmitter, serving as an exciter section, with the addition of
an amplifier section. The complete transmitter is housed in an
attractive cabinet assembly consisting of the BTA-250L cabinet, a matching amplifier cabinet, and a center section which
contains the heavy power equipment. The completely accessible
RCA open vertical chassis construction, which is used throughout, insures mechanical rigidity and good ventilation. The
equipment is- mounted in such a manner that every item can
be easily removed by one man. Controls for each of the two
units are grouped on indirectly illuminated panels conveniently
placed on each of the two cabinets. There are no variable
capacitors used in this transmitter. The tuning elements are
continuously variable inductors which are connected to the
control knobs by means of beveled gears and extension shafts.
The tuning controls are provided with indicators so that their
positions may be accurately logged. The cabinets and center
section are finished in two-tone umber gray with trim strips
of satin chrome.
96
AM TRANSMITTERS
Carrier Shift-from zero to 100%
taken off an r-f voltage divider across a capacitor in the
ground side of the buffer stage. A -f monitoring is accomplished by means of a voltage developed across a resistor connected in series with the secondary of the modulation transformer, at which point a level of approximately +10 dbm is
available at 100% modulation.
Control circuits are simplified and offer maximum protection
to the transmitter and operating personnel. A distinctive feature
is a relay which eliminates the necessity of recycling of the
time delay when momentary power failures or interruptions
occur. Overload protection is provided by using magnetic circuit breakers that also serve as switches.
The BTA-1L is normally supplied for operation at 1000 watts
output. Where power change is required, a kit of power change
equipment (MI -7188-A) is necessary and is easily installed on
the chassis in the center section of the equipment. This equipment will reduce the power output from 1000 to 500 or 250
watts or from 500 to 250 watts as required. A variable transformer adjustable from the control panel provides a means
of maintaining the proper voltages as required. A separate
110 volts, 50 to 60 cycle supply is required for the crystal
heaters.
The BTA-1L is furnished with two sets of tubes and two
crystals.
modulation_less than
Carrier Noise and Hum Level
(unweighted below 100% modulation)
Audio Frequency Response (30 to 10,000
-60
-
5%
db
cycles)-
±1.5 db
+11 dbm**
Audio Input for 100% Modulation
Audio Frequency Harmonic Distortion (50 to 7,500 cycles,
0 to 95% modulation)
not to exceed 3% rms
R -f Load Impedance
(unbalanced transmission line or antenna)_20 to 250 ohms
Dimensions, overall
Width
Depth (door swing 183/4")
Height
1083/4"
20t/"
847/8"
Weight (unpacked)
3,410 lbs.
Stock Identification
BTA-1L Transmitter
BTA-1L Amplifier (for 250R and BTA-250-L)
(complete with conversion accessories) _
.-MI.7186-B
MI -7187-A
Specifications
Accessories
Carrier Frequency Range
540 to 1600 kcs
±10 cycles
Carrier Frequency Stability
Carrier Power Output
(c) 500/1,000 watts*
(a) 1,000 watts
(d) 250/1,000 watts*
(b) 500 watts
(e) 250/500 watts*
below .05%
Carrier Frequency Harmonics
A -c Power Input (220 to 240 volt, 50/60 cycles, single phase
(Line voltage regulation and variation not to exceed 5%)
4,500 watts
Average Program Level at 1,000 watts
500
250
1,000
500
250
100% Modulation
A -c
Power Input (crystal heaters)
YAK
nta47«
watts
watts
watts
watts
watts
Power Change Equipment Kit
Type BPA-1 Antenna Tuning Equipment
Remote Metering Kit for Antenna Current
Tube Kit
For BTA-1L Transmitter Exciter Only
RCA -810
3 828
2 RCA -8008
For Type BTA-1L Amplifier Only
4 RCA -833-A
4 RCA -8008
1
3,700 watts
3350 watts
5,700 watts
4,900 watts
4,450 watts
110 volts, 28 watts
*
RCA -807
uernat
ran
II
---
1,14781
..òò'%(ó.i""
Simplified Schematic Diagram of BTA-JL
97
1
MI.7320
RCA -6J7
1 RCA-5Y3GT
MI -7318
RCA -866/866A
2
2
MI.7188-A Power Change equipment is required.
= no. of db above one milliwatt when single frequency
tone modulation is used.
** dbm
ee-
14b.
MI.7188-A
MI -28901-A
MI.19404-B
AM TRANSMITTERS
Broadcast Transmitter Type BTA-5F
Features
Automatic reclosure without recycling on instantaneous power
drop -outs.
Class C r -f Stages-easy tuning-no critical adjustments.
Class B Modulators-simple circuit design-high efficiency.
Equalized Feedback-low distortion operation-no adjustments.
Fixed Neutralization-stable performance.
Low operating cost-long life tubes-high efficiency circuits.
Low installation cost-built-in wire channel-efficient layout.
Vertical chassis construction-utmost accessibility.
Push button electric tuning-complete circuit meteringpanel viewing windows.
Equipped with control console-centralized control system.
Entirely air cooled-all cooling air filtered.
Can be operated at 1 kw by the flick of a switch.
Quickly and inexpensively converted for 10 kw operation.
Extension wing cabinets available for housing phasing,
monitoring, testing and audio equipments.
The BTA-5F represents a distinct advance in tube economy.
Fewer tubes are employed which reduces the number of spares
required. Only 6 tube types are used as compared to 11 tube
types in a previous design. Greater use is made of beam power
tubes with consequently lower drive requirements and increased efficiencies. All tubes are air-cooled and each high
power tube has its own blower, insuring an adequate supply
of air and eliminating any possibility of overheating.
Description
The BTA-5F 5 kw Broadcast Transmitter is considered one of
the finest, most efficient equipments ever offered to broadcasters. Its excellent design includes refinements in circuits,
carefully planned mechanical layout, long life components, and
complete protection for personnel and equipment. The design
of this transmitter is so conservative that it may be operated
on 10 kw with only minor modifications. The BTA-5F has
all of the exclusive features of the S -F which it supersedes-the
principal difference being front panel appearance and construction. The front panel view of the new BTA-5F shows the attractive unified panel with two-tone umber gray finish and light
trim.
The BTA-5F offers a new concept of accessibility. When the
front doors are opened, components and tubes are immediately
accessible. This feature provides ready access for servicing,
and allows a quick change of tubes when failures occur. In
addition it is possible to erect a smaller and less costly structure to house the transmitter.
Vertical chassis construction is employed throughout. This
type of construction facilitates the removal or testing of components and insures better ventilation of the cabinet with
resultant longer life for individual units.
No trick circuits are used in the BTA-5F. Basic circuits have
been time -tested and proved in at least one hundred 5-D, 5 -DX,
5-E and 5-F installations throughout the world. The use of
straight -forward circuits which are easily adjusted and maintained, prevents loss of time, eliminates the necessity for buy
ing extra test equipment and simplifies tuning and maintenance. Some of the time proven circuit design features are:
The control console for the BTA-5F has been designed to provide a maximum of ease and efficiency in station operation.
Each major control function of the transmitter is at the engineer's fingertips, and important meters are placed within easy
viewing distance.
For the purpose of housing phasing components and monitoring, test, and audio equipments, extension cabinets may be
added to either or both ends of the BTA-5F.
Increasing Power to 10 KW
The BTA-5F may be easily and inexpensively changed over to a
standard RCA Type BTA-10F, 10 kw Transmitter by the installation of a 10 kw kit (MI -7267-A). The spare tube position of
the BTA-5F provides a socket for the additional required Type
892-R Tube. Sockets, completely wired, are provided for two
additional 828 modulator driver tubes. The MI.7267-A conversion kit includes a blower, filament transformers, 10 kw Modulation Transformer and Reactor, and all necessary accessories.
Mounting facilities have been provided for new components so
that conversion is rapid and easily made.
The BTA-5F is shipped with control console, 2 type TMV-129-B
crystal units, 2 complete sets of tubes, 1 installation material
kit, 1 touch-up kit and 2 instruction manuals.
98
AM TRANSMITTERS
Electrical Specifications
Mechanical Specifications
Carrier Frequency Range
540 to 1600 kc
Carrier Frequency Stability
±10 cps
Carrier Frequency Harmonics
below .05%
Carrier Power Output
5000/1000 watts
(40 to 350 ohms unbalanced load)
Carrier Shift
(50 to 7500 cps up to 100% mod.)-does not exceed 5%
Carrier Noise and Hum Level
(unweighted below 100% mod.)
60 db
Power Supply Requirements_208/230 volts, 6 cycles, 3 phase
capable of supplying loads up to 18 kw at 85% power
Dimensions
171%"
Overall Length
85%"
Overall Height
38%"
Enclosure Depth
Base 34" x 21", height 26"
Plate Transformer
Base 26" x 19%", height 23%"
Modulation Transformer
Base 60" x 34í/z", height 41í/z"
Console
wide 87" high
Building Entrance (minimum)
_89í/z"
Maximum Length of Single Unit
Weight
6000 lbs.
Transmitter Weight (net approx.)
992 lbs.
Modulation Transformer
735 lbs.
Plate Transformer
393 lbs.
Console
Stock Identification for Transmitter
factor and peak loads
with an instantaneous
average regulation not
30 watts at 115' volts,
A -c
-
_381/2"
up to 25 kw at 88% power factor
regulation not exceeding 3% and
exceeding 5%. Also approximately
60 cycle, single phase is required
Power Input
30% Modulation
5000 watts
17 5
10 8
1000 watts
100% Tone Modulation
5000 watts
1000 watts
Carrier Only
kw
kw
MI.11623
Transmitter Monitor and Amplifier Rack
MI.7485-F
Left Wing (Phasing Cabinet)
MI.7485-E
Right Wing (Audio Cabinet)
MI.7083-A
Set of Tubes for BTA-5F
MI -72674
10 kw Modification Kit (60 cycle)
-MI.7267-B
10 kw Modification Kit (50 cycle)
Set of Tubes for MI -7267 A/B Modification Kit_MI.19654
±1.5 db, 30 to 10,000 cps
Audio Frequency Response
Audio Input Level
+ 12.5 dbm'
5000 watts, 100% mod
1000 watts, 100% mod
+5.5 dbm'
Frequency
Distortion
Audio
not to exceed 3% rms
(0 to 95% mod. 50.7000 cps)
MI -7083-A
set)
Tube Complement (1
3 RCA -892-R
2 RCA -807
2 RCA -1620
5 RCA -828
10 RCA -8008
2 RCA -810
A.CA
.MI.7260-D
Accessories
215 kw
115 kw
16 5 kw
10 25 kw
5000 watts
1000 watts
_MI.7260-C
60 cycles
50 cycles
Conversion Kit
BPA-10 Antenna Tuning Equipment
(less Monitor)
(with Monitor)
50 Cycle
MI -7085-A
MI -28902-A
MI.28902-B
dbm = no. of db above one milliwatt when single frequency
tone modulation is used.
Oie
Simplified Schematic Diagram of BTASF Transmitter
with BPA-10 Antenna Tuner
99
AM TRANSMITTERS
Broadcast Transmitter Type BTA-10-F
Features
The BTA-10F Transmitter is equipped with an attractive, unified front panel finished in two-tone umber gray and light trim.
Extension cabinets are available for both ends for phasing
components and monitoring, test and audio equipment. This
compact design not only represents the ideal installation but
also permits transmitter houses to be planned for a complete
installation with minimum space requirements.
The BTA-10F is shipped with control console, 2 type TMV-129-B
Crystal Units, 2 complete sets of tubes (except only seven
892-R tubes are supplied), interconnecting wire kit, 1 touch-up
paint kit and 2 instruction manuals.
Low operating cost-long life tubes-high efficiency circuit.
Low installation cost-efficient layout-built-in wire channel.
Vertical chassis construction-utmost accessibility-tubes
easily removed.
Entirely air-cooled. Push button electric tuning.
Automatic reclosure without recycling on instantaneous
power drop -out.
Equipped with control console-centralized control system.
Power output may be reduced to 2 kw in emergencies by
operation of one switch.
Extension wing cabinets available for housing phasing,
monitoring, testing and audio equipments.
Tube hour meter.
Dry or oil filled transformer.
Specifications
Carrier
Carrier
Carrier
Carrier
Description
Frequency Range
Frequency Stability
Frequency Harmonics
Power Output
(40 to 250 ohms unbalanced load)
540 to 1600 kc
±10
cps
below .05%
10,000 watts
Carrier Shift
(50 to 7500 cps up to 100% mod.)-does not exceed 5%
Carrier Noise and Hum Level
60 db
(unweighted below 100% mod)
Power Supply Requirement____208/230 volts, 60 cycles, 3 phase
capable of supplying normal loads up to 26 kw at 89%
power factor and peak loads up to 40 kw at 91% power
factor with an instantaneous regulation not exceeding 3%
and average regulation not exceeding 5%. Also approximately 30 watts at 115 volts, 60 cycle, single phase is
required for the crystal heaters.
A -c Power Input
Average Program
26 kw
(equivalent to 30% sine wave modulation)
33 5 kw
100% Tone Modulation
24 kw
Carrier Only
+1.5 db 30 to 10,000 cycles
Audio Frequency Response
Audio Input Level (for 100% mod.)-approx. 12.5 dbm'
Audio Frequency Distortion
The Type BTA-10F provides a 10 kw transmitter which is outstanding in appearance, performance, and reliability. Fidelity,
distortion, and noise level are held to standards meeting the
highest requirements. Economy is assured by the use of extremely long life tubes, and the highly efficient high level system of modulation. The cost of operation per hour of this
10 kw equipment has been shown to be considerably less than
that of many 5 kw installations. Except for front panel appearance and construction the BTA-10F is similar to the type 10-E
Transmitter which it supercedes.
Basically this 10 kw Transmitter is similar to the Type BTA-5F
5 kw Transmitter. It differs in that it includes an additional
892-R tube with its associated filament transformers and blower
motor, a larger modulation transformer, a reactor and two
additional 828 modulator driver tubes. The conditions of operation of the tubes are the same, permitting similar performance
and the same long tube life which experience has proved to be
attained in the BTA-5F Transmitter. The fidelity of transmission and operating efficiency of the Type BTA-10F Transmitter
is exceptional. Its high level modulation system is identical to
that incorporated in the BTA-5F. The audio feedback circuit
is extremely stable and unaffected by adjustments of the radio
frequency circuits. Other exclusive circuit design features of
the BTA-10F will be found under the description of the type
BTA-5F Transmitter.
(0 to 95% mod., 50-7500 cps)
Tube Complement (one set)
2
7
2
*
100
RCA -807
RCA -828
RCA -8]0
not to exceed 3% rms
MI.7084-A
4 RCA -892-R
2 RCA -1620
10 RCA -8008
dbm = no. of db above one milliwatt when single frequency
tone modulation is used.
AM TRANSMITTERS
Mechanical Specifications
Overall Length
Overall Height
Enclosure Depth
Plate Transformer
Modulation Reactor
Modulation Transformer
Console
Building Entrance (minimum)
Maximum Length of Single Unit
Console
Stock Identification for Transmitter
60 cycles
50 cycles
171'/2"
85'/2"
38'/2"
Base 34" x 21", height 26"
Base 29'/2" x 24'/2", height 21"
Base 26" x 20", height 24'/2"
Base 60" x 34%", height 41'/2"
381/2"
Transmitter Monitor and Amplifier Rack
Left Wing (Phasing Cabinet)
Right Wing (Audio Cabinet)
Set of Tubes for 10-F
wide 50%" high
89'/2"
Kit-
Conversion
Conversion Kit
BPA-10 Antenna Tuning Equipment
(Less Monitor)
(With Monitor)
50 Cycle
60 Cycle
-
MI.7266-C
MI.7266-D
Accessories
Weight
Transmitter (net approx.)
Modulation Transformer
Modulation Reactor
735 lbs.
393 lbs.
Plate Transformer
Dimensions
6500 lbs.
1138 lbs.
1382 lbs.
Mí.11623
MI -7485-F
MI.7485-E
MI.7084-A
MI.7085-C
MI.7085-D
MI.28902-A
MI.28902-B
Front view with doors open showing interior construction.
BTA-1OF Transmitter with left and right wing extension cabinets.
-11111111
101
AM TRANSMITTERS
Transmitter Control Console MI -11616
Features
Description
All controls, switches and meters are mounted on three panels
which are assembled in the turret mounted on a metal desk.
Each panel is hinged at the bottom so that it may be opened
for easy servicing and the entire rear cover of the turret may
be removed to facilitate installation or basic changes. Desk
and turret are of metal construction throughout. The left hand
pedestal contains a typewriter shelf and the right pedestal contains two convenient drawers. A third drawer is located in the
center between the pedestals. A cylinder lock on this drawer
also locks the drawers in the pedestal. Skirts have been provided below the pedestals to conceal the wiring conduits and
all wiring is carried inside the desk. The desk top is covered
with black linoleum with rounded corners and metal trim.
Mechanically interlocked push-keys permit instant selection of
the circuit to be monitored by the vu meter or by the monitoring amplifier. By means of these keys, the monitoring speaker
may be used to check (1) transmitter audio input, (2) transmitter audio output, (3 and 4) two incoming lines and (5)
turntable output.
Balanced, high quality, step-by-step mixers are provided for
the (1) incoming line, (2) announce microphone and (3) turntable. A master or transmitter input control and a monitor
amplifier volume control are also furnished. Key switches in
the outputs of the microphone and turntable mixers are
equipped '.rith indicating lamps. The microphone key is interlocked with the monitoring speaker through a relay and disconnects the speaker whenever the microphone is on. A line
transfer key permits ready selection of two incoming lines and
transfers the telephone set to the line not being used for the
program. A three position key switch selects the studio line or
the local microphone and turntable. Chromium plated guards
prevent accidental operation of the important keys. A spare
Simplifies transmitter installation.
Major control functions are at engineer's fingertips and
important meters are within easy viewing distance.
Contains all required mixing and switching facilities.
Standardized vu meter plus extension modulation monitor
and antenna current indication.
All necessary controls for transmitter operations plus visual
indicating lamps.
Uses
The MI-11616 Transmitter Control Console is an attractive desk
type console containing all the mixing and switching facilities
required at the transmitter plant. It is equipped with a standardized vu meter, extension modulation monitor meter and
antenna current meters. Designed primarily for use with the
RCA BTA-5F and BTA-10F Broadcast Transmitter, it may be
combined with the MI-11623 Transmitter Monitor and Amplfier Rack to provide a most flexible and complete system of
control and monitors.
102
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Block Diagram MI -11616 Transmitter Control De.,k
D. P. D. T. lever key is furnished for the convenience of
Specifications
station personnel. The center panel contains a standardized
vu meter, with a step-by-step control making it possible to
read levels of +4 vu to +40 vu; a modulation meter intended
to operate as an extension for a type 66A modulation monitor
and an antenna current indicator consisting of a 0-50 ma,
d-c movement with a scale of 50 divisions calibrated linearly
from 0 to 10 amperes rf (other scales are available) and
intended to be connected into the rectified carrier circuit.
Cutouts are provided for two additional meters such as an
extension db compression meter for the limiting amplifier;
an extension meter from a frequency monitor or additional
antenna current indicators where required. The attenuator
controls are located below the meters on the center panel.
Input Impedances
Lines 1 and 2, Studio, Master and Monitor Controls -600 ohms
Telephone Set
600 ohms
Microphone and Turntables
950 ohms
Monitor-Transmitter in and out (Bridging) -20,000 ohms
Monitor-Lines 1 and 2
20,000 ohms
Output Impedances
Lines 1 and 2, Lever Key; Microphone and Turntable Mixer;
Studio, Master and Monitor Control
600 ohms
Microphone and Turntable Controls
250 ohms
±0.1 db
Frequency Response (30 to 15,000 cycles)
Insertion Losses
7 db
(microphone and turntable mixer circuit)
Noise Level: Circuits are isolated so that residual noise level
will not exceed the aggregate noise level of the associated
ampifiers.
A -c Power Input for Lamps and Relays
1 ampere, d -c power supply furnishes power to
the speaker interlocking relay and to the audio circuit indicating lamps. The power supply utilizes a copper sulphide
dry rectifier and capacity filter.
A 12 volt,
(105-125 volts, 50-60 cycles)
95 watts
overall_Width 60", depth 34%", height 411/2"
Note-Turret extends approximately 11" above desk top
Dimensions,
The power control switches are mounted on the left hand
panel and are designed for 230 volt operation. Associated
lamps are furnished and may be arranged for operation on
115 volt for audio power and 230 volt for transmitter power.
Switches and lamps are provided for (1) transmitter filaments,
(2) transmitter plate, (3) overload reset, (4) transmitter
highlow power transfer, (5) tower lights, (6) audio equipment and (7) spare.
Weight (unpacked)
Stock Identification
-
393 lbs.
MI -11616
Accessories
Transmitter Monitor and Amplifier Rack
Extension Meter for 86 -Al Amplifier
MI.11623
Stock No. 43504
5/1O KW Conversion Kits For RCA AM Transmitters
Moreover, this does not make the installation an orphan, for
with this change the former 5 KW transmitter becomes a
standard RCA 10 KW unit which is registered with the FCC
as such, and for which replacement parts can be readily
obtained.
MI.7303
5D to 10D Conversion Kir
MI.7303-A
5DX to 10DX Conversion Kir
MI -7267-A
5F to BTA-10F._
or
Any RCA 5 KW broadcast transmitter from type 5D to type
BTA-5F may be easily and inexpensively modified to a standard 10 KW RCA transmitter by installing a 5/10 KW conversion kit. The conversion kit includes a blower, filament
transformers, modulation transformer, reactor and all other
necessary accessories and instructions.
Conversion can be easily and rapidly accomplished without
loss of air time since only minor changes in the existing installation are required. The converted transmitter is efficient
and reliable and has quality equal to that of the original.
BTA-5F to BTA-10F
103
MI.7267-A
AM TRANSMITTERS
Broadcast Transmitter Type BTA-50F
Features
operation of components. Power input costs are kept to a
minimum by the use of high efficiency Class "C" r-f amplifier
and Class "B" modulator circuits.
Economical operation-lower power input.
Reliable performance-conservative employment of parts
and tubes.
Reduced floor space requirements-compact design.
The new type 9C22 tubes using single phase filaments are
utilized in the power amplifier and modulator positions. The
design of this tube permits more precise alignment of elements, smaller overall size, short filament and grid leads and
uniform heat dissipation. The well known RCA -857-B rectifier
tubes have been chosen for the BTA-50F because of their
exceptionally long life which has been proved by years of
actual operation in previous RCA transmitters. An automatic
regulator maintains constant filament voltages on all tubes and
high reactance type filament supply limits the starting current,
thus reducing filament stress.
Lower cost installation-built in wiring ducts.
Air cooled entirely-no water connections of any kind.
Simplified tuning and maintenance-single ended r-f circuits
from crystal to output.
Simplified power supply circuits-only
3
tube rectifiers.
Single phase filaments throughout.
Simplified, effective control circuit-high speed air circuit
breakers--console fault indication.
Push button motor tuning.
A simplified and straightforward control circuit provides complete protection to equipment and station personnel. Because
of their higher operating speed and ease of maintenance, air
circuit breakers of 600 volt rating are used in the power input
circuits. A reliable power station type reclosing relay will
Low distortion-non-critical feedback with cathode follower
driver for modulator.
High efficiency-Class "B" modulator-high level modulation.
Convenient console with audio and power controls.
Spare tube positions in power amplifier, modulator and
main rectifier.
reapply plate voltages immediately after an overload occurs,
but if the overload persists, the relay will reclose two additional times and will then lock out the plate voltage until the
reset is operated by hand. However, if a second overload does
not recur within 90 seconds, the reset function is automatic.
No fuses are used in the power feed circuits of the BTA-50F
Transmitter.
Minimum number of tube types.
Adaptable to single or dual floor layout.
Spare tubes are provided in the modulator, r-f power amplifier and high voltage rectifier units. Should a failure occur,
the wiring is arranged to permit a quick change of connections to the spare tube. A hydraulically operated tube jack
is furnished with the BTA-50F to facilitate the handling of the
large power tubes.
Description
The RCA Type BTA-50F is a 50 kw amplitude modulated,
high fidelity broadcast transmitter for operation in the band
of 540 to 1600 kilocycles. In its design, every consideration has
been given to the simplification of mechanical and circuit design
for ease in operation and maintenance and reduction of installation and operating costs to a minimum. Attractive panel
appearance has been achieved through the application of functional design principles.
Three single-phase, high -voltage plate transformers are used.
These transformers are connected delta -delta for normal operation but remotely operated circuit breakers are provided to
permit operation with a wye-delta connection giving low voltage
(16 kw output) for tuning and test purposes.
Low installation costs have been made possible by a single floor layout, built-in wiring ducts and the RCA "unified"
front. Low operating costs result from the use of high efficiency circuits, long -life, all air-cooled tubes and conservative
50/10 kw operation may be automatically accomplished by
installation of an MI.28905 power reduction kit.
104
AM TRANSMITTERS
-+
10 dbm ±2 db
Audio Input Level for 100% Sine Wave
(0 dbm = .001 watts in 600 ohm line)
150/600 ohms
Audio Input Impedance
Noise Level-rms
60 db below 100% modulation
Carrier Shift
Does not exceed 5%
70 db below carrier fundamental
R. F. Harmonics
measured at one mile
Tube Complement (one set)
1 RCA-5X5GT/G
2 RCA -807
4 RCA -9C22
1 RCA -89
7 RCA 828
1 RCA-5V4G
3 RCA -6C6
2 RCA -810
4 RCA -8008
2 RCA-5R4GY
1 RCA -892-R
6 RCA -857-B
1 RCA-5Y3GT/G
Power Consumption
110 kw at 87% P.F. without modulation
120 kw at 88% P.F. for 25% modulation
156 kw at 90% P.F. for 100% modulation
Power Supply Requirements
460 volte, 60 cycles, 3 phase,
3 wire, with 5% maximum combined regulation and variation. The equipment can be adapted for 50 cycle operation
by minor modification (MI.7037 Kit). A separate power
source of 115 volts, single phase, 30 watts, is required for
the crystal heaters.
Dimensions, overall
Transmitter Panel and Equipment Enclosures
33' long x 84%" high (allow depth of 9' to rear wall)
Plate Transformer (each)
27%" dia. x 563/" high
Modulation Transformer (incl. drain)
48t/a" x 56%" x 88%" high
Modulation Reactor
39%" x 43" x 90%" high
Filter Reactor
_293% x 37%a" x 56H" high
Switchgear Unit
44" x 48" x 90" high
Console
60" long x 341/" deep x 41%" high
Weight, total unpacked
43,000 lbs., approx.
Finish
Two tone umber grey
Stock Identification for Transmitter
MI.7050
A slow speed blower is utilized having a rated capacity of
10,500 c.f.m. at a static pressure of 2 inches at sea level. A
spare is provided and each blower is equipped with its own
three-phase motor and starter. An intake air filter is supplied
and consists of 12 permanent, non -corrosive filter units which
are easily cleaned.
The BTA-50F control console is similar to the MI.11616 Desk
described elsewhere in this catalog. It differs from the MI.11616
in that it contains switching circuits adapted to the BTA-50F
plus fault indicating lamps which are operated by the transmitter overload relays. All the audio mixing and switching
facilities required at the transmitter are provided in this console. It is equipped with a VU meter, an extension modulation
percentage meter, a "Time of Outage" clock and a "Duration
of Outage" clock.
Because the design requirements of such equipment usually
vary with each installation, transmission lines, antennas, transmission line terminating, antenna phasing or antenna tuning
equipment are not made a standard part of the BTA-50F Transmitter. RCA will be pleased to submit proposals covering such
equipment complete with tower lighting chokes, monitoring
equipment and other associated apparatus.
The BTA-50F is supplied complete with two crystals, two complete sets of tubes (less one RCA -9C22), antenna monitor and
remote meter, MI -11621 supervisory control desk, and 15 days
tune-up service.
Specifications
Radio Frequency Range._Any specific frequency in the band
from 540 kc to 1600 kc
Radio Frequency Power Output
53 kw at transmitter output terminals
Output Load Impedance
40 to 250 ohms, non -inductive, unbalanced
Radio Frequency Stability
±10 cycles
Audio Frequency Response-Within 1 db of the arithmetic
mean value of the two extremes of response
between 30 and 10,000 cycles
Audio Distortion_Less than 3% rms from 50 to 7500 cycles
at 90% modulation
TMv-1255
RCA-e0T
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NO.2
Accessories
Modification Kit for 50 Cycle BTA-50F
Antenna Tuner
Power Reduction Kit
TO
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DUFFER
DIME OPTION
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UNIT
MI-7037
MI.28903-A/B
MI -28905
SRIEECn
AMKIFIER
SPEECH
MARLINE.,
-
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MODULATOR
DRIVER
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AUDIO
REGULATED A.C.
411=131.1
Built
Antenna Phasing Equipment
RCA Custom
Features
Individual custom design provides an optimum circuit for
any array.
rotary coils, one for each radiator. This gives independent
amplitude control for each antenna and allows for a maximum
of flexibility in power division. When the network is adjusted
to parallel resonance, the input line from the transmitter may
be tapped in at the point of proper resistance.
Lower cost-no excess equipment included.
Quick delivery-components carried in stock.
Each phasing network consists of a "T-Network" with a 1:1
impedance transformation. The two series legs consist of rotary
coils, ganged, with a single front -of-panel control. For a fixed
shunt element, this allows phase variations from approximately
60° to 120° with no appreciable change of impedance transformation.
Economical installation-completely wired-supplied with
tuning instructions.
Monitoring rectifiers, lighting circuits, automatic switching
and electric tuning furnished, if desired.
Metering facilities may be expanded or minimized as
required.
The line terminating unit consists of a "T -Network" designed
with a phase angle as near 90° as possible consistent with
system phase and transmission line lengths, and with impedance -transformation ratio as required based upon the characteristic impedance of the transmission line and the caloulated
radiator operating impedances. Account is taken of negative
operating resistances by suitable system phasing. In the event
of operating resistance of very low values, approaching zero,
special recommendations may be made.
Enclosure cabinets available in several types to match appearance of transmitters.
Uses
Antenna Phasing Equipment is used to obtain and maintain
proper magnitude and phase relationship of currents fed to
the individual towers in a directional antenna array. To obtain a directional pattern each tower is supplied a certain
prescribed portion of the total power output from the transmitter. The power fed to each tower must be accurately controlled ae to magnitude and must radiate from each tower at
the correct instant of time relative to the power from each
other tower.
Faradon, polystyrene treated, mica capacitors are generally
supplied and are operated at approximately 50% of the nameplate rating. Polystyrene treated capacitors provide lower losses
than the wax treated type and are also more stable under high
temperatures sometimes encountered in unventilated antenna
tuner houses. Gas-filled capacitors, operated well within their
nameplate rating, are used where they become an economical
choice or when requested by the customer. In general, RCA
does not recommend the use of open, air-dielectric capacitors
due to their vulnerability to the accumulation of dust and
foreign matter, but in those cases where air capacitors are
specifically desired, they will be supplied.
Inductors consist of high-Q copper coils supported by low
loss ceramic insulation. In high current circuits, large coils
wound with copper tubing supported by mycalex and ceramic
insulation are used. All inductors are adjustable and normally
include ample inductance to allow for variations in the adjustment of an array not predicted by the design. Remotely -controlled, motor-driven variable inductors are supplied where
requested or required. All inductors are carefully chosen and
are operated well within their current rating and in no case is
excessive temperature rise permitted.
The r-f meters supplied employ expanded scales and have a
full scale range between 1.3 and 2 times the RMS carrier
value of the current being metered.
Facilities for remote control switching from directional to
non-directional operation, or from night-time to day-time patterns, are supplied if required. Other optional items are:
(1) Antenna monitoring rectifiers, (2) Circuit components for
isolating the tower lighting system, (3) Current sampling coils,
(4) Electric tuning, (5) Remote metering.
Directional arrays have become of considerable importance
in the broadcast band of frequencies The purpose has been
twofold. In some cases, the energy is directed into a desirable
or densely populated territory with a resulting decrease in the
energy sent out into thinly populated territory, waste land or
large bodies of water. The greatest use of the directive array
has been to prevent energy from going out in directions which
point toward the service areas of other stations on the same
or adjacent channels. The use of such arrays allows stations to
increase their power without increasing the amount of interference they cause to other stations.
Description
RCA has adopted the policy of custom -building antenna phasing equipment in accordance with individual design to meet
the particular requirements of the user. Experience has shown
this policy to be more economical and satisfactory than to
attempt to standardize on one elaborate design with sufficient
components to meet the requirements of a wide range of
powers, various numbers of towers and an almost infinite
combination of networks Such designs will inevitably have
excess equipment and must, therefore, be a compromise rather
than the optimum design. Several types of enclosures and
all circuit components are manufactured in quantities and are
available from stock, thus making possible a quick delivery
of an individual and economical design.
PHASING AND BRANCHING UNIT
It will be noted from the simplified schematic of a typical
directional array installation that, where possible, "T -Networks, having a lagging phase shift, are used in order to
take full advantage of their well known harmonic suppressing
qualities and relative ease of adjustment with a minimum number of components and maximum efficiency.
The dividing network consists of a parallel -resonant tank circuit having a KVA to KW ratio of approximately two. The
inductor is an adjustable unit shunted at various points, depending upon the power division, by front -panel controlled
Schematic of
106
a
basic 2 element array.
PHASING
Specifications
RCA antenna phasing equipment is custom built to the purchaser's specifications. RCA will assemble standard circuit
components and, where necessary, will specially build components to meet these specifications. The purchaser's specifications may be completely detailed or, if desired, RCA engineers
will submit overall and detailed layouts to meet the purchaser's
requirements of power division and current phasing.
Enclosures are available to match or install as an extension
wing of 5/10 and 50 KW transmitters. Lower power branching equipment may be mounted in cabinets styled the same
as RCA's new audio cabinet rack and FM transmitters. Economical out -door and/or wall mounted enclosures are also
available.
All RCA Custom Built Phasing Equipment is factory -assembled
and wired, and shipped in such state of assembly deemed suitable for domestic shipment. All components are clearly marked
and bus leads clearly tagged. Photographs of the equipment
prior to disassembly are supplied. Also supplied is a schematic
diagram and parts list together with recommended initial network adjustments based upon design calculations.
Unless otherwise specified, quotations for RCA phasing equipment include a dividing network, one line terminating unit
for each radiator, phasing networks in the quantity one less
than the total number of radiators, and all necessary meters.
Exterior view of a I KW phasing and branching equipment
in standard 84" cabinet
Interior view of a
1 KW phasing and
branching equipment
,--
-üruirlNflunnniu
----i
Exterior view of a I KW line terminating unit
in weatherproof cabinet
1
i
Interior view of a l KW line terminating unit with
relay switching and motor tuning
KW
One kilowatt phasing and branching equipment is usually supplied in an MI -7485.G cabinet. This cabinet has both front
and rear doors. The components are mounted on a sub -panel
behind the front door and controls of rotary coils are brought
out through the sub -panel. All controls are available behind
the front door. The rear door gives access to all components
and wiring. The MI.7485-G cabinet is 84" high, 31" wide and
31" deep overall.
The line terminating units are supplied in a weatherproof
metal box. The interior view shows a typical arrangement of
components for an installation having motor -driven rotary
coils and switching for day -night pattern changes. During the
manufacturing of the equipment, provision will be made for
entrance of coaxial transmission line or open wire type line,
depending upon the customer's preference. The line terminal
ing unit cabinet is 30" high, 22" wide and 16" deep.
107
PHASING
5 / 10 KW
The 5/10 KW phasing and branching equipment is available
in two cabinet styles, the MI.7485-F or the MI.28935-B. When
supplied in the MI -7485-F, the equipment is intended to form
a left-wing extension for the RCA BTA-5F or BTA-10F transmitter. This cabinet matches the transmitters both in appear
ance and quality of material and workmanship. The decorative
front panel is finished with a two-tone umber gray, rubbed
and waxed, with stainless steel trim and handles. An interlocked door in the left side of the cabinet allows operating
personnel to walk inside the cabinet for inspection of phasing
components. Meters for measuring branch line and main line
currents are mounted on a sub-panel behind the front door
and may be read through the glass panel in the door. Controls
for the phase and amplitude of the current in each tower are
mounted on the same sub -panel. Switches for controlling remote motor tuning of the line terminating units (where such
control is desired) may also be mounted on this panel. Rotary
coils used in the phase shift networks are so arranged that
one control operates the two coils in each network. The values
chosen provide a wide range of phase shift without affecting
impedance transformation. Rotary coils are also provided in
the power dividing network to assure flexible control of the
current amplitude in each tower. In the phase shift networks,
tapped inductors, to provide a wide range of adjustment, are
included in series with the capacitors in the shunt leg network. The input circuit of the phasing and branching equipment may be adjusted to match the impedance of the transmission line between the transmitter and phasing equipment.
The components used in this phasing and branching equipment are of the same high quality supplied in all RCA broadcast equipment. Components are conservatively rated and are
normally operated at approximately half their nameplate rating.
Typical, double section, standard, rack type cabinet, MI -28935-B
with stainless steel handles and trim. Necessary meters are
mounted on the meter panel over the front doors. All controls are brought out through a sub -panel behind the front
doors as described for the wing type cabinet. Interlocked,
double doors in the rear of the cabinet provide access to all
components for inspection. With installations involving unusual complexity, or those employing more than five towers.
it may be necessary to supply phasing and branching equipment in a three section cabinet of the same design as the
The MI.28935-B standard rack type cabinet installation is designed for those stations where it is desired or necessitated
by space requirements that the phasing and branching equipment be set apart from the transmitter. The two typical floor
plans illustrated below show, in one case, a typical transmitter room where the phasing equipment is housed in the
left wing extension cabinet, and in the other case, an application of the self-contained, standard rack type phasing cabinet. This cabinet is finished in two-tone umber gray lacquer
MODULATION
J
DOOR
one illustrated.
PLATE
PLATE
DOOR
TRANSFORMER
DOOR
MODULATION
TRANSFORMER
TRANSFORMER
TRANSFORMER
DOOR
TRANSMITTER
TRANSMITTER
AUDIO
PHASING
EQUIPMENT
EQUIPMENT
CONSOLE
CONSOLE
AUDIO
PHASING
EQUIPMENT
DOOR
EQUIPMENT
,
DOOR
t
ì
Typical floor plan where audio and phasing equipment is
housed in the separate standard rack type cabinets
Typical floor plan using left and right wing
extension cabinets
108
Interior rear view of a 5 KW phasing
and branching equipment housed in
MI.7485-F left wing extension cabinet
Exterior front view of a 5 KW phasing and branching equipment housed in
MI -7485-F left wing extension cabinet
The five kilowatt line terminating unit is supplied in a
weatherproof metal cabinet. The unit is designed for mounting on a wooden platform or steel angle cradle by means
of side flanges at the bottom of the housing Rear mounting
strips are also provided to permit wall mounting. The antenna
ammeter may be read through a circular window in the door
and is protected from lightning surges by a short circuiting
switch, which is operated by means of a knob extending
through the side of the house. The line terminating unit cabinet is 45" high, 35" wide and 24" deep.
Interior view of a 5 KW line terminating unit with relay switching and motor
tuning in wall mounting cabinet
Exterior view of a 5 KW line terminating unit
in wall mounting cabinet
109
PHASING
50 KW
The fifty KW phasing and branching equipment is supplied
in an MI-7485-J cabinet which may be used to provide a unified front left wing extension for an RCA BTA-50F transmitter.
The MI -7485-J cabinet is 84" high, 103" wide and 79" deep.
The line terminating unit for 50 KW equipment is designed
to be mounted in a tuner house at the base of the tower.
RCA does not supply the tuner house but does supply all
inductors, capacitors (gas or Faradon as required), meters,
meter panels, static drain choke, bowl insulators, lightning
gap, surge suppressor, wiring material, brackets and hardware.
Not included are the protective grill, interlocks, ground strap,
and light and telephone auxiliaries. The line terminating unit
will require approximately 70 square feet of floor space and
an 8 foot ceiling.
How to Order
RCA will be pleased to furnish a proposal on custom built
phasing equipment upon receipt of general requirements such
as (1) number, height, type, self and mutual impedances, and
spacing of towers, (2) phase and amplitude of current in each
tower, (3) type of enclosures to be used, (4) data on transmission lines, (5) relative location of transmitter house and
tower (a simple sketch with approximate dimensions), (6)
special requirements such as (a) automatic switching, (b)
front of panel phase control, (c) metering facilities and
(d) monitoring facilities. To facilitate the transmission of this
information, copies of an "Engineering Specification for Broadcast Antenna Phasing Equipment Form" are available at all
RCA Broadcast Sales Offices. Those interested in phasing equip.
ment are invited to communicate with their nearest RCA Sales
Interior view of a
Office for additional information.
50 KW
Exterior view of a 50 KW phasing and branching equipment
110
phasing and branching equipment
PHASING
Antenna Current Sampling Equipment
Pickup Loop MI -8217-C, Isolating Coil MI -7327-4, Sampling Coil MI -8217
Two general methods of obtaining samples of antenna current
for phase and amplitude monitoring are commonly used.
The first method employs an electrostatically shielded, resonant, pickup coil mounted adjacent to the antenna feed line
in the line terminating unit or tuner house. The tuned sampling
coil can be coupled at virtually any point along the radiator
or feed line in many installations and still pick up enough
votage to operate the current and phase indicators. Since the
tuned circuit is more sensitive than a non -resonant loop, care
must be taken to avoid pickup from adjacent towers or voltages induced by other inductors in the installation. Pickup
from an extraneous field will cause error in phase indication
and may also produce non-linearity in current indicators.
Mounting the pickup coil inside a metal shield through which
the feed line is run will generally produce satisfactory results.
The RCA MI -8217 remote metering and sampling coil kit supplies the pickup coil and also the thermo-milliammeter to be
mounted on the panel of the WM -30A phase monitor.
The second method of sampling antenna currents employs a
non-resonant loop mounted on the tower. This type installation
has the advantage that indicators are not usually influenced
by base currents if the loop is located up from the hase of
the tower. In the tower mounting loop type of installation,
the sampling line, which may be clamped to the tower, must
be brought across the tower base insulators. This may be accomplished by using the RCA MI -7327-4 isolation coil, which
is a %" concentric line formed into a high impedance coil at
broadcast frequencies. This coil, supplied with the necessary
insulators for mounting, is usually located within the tuner
house at the base of the tower. In some cases the sampling
lines can be spaced from the tower by high voltage insulators,
and brought across the base without an isolating network.
The RCA MI -8217-B remote metering and sampling loop kit
supplies the pickup loop, mounting insulators, and also the
necessary thermo-milliammeter to be mounted on the panel of
the WM30A phase monitor.
WM -30A Phase Monitor. Blanks in top of panel
are to provide for additional meters
Type WM -30A Phase Monitor
The RCA Type WM-30A phase monitor provides a simple
means of accurately measuring phase differences between currents in the various towers of an antenna array. It is particularly useful in checking the directional arrays to insure
proper phasing and hence proper field pattern. All phase
angles up to 360° at any frequency between 225 and 1800 KC
can be measured. The Type WM -30A can be used to adjust
the phase shifting networks, to measure impedances of arrays,
and to facilitate calculation of mutual impedances of antennas.
The RCA phase monitor can be used for remote indication
of both relative amplitude and phase of antenna currents in
arrays employing up to three elements. Used in conjunction
with the MI -8216-C remote meter panel, correct relationships
can be maintained between phase and magnitude of currents
in directional arrays having as many as six elements.
MI -8217-C
PICKUP LOOP
TO ANTENNA
TUNING EQUIPMENT
TO ANTENNA
TUNING EQUIPMENT
SHIELD
MI -7327-4
ISOLATING COIL
L
J
MI -8217
SAMPLING COIL
TO WM -30A
PHASE MONITOR
IN TRANSMITTER BUILDING
TO WM -30A
PHASE MONITOR
IN TRANSMITTER BUILDING
Typical installation of MI-8217-C Pickup Loop and
MI.7327-A Isolating Coil
Typical installation of MI -8217 Sampling Coil
111
ANT. ACCESSORIES
Radio Frequency Transmission Lines
Six Wire Open Line Accessories
Features
appropriate spacing between conductors, a characteristic impedance of 230 ohms is obtained which results in an economy
of phasing and terminating equipment.
Simplicity.
Low maintenance cost.
Open for constant inspection.
Requires no auxiliary apparatus (dehydrators, gas, etc.).
High power handling capacity at low cost.
Specifications
MI.19421 TRANSMISSION LINE BAYONET INSULATOR
This kit consists of a bracket designed for mounting station
post insulator and also supporting the four ground wires of
the 6 wire transmission line. It is designed to be mounted
on an MI.28013 or other suitable pole. Included are 1 bayonet
bracket, 1 insulator, 4 ground wire connectors.
Uses
The six wire open line is intended for transmission of RF
power from the transmitter to the antenna. The six wire line
may be used for either phased arrays or non -directional antennas. It is suitable for use at any standard broadcast frequency and is designed for use in all weather conditions.
MI -28010 TRANSMISSION LINE WIRE
Transmission line wire consisting of hard -drawn, stranded,
number 6 AWG copper wire may be ordered by the foot in
any convenient length.
Description
Open wire transmission lines when properly designed and constructed, provide high power handling capabilities at low cost.
The open wire line is reliable and may be serviced easily.
The various RCA transmission line kits simplify the installation of an efficient line suitable for RF powers up to 50 KW.
Radiation is made negligible by using a six wire line consisting of two central power conductors surrounded by four
grounded conductors. By use of this line configuration, with
MI -28011-A TRANSMISSION LINE LEAD-IN KIT
This kit provides lightning protection to transmitter or tuner
at the point where the transmission line enters the transmitter
or tuner house. Included are horn gap, station post insulator,
bracket for mounting insulator, anti -surge inductor, necessary copper tubing for ground and lead-in connections, all
necessary hardware.
112
ANT. ACCESSORIES
MI.28012-A TRANSMISSION LINE DEAD-END KIT
(USING POLE)
This kit includes all parts necessary to terminate a 6 wire
open line on a 4" steel pole. Wing type ground anchor and
guy wire for supporting the pole are also supplied. The pole
is not part of this MI. Included are two cross channels, 1
conductor plate, 4 turnbuckles for ground wires, 1 turnbuckle
for center conductors, 1 Clevis for eye bolts, 1 insulator, 1 guy
wire, 1 wing anchor, necessary clamps, hardware, etc.
MI -28012-B TRANSMISSION LINE DEAD-END KIT
(USING BUILDING)
This kit consists of all parts required to terminating open wire
line on the wall of the transmitter or tuner house. Included
are one connector plate, 4 turnbuckles for ground wires, 1
turnbuckle for center conductors, 1 Clevis, 1 line connector,
6 dead-end clamps, 1 line insulator, 4 servisleeves -A" x PA",
5 shoulder eye bolts.
Typical installation of MI28012-A Dead-end Kit
(using pole)
MI-28013 TRANSMISSION LINE POLE AND CAP
The transmission line pole is a 4 inch diameter steel pole
20 feet long. It is supplied complete with cap to close the
upper end and is suitably treated to render it corrosion resistant. It may be drilled at installation for use with either
the MI.28012-A pole dead-end kit or MI -19421 bayonet and
insulator.
MI-28014 TRANSMISSION LINE BAYONET ACCESSORIES
This kit consists of rack saddles and bolts necessary to mounting an MI -19421 bayonet and insulator on an MI -28013 pole.
Five feet of 080 diameter copper wire for use in wiring transmission line center conductors to the station post insulator is
also supplied.
MI.28015 LEAD-IN AND GROUND ACCESSORY KIT
This kit includes 1 plate drilled for mounting an MI.19413.1
entering insulator, 4 line termination clamps,
2 terminal lugs t/Z" x 2A".
Building dead-end installation using MI-2801I -A,
MI28012-B and MI-28015
1S
s
.I
r
MI -18421
'6
STRANDED
CONDUCTORS
SIN
RATONET ASSE
3111111
d
Iv. STEEL POL
RACK SADDLE
SAFETY GAP
VIEW
6 RETARD
T
PROM
RANSMITTER
TUNING HOUSE BUSKING
ALL SPANS
50
0
/BM
SUB
STATION GROUND
CONCRETE POLE
FOOTINGS
113
GROUND
LINE
45
AT
A-A
1
ground strap,
ANT. ACCESSORIES
1
KW Antenna Tuning Unit Type BPA-1A
Features
Specifications
Designed for carrier powers up to 1 kw.
Protective switch reduces damage to antenna ammeter from
static discharges.
Self extinguishing horn type gap protects equipment from
lightning.
Reliable operation-oversize capacitors and inductors.
Equipment housed in weatherproof metal box with hinged
door and lock.
Designed for quick installation of remote metering kit.
Input Impedance (unbalanced open wire or concentric line)
20-350 ohms
Output Matching-Will match any antenna having a reactance
of +j500 to -j500 and a resistance of from 25 to 1000 ohms
Lightning Protection
Horn type gap and meter
protective switch
Dimensions
30" x 22" x 16"
Weight (unpacked)
67 lbs.
Finish
Durable grey
Stock Identification
MI.28901-A
Uses
The Type BPA-1 Antenna
Tuning Unit serves to match
broadcast antennas to either
concentric or open wire .transmission lines and also aids in
suppressing carrier harmonics.
Accessories
Open Wire Line Entrance Insulator
Remote Metering Kit
MI-19406
MI.19404-B
Description
The BPA-1 consists essentially
of line terminating and antenna -tuning elements housed
in a weatherproof metal box.
Access to the interior and
component parts of the tuning unit may be had through
the front door which is provided with a lock, keys and
two pivoting clamps. An opening is provided in the bottom
of the housing for entrance
of a concentric tube transmission line, but the unit may also
be used with an open wire type of line by additioh of an
entering insulator, MI -19406. Provision has been made for
ready installation of Remote Metering Kit (MI -19404-B)
which will provide for remote indication of antenna current.
Electrically, the unit consists of a low-pass impedance -matching
filter using a "T" type network.
Remote Metering Kit MI -19404-B and Remote Ammeter MI -7157-D
The MI -19404-B Remote Metering Kit permits metering at the
transmitter of the current in a remotely located antenna. It
has been designed for use with the BPA-1A Antenna Tuning
Unit but it may be installed in similar tuners employed with
transmitters of 1000 watts or less; provided the rms voltage
between the external thermocouple and ground does not exceed 2000 volts.
The MI -19404-B kit contains an adjustable resistor, terminal
block, two by-pass capacitors, ground straps, miscellaneous
hardware and installation instruction sheet.
This kit is intended to be used with MI -7157-D Remote Ammeter which includes the necessary thermocouple.
The R.F. Ammeter and the variable resistor are to be mounted
in the transmitter house while the balance of the parts are
to be mounted in the antenna tuner housing.
The remote meter has a 150 ma. movement and is calibrated
for a resistance of 10 ohms between meter and thermocouple.
A coupling line of less than 10 ohms should be used and the
final calibration made with the adjustable 10 ohm resistor.
The remote meter is available in various ranges to match the
scale at the antenna ammeter. When ordering specify meter
scale and material of panel (steel, bakelite, etc.) on which
the remote meter is to be used.
Remote Ammeter MI.7157-D
Remote Metering Kit MI -19404.B
114
ANT. ACCESSORIES
5-10 KW Antenna Tuning Unit Type BPA-10
Features
Specifications
Designed for carrier powers of
5
Operating Limits
Carrier Frequency
540 to 1700 kc
Transmitting Power (maximum)
10 kw
Input Impedance
(unbalanced open wire or concentric line
40.350 ohms
Antenna Resistance (approximately)
20 to 1100 ohms
Antenna Reactance
+J500 to -J500
(can be extended in a positive direction by the addition
of a series capacitor; and in a negative direction if operating from a line of lower impedance than the antenna
resistance.)
Monitoring Rectifier
Output Impedance
(Balanced)
designed to operate into a 500 ohm line
Note: Load should be bridging with not less than 20,000
ohms d-c resistance.
Output Level to 500 ohm line
At 5-10 kw Output__
+17 dbm
At 1 kw Output
+11 dbm
Rectified Current
75 ma d -c maximum into a maximum of 1000 ohms
Audio Frequency Characteristic (50 to 10,000 cycles)_ ±2 db
Power Supply (230 volts, 60 cycles)
approx. 12 watts
Tube Complement (monitoring rectifier)
1 RCA 5V4G
Type Antenna Meter (scale range determined at time of installation)
Weston Model 425
Dimensions
Height
44"
Width
34"
Depth
23"
Weight (unpacked)
_330 lbs.
Finish
Durable grey
Stock Identification
(with MI.7488-A monitoring rectifier)
MI.28902-B
(less MI.7488-A monitoring rectifier)
MI.28902-A
and 10 kw.
Matches open wire or concentric transmission lines to antennas of widely divergent characteristics.
Built-in monitoring rectifier supplies rectified current for
remote antenna meter and furnishes audio voltage for program monitoring.
Uses
The Type BPA-10 Antenna
Tuning Unit serves the double
purpose of matching broadcast
antennas of widely divergent
characteistics to either concentric or open -wire transmission
lines and of suppressing carrier
harmonics.
Description
All parts of this equipment are
enclosed in a weatherproof
metal housing equipped at the front with a door affording
ready access to the interior. This door is provided with a lock.
The unit is designed for mounting on a wooden platform or
a steel angle cradle by means of side flanges at the bottom of
the housing. Rear mounting strips also are provided to permit
mounting the unit on two upright posts. The Antenna ammeter
may be read through a circular window in the door. This
meter is protected from lightning surges by a double-throw
switch, which is operated by means of a knob extending
through the side of the housing.
Accessories
The circuit of the BPA-10 essentially consists of a single "T"
section low pass filter which reduces the number of elements
to a minimum. The two series inductors of the "T" network
are employed to adjust independently the respective terminating impedances of the transmission line and the antenna circuit. The capacitive *hunt leg, which is common to the two
branches, is fixed at a value determined by the operating frequency of the station. Faradon capacitors are used and the
values of these capacitors are determined at the time of
installation.
Tube Kit (1 Type 5V4G)
MI -7321
1 Bowl Insulator (required for open wire lines) Ml 19913.1
"
A monitoring rectifier unit (MI -7488-A) is contained within
the housing to furnish, if desired, audio frequency voltage for
program monitoring and rectified carrier current for remote
antenna current indication and protective relay operation. Signal energy for operation of this rectifier is obtained from a
tuned pickup coil which is coupled to the antenna loading
inductor. This energy is rectified in a full wave circuit using
an RCA 5V4G tube and the outgut is balanced to ground for
excitation of a monitoring amplifier. For applications where
the MI.7488-A Monitoring Rectifier unit is not required the
Type BPA-10 Antenna Tuner may be purchased less the
rectifier by specifying MI.28902-A. Terminals are also provided for connection to a remote antenna ammeter and interlock relay located in the transmitter house.
The antenna lead-in insulator is located on the top of the
unit, and provision is made for mounting a similar insulator
(MI.19413-1 bowl insulator) on the left hand side of the
housing in case an open -wire line is used. A hole is provided
in the bottom of the cabinet for bringing in a concentric line.
When ordering specify:
1. Transmitter carrier power
2. Frequency
3. Antenna resistance and reactance
4. Transmission line impedance
dbm = db level above one milliwatt reference when single
frequency tone modulation is used.
eeeeuwm.aLL11niti"Ntumüuúl
ft
Interior view o/ BPA-10 with MI.7488A Monitor Rectifier
115
ANT. ACCESSORIES
50 KW Antenna Tuning Equipment Type BPA-50
CAR
ID
Features
/11=1113
00 NC
re AI
I.
MAO
»MO
SISTUR
Specifications
Matches open wire or concentric transmission lines to antennas of widely divergent characteristics.
Self extinguishing horn gap helps protect equipment from
lightning surges.
Oversize capacitors and inductors for reliable operation.
Static drain choke.
TUNER
Operating Limits:
Carrier Frequency
550-1700 kc
Transmitter Power (maximum)
50 kw
Input Impedance (unbalanced open wire or concentric line)
40 to 350 ohms
20 to 1100 ohms
Antenna Resistance (approximately)
+j500 to -j500
Antenna Reactance
(Can be extended in a positive direction by the addition
of a series capacitor; and in a negative direction if operating from a line of lower impedance than the antenna
resistance.)
Uses
The type BPA-50 antenna tuning equipment serves to match
broadcast antennas of widely divergent characteristics to either
concentric or open -wire transmission lines at powers up to
50 kw.
Description
MONITORING RECTIFIER
Output Impedance:
Designed to work into a 500 ohm line
(Balanced)
Note: Load should be bridging with not less than 20,000
ohms resistance.
Rectified Current:
75 ma d -c Maximum into a maximum of 1000 ohms
±2 db
Audio Frequency Characteristics (50.10,000 cycles
Approx. 12 watts
Power Supply (230 volts, 60 cycles)
1 RCA 5V4G
Tube Complement (monitoring rectifier)
Approximately 70 sq. ft. floor area
Space Requirements
with 10 ft. ceiling
500 lbs.
Net Weight (approx.)
Stock Identification:
MI-28903-A
For 230 Ohm Line
MI-28903-B
For 70/51.5 Ohm Line
The type BPA-50 antenna tuning equipment is designed to be
mounted in a tuner house at the base of the antenna tower.
The tuning equipment does not include the tuner house, but all
the necessary electrical components, brackets, wiring material
and hardware are supplied. Complete blueprints, diagrams and
instructions for assembly of the tuner are also included.
Essentially, the circuit of the BPA-50 consists of a single "T"
section low pass filter which reduces the number of elements
to a minimum and provides maximum harmonic suppression.
The two series inductors of the "T" network are employed to
adjust independently the respective terminating impedances
of the transmission line and the antenna. The capacitive shunt
leg, which is made up of Lapp variable gas capacitors, is set
to a value determined by the operating frequency of the station. Faradon capacitors are used when very large values of
capacitance are required.
A monitoring rectifier unit, MI.7488-A, may be purchased separately to furnish audio frequency voltage for program monitoring and rectified carrier current for remote antenna current indication and protective relay operation. A similar
monitoring rectifier, MI -7389, is supplied as standard equipment with the RCA type BTA-50F transmitter.
The antenna ammeter is protected from lightning surges by
a double -throw switch which cuts the meter out of the circuit.
Accessories
Extra Bowl Insulator
Monitoring Rectifier
Tube Kit (1 RCA 5V4G)
116
MI.19413.1
MI.7488-A
MI.7321
ANT. ACCESSORIES
Austin Tower Lighting Transformers
Features
Independent of frequency. No tuning adjustments.
No housing
required-eliminates leakage losses.
Trouble-free operation under all conditions.
Excellent regulation and efficiency.
Cost is comparable to other types of tower lighting units.
Uses
The Austin insulating transformer is a device for supplying
a -c power to the lighting circuits of an insulated or sectionalized radio tower. Being independent of frequency, the same
transformer may be used for any radio frequency and for a
wide range of transmitting power.
Description
The Austin insulating transformer provides the radio engineYr
with a means of supplying current to tower lighting circuits
which is more efficient, reliable and easier to install than other
types of tower lighting filters. The transformer consists of
ring type windings with a clear air gap between primary and
secondary rings. This type of construction makes the Austin
transformer independent of radio frequency and therefore it
requires no tuning or adjustment. Since the windings are fully
enclosed, no transformer housing is required, and the air gap
between primary and secondary rings eliminates the possibility
of surface leakage which may be appreciable in the housing
covering other types of tower lighting filters. The total capacity
added at the tower insulating zone is of the order of a very
few micro-microfarads which produces only a slight effect
upon the radio frequency circuit, and is constant under all
weather conditions.
Typical Installation of an Austin
Tower Lighting Transformer
Specifications
Primary Voltage
Installation is simplified since the Austin transformer requires
no housing, chokes or filters. The primary of the transformer
is usually attached to the base of the tower insulator or pier
supporting the insulator. The secondary is supported by a
conduit attached to the top of the insulator or to the tower
above the insulator. Protection from lightning surges may be
accomplished by installating an arc gap to by-pass static
Capacity:
Type A-2101-_Type A-1971
Primary Taps
Secondary Taps:
Type A-2101
Type A-7971
charges.
Austin tower
ing from 700
furnish extra
tower, or for
115/230
Secondary Voltage
Net Weight:
Type A-2101
Type A-1971--
lighting transformers are available in sizes rangwatts to 7 kw. The larger sizes may be used to
energy for lighting neon or other signs on the
115
1
to 1.75 K.V.A.
2 to 3 K.V.A.
2
None
10% over -voltage
85
201
Other sizes available up to 7 kw.
Detailed information will be furnished on request.
de-icing.
117
lbs.
lbs.
ANT. ACCESSORIES
Pyrex Entering Insulator MI -19413-1
For transmitter carrier powers up to and including 50 kw, this
insulator assembly is ideal for taking r -f leads into or out of
antenna tuner or phasing equipment.
The insulator has an 8%" diameter flange with six 1/2" mounting studs spaced equidistant on a 7%" bolt circle. The insulator
is approximately 6" high from the bottom of the lower flange
to the top of the center lead-in stud. The assembly is shipped
complete as shown with corona shield and a lead-in stud which
is %" in diameter and 81/2" long. The unpacked weight of the
howl assembly is 113/ lbs.
Steatite Entering Insulator MI -19406
This insulator is recommended for antenna tuner or phasing
equipment r -f lead-ins for carrier powers up to and including
1
kw.
The insulator flange is 51/4" in diameter and has a holt circle
diameter of 4%". The six equally spaced mounting bolt holes
are each 17/64" in diameter and the insulator is designed for
mounting in a 33/" hole. The lead-in stud is 1/2" in diameter
and is 6" long. The unpacked weight of the bowl assembly
is 2 lbs. 2 owl.
Antenna Lighting Choke Coil Type 92-A
Uses
In broadcast transmitter installations where the tower itself
forms the antenna, special transformers or radio frequency
choke coils must be employed to feed power to the lighting
circuits on the tower. Type 92-A antenna lighting choke coil
has been designed for this purpose. Its electrical characteristics
are such that it presents a low impedance to commercial lighting frequency and a high impedance to the radio frequency in
the broadcast range. It, therefore, provides a means for supplying energy to the tower lighting circuits and at the same time
prevents any appreciable loss of r-f energy supplied to the
tower by the radio transmitter.
Length
Diameter
Weight Unpacked
Stock Identification
Accessories:
1.5 KVA Isolation Transformer
Capacitors .01 MFD
Description
The coil consists of a double winding on a bakelite form. The
windings are coated with an insulating varnish which binds
the turns together and prevents moisture absorption. This coil,
however, must be protected from the weather by installing it
within some weatherproof enclosure. Such an enclosure or
housing is not provided with the unit. The natural resonant
frequency of the coil is well removed from any frequency
within the broadcast band. Its characteristics, therefore, are
such that it presents a relatively high impedance in the order
of several hundred ohms to all broadcast frequencies. All
windings that are not directly connected to the tower or
ground should he properly bypassed by suitable capacitors as
illustrated.
Specifications
Isolation Circuit
(Single Choke)
with MI-7014 Isolation
Transformer
18 amperes
Maximum Continuous Current (50/60 cycles)
Approx. 1.1 ohms
D -c Resistance (total both windings)
520 microhenries
Inductance -60 Cycles
800 microhenries
1000 KC
118
331/2"
4"
91/ lbs.
MI.7112
MI.7012
UC3006
FM
TRANSMITTING
EQUIPMENT
Page
FM TRANSMITTERS
120
FM ANTENNAS
138
M
Making adjustments on the three kilowatt FM transmitter, Type BTF3B, at KSCJ-FM, Sioux City, Iowa.
Three kilowatt FM transmitter, Type BTF-3B, as viewed
from studio B, at WATG-FM, Ashland, Ohio.
i
e
Adjusting line voltage or_ the tl-ree 1ilewatt
FM transmitter, Type 9T. 38, a: WG?A-FM,
BethleF,em. Pa.
9n
kilowatt FM transmitter, Type BTF-1C, as installed
at radio station WBRE-FM, Wilkes-Barre, Pa.
FM TRANSMITTERS
FM Broadcast
Transmitter Ty pe BTF-250A
Features
Incorporates RCA's new "Direct FM" system which requires
fewer and less expensive tubes and parts, assures low distortion and less adjustment.
Uniquely designed frequency control circuit provides crystal control precision.
Excellent frequency response
Low
±1
distortion-less than 1.5%,
db 30 to 15,000 cps.
30 to 15,000 cps.
Single ended r-f circuits throughout-easy to tune.
Simplified controls with complete circuit protection.
Equipment protected against transmission line or antenna
failures.
Multi -unit construction permits easy addition of higher
powered units.
Vertical chassis construction --front and rear door accessibility.
Inexpensive tube complement.
Cabinets with similar styling available for Musing audio,
monitoring, and test equipment.
Completely self-contained.
Description
The new BTF-250A FM Transmitter incorporates all the latest
engineering advances and many desirable basic features. Attractively housed in a single standardized cabinet, this compact
unit will provide a maximum of 250 watts output at any
specified frequency between 88 and 108 mc. Installation is
simple and economical. Future power increases are easily made
by adding one or more power amplifiers and power control
units housed in matching cabinets. Accessibility is assured by
vertical chassis construction plus surface mounting of components and exposed wiring for easy and speedy circuit tracing
and servicing.
The exciter unit of the BTF-250A contains RCA's newly developed "Direct FM" modulator circuits plus a new frequency
control circuit of unique design. Fewer circuits and fewer
components are used in this new exciter than in previous designs. Only 16 inexpensive tubes are used (about half as many
as in some exciters) with only six tubes in the r-f chain. All
components are mounted on a single vertical panel and are
easily accessible. The exciter power supply is on a separate
chassis.
Tube costs have been kept low by using sturdy receiver type
tubes in the FM exciter and high efficiency circuits plus inexpensive low power transmitting tubes in the r-f amplifiers.
The same tube type is employed in several stages thus reducing
spare tube requirements.
All power circuits are protected by magnetically -tripped circuit breaker type switches. A transmission line monitor which acts
as watchman over the antenna and transmission line system
is provided. Any unwarranted change in the signal intensity
such as might result from an arc in the transmission line, or
a fault in the antenna itself, actuates this monitor and shuts
down the transmitter. An interlocking control circuit prevents
the application of plate power until the rectifier filaments
have reached operating temperature. Filament voltage is eon -
Frequency modulation is accomplished directly by push-pull
reactance tubes connected across the frequency -determining circuit of the modulated oscillator. This "direct modulation"
process eliminates numerous multiplier and converter stages
with a resulting lower noise and distortion level.
Simplified single-ended amplifiers operating Class "C" and
comprising a minimum of variable elements form the r -f section of the BTF-250A.
122
FM TRANSMITTERS
trolled by tapped transformers and a common filament rheostat.
Door interlocks are provided, where required, for the safety of
operating personnel. In addition, high voltage compartments
are equipped with mechanically operated grounding bars which
are automatically released when the doors are opened.
The entire transmitter is housed in a single fabricated steel
cabinet which is bolted to a base frame. This cabinet is
equipped with both front and rear doors which are provided
with observation windows. End shields and a meter panel complete the cabinet-type enclosure which has been styled functionally and presents a pleasing appearance. A filtered air
supply for the cabinet is supplied through the air inlet opening, and a removable filter is provided in the base frame.
An exhaust fan in the roof expels the warm air.
The BTF-250A is shipped complete with two crystals, two sets
of tubes and transmission line monitor.
Power Supply Requirements________208/230 volts, 50 or 60 cycles
single phase, capable of supplying approximately 1200 watts
at 85% power factor, and 5% maximum regulation and
variation. Also approximately 30 watts at 115 volts, 50/60
cycles single phase, is required for the crystal heaters.
TUBE COMPLEMENT
4 RCA 6V6
4 RCA 1614
1 RCA 6SH7
4 RCA 5U4G
2 RCA 0D3/VR150
1 RCA 0C3/VR105
1 RCA 6AL5
Specifications
Frequency Range
Any specified frequency between
88 and 108 mc.
Power Output (into transmission line)
50 to 250 watts
R -f Output Impedance (SWR 1.75 or less)
35 to 90 ohms
Carrier Frequency Stability, deviation less than-±1000 cycles
Modulation Capability
±100 kc.
Method of Modulation
Reactance-tubes
Audio Input -Impedance
150/600 ohms
+10 ±2 dbm
100% Modulation Level
Audio Frequency Responses
±1 db
30 to 15,000 Cycles, 1000 Cycle Reference, within
1
3
2
I
RCA
RCA
RCA
RCA
RCA
RCA
2E26
6AC7
2BP1
4.125A /4D21
866A/866
2D21
Dimensions in Inches
Overall Width
Overall Height
Overall Depth
Maximum Crate Size
98" x 30" x 84"
Weight in Pounds (unpacked-assembled)
1025
31"
84"
31*"
Maximum Ambient Temperature
Finish
(approx.)
45° C.
Two-tone umber gray with brushed chrome
trim and fitting
Stock Identification
MI -28911
Accessories
Set of Tubes for BTF-250A
250 watt to 1 kw Conversion Kit
Set of Tubes for above Conversion Kit
Audio Frequency Distortion2
30-15,000 cycles
Less than 1% rms
Including all harmonics up to 30 kc/s at 75 kc swing
FM Noise Level, below 75 kc. swing
-65 db.
AM Noise Level, below 100% amplitude modulation2 --50 db.
1
2
5
Mí.28156
MI -28919
MI.28160
For pre-emphasized response the pre -emphasis filter (MI.4926A)
is provided to be inserted in the 600 ohm audio input line.
2 Distortion and noise are measured following a standard deemphasis network.
s
4-125A/4021
2
4.125A/4021
POWER AUPLIFIER
DOUBLER
OR
1
FM EXCITER
M1-7016
1
to. ..1
LOW
VOLTAGE
RECTIFIER
OA AURG
Simplified Schematic of BTF.25°A
123
.101-1
RECtIAJER
2
RCA
866A
AAA
FM TRANSMITTERS
FM Broadcast
Transmitter Type
BTF-IC
Features
Incorporates RCA's new "Direct FM" system which requires
fewer and less expensive tubes and parts, assures low distortion and less adjustment.
Uniquely designed frequency control circuit provides crystal control precision.
Excellent frequency response
±1
db 30 to 15,000 cps.
Grounded grid amplifiers reduce overall transmitter and
tube costs, reduce installation and maintenance costs and
insure stable operation.
Single -ended r-f circuits throughout.
Simplified controls with complete circuit protection.
Minimum of different tube types.
Equipment protected against transmission line or antenna
failures.
Multi -unit construction permits easy addition of higher
powered units.
Vertical chassis construction-front and rear door accessbility.
Cabinets with similar styling available for housing audio,
monitoring and test equipment or spare exciter.
Completely self-contained-no external units.
Description
Attractively housed in two compact standardized cabinets, the
new BTF-1C FM transmitter will provide 1000 watts output at
any specified frequency between 88 and 108 mc. Initial installation is simple and economical. Conversion to 3 kw or
10 kw operation is quickly and inexpensively made by the
addition of one grounded -grid amplifier unit and a power and
control unit housed in matching cabinets.
Variable output coupling, provided by front panel control,
varies the output into the antenna transmission line from 250
to 1000 watts. Power circuits are protected by magneticallytripped circuit -breaker type switches and overload relays. A
transmission line monitor which acts as a watchman over the
antenna and transmission line system is provided. Any change
in transmission line characteristic which might result from an
arc in the transmission line, or a fault in the antenna itself,
actuates this monitor and shuts down the transmitter. An
interlocking control circuit prevents the application of plate
power until the rectifier filaments have reached operating temperature. Filament voltage is controlled by tapped transformers and a common filament rheostat. The 7C24 tube has a
separate filament rheostat control. Means are provided for reducing the plate voltage for tuning purposes. Door interlocks
are provided, where required, for the safety of operating personnel. High voltage compartments are equipped with mechanically operated grounding bars which are automatically released when a compartment door is opened.
The exciter unit of the BTF-1C contains RCA's newly developed "Direct FM" modulator circuits plus a new frequency
control circuit of unique design. Fewer circuits and fewer
components are used in this new exciter than in previous designs. Only 16 inexpensive tubes are used (about half as many
as in some exciters) with only six tubes in the r-f chain. All
components are mounted on a single vertical panel and are
easily accessible. The exciter power supply is on a separate
chassis.
Frequency modulation is accomplished directly by push pull
reactance tubes connected across the frequency -determining circuit of the modulated oscillator. This "direct modulation"
process eliminates numerous multiplier and converter stages
with a resulting lower noise and distortion level.
Simplified single ended amplifiers, operating class "C" and
comprising a minimum number of variable elements, form the
r-f section of the BTF-1C. The same type tube is employed in
several stages-an important item when considering spare tube
needs. The final stage using a 7C24 tube is operated grounded grid thus reducing tube, installation and maintenance costs and
insuring stable operation. All tubes are air cooled.
Multi -unit construction is employed in the BTF-1C and the
entire transmitter is housed in two fabricated steel frames
which are bolted to a base frame. Each compartment is
equipped with both a front and rear door. These doors are
124
FM TRANSMITTERS
provided with windows for observation of the interior of the
transmitter while in operation. End shields and meter panels
complete the cabinet -type enclosure which has been styled
functionally, and presents a pleasing and dignified appearance.
A filtered air supply for each compartment is supplied through
individual air inlet openings and removable filter sections provided in the base frame. The warm air is exhausted through
the roof. For ease in shipment and installation the equipment
is partially disassembled. The transmitter is furnished with one
k 31
exciter. A second exciter unit plus a transfer panel
mounted in a separate cabinet are available as optional equipment. With dual exciters, instantaneous transfer of operation
froul one unit to the other is accomplished by the flick of a
Power Supply Requirements -208/230 volts, 50 or 60 cycles
single phase, capable of supplying approximately 3700 watts
at 89% power factor, and 5% maximum regulation and
variation. Also approximately 30 watts at 115 volts, 50 or
60 cycles single phase is required for the crystal heaters.
switch.
Dimensions in Inches
Overall Width
56 3/32"
31,I, "
Overall Depth (including door handles)
Overall Height
84"
Maximum Crate Size
98" x 30" x 84"
Weight in Pounds (unpacked-assembled)_1900 (approx.)
Maximum Ambient Temperature45° C.
Finish
Two-tone umber gray with brushed chrome trim
Tube Complement
4 RCA 6V6
4 RCA 1614
1
2
1
1
Specifications
Frequency flange
Any specified frequency between
88 and 108 me
950 to 1000 watts
Power Oultlut (into transmission line)
35
Carrier Frequency Stability, deviation less
Modulation Capability
Method of Modulation
Audio Input-Immpedance_100% Modulation Level
RCA 6SH7
1
3
RCA 0D3/VR150
RCA 0C3/VR105
RCA 6AL5
4
1
1
RCA
RCA
RCA
RCA
RCA
RCA
RCA
2E26
6AC7
2BP1
4-125A/4D21
8008
7C24
2D21
Stock Identification-
to 90 ohms
-
MI -28912
than-±1000 cycles
±100 kc
Accessories
Reactance-tubes
150/600 ohms
+10 ± 2 dbm
(O dbm = 1 milliwatt)
Set of Tubes for BTF1C
1 kw to 3 kw Conversion Kit
Set of Tubes for Above Kit
1 kw to 10 kw Conversion Kit
Set of Tubes for Above Kit
Audio Frequency Responses
30 to 15,000 Cycles, 1,000 Cycle Reference, within ± 1 db
Audio Frequency Distortion'
30.15,000 Cycles
Less than 1% rms
(Including all harmonics up to 30 kc/s at ±75 kc swing.)
FM Noise Level, below ±75 kc swing2
-65 db
AM Noise Level, below 100% amplitude modulation
--50 db
1
5
4 RCA 5U4G
The BTF-1C is furnished with two crystals, two sets of tubes,
interconnection wire kit, harmonic filter, and transmission line
monitor.
R -f Output Impedance
2
4-12SA/4021
DOUBLER
2
4-12!
1
2
Mí.28161
MI-28921
MI -28162
For pre-emphasized response the pre-emphasis filter (MI -4926A)
is provided to be inserted in the 600 ohm audio input line.
Distortion and noise is measured following a standard de
emphasis network.
/4021
1°[44C2
Nr210113,1r2 IOWA 4YIurIC11
10ViEE
uw.Inu
o
j
FM EXCITER
MI -7016
1
o
1[2-,21
MI -28157
MI-28920
t.1
1.2 2.1
LOW
VOLTAGE
HIGH
CIVIC
12A..
TA611
W[CTIIICR
R[A EOOE
Simplified Schematic of BTF1C
125
FLIER
FM TRANSMITTERS
FM Broadcast
Transmitter Type BTF-3B
Gliii
ar
111111911113
111
Features
Incorporates RCA's new "Direct FM" system which requires
fewer tubes and parts, assures low distortion and needs
less adjusting.
Accessibility is assured by vertical chassis construction plus
-airfare mounting of components and exposed wiring for easy
and speedy circuit tracing and servicing.
The exciter unit of the BTF-3B contains RCA's newly developed "Direct FM" modulator circuits plus a new frequency
control circuit of unique design. Fewer circuits and fewer
components are used in this new exciter than in previous designs. All components are mounted on a single vertical panel
and are easily accessible.
Frequency modulation is accomplished directly by push-pull
reactance tubes connected across the frequency determining
circuit of the modulated oscillator. This "direct -modulation"
process eliminates numerous multiplier and converter stages
with a resulting lower noise and distortion level.
Simplified single -ended amplifiers operating class "C" and
comprising a minimum number of variable elements form the
r -f section of the BTF-3B. The number of tubes has been reduced to a minimum. The same type tube is used in several
stages thus greatly reducing spare tube requirements. High
stability grounded grid circuits using RCA type 7C24 tubes
are employed in the last two stages.
Uniquely designed_frequency control circuit provides crystal control precision.
Excellent frequency response ±1 db 30 to 15,000 cycles.
Grounded grid amplifiers reduce overall transmitter and
tube costs, reduce installation and maintenance costs and
insure stable operation.
Single -ended r -f circuits throughout.
Simplified controls with complete circuit protection.
Minimum of different tube types.
Equipment protected against transmission line or antenna
failures.
Automatic recycling in case of momentary overload.
Fixed -tuned harmonic attenuator.
Multi -unit construction permits easy addition of higher
powered units.
Vertical chassis construction-front and rear door accessbility.
Space provided for spare exciter.
Cabinets with similar styling available for housing audio,
monitoring, and test equipment.
Completely self contained-no external units.
variable output coupling provided by front panel control
permits adjusting the power output to the antenna transmission line over a range from 1000 to 3000 watts. A fixed -tuned
harmonic attenuator (externally mounted) designed to reduce
all harmonics 30 db or better is located in the output circuit
and is provided as standard equipment. Filament voltage, except for the 7C24 tube, is controlled by tapped transformers
and a common filament rheostat. The 7C24 tubes have separate
filament rheostat controls.
The entire transmitter is housed in three fabricated steel frames
which are bolted to a base frame. Each compartment has
both front and rear doors which are provided with observation windows. End shields and meter panels complete the
A
Description
The BTF-3B FM transmitter will provide a maximum of 3000
watts output at any specified frequency between 88 and 108 mc.
Attractively housed in three standardized cabinets, this compact unit is easily and economically installed. Power increases
can be made by the addition of a grounded grid rf amplifier,
a power unit and a control unit housed in matching cabinets.
I
2
FM TRANSMITTERS
cabinet type enclosure which has been styled functionally
to present a pleasing and dignified appearance. Filtered air,
supplied through individual air inlet openings and removable
filters are provided in the base frame. Warm air is expelled
through the roof.
A transmission line monitor externally mounted which acts as
watchman over the antenna and transmission line system is
provided. Any unwarranted change in the signal intensity such
as might result from an arc in the transmission line or a fault
in the antenna itself, actuates this monitor which shuts down
the transmitter. Both manual and automatic sequence starting
are provided. When in the automatic position, a three shot
recycling sequence is provided by the control "brain center"
which automatically returns the transmitter to the air up to
three times in case of repeated overloads and then if such overload condition persists the transmitter is automatically shut
down. All high power circuits are doubly protected by highspeed overload relays backed up by magnetic-trip circuit breaker type switches. Door interlocks are provided, where required, for the safety of the operating personnel. High voltage
components are equipped with mechanically operated grounding bars which are automatically released when a door is
opened.
Audio Frequency Distortion2
30.15,000 Cycles
Less than 1% rms
(Including all harmonics up to 30 kc/s at 75 kc swing.)
FM Noise Level, below 75 kc swing2
-65 db
AM Noise Level, below 100% amplitude modulation2 -50 db
Power Supply Requirements--208/230 volts, 50 or 60 cycles
three phase, capable of supplying approximately 8600 watts
at 88% power factor, and 5% maximum regulation and
variation. Also approximately 30 watts at 115 volts, 50/60
cycles single phase is required for the crystal heaters.
Tube Complement
4 RCA 6V6
4 RCA 1614
1
4
2
1
1
Specifications
-Any
specified frequency between
88 and 108 me
Power Output (into transmission line)
1000 to 3000 watts
R -f Output Impedance
35 to 75 ohms
Carrier Frequency Stability-Deviation less than ±1000 cycles
Modulation Capability
-100 kc
Method of Modulation
Reactance -tubes
Audio Input-Impedance
150/600 ohms
100% Modulation Level
+ 10 ±2 dbm
Audio Frequency Responses
30 to 15,000 Cycles, 1000 Cycle Reference, within_±1 db
ies./.uzi
1
3
2
6
1
RCA
RCA
RCA
RCA
RCA
RCA
RCA
2E26
6AC7
2BP1
4-125A/4D21
7C24
8008
2D21
Accessories
Set of Tubes for BTF-3B
3 to 10 kw Conversion Kit
Set of Tubes for Above Kit
Spare FM Exciter Kit
Set of Tubes for Spare Exciter
MI -28158
MI-28922
MI-28163
MI-7015
MI.7020
For pre -emphasized response the pre -emphasis filter(MI.4926A)
is provided to be inserted in the 600 ohm audio input line.
2 Distortion and noise is measured following a standard de emphasis network.
I
4-l15./.0:1
.l..
wmmx .w....
rua-
/M fxCITCR
N11-7 016
fM[x70
2
5
6SH7
5U4G
0D3/VR150
0C3/VR105
6AL5
Dimensions in Inches
Overall Width
81iß"
Overall Height
84"
Overall Depth (including door handles)
31AE"
Maximum Crate Size
28" x 30" x 84"
Weight in Pounds (unpacked-assembled)__2900 (approx.)
Maximum Ambient Temperature
45° C.
Finish
Two-tone umber gray with brushed chrome trim
Stock Identification
MI -28913
The transmitter is furnished with one FM exciter. A second
exciter plus a transfer panel are available as optional equipment. Instantaneous transfer of operation from one exciter to
the other is accomplished by the flick of a switch.
The BTF-3B is furnished with one exciter, two sets of tubes,
two crystals, interconnection wire kit, harmonic filter, and
transmission line monitor. An interconnection wiring kit is
furnished with each transmitter.
Frequency Range
RCA
RCA
RCA
RCA
RCA
SR
111J
RCA
0411
Simplified Schematic of BTF3B
127
/WM Mino
FM TRANSMITTERS
FM Broadcast
El
Mil
13
Transmitter Type
® ®
1'111®
3
2
i
e
Description
Features
The RCA BTF-10B is a new frequency modulated transmitter
designed to supply up to 10,000 watts of power at any specified
frequency in the 88 to 108 me. band. Incorporating the latest
developments in FM transmitter design, the BTF-10B is outstanding in performance and reliability. Compact and simplified mechanical construction plus attractive cabinet styling
make for an economical installation with dignified appearance. The entire transmitter is housed in five fabricated steel
frames which are bolted to a base frame. Each compartment
has both front and rear doors with observation windows.
Accessibility is assured by vertical chassis construction, surface mounting of components and exposed wiring for speedy
circuit tracing.
The exciter unit of the BTF-10B contains RCA's newly developed "Direct FM" modulator circuits plus a new frequency
control circuit of unique design. Frequency modulation is accomplished directly by push-pull reactance tubes connected
across the frequency determining circuit of the modulated
oscillator. This "direct modulation" process eliminates numerous multipler and converter stages with resulting lower noise
and distortion level.
Incorporates RCA's new "Direct FM" system.
Uniquely designed frequency control circuit provides crystal control stability.
Excellent frequency response
BTF-1OB
-f--1
db, 30 to 15,000 cycles.
Grounded -grid amplifiers reduce overall transmitter, tube
and maintenance costs.
Simplified controls with motor driven tuning for high -power
stages.
Equipment protected against transmission line or antenna
failure.
Instant carrier return after momentary power failure.
Fixed -tuned harmonic attenuator.
Simplified single-ended ampifiers operating class "C" and
using a minimum number of variable elements form the RF
section of the BTF-10B. High stability grounded -grid circuits
are employed in the last three stages using RCA type 7C24
tubes. This use of the same type tube in several stages results
in greatly reduced spare tube requirements.
Compact multi -unit construction. Reduced floor space requirements.
Space provided for spare exciter unit.
variable output coupling with front panel control permits
adjusting the power output into the transmission line over a
range from 3,000 to 10,000 watts. Harmonic radiation is held
to a minimum by a fixed -tuned harmonic attenuator which is
located in the output circuit and is provided as standard
equipment.
A
Vertical chassis construction-front and rear door accessibility.
Cabinets with similar styling available for housing audio,
monitoring and test equipment.
128
FM TRANSMITTERS
±10 ± 2 dbm
Audio Frequency Response** 30 to 15,000 cycles
±1 db
Audio Frequency Distortion*** 30 to 15,000 cycles (including
all harmonics up to 30 kc/s at ±75 kc swing)
Less than 1%
FM Noise Level, below 75 kc swing* * *
Not more than -65 db
AM Noise Level, below 100% amplitude modulation***
Not more than -50 db
Power Line Requirements-Transmitter:
908/230 volts
Line Voltage
3
Phase
60 cycles
Frequency
(50 cycles equipment available at slightly higher cost)
5%
Instantaneous Regulation and Variation
22 5 kw
Power Consumption (approx.)
90%
Power Factor (approx)
Tube Complement:
4 RCA 6V6
2 RCA 2E26
4 RCA 1614
5 RCA 6AC7
1 RCA 6SH7
1 RCA 2BP1
4 RCA 5U4G
3 RCA 4.125A/4D21
2 RCA OD3/VR150
4 RCA 7C24
1 RCA 0C3/VR105
6 RCA 673
1 RCA 6AL5
1 RCA 2D21
Dimensions:
Overall Length
1313/a"
Overall Height
84"
Overall Depth
31-h"
Building Entrance Requirements
95" x 80"
Weight in Pounds (unpacked-assembled)__. .5000 (approx.)
Maximum Ambient Temperature
45° C.
Finish
Two tone umber gray with brushed chrome
trim and fittings
An externally mounted transmission line monitor acts as a
watchman over the antenna and transmission line system. Any
unwarranted change in standing wave ratio, such as might
result from an arc in the transmission line, or a fault in the
antenna itself, actuates this monitor which removes plate
voltage from the transmitter to prevent damage. A three -shot
recycling sequence is provided by the control "brain center"
which automatically returns the transmitter to the air up to
three times in the case of repeated overloads, and then, if
such overload persists, shuts the transmitter down. A reset
switch is provided which may be used to restore the transmitter to normal after one, two or three overloads. This
switch can be set to lock out the recycling circuit.
100% Modulation Level*
All high power circuits are doubly protected by high speed
overload relays backed up by magnetic -trip circuit -breaker type
switches. Door interlocks are provided, where required, for
the safety of operating personnel. High voltage components are
equipped with mechanically operated grounding bars which
are automatically released when a door is opened.
To minimize lost "air time", an antenna cut-back kit is available as optional equipment. When it is incorporated in the
BTF-10B, the antenna can be instantly switched to the 3 kw
intermediate power amplifier output. At the same time, the
power amplifier plate voltage is removed and the plate circuit grounded. P. A. tube changes or necessary servicing in
the power amplifier compartment can then be carried out
in complete safety while program continuity is maintained
through the driver.
Filtered air is supplied by an external blower for the 1, 3 and
10 kw stages. Individual, internal blowers for these stages are
available as optional equipment where the single external
blower is not desired. Space is provided in the exciter cabinet
for a spare exciter which can be supplied as additional equipment. Instantaneous transfer of operation from one exciter to
the other can then be accomplished by the flick of a switch.
Level at input of 600 ohm pre -emphasis network. Insertion loss of this network is approximately 24 db.
**For pre-emphaszed response, the pre -emphasis filter
(MI.4926A) is provided to be inserted in the 600 ohm
audio input line at the most effective point.
* * * Distortion and noise is measured following a standard 75
microsecond de-emphasis network.
MI.28914
Stock Identification
*
The transmitter is furnished with one FM exciter, two sets of
tubes, two crystals, interconnecting wire kit, harmonic filter
and transmission line monitor.
Specifications
Frequency Range
88 to 108 me
Power Output (into transmission line) -3,000 to 10,000 watts
RF Output Impedance
515 ohms (standing wave ratio
Accessories
Tube Kit for BTF-10B
Spare FM Exciter KitSet of Tubes for Spare Exciter
Power Cutback Equipment
Modification Kit for 50 Cycle Operation
or less)
Carrier Frequency Stability_Deviation less than ±1,000 cycles
±100
Modulation Capability
kc
Method of Modulation
Reactance tubes
Audio Input Impedance
600/150 ohms
1.75 to
.ESw/ROE.
INCA
DoUELER
1
z CA. uE/Roz.
.ST
IRi
AMPLIFIER
RCA
2ND
R
uR
I AURLn.ER
INCA
7,24
z
R
tCIA
POWER AM LIIER
tea
POWER
MI-28159
Mí.7015
MI-7020
MI-28154
MI-28178
AILR.ER
R.
MON
IME CITER
61-7016
SIRRE
yEXCITER
RIA
MIOR WLTACS RECOPY
E
RECTI11R
RU S"EO
Simplified Schematic Diagram of BTF-10B
129
RCA YOOY
FM TRANSMITTERS
FM Broadcast
Transmitter Type BTF-50A
Features
bility is assured by conservative operation of all components
and dependable forced air cooling.
The general arrangement of the transmitter consists of a series
of vertical chassis supported by steel frames which are in
line with an attractively styled, sectionalized front. All units
employ "dead front" construction with doors in the front panel
allowing free access to the low power RF cabinets and to the
transmitter area. The entire radio frequency portion of the
transmitter can easily be installed in a space only 16% feet
wide by 9 feet deep. External blower and power equipment
may be installed either in a basement or on the same floor,
depending on individual choice.
A new RCA transmitter control console (BTC-JA) is supplied as standard equipment with the BTF-50A. This control
console contains audio mixing and monitor controls, primary
power switching for the transmitter and tower lights. "Block
type" construction permits the addition of control sections if
other transmitters are to be operated in the same building.
The exciter unit of the BTF-50A contains RCA's new "Direct
FM" system in which frequency modulation is accomplished
directly by push-pull reactance tubes connected across the frequency determining circuit of the modulated oscillator.
Entirely air cooled-no water connections of any kind.
Low cost installation-small space requirements-adaptable
to single or dual floor layout.
Vertical chassis construction for maximum accessibility and
ventilation.
Incorporates RCA's new "Direct FM" system.
Grounded -grid amplifiers.
Simplified power supply-only one high-power rectifier.
Single phase filament heating of all tubes. Voltage regulated
filament supply.
Reduced power operation feature assures uninterrupted
program service.
Motor driven tuning for high-power stages.
Protection against transmission line or antenna failure.
Sectional fault indicator lamps on front panel.
Simplified single ended amplifiers operating class "C" and
using a minimum of variable elements form the RF section
of the BTF-50A. Only 26 of the 43 tubes used in this transmitter are required to maintain full 50 kw operation. The remaining tubes are used in frequency control, voltage regulator
and monitoring circuits. High stability grounded -grid ampli.
fiers using the new RCA 7C24 and 5592 tubes are employed
in all stages above the 250 watt level. This use of the same
type tube in several stages results in greatly reduced spare
tube requirements. Inherent advantages of grounded -grid
amplifiers at FM frequencies include greater stability, higher
efficiency, simpler circuits and elimination of the need for
neutralization.
New BTC-1A control console supplied as standard equip.
ment.
Description
The BTF-50A is an all-new 50 kw FM transmitter incorporating the latest tevelopments in high power FM transmitter design. This RCA transmitter will supply 50,000 watts at any
specified frequency in the 88 to 108 mc. band. Installation
and operating costs have been held to a minimum through the
use of compact mechanical construction and efficient, grounded grid circuits using a minimum of different tube types. Relia130
FM TRANSMITTERS
Variable output coupling with a front panel control permits
adjusting the power output into the transmission line over a
wide range. Harmonic radiation is held to a minimum by a
fixed -tuned attenuator, which is located in the output circuit.
Full protection from antenna or transmission line failure is
provided by a transmission line monitor which automatically
shuts down the transmitter when any unwarranted change in
standing wave ratio at the input of the transmission line is
detected. An automatic "three shot" reclosing system will return full power up to three times when plate voltage is removed by operation of the transmission line monitor or other
overload devices.
Carrier Frequency Stability-Deviation less than ±1000 cycles
+100 ke
Modulation Capability
Method of modulation
-Reactance tubes
Audio Input Impedance
600/150 ohms
Audio Input Level for 100% Modulation*
-}-10 ±2 dbm
±1 db
Audio Frequency Response** 30 to 15,000 cycles
Audio Frequency Distortion*** 30 to 15,000 cycles (including
all harmonics up to 30 kc/s at ±75 kc swing)
Less than 1.0%
FM Noise Level * * *
(below
Not more than
kc swing)
-65
-50
db
db
Not more than
Power Line Requirements:
440/480
Line Voltage (normal open circuit)
3
Phase
Frequency
60 cycles
Total Variation from Normal Including Regulation
5%
Power Consumption (approximate)
125 kw
Power Factor (approximate)
87%
The power control system of the BTF-50A is carefully engineered to provide proper starting sequence. All high-powered
circuits are doubly protected by high speed overload relays
backed up by magnetic -trip circuit breaker type switches, and
circuit indicator lamps provide a quick means for analyzing
faults such as air failure, tube failure, etc. A single high -power
rectifier supplies all anode voltages for the RF stages, and a
heated spare tube is provided which may be quickly connected
into the circuit, if necessary. Two small rectifiers are used for
RF screen and exciter plate voltages. Door interlocks and
high voltage grounding bars are provided, where required.
for the safety of operating personnel.
Tube Complement:
4 RCA 6V6
1 RCA 6AL5
1 RCA 2BP1
4 RCA 1614
2 RCA 2E26
3 RCA 4-125 /4D21
1 RCA 6SH7
1 RCA 2D21
4 RCA 7C24
4 RCA SU4G
3 RCA 5592
1 RCA 6X5
6 RCA 857B
2 RCA OD3/VR150
5 RCA 6AC7
1 RCA 0C3/VR105
I)imensions:
Transmitter Panel and Equipment Enclosure
198" long x 841/2" high (allow depth of 9' to rear wall)
Plate Transformer
Base 25" x 49"; height 50"
Filter Reactor
Base 32" x 40"; height 50"
Rectifier
50" wide x 70" long x 84" high
Control and Distribution Unit -48" wide x 82" long x 80" high
High -power Blower Enclosure
8' x 8' x 6' (approx.)
Console
Base 46" x 36"; height (including turrets) 381/2"
30" x 84"
Minimum Entrance Requirements
Weight, total unpacked
.-.Approx. 24,000 lbs.
Finish
Two tone umber gray
MI -28926
Stock Identification
To provide for continuous broadcast service with a minimum
of interruption, the transmitter is equipped with an antenna
cut-back arrangement. Operation of a single control switch
transfers the antenna from the final amplifier to an intermediate amplifier which supplies approximately 7.5 kw. At
the same time, the driver and power amplifier plate voltage
is removed and the plate circuits grounded. Tube changes or
necessary servicing in the driver, P.A. or high power blower
compartments can then be carried out in complete safety,
while program continuity is maintained through the intermediate power amplifier.
-
Air for all RF stages up to and including the intermediate
power amplifier is supplied by a single blower. Air for the
driver and final stages is supplied by a separate blower which
draws filtered air from outside the transmitter area and may
be exhausted into a manifold for outside delivery or for heating purposes, if desired.
*
The BTF-50A is furnished with a transmitter control console,
two sets of tubes, two crystals, harmonic filter, transmission
line monitor and one FM exciter. A spare exciter can be supplied as extra equipment for installation in the space provided
in the exciter cabinet.
* *
** *
Specifications
Frequency Range
Power Output (into transmission line)
RF Output Impedance
75
AM Noise Level (below 100% amplitude modulation)
Level at input of 600 ohm pre-emphasis network. Insertion
loss of this network is approximately 24 db.
For pre-emphasized response, the pre-emphasis filter
(MI.4926A) is provided to be inserted in the 600 ohm
audio line.
Distortion and noise is measured following a standard
75 microsecond de -emphasis network.
Accessories
Spare FM Exciter
Set of Tubes for Spare Exciter
Modification Kit for 50 Cycle Operation
88 to 108 me
10 to 50 kw
515 ohms
:oTO
6.1
F
L
Simplified schematic diagram of BTFSOA
131
e`or
GU/
MI.7015
MI -7020
MI -28248
FM TRANSMITTERS
Universal Transmitter Control Console Type BTC-1A
BTC-1A Universal Transmitter Control Console
Features
console, additional control turrets and desk sections may be
attached to the basic unit to form a console having facilities
for control of AM, FM and/or television transmitters. The
BTC-1A is flexible enough to permit a variety of possible
combinations.
Contains all mixing and switching facilities required for
supervisory transmitter control.
"Block Type" construction allows the addition of control
turrets and desk sections when other transmitters are
installed.
Provides a VU meter, and facilities for mounting three
remote indicating meters.
Seven position monitor selector switch and monitor gain
control.
Mixing and switching provided for six audio inputs.
Transmitter power switches and indicating lamps on r -f
turret for routine transmitter control.
Attractively styled and finished to match RCA transmitters
and auxiliary equipment.
Description
The Universal Control Console consists of an audio control
turret and an r -f control turret mounted on an attractive two
section desk having removable end sections. Control turret
Front panels have a satin chrome finish and the desk is twotone umber gray with a durable black linoleum top. All
meters are recessed behind the front panel and each panel
is hinged at the bottom so that it may be opened for easy
servicing. The rear turret covers may be removed to facilitate
installation or basic changes.
Uses
The RCA Type BTC-1A Universal Transmitter Control Console is meant to be used at transmitting plants to provide
centralized control of all mixing and primary switching operations. Intended primarily for use with RCA 3 kw, 10 kw and
50 kw FM transmitters, this unit may be combined with the
MI.11623 Transmitter Monitor and Amplifier Rack to provide
audio amplification from program line to transmitter input, and
a very flexible and complete system of controls and monitors.
The audio turret contains a standardized VU meter with a
range switch to alter the maximum level indicated by the
meter from +4 to +24 db in two db steps. Three high
quality mixers and associated transfer keys provide for control of the six inputs, which are:
1.
2.
3.
Microphone-Oscillator/Remote
Line 1, Line 2
Turntable 1, Turntable 2.
Operation of the microphone key cuts off the signal to the
monitor amplifier to prevent feedback when the microphone
is being used. The line transfer key removes equalization and
connects the telephone set to the line not being used for pro -
The BTC-1A Universal Control Console is designed to satisfy
the requirements of modern broadcast transmitting stations
where it is often desirable to combine the operation of several
transmitters. Because of the "block type" construction of this
132
FM TRANSMITTERS
RTC -IA Plus Accessory Sections Arranged to form a Combined Console for AM -FM and Television
to form a single console having control facilities for television
and FM or AM transmitters.
gram. A chrome plated guard prevents accidental operation of
the line key. A seven position selector switch permits monitoring of all important circuits, and individual bridging pads
mounted inside the turret provide a means for equalizing the
level of the various signal sources. A master monitor gain
control on the front panel adds to the flexibility of the
monitor system.
The BTC-1A is shipped complete with one audio turret, one
r -f turret, a kit of meter nameplates and complete installation
instructions.
Specifications
The r-f control turret contains all power control switches
necessary for normal operation of the transmitter and provides
for mounting three remote indicating meters. Control switches
and associated indicator lamps are included for: (1) Transmitter start; (2) Transmitter plate voltage; (3) Overload
reset; (4) Time delay by-pass; (5) Manual -automatic control;
(6) Day-night power switching; (7) Tower lights; (8) A
spare switch and indicating lamp which may be connected
as desired.
Input Impedance:
600 ohms
Lines 1 and 2, and Osc./Remote
600 ohms
Telephone Set
950 ohms
Microphone and Turntables
10,000 ohms
Monitor Input (bridging)
±0.1 db
Frequency Response (30 to 15,000 cycles)
Noise Level-Circuits are isolated so that residual noise level
will not exceed the aggregate noise level of the associated
amplifiers.
A -c Power Input for Lamps
10 watts
105-125 volts, 50-60 cycles
Dimensions Overall:
Width 46"; Depth 36"; Height 38%". Note-Turrets extend
approximately 10 1/" above desk top.
300 lbs. (approximate)
Weight (unpacked)
MI.28950
Stock Identification
No meters are supplied with the r-f control turret since the
requirements may differ with each installation. A typical meter
arrangement for FM would include a remote indicating modulation meter, a frequency deviation meter and a limiting
meter. The turret is arranged to accommodate three standard
4" square face meters which mount behind the meter windows on the front panel. A kit of nameplates is supplied to
properly designate the meters used. All wiring and conduits
to the control turrets are concealed inside the desk sections.
Accessories
AM/FM Audio Control Turret._
Universal Transmitter Control Turret
Accessory items include desk sections and turrets which may
be added to the BTC-1A if desired. Two basic desk sections
may be ordered to provide writing and typewriter space.
90° desk sections are available for building an "L" or "U"
shaped console. Turrets with blank panels can be supplied in
those cases where the customer desires to install special com
ponents. The MI.19292-A television control console is composed
of the same basic desk sections and turret housings as those
used in the BTC-1A console and these units may be combined
Basic Desk Section
90° Desk Section
Complete Turret with Blank Panel
Wing Turret with Blank Panel
Console End Sections
Remote Gain Reduction Meter for Use with
Limiting Amplifier
133
Mí.28410
MI.28420
MI.28401.1
MI -28401-2
MI -28403-1
MI.28404-1
MI-26265.1
MI.28425
FM TRANSMITTERS
FM Exciter
Unit MI -7016
Power Supply MI -7017
Features
Simplicity of circuit.
Crystal -controlled frequency stability.
Only six tubes in r-f chain.
Distortion less than 1% through range of 30 to 15,000
cycles. (See curve.)
Stability independent of circuit adjustments.
Frequency dividers of relatively high ratio and simple design; thus requiring fewer tubes and circuits.
Only crystal unit is temperature -controlled.
Every component and connection is easily accessible.
Built-in device for checking performance of frequency
control circuits, frequency multipliers, and reactance
modulators.
No auxiliary equipment necessary for setting up to de-
sired frequency.
Description
The FM Exciter consists of two vertical panels. The upper
panel contains the RF and modulator circuits, and the lower
panel the regulated power supply. These panels are intended
to be mounted in one of the RCA standard cabinets which
house all the new RCA FM transmitters. This method of construction provides a degree of accessibility seldom realized
in' this type of equipment. All tubes and large components
are mounted on the front of the panel. Wiring on the rear
of the panel is "in the clear" with all terminals clearly marked
and easily accessible.
mean carrier frequency. This system eliminates the need for
temperature control of any components except the crystal,
and makes possible the vertical -panel, easily -accessible type of
construction. Its fast action and complete freedom from temperature variations provides a higher degree of frequency
stability than formerly possible. Fewer parts are required, and
likewise, the number of required adjustments is reduced.
Failure of the automatic frequency control does not take the
transmitter off the air, since operation may be continued by
locking the motor shaft and making occasional manual frequency corrections.
This new FM Exciter employs the principle of direct FM
which was developed by RCA engineers. Direct FM uses
fewer tubes and introduces less audio distortion, (especially
at low frequencies) than the indirect method. In this system,
the mean, or "carrier" frequency is produced in a simple and
straightforward manner by a master oscillator which is modulated directly by means of a reactance tube modulator. The
oscillator is then followed by a relatively small number of
multiplier stages. This is undoubtedly the simplest method of
producing high fidelity frequency modulation.
The operation of the circuits may he checked easily and
rapidly by means of a built-in cathode ray oscilloscope, milliameter, and associated selector switches. It is possible to check
the operation of all stages, and also the functioning of the
automatic frequency control. A buzzer, operated by a cam
switch on the frequency control capacitor shaft, gives warning
if at any time the frequency control capacitor approaches control limits. The buzzer will sound, also, if there is maladjustment of oscillator tuning control or for the failure of any
essential frequency control circuit elements.
automatic frequency control system is employed
of the FM master oscillator
are compared with sub -harmonics of a low frequency crystal
oscillator (100 to 125 kc). Any difference between these frequencies operates a two-phase, reversible, induction motor
attached directly to the shaft of a variable capacitor. The
motor never turns more than 45 degrees either way. No gears,
counter circuits, or compensating voltages are involved. The
variable capacitor is connected directly across the oscillator
tank circuit, and instantly corrects any deviation from the
A new -type
in this exciter. Sub -harmonics
The audio distortion of this exciter is less than 1% for
modulating frequencies from 30 to 15,000 cycles. The noise
level in the output is 70 db below 100% modulation.
134
FM TRANSMITTERS
4.5-6
M.C.
FREQUENCY
MODULATED
OSCILLATOR
AUDIO REACTANCE
INPUT
TUBES
X3
X3
I
P
OUTPUT
2
i
9f
f/240 0
BAL.
MOTOR
SHIFT
MOD.
f
90°
BAL. 4,
f/240
MOD. 44
-4
SHIFT
XTAL
f/240
OSC
18.75-25.KC
240
0
Him
94 -125
=5I
KC
RCA FM EXCITER
Block diagram of the RCA FM Exciter. The frequency is doubled in the amplifier section.
Specifications
44 to 54 me
Frequency Range
Frequency doubled in amp. section to 88-108 me
Carrier Frequency Stability, at FM output frequency
Deviation less than 1000 cydes
+100 kc
Modulation Capability
Push-pull reactance -tubes
Method of Modulation
600/150 obus
Audio Input Impedance
Audio Frequency Response
±1 db
30 to 15,000 cycles, 1000 cycle reference
Audio Frequency Distortion
30 to 100 cycles
100 to 7,500 cycles
7,500 to 15,000 cycles
1
0
1
(including all harmonics up to 30 kc at
Power Line Requirements
908/230 volts
Line Voltage
Phase
1
50/60 cycles
Frequency
5%
Instantaneous Regulation (maximum)
370 watts
Power Consumption (approx )
67%
Power Factor
Power Line Requirements-(Crystal Heaters)
100 to 125 volts a -c or d-c
Line Voltage
Phase
1
28 watts
Power Consumption_
29"
Overall Height-(RF and Power Supply)
221/"
Overall Width
47 lbs.
Weight (RF Unit)
66% lbs.
Weight (Power Supply)
Stock Identification:
MI -7016
Exciter
MI.7017
Power Supply
0%
5%
0%
kc swing)
70 db
FM Noise Level, below ±75 kc swing
db
AM Noise Level, below 100% amplitude modulation.
75
-60
Da
Oa
1000 MODULATION
0.0
'a *I
º 0
0.7
0
N
vwI
1000
10000
O30
0 000
FREQUENCY IN CYCLES PER SECOND
LESS
RESPONSEI
PRE EM
100
SIS
ODO
rREOIENCY IN CYCLES PER SECOND
Audio frequency response less pre-emphasis
Percentage distortion at 100% modulation
135
0000
FM TRANSMITTERS
Transmitter Monitor and Amplifier
Cabinet Rack MI -11623
Features
Simplifies transmitter installations.
Provides complete monitor and amplifier facilities in one
rack.
Provides extreme flexibility through termination of all
audio units in jack strips.
Wiring and monitoring facilities furnished for addition of
optional equipment.
Attractive styling-matches all RCA transmitters and auxiliary equipment.
Uses
The transmitter monitor and amplifier cabinet facilitates :he
grouping of all appropriate apparatus necessary to simplify
the installation of any broadcast transmitter. This cabinet
utilizes the new modernistically styled cabinet of the BR -84
series which blends with all RCA transmitters and equipment.
The cabinet is factory wired to accommodate all the required
items for transmitter, speech input equipment, modulation and
frequency monitors, and power change switch, etc. The
MI -11623 has been designed to operate with the control desks
supplied with the BTA-5F/BTA-10F, BTA-50F and BTF-50A
Transmitters to provide a complete and flexible system of
controls and monitors.
Description
The transmitter control cabinet embraces all the functional
equipment, amplifiers, jack panels, etc., required for the Opel,
ation of an RCA broadcast transmitter in conjunction with
the transmitter control console. The MI.11623 consists of one
Standard Cabinet Rack complete with a ventilated rear door,
one BA -4C monitoring amplifier, one type 86 -Al limiting
amplifier, two type 33-A jack strips complete with mat, and
one type 57-C switch and fuse panel. An additional BR -2A
panel and shelf is supplied and wired to accommodate three
type BA -1A pre -amplifiers, with one type BX-1B power supply
for the pre -amplifiers. This arrangement allows microphones and
transcription turntables to be used directly from the transmitter in the event of an emergency.
Mountings and all wiring are also provided for the following
accessory equipmment:
Two type 56-C Fixed Line Equalizers
Two MI -4925-A 15 KC High Frequency compensators
One MI -4926-A FM pre -emphasis equalizer
One MI.4309-B Power Reduction panel (BTA-5F/10F)
One MI -7264-E Hum Equalizer (BTA-50F)
A blank panel is drilled and tapped for mounting three
MI.10253 line transformers.
Measuring equipment space and wiring are available at the
top of the rack for mounting the AM Frequency Monitor type
WF-48A and the Modulation Monitor type WM -43A, or the
combination FM Frequency and Modulation Monitor type
MI-11623 fitted with MI30541-G84 Side Panels
and MI -30566-G84 Trim Strips
Specifications
Frequency Response (line in to transmitter in)
±2 db 30-15,000 cycles
Noise Level (below +10 db output)
-75 db
Power Supply (115 to 125 volts, 50-60 cycles)
450 watts
Dimensions:
Height
84"
Width (less side panels and 28" side panels)
92"
Overall Depth (including door handles)
19"
Panel Width
19"
Weight (unpacked)
400 lbs. (approx.)
Stock Identification (including tubes)
MI.11623
Accessories
Side Panels (each)
MI.30541-G84
Single Trim Strip (each)
MI.30566-G84
AM Frequency Monitor
Type WF-48A
AM Modulation Monitor
Type WM -43A
FM Frequency and Modulation Monitor (RCA)_Type WF-5A
BA -1A Pre -Amplifier
_MI -11218-A
Tube Kit for BA -1A
MI -11288
BX-1C Power Supply for Pre -Amplifier
MI -11305-B
Tube Kit for BX-1C Power Supply
MI -11262
Power Change Panel for BTA-5F and BTA-10F
Transmitter
MI.4309-B
Line Transformer
MI -10253
56-C Fixed Equalizer
MI -4168
15 KC High Frequency Compensator
MI -4925-A
FM Pre -Emphasis Equalizer
MI -4926-A
Sola Voltage Regulator
60 cycle
MI-11280
50 cycle
MI.11280-A
WF-5A.
The two type 33-A jack panels provide flexibility for all the
described audio circuits with spares for utility apparatus according to local requirements.
The photograph illustrates the MI.11623 complete with accessory side panels, MI -30541-G84 and MI-30566-G84 Trim Strips.
These are not supplied, but are available for the user's individual requirements. Where fluctuating mains prevail, the
Solar voltage regulator is available to regulate the a -c to the
86 -Al limiting amplifier.
' Note:
tubes.
Limiting and monitoring amplifiers supplied with
136
FM TRANSMITTERS
Pre -emphasis Filter MI -4926-A
Features
Accurate within 1.5 db from 30 to 15,000 cycles.
Minimum insertion lose.
Operation for levels up to +30 db.
Compact design-completely shielded.
Output:
Load Impedance
Output Impedance
Physical Specifications:
Diameter
3"
Height
4%"
Weight (unpacked)
91/4 lbs.
Base Plate
Mounting
Four holes with center lines 23/" x 23/"
Description
db
0
The MI -4926-A filter is of the constant impedance, balanced,
"bridge T" type. The characteristic frequency curve of the
filter follows a 75 -microsecond curve in accordance with RMA
and FCC recommendations.
Mechanically, the filter consists of two reactors, two capacitors
and eight resistors sealed inside metal can. Connections are
made to the filter by means of solder terminals on top of
the can.
The filter may be inserted at any point in the audio system
where the signal does not exceed +30 db, and may be mounted
in any convenient place so long as the magnetic fields of transformers and similar equipment are avoided.
=
.001 watt.
TIME CONSTANT 75 MICROSECONDS
SOURCE IMPEDANCE 600A 75%
LOAD IMPEDANCE 600A 75%
6
........_____/
Specifications
Input:
Input Impedance
Maximum Input Level
±5%
±5%
Insertion Loss (from 600 ohm source to 600 ohm load) :
Minimum Lose at 15,000 cps
Approx 5 db.
Maximum Loss Below 500 cps
_Approx 22 db.
Frequency Response
Corresponds to FCC 75 microsecond
pre -emphasis curve within ±1.5 db from 30 to 15,000 cycles
Attenuation Characteristic
Fixed (See curve)
Uses
The MI -4926-A filter is designed for use in such equipment as
disc recorders and frequency modulated transmitters to produce the FCC standard 75-microsecond audio pre -emphasis
characteristic. The MI-4926-A is supplied as a part of all RCA
FM and Television transmitters, as well as the studio-transmitter link equipment. It is also used in conjunction wall
disc recorders to obtain recordings having the 75 micro-second
pre-emphasis characteristic. In FM transmitter installations, if
a spare FM exciter is ordered, and it is desired to switch
ahead of the filter rather than after, an additional pre -emphasis
filter will be required. The MI -4926-A may also he used with
composite transmitters.
Source Impedance
600 ohms
600 ohms
30
±5%
±5%
+30 db
600 ohms
600 ohms
00
000
FREQUENCY IN CYCLES PER SECOND
Frequency response of MI.4926-A
137
I0000
20000
FM ANTENNAS
The RCA Pylon Antenna For FM
Features
Single element. self-supporting structure.
Easy to install.
High gain.
High power handling capacity.
Broad
band-no tuning or adjusting.
Low in weight.
Mechanically strong and needs no guying.
RCA Television Super Turnstile may be mounted on top.
One feed point per section.
Icing problem negligible.
Easy to maintain.
Description
The new RCA Pylon Antenna is a radically new design of
antenna for the FM broadcast band. This antenna is simpler
in design, poses fewer installation problems, and provides
higher gain (height for height) than any other type of FM
antenna.
The Pylon is essentially a cylinder of sheet metal, mounted
in a vertical position, with a narrow slot running from top to
bottom. This cylindrical structure itself is the radiator. The
operation may be best understood by considering the edges
of the slot as an open wire transmission line, and the cylinder
as an infinite number of horizontal loops. The cylinder is
approximately a wave length long and a half wave length in
circumference. When properly excited, at the midpoint, there
is a voltage distribution along the slot similar to that along
any full wave transmission line shorted at both ends. This
voltage excites the cylindrical portion, and results in hon
zontally polarized radiation. The Pylon has an essentially circular radiation pattern. Its gain depends upon the number of
stacked sections. The basic cylindrical section is approximately
thirteen feet high and twenty inches in diameter. The sections
may be stacked, one on top of the other, with the gain increasing in a direct linear proportion. For example, at 98
megacycles, a single section will have a gain of one and a
half, two sections will have a gain of three, and four sections
.
138
FM ANTENNAS
gain of six. For a given number of sections, there is a
model of the Pylon designed to operate in either the lower
or upper half of the FM broadcast band.
Pylon is designed for those special applications where high
winds of hurricane intensity are normally to be expected. In
addition, it is especially applicable to FM/TV installations
wherein the RCA Television Super Turnstile is mounted on
top of the Pylon. When used in this manner, the combination
meets the RMA recommended wind loading capacity of at least
87 mph.
a
The Pylon can be safely mounted almost anywhere. Its low
weight places a minimum of load and stress on any building
or tower on which it might be mounted, and it is entirely
self-supporting in its mounting. There are no appendages or
protruding elements which high winds would cause to loosen
or fall, or which would require bracing against the possibility
of ice loading. Icing is a negligible problem with the Pylon
because the transmission lines are inside the cylinder where
ice formation is unlikely. The formation of ice on the outside
will add only a negligible amount to the total weight and
loading. De-icing equipment is not considered necessary.
Low Power Pylon
The Low Power Pylon is the ideal interim antenna. It will
handle a power of 3 kw, and will withstand a wind velocity
of 87 mph. The Low Power Pylon is also a low cost installation, and may be used as the final antenna for many low
power FM stations not necessarily requiring exceptionally high
gain. It does, however, have the same gain as the other single
section Pylons. When purchased originally to serve an interim
function, it may always he used thereafter as a standby antenna.
The Pylon presents extremely simple installation problems.
One feed point per section is all that is required. For most
installations, the interconnecting feed line may be mounted in
place on the ground, and the whole assembly raised at once.
Maintenance problems for this antenna are reduced by the
extreme simplicity of the feed line arrangements, the small
number of end seals, and the fact that the lines are enclosed
within the cylinder. Provision is made for mounting a standard
300 mm. code beacon on the top of the antenna. The 300 mm.
code beacon and associated equipment for the Pylon are contained in MI -28216-A tower lighting kit. Steps on the cylinder
provide a means of servicing the lamp or inspecting the slot.
The slot is normally covered with a strip of polyethelene for
the purpose of excluding water, ice and other foreign matter.
If it should ever become necessary to service the transmission
line harness within the Pylon, the securing bolts, which are
accessible at the slot, may be removed, and the harness lowered to the ground. Shackles are provided at the top of the
Pylon, both inside and out, to permit the rigging of a boatswain's chair and for the purpose of facilitating the lowering
and raising of the harness.
There Is A Pylon For Every
Application
In order to meet the requirements of the many different sets
of circumstances under which an FM antenna may be installed, the Pylon has been made available under three different classifications, each of which serves the needs of a
particular application. These three types of Pylons are designated as: the Standard Pylon, the Heavy Duty Pylon, and the
Low Power Pylon.
Standard Pylon
The Standard Pylon is designed to meet the requirements of
the majority of FM installations. It meets all of the RMA
specifications, and will safely handle the output of any presently designed FM transmitter-up to 50 kw. This Pylon is
constructed of light weight sheet metal and is designed to
combine the maximum of strength and rigidity with the
minimum of weight. It meets the RMA recommended wind
loading capability equivalent to a wind velocity of 87 mph,
assuming the structure to he covered with a half inch layer
of ice.
Heavy Duty Pylon
The Heavy Duty Pylon, when used alone, far exceeds the RMA
specifications. Like the Standard Pylon, it is also capable of
handling any power up to 50 kw. This Pylon, however, is
fabricated from a much heavier gauge metal and will withstand a wind velocity in excess of 160 mph. The Heavy Duty
Low Power Pylon
139
FM ANTENNAS
Engineering Data For Pylon Antennas
-D-STANDARD PYLONS
Fre-Nominal
Sec-Range Power
quency
hyPe
No.
R
h,
h,
D,
D,
W
tions
(Mcs.)
Gain
(lbs.)
(ft.)
(ft.)
(in.)
(in.)
(lbs.)
1
88-97.4
1.5
501
7.5
13.5
19.5
22%
350
1
96.4.108
1.5
501
7.5
13.5
19.5
350
BF-11A
BF-11B
BF-12A
BF-12B
BF-14A
88-94.5
3.0
950
14
27
19.5
22%
22%
,
94.5-108
3.0
950
14
27
19.5
22%
700
4
88.97.4
6.0
1868
27.5
54
19.5
22%
2000
700
6.0
1868
27.5
54
19.5
22%
BF-18A
8
88-97
12.0
3887
54
108
20.0
27
12497
BF -18B
8
97.108
12.0
3887
54
108
20.0
27
12497
1058
14
27
20.0
25
4322
97.4-108
BF -14B
2000
Stock
Identification
MI -28221-A
MI.28221-B
MI -28222-A
MI-28222-B
MI.28224-A
MI -28224-B
MI -28228-A
MI -28228-B
h2
HEAVY DUTY PYLONS
BF-12E
BF-12F
BF -14C
BF -14D
2
88-98.5
3.0
2
96-108
3.0
1058
14
27
20.0
25
4322
4
88-96
6.0
2074
28.5
54
20.0
27
10497
96-108
6.0
2074
28.5
54
20.0
27
10497
88-96
1.5
515
7.5
13.9
19.8
22
376
96-108
1.5
419
7.0
12.2
17.8
20
312
1
MI -28222-E
MI -28222-F
MI -28224-C
MI -28224-D
LOW POWER PYLONS
BF -21A
BF -21B
1
1
MI -28231-A
MI-28231-B
-
LEGEND
R Wind force. Equivalent to 87 mph wind, RMA Standard.
h, Height of center of wind force.
h, Height of antenna. Does not include beacon (3 feet).
D, Diameter of cylinder.
D, Diameter of flange bolt circle.
W Total weight including beacon lamp.
The Pylon is furnished complete with transmission line harness, fittings, mounting flanges, and all hardware. The harness
of the Pylon terminates in a 51.5 ohm, 3%" flanged line at the
hase of the antenna. The standing wave ratio is, in all cases,
less than 1.5. Connectors are available to couple the antenna
to a %", 1%", 3%", or 6%" plain or flanged transmission line.
Where requested, RCA will also be glad to quote on tower
and installation.
Accessory Equipment
Plus Cable:
For Pylon of one or two sections
For Pylon of four or more sections
300 mm Code Beacon
Supporting Structures and Fittings
MI.28216
MI -28216-A
-
On application
Coaxial Transmission Line for use from Antenna
On application
to Transmitter
FM -AM Isolation Unit Type BAF-4A
AM -FM Isolation Unit
140
MI-28217
FM ANTENNAS
66-E8MC-T V
ANTENNA SHOWN.
Engineering Data For Pylon
Super Turnstile Combination
174-216 M C -T V
The combined antenna structures are designed to withstand a
maximum wind velocity of 85 mph when coated with 1/2" radial
ice. Maximum unit stress = 20,000 lbs. per square inch. Reaction "R" shown is for estimating purposes only and is
calculated on the basis of 20 lbs. per square foot of projected
area without ice. All sections are rounds. "W" = total dead
weight, including pole, 300 mm code beacon, pole steps, special
connection between FM pylon and TV pole, transmission lines.
Pylon, and miscellaneous hardware.
ANTENNA SHOWN.
4-1-,
. 1.
C3¡
TV
-
ELEC. CENTER
u
I.\RLE OF ORDERING INFORMATION
W
C
-
3
<
F
i
t,
QJ
88-47MC
28228E BF-12E
97-1065lC
28222-F
BF-12F
88-99MC 28224C
2 'TO 174-216 6 19013-2 4 99-108MC 28224-D
ER MC ^
88-97 MC 28222-E
ìY
3 Y 66-86 319012297-106MC 28222-F
MC
82
VI
4 ty
68-99 MC 28224{
Y 66-88 319012- 4 99-108MC 28224-D
BF-14C
1
174-216 6190113-2 2
TO
XIII
5
MCEa
MC
6
82
II
88-97 MC
54,4138319A02- 2 97-108MC
II
B
54-66 319012- 4 88-9ºMC
in
MC
r
i
IrZ
I'(
I
TF -68
I¡
II
11
I1
BF-12E
I
8F -12F 1F"38
II
BF-14C
WINO
LOAD
TV
TF-38
13F-140YI
21
2822E
7
r
BE14D TF-88
TRANSMISSION LINES
BF-12E
TF-3B
BF-12F
28222-F
28224C
99-I08MC 28224-0
A2
i1
ItIálj4 FLANGED.
BF-I4C
BF-I4DTF3B
TABLE OF SPECIFICATIONS
ITEM
FREQ MC.
174-216
Tv NO OF SECTIONS
6
APPROX. PWR. GAIN
7
2
NO. Of SECTIONS
FM
APPROX. PWR. GAIN
3
5
54-66
54-66
3
3
3
7
4
3.8
3.8
4
2
4
4
E
4
6
3
13'11"
6
3
6
27'10"
55'8"
56.0'
D
27'I0' 55'8" 27'10"
45.25' 33.5' 45.75' 42.6'
32.0'
54'4» 82'2. 56 2i" 84 01" 6Ó.I"
E
3'
13'
B
27'10"
I
2"
27'10"
27'10"
55' 8"
7'3"
3'2"
I00'3í 75 III"
7'3"
"
103'91
8' II"
84'1"
72 511
R
LBS
2133
3119
2133
W
LBS
7092
13267
7442
108.
161.
110
163
142.
195.
145
205
140
200
190
250
WITHOUT
ICE
AREA SQ. FT. WITH
2" RADIAL ICE
MOMENT IN FOOT POUNDS
68,256
NO ICE AT TOWER TOP
34.75'
RADIAL ICE 2374
i"RADIAL
R. -..LBS WITH
i"
ICE
IOMENT-FOOT POUNDS
WITH j" RADIAL ICE
TOWER
141,136
47,0'
3482
82,497 162,714
71,456
3149
2962
8988
144,067 126,181
33.9'
46.1'
43.0'
2218
3306
3168
75,190
FM ELEC. CENTER
8'11"
FT
13617
L
87.11"
F
AREA SQ. FT.
AT
4
3
66-88 66-88
13'11"
I"
A
C
C' WITH
3
6
174-216
III
3978
15163
3.
222,788
56.5'
4258
162,406 136,224 240,464
TOP
141
FM ANTENNAS
AM-FM Isolation Unit Type BAF-4A
Features
No tuning adjustments required.
Minimum effect on AM tower impedance.
Efficient FM power transfer.
Maintains low standing wave ratio on any FM channel.
Uses
The RCA type BAF-4A FM -AM isolation unit is a device for
transferring VHF power accross the insulating zone of an AM
antenna tower to feed an FM antenna mounted atop the tower.
It is designed to provide complete isolation of FM and AM
signals and efficient operation over the entire FM frequency
range.
Description
The circuit of the FM -AM Isolation Unit consists of two series
resonant circuits coupled together to such a degree as to pro.
vide good band-pass characteristics over a range of frequencies
from 88 to 108 megacycles. The inductors consist of copper
loops, and the capacitors consist of capacitor rings mounted
concentric with the input and output transmission lines. The
input assembly is insulated from the output assembly and
there remains a stray cap ¡chance of approximately 75mmfd.
across the insulator. The effect of this capacitance in shunt with
the input impedance will be negligible, except in the case of
extremely high base impedance of the AM tower. In such
cases, the stray capacitance may be parallel resonated by means
of an auxiliary inductor.
The isolation unit is housed in a weatherproof metal box and
includes provisions for mounting on a wooden pole or supporting platform either at the base of an insulated broadcast
tower or in the immediate vicinity. A standard 1%" diameter
51.5 -ohm transmission line extends six inches from the top
and bottom of the unit for connection to the FM antenna line
running up the tower and to the FM transmitter line running
back to the transmitter house. Access to the interior of the
housing for inspection or servicing is by means of a removable
panel on one side. Provision is made for carrying the gas
pressure across the unit by means of a composition high pressure hose.
Specifications
Frequency Range
88-108 mcs
Transmission Line Impedance
Input Impedance
Maximum FM Power
Maximum AM
515 ohms
515 ohms with 1.3 VSWR
10 kw
Power-Base insulator voltage should not
ex-
ceed 10,000 volts peak at 100% modulation
Dimensions:
Height (housing)
Height (overall)
171/2"
291/2"
Width
Depth
191/2"
191/2"
Weight (net)
60 lbs.
Accessories
Adaptor for 3t/s" 51.5 ohm lisie
Communication Products Catalog #84-506
Adaptor for
ohm line (1 of each required)
Communications Products Catalog #88-505
#98-505
%s" 51.5
These adapters are necessary only if an FM feed line
other than 1%" diameter is used.
Interior view of BAF4A
142
FM ANTENNAS
Tower Erection:
Antenna and Harness Installation:
Antenna Towers
RCA is a distributor of antenna towers for several
prominent manufacturers. A wide selection of
towers is available for all applications. These include standard self-supporting and guyed designs
as well as custom made designs for special requirements, such as supporting structures for FM
and TV antennas.
Transmission Line Installation
Lighting Equipment
)
(
)
(
)
Tower Height: Ground to top of tower
Ground to top of base insulator_
Tower Use:
Antenna support
AM Radiator
Price and delivery quotations for towers and
services may be obtained by forwarding essential
information to RCA. The following questionnaire
is provided as an aid to the station in determining specific requirements.
AM Power
KW
Frequency
kcs
FM Antenna: Type
Description
TV Antenna: Type
Description
Antenna Tower Questionnaire
Transmission Lines:
LOCATION
Size
Nr.
Design Load: B-1 Open Country
B-2 Congested Area
State
QUOTATIONS TO BE FURNISHED
Guyed
Tower:
Self -Supporting
)
TV_(
SPECIFICATIONS
RCA can also furnish tower lighting equipment
and tower erections, if desired. This may include
erection and installation of FM or TV antennas
and associated transmission lines.
City
FM____(
(
)
(
)
Remarks:
(Special requirements, site accessibility, etc.)
Coaxial Line
RCA is prepared to furnish aid in determining the coaxial
transmission line requirements of any FM, AM, or TV station.
As a distributor for prominent coaxial line manufacturers,
RCA is able to supply the necessary transmission line, associated fittings, and accessories for any type of complete antenna
installation.
Interested stations are invited to submit detailed drawings
or sketches of their proposed station and antenna layout
plans for study and transmission line requirement recom
mendations by RCA.
143
Tower mu. two -sortir Pylon es WSdA-FM, York, Pn.
Raising the four-secs&nt Pylos an mu, cornpleteh assembled unit at T'7PGFN. Gern ROT. Wisr.
i
Insertinz the transmission lins harness into the two -section
Pylon a: WFSBA-FM, York, Pa.
Pour -section Pylon in: ta!6tior_ with supporting tower atop
building et VSUI. loose City, Iowa.
TELEVISION
STUDIO
EQUIPMENT
Page
CAMERAS
153
FILM PROJECTORS
157
SWITCHING EQUIPMENT
161
MONOSCOPE
162
SYNCHRONIZING GENERATOR
164
AMPLIFIERS
166
POWER SUPPLIES
169
How A Television Station Can Grow In Easy Stages
A Minimum Layout Providing Facilities
STAGE ONE. For Film and Network Programs Only
The diagram below shows the minimum equipment required
for satisfactory operation of an independent (i.e., not a satellite) television station. Such a station would have all of the
facilities necessary to transmit network programs or film programs originated locally. Live talent local programs would
not be provided for during the initial period of station operation because of the relatively high cost of the additional
facilities and staff required.
Many broadcasters, particularly in the smaller market areas,
will want to start in television on a small scale. It will obviously be desirable for them to make their plans in such a
way that investment and operating costs are relatively low
during the initial period-increasing later as the scope of
operations is broadened in accordance with the growth of the
local television audience.
RCA television studio and transmitting equipment units have
been designed to facilitate this normal expansion by making
it easy and economical to add additional units as they are
required. Two features are of outstanding importance. The
first is that the basic units used in all RCA systems, large or
small, are identical. The second is that the breakdown of the
equipment into individual units has been carefully planned so
that adding additional units does not make obsolete or useless
any of the original units. The manner in which these features
enable a television station to "grow" by easy stages is indicated by the illustrations on this and the following pages.
The studio and control equipment for a station of this type
is relatively simple. Two 35 mm projectors are provided in
order that continuous film programs (i.e., no break for rewinding) will be possible. A single film camera suffices, as
it may be moved easily to face either projector port. The
control console consists of a standard audio unit and a
single video control unit. Auxiliary items include a transcription turntable, announce microphone and monitoring
loudspeaker.
PtAUDIO
NETWORK
IN
VIDEO
FIRE
WALL
FILM
PROJECTORS
FILM
CAMERA
CONTROL
CONSOLE
TURNTABLE
PROJECTION
ROOM
AUDIO
0
VIDEO
CI=
00Ó000
CI
.0.
o.
STUDIO AUXILIARY
EQUIPMENT
AND
SYNCH GENERATOR.
MON TOR
MICROPHONE
SPEAKER
CONTROL ROOM
AUDIO OUT
SMALL TELEVISION STATION STUDIO SYSTEM
Ir,
VIDEO OUT
Ow-
THE TRANSMITTER ROOM
By contrast, the equipment shown here in the transmitter room
is fairly complete. It includes practically all of the units
equipment, and auxiliary items such as record turntable, monitor speaker and microphone. Naturally, in addition to this
equipment the station must also have an antenna and its associated tower.
necessary for a television station. Since the transmitter room
is much the same for all television stations, regardless of how
elaborate or simple the studio facilities may be, only this one
layout is shown. It is presumed that the station can grow
completely through the four stages depicted here without
necessitating any changes in the transmitter room equipment.
This is necessarily so because even in the smallest station there
can be no compromise in transmission quality or in compliance with FCC standards. The only marked difference in
larger stations is that the transmitter and studio will nearly
always be at different points, thereby requiring a coaxial or
micro -wave link circuit.
The four stages in the development of a television station
which are outlined in these pages can, of course, be varied
in many ways. In most stations the additions indicated will
probably be made in smaller steps than those shown. However,
the arrangements shown here serve to illustrate the main
stages and to indicate how the station may grow in accordance
with its audience, starting in a small way with a minimum
investment and operating staff, and adding facilities and personnel as the economics justify. The design of RCA Television
equipment units makes it possible to do this without making
original equipment obsolete, and with a minimum of interference to station operation during periods of equipment
expansion.
The standard transmitter room installation includes the following basic pieces of equipment: five kilowatt television
transmitter, vestigial side band filter and coupling network,
transmitter console, audio and video amplifier and control
TRANSMITTER
4
000 000 000
000 000 000
AUDIO
VIDEO
1
SIDE BAND FILTER
AND COUPLING
NETWORK
TURNTABLE
TRANSMITTER
AUXILIARY
EQUIPMENT
)`
II'
O O
o
o
o
0 :0: O
O O O
o
o
o
MONITOR SPEAKER
-40
TRANSMITTER
CONSOLE
.2
MICROPHONE
AUDIO IN
VIDEO IN
1
TELEVISION TRANSMITTER SYSTEM
ale
ANTE NNA
Addition of Portable Equipment Provides For
STAGE TWO: Field Pickups and Live Talent Studio Shows
trot console. This desk is recessed so that the suitcase -type field
units sit at an angle which brings their front panels flush
with the panel of the control console. This gives the assembly
the appearance of having been "built -in-one-piece," and provides a compact and convenient operating unit. The portable
synchronizing generator, and the power supply units may be
placed beneath the desk or in any convenient nearby location.
When it is desired to increase the facilities included in Stage
One this can be most easily and economically done by adding
a set of RCA portable pickup equipment. This equipment consists of one or more cameras, an equal number of camera control units, a video master monitor unit, and audio and power
supply units-all of which are designed and constructed in
auch manner as to be easily portable. While this equipment
is intended primarily for field use its flexibility is such that
it can easily be set up in the studio to produce the simple
types of live talent shows. Thus, in Stage Two of the television
plan outlined here, a set of this portable equipment will
double as field and studio video equipment. This will make
it possible for the station to put on a remote pickup-such
as a football or basketball game--one night, and a local studio
show the next night. Together with network and film programs
this will make possible a reasonably varied program schedule.
From one to four cameras may be used with this equipment.
Since each camera "chain" (i.e., camera plus camera control
unit) is independent of the others, it is entirely practical to
start with one or two cameras and add others as required.
For field use, the portable control equipment may be installed in a light truck, or it may be transported to the location and there set up wherever convenient. When it is to be
operated in the truck it is handy to have a recessed desk
similar to that used in the studio. Cabinets in the truck provide storage space for cameras, cables, microphones, etc. With
a truck setup the cameras may be as much as 500 feet away
with interphones providing communication between camera
men and the control position. Where the truck cannot be
brought within 500 feet of the camera positions it is necessary
to set up the control units at some other convenient location.
In many cases it will be possible to send the video signal to
the studio by means of specially -equalized telephone lines.
When this is not feasible an RCA Microwave Relay Transmitter can be used.
When the cameras are set up in the studios, the camera control units and the video master monitor unit are placed on
a desk in the control room immediately adjacent to the con -
BOOM
MICROPHONE
FIELD
TYPE CAMERAS
MICROPHONE
STUDIO
NETWORK IN
O
FIRE WALL
FILM
1
i
C
z
FILM
CAMERA
PROJECTORS
TURNTABLE
CONTROL
CONSOLE
STUDIO AUXILIARY
EQUIPMENT
AND
SYNCH GENERATOR
VIDEO
MONITOR
SPEAKER
PROJECTION
ROOM
MICROPHONE
CONTROL ROOM
SMALL TELEVISION STATION STUDIO SYSTEM WHEN PORTABLE
EQUIPMENT IS USED FOR LIVE TALENT STUDIO PRODUCTIONS
148
AUDIO
VIDEO
OUT
OUT
Studio -Type Cameras and Video Equipment
a Permanent Video System
STAGE THREE: Added to Form
boom -type stand while the other is suspended from overhead.
In the film projection room a 16 mm projector and two slide
projectors are added to the two 35 mm projectors previously
installed, while in the control room a second film camera is
installed. It will be noted that in thus enlarging the film facilities all of the original equipment is used-none is wasted.
The equipment facilities included in Stage Two will provide
for simple types of live talent studio programs in the early
stages of station operation. However, as the station activities
increase, several disadvantages will become evident. It will
not, for instance, be possible to switch from a remote pickup
to a studio show. Moreover, the equipment will not always be
available for studio rehearsals and, in general, it will be less
convenient to operate and maintain than would a permanent
setup.
In the control room proper the video and control equipment
is, of course, greatly expanded. Here again, however, all of
the original equipment is used without change. The audio console remains exactly as is, except that there are now more
audio inputs brought into it. The video console now consists
of five standard camera control units.
In going to Stage Three permanent equipment of fairly elaborate nature is installed in the live talent studio; the film
equipment is greatly increased, and the control room facilities
are expanded to include a large video console, a director's
console and various additional auxiliary items.
One entirely new item is the Director's Console. This desktype unit contains three picture tubes which portray, respectively, the picture being transmitted, the picture on the second
camera, and the "cue" picture on a program coming up.
The equipment in the studio (which, of course, can be varied
to meet individual needs) includes three deluxe-type cameras.
Two of these are usually mounted on small dollies while the
third is mounted on a large crane -type dolly to provide for
angle shots and shots from above. Two microphones are included (usually a number of additional microphone outlets
are provided for). One of these is usually mounted on a large
BOOM MICROPHONE
In Stage Three the portable equipment is, of course, assigned
entirely to field duty. The availability of special equipment
for remote pickups, which is always ready (and preferably
stored permanently in the field truck), is an advantage any
broadcast engineer will appreciate.
STUDIO CAMERAS (ICRANE TYPE DOLLY)
STUDIO
/^
.35MM.
PROJECTORS
MICROPHONE
//
0 00 O 000
o 010
AUDIO
CONSOLE
DIRECTOR'S
CONSOLE
0000
0000
g ºI º1818
am-
FILM
CAMERAS
VIDEO
CONSOLE
I'll
AZIMmeo.
r)o
STUDIO AUXILIARY EQUIPMENT
CONTROL ROOM
MONITOR
SPEAKER
u
SLIDE
PROJECTORS
AUDIO VIDEO VIDEO
NETWORK IN
OUT
AUDIO
OUT
1
STANDARD TELEVISION STATION STUDIO SYSTEM
I
1
PROJECTION
ROOM
Studio Provided and Master Control Room
STAGE FOUR Additional
Added to Form a "Master Television Studio System"
The equipment facilities included in Stage Three (preceding
page) will provide for the requirements of most stations during
at least the initial period of station development. Moreover,
the unit plan on which RCA equipment is based makes it possible to add additional equipment, for example extra cameras, as these are required. It is even possible to add additional studios which can be handled from the original control
room by the provision of additional camera control units.
However, it is felt that major stations in large cities, and
certainly all network stations that must originate many studio
programs, will eventually require a master control setup, in
which each studio has its own individual control booth and a
separate master control room, is provided for centralizing all
operations. Such an arrangement, which is similar in principle
to that presently used in large broadcast stations and network
studios, is the next stage in the television plan outlined here.
in others. Moreover, such rehearsals can be complete with the
whole staff, including control room operators, in their final
positions (which would not be possible if there were but one
control room for all studios).
The number of live talent studios in an installation of this
kind is not limited. A possible arrangement would be to provide space for as many as five or more, but to install equipment initially in only two or three. Each of these studios, with
its associated control booths, would be equipped approximately as indicated for "Studio A" in the diagram below. It
will be immediately noted that this equipment is the same as
that provided in the studio and control room of Stage Three
(except that film equipment has been moved to a new location). In fact, in progressing from Stage Three of this plan
to Stage Four, it will often be possible to leave the original
studio and control room intact. The transition can be made
in easy steps by adding, one at a time, additional studios,
each with its own control room.
The arrangement depicted for Stage Four is a multi -studio
installation in which each studio, whether film or live talent,
is ,a complete operating unit in itself. Thus, while a program
is being aired from one studio, rehearsals may be carried on
CAMERAS
STUDIO
MICROPHONES
FIREWALL
STUDIO A
FILM CAMERAS
oloIo
L0J AUDIO
STUDIO A
CONTROL ROOM
TURNTABLES CONSOLE
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35 MM. PROJECTORS
VIDEO
CONSOLE
DIRECTOR'S
CONSOLE
MONITOR
SPEAKER
VIDEO
CONSOLE
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MONITOR
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NETWORK OR
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STUDIO
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SLIDE PROJECTORS
VIDEO OUT
PORTABLE VIEWING MONITOR
OPERATOR'S CONSOLE
Q
ANNOUNCE
STUDIO
0
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FILM CONTROL
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ROOM
PROJECTION
0
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150
STATION
SYSTEM
ROOM
RCA Television Studio Equipment
can buy to suit his particular needs. All units have matching
appearance and umber-gray finish. Moreover, they are electrically and mechanically designed to operate together. Additional units can be added at any time without fear of filling studios and control rooms with a number of dissimilar
RCA Television Studio Equipment is designed for all television
transmitting installations, large or small. It is economical for
stations starting out in a small way, because a minimum number of equipment units will handle their early requirements.
As these stations grow, and new sources of program material
become available, additional equipment units can be added
without discarding previously installed equipment. In this way
the small broadcaster can expect to have eventually a station
which duplicates in appearance and facilities those stations
which start on a larger scale.
components.
arrangement of what we consider to be
the basic equipment required for even the smallest station
with studio facilities is shown in the block diagram above.
A typical electrical
RCA add -a -unit designs are also economical for larger television stations; first, because they eliminate costly duplication
of apparatus, and second, because their manufacture in relatively larger quantities makes it possible to offer better quality
at lower prices.
For all television broadcasters who plan to provide studio and
film telecasts, there are five basic types of equipment required.
These are, namely: (1) Pickup equipment, i.e., studio cameras,
film and slide projectors; (2) a switching system for the cameras (or for the studios) ; (3) sync generating equipment; (4)
program monitoring equipment; and (5) camera dollies and
pedestals, line amplifiers, power supplies, etc. These items can
be obtained separately, so that in each case, the broadcaster
151
Use is made of two Type TK -10A Studio Camera equipments,
two TK -20A Film Camera equipments, a TG-1A Studio Sync
Generator, and a TS -10A Switching System. The switching system can handle six input lines. As shown in the diagram, two
of these six inputs are used for remote lines such as network
or field pickups, and the other four are divided between two
room, the video console formed by the camera control units
and one switching unit will in most cases be adequate for
satisfactory supervision and direction of programming. This
video console is made up by bolting side by side one camera
control section from each camera equipment plus a switching
section. The addition of trim end-sections then forms an attractive desk -type console. Any number of these units can be
fastened together.
studio cameras and two film cameras. Sync is fed from the
Sync Generator through a pulse distribution box to the four
camera equipments. Ordinarily, video signals fed to the remote
inputs already contain sync which is supplied by the field
equipment, or, in the case of the network input, is supplied
at the station of origin. However, the switching system can
also add sync automatically to remote input signals when
necessary.
Stations employing several studios and facilities for network
programs will require a program director's console. This console is styled similarly to the video console, but the viewing
monitors are built inside the housing and viewed through an
opening in the top of the console. Thus, light cannot strike
the screens. The director's console is provided with three
monitors, two for preview and one for the program line. A
switching panel allows the director to fade, lap -dissolve and
switch the video signals.
Program monitoring equipment required depends upon the
number of studios employed by the broadcaster. For the
-maller stations with perhaps one studio plus a projection
RCA TELEVISION STUDIO CAMERA EQUIPMENT
Max. NumberofCameras, Four
r
r
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TK -10A STUDIO CAMERA EQUIP. #1
STUDIO
CAMERA
CAMERA
STUDIO
PULSE
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GENERATOR
POWER
CAMERA
SUPPLIES
MONITORI
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REMOTE INPUTS
TK -10A
STUDIO CAMERA EQUIP.#2
STUDIO
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CAMERA
CONTROL
CAMERIA
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SWITCHING
1r
POWER
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SUPPLIES
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STUDIO CAMERAEQUIP.#3
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STUDIO CAMERA UNIT #4
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152
J
Studio Camera Type TK-1OA
Features
Camera does not require costly, uncomfortably -hot lights.
Camera mounting designed for
type dolly or studio pedestal.
Four lens positions provided on
standard tripod,
a
a
a
crane
rotatable turret.
Optical focusing easily accomplished by
side of the camera.
a
knob on the
Hinged doors and covers permit easy access to camera circuits and controls.
Five tally lights, two on the front of the camera, one on
rear of camera, one on the viewfinder and one along the
viewfinder kinescope, indicate to the cameraman and performers when the camera is on -the -air.
combination microphone and headset for each operator
produces program sound in one earphone and order wire
conversation in the microphone and other earphone.
A
Two jacks on camera --one for cameraman, one for production man.
Uses
The TK -10A Studio Camera Equipment is designed to pick
up scenes produced in television studios, and provide composite video signals that can he fed to a television transmitter.
The camera uses a studio type Image Orthicon pickup tube
which requires much less light than former studio cameras
employing the Iconoscope pickup tube. Under normal lighting conditions (100 to 200 foot-candles) an excellent picture
is obtained. In fact, the quality of the picture compares favorably with that produced by the Iconoscope operating with
light values of 1000 footcanxlles.
Description
The TK10A Studio Camera Equipment consists of the Cam
era itself, which can he mounted on a crane type dolly or
studio pedestal, a Camera Control mounted in a desk -type
console section, and power supplies designed for rack mounting. The size and general appearance of the console section is
identical to that of the Film Camera Equipment and the Studio
Switching System. Therefore, the studio camera control unit
can be used in conjunction with other studio and film units.
Any number of these console sections (one for each camera)
can Ise bolted together to form a convenient desk -type console.
board below the shelf. The deflection and high voltage pulse
supply circuits are mounted in a similar manner on the other
side of the camera. Hinged doors on either side of the camera
swing down to provide easy access to the camera circuits.
Four EKTAR type lenses are mounted on a lens turret which
can he rotated by a handle at the rear of the camera. These
lenses are relatively small due to the small size of the photocathode in the pickup tube. They are available in sizes from
35 mm f2.8 to 135 mm f3.8. Optical focusing is accomplished
by adjustment of a knob on the side of the camera. This
knob moves the pickup tube and its focus and deflection coil
assembly with respect to the lens.
STUDIO CAMERA
The general arrangement of the controls and components of
the Studio Camera resembles that of the RCA Field Camera.
Like the field camera, the studio camera employs image
orthicon deflection circuits, a picture preamplifier, and an
electronic viewfinder which is mounted directly on the camera.
The viewfinder, which enables the camera man to view the
scene he is picking up, uses a small picture tube (RCA-5FP4A)
which operates with an image brightness satisfactory for viewing scenes even in brightly lighted studios. Camera circuits
are arranged on either side of the tube and coil assembly. On
one side, the video preamplifier tubes are mounted on a shelf
with the circuit components easily accessible on a terminal
Controls for the studio camera circuits are located on the rear
of the camera in two rows behind hinged covers. All these
controls are normally preset and do not require adjustment
during a program. Communication and tally light circuits are
provided in the camera cable.
153
CAMERAS
Specifications
Number of Lines_
Odd Line Interlacing__-_
Frame Rate
Field Rate
Picture Signal Level
525
to 1
30 per sec.
60 per sec.
15 volts, peak -to -peak max.
(conforms to RMA standards)
Black negative
Picture Polarity at Output
75 ohms
Impedance of Coaxial Transmission Line
1000 ft.
Maximum Length Camera Cable
Total Included Angle of Lenses:
50°
(a) 35 mm f2.8 Ektar
34°
(b) 50 mm f1.9 Ektar
(3 lenses
0°
Ektar
(c)
mm
furnished)
13°
(d) 13590 mm f4f2.855
25 foot-candles
Incident Illumination (min)
Incident Illumination for Best Results__100 to 200 foot-candles
117 volts, 60 cycles
Power Source_
Power Consumption:
375 watts
-(a) Heater Supply Camera Control
800 watts
(b) Two WP -33A Power Supplies
370 watts
(c) One 580-C Power Supply
15 watts
(d) Current Regulator
9
1560 watts
Total for One Camera Chain
MECHANICAL SPECIFICATIONS
Camera (including Viewfinder)
Length
Width
Height
Camera Control Console:
Depth
Width
Height (overall)
Weights:
Camera (including Viewfinder without lenses)
Camera Control Console Assembly
(including Master Monitor)
Studio Camera Control Unit
STUDIO CAMERA CONTROL
The Studio Camera Control enables the video operator to
monitor and control the quality of the picture signal produced
by the studio camera. It is a desk -type console section with a
TM -5A camera monitor mounted in the upper part, and the
control chassis mounted in the compartment below. The camera
monitor has a 10 -inch picture tube for displaying the picture,
and a 5 -inch oscillograph tube which reproduces the picture
signal waveform. Controls for gain and black level setting are
brought out on the monitor front panel.
Camera Cable
04
35"
13"
20"
36"
13'/4"
41"
105 lbs.
140 lbs.
lbs. per foot
The control chassis contains the necessary circuits for ampli.
fying the video signal, establishing black level, mixing in a
sawtooth correcting signal, adding picture blanking to the
picture signal, adding the synchronizing signal, and providing
3 separate outputs. It is a vertically mounted chassis with a
bracket projecting from the top part of the chassis supporting
the operating controls. Four commonly used controls project
through the desk top surface. These are:
1. Orthicon Focus
2. Beam Current
3. Target
4. Image Focus
Three less frequently used controls are recessed under a small
panel in the top surface.
The control unit complete with its controls can be removed
easily from the console by removing the lower front panel
and eliding the unit out. All electrical connections are made
with plug-in connectors.
POWER SUPPLIES
Four power supplies are required for each camera chain. These
are as follows:
L Type WP -33A to supply B-{- to master monitor.
2. Type WP -33A to supply 13-1- to camera and viewfinder.
3. Type 580-C to supply BI-- to camera control and to current
regulator.
4. Current regulator to supply constant current to camera focus
coil.
These four power supplies are designed for mounting in a
standard rack in the studio control room.
Close-up of Camera Control Unit controls (on sloping
panel to right of TM -5A Monitor)
151
CAMERAS
Film Camera Type TK -20A
Features
Description
Either positive or negative film can be used.
Tubes and parts are easily accessible.
The Film Camera Equipment is designed to meet the requirements of any size television station. Ordinarily, the film
camera is permanently mounted to the floor in the projection
room, although it also can be mounted on a wall track so
that it can be moved easily to any one of several film projectors
installed in the room.
The Camera Control Unit consists of a chassis type unit containing circuits for control of the signal generated in the film
camera, and a Type TM -5A Camera Monitor for analysis of
the video signal and observation of its picture quality. These
two units are mounted in a desk-type console section which is
located in the transmitter room or studio control room. This
console section can be grouped with other console housings
(with end sections for trim) to form a neat convenient operating desk. The monitor unit contains a 10 -inch picture tube
and a 5-inch oscilloscope. D -c voltages for the TK -20A camera
equipment are supplied by two Type WP -33A Heavy Duty
regulated power supplies. These power supplies are rack mounted in the control room or transmitter room. The TK-20A
equipment is finished in umber gray to match other RCA
television equipment.
Operation is simple --few controls are used.
Camera can be operated 50 feet from control console.
Oscilloscope in monitor can be used for measuring pulses.
10 -inch
aluminized tube for picture monitoring provides
very bright picture.
Clamp circuit eliminates low -frequency microphonics from
video signal.
Uses
The RCA Film Camera Equipment consists of a Film Camera,
a Camera Control Unit, and associated power supplies and
cables. This camera chain when properly set up with a motion
picture film projector or a slide projector, and supplied with
synchronizing signals, will produce standard video signals which
can be fed to the television transmitter. By use of an RCA
Multiplexer, which is a small, compact device having two
mirrors mounted at the required angle, a single film camera
can be arranged to serve two film projectors and a slide projector. The TK -20A can be used with either 16MM or 35MM
projectors.
FILM CAMERA
In the illustration, the film camera is shown mounted on a
pedestal, which provides for permanent mounting to the floor.
If the camera is to be mounted on a wall track, the pedestal
of course is not required. Contained in the film camera case
135
CAMERAS
POWER SUPPLIES
The Type WP -33A Heavy Duty power supplies each furnish
extremely well -regulated d-c voltages at loads from 200 to 600
milliamperes. Output voltages are adjustable between 260 and
295 volts. The components are assembled on recessed type
chassis for mounting in standard cabinets or open racks.
Specifications
POWER REQUIREMENTS
105-125 volts, 60 cycle, single phase
Line Rating
1000 watts
Power
101 amps.
Current
0 94
Power Factor
INPUT SIGNALS
Horiz. Drive
Vert. Drive
CRO Drive (optional)
Mixed Sync (optional)
Mixed Blanking
Communication Circuits
volts, 15,750 cps, 10% pulse width
4 volts, 60 cps, 4% pulse width
8 volts, mixed 30 cps and 7,875 cps
4 volts, RMA signal
4 volts, RMA signal
4
OUTPUT SIGNALS
1 5 v. peak -to -peak (picture signal)
Picture Output
1.5 v. peak -to -peak (picture signal)
Remote Monitor Output
Flat within 1 db to 6 megacycles
Frequency Response
High
Input Impedance for Pulses
Camera Control Unit showing interior arrangement. This unit
is normally housed in the master control console.
are the RCA 1850 Iconoscope pickup tube, blanking and deflection amplifiers and a 6 -stage video preamplifier. Since the
picture from the projector is focused directly on the mosaic
of the Iconoscope, no focusing lenses are required for the film
camera.
CAMERA CONTROL
The Camera Control consists of the control unit proper and
the Type TM -5A Camera Monitor. The control unit contains
a picture signal amplifier fed by the preamplifier in the camera, pulse line amplifiers to feed driving signals from the
studio sync generator to the camera, and several controls directly associated with the operation of circuits in the camera.
All components of the control unit are mounted on a chassis
installed in the console desk directly below the camera monitor, the controls projecting through a sloping panel on the
top of the console.
Electrically, the Camera Monitor is identical to the TM -5A
Master Monitor used with the field camera equipment. It
contains a 10-inch aluminum-backed Kinescope for observation
of the composite video signal fed to the transmitter, and a
5 -inch oscilloscope for viewing the signal waveform and for
quickly and accurately measuring signal levels. A calibration
circuit in the monitor permits quick reference to a fixed
voltage level. Circuits in the camera monitor include separate
low -capacity inputs, video amplifiers and scanning generators
for both the Kinescope and oscilloscope tubes. Transformers
within the TM -5A provide filament voltages for all tubes in
the monitor. Plate voltages are supplied by one of the WP -33A
power supplies.
Typical arrangement of TK -20A Film Camera and
TP -16A Film Projector
156
PROJECTORS
Film Projector Type TP -16A
Features
Simple, straightforward film path provides for quick and
easy threading.
Removable film gate makes aperture cleaning easy.
Constant light source provides utmost simplicity in design.
Film lengths up to 2000 feet can be used without replacing
reels.
Coated lenses minimize reflections and improve contrast.
Resolving power of lens is 60 lines per millimeter at any
point in the field.
Projector can be operated on
a
current supply of
50 cycles
as well as 60 cycles.
Uses
The TP -16A Film Projector is used in television studios to
provide regular program material using standard 16mm sound
motion -picture film. To obtain the video signal, the projector
is used in conjunction with the TK -20A Film Camera, and
the two units are mounted in such a position that the TP -16A
projects a picture directly onto the mosaic of the picture
tube in the film camera.
The TK-20A Film Camera is similar to a studio camera except that it is not provided with any optical focusing system.
Instead, the optical system of the projector is used to size
and focus the picture which is projected on the pickup tube
mosaic.
When more than one projector is used, it is not necessary to
have a separate camera for each projector. If the film projectors are arranged in pairs, a mirror switching arrangement
may be employed to make one camera serve both projectors.
Since projectors are ordinarily used in pairs (for showing
alternate reels) this is a very practical arrangement.
Description
The TP -16A Projector is entirely self-contained and, with the
exception of the film feed arrangement, is entirely enclosed.
The projector housing is provided with an attractive umber gray crackle finish matching that of other RCA television
equipment. The projector proper is mounted on a heavy cast
base frame. This frame in turn is mounted by means of leveling screws on a lightweight pedestal of matching design and
finish. This pedestal greatly improves the appearance and
provides a convenient place for mounting the controls and
field-supply for the special three-phase motor which is a
feature of the TP-16A.
illumination on the mosaic of the camera iconoscope and is,
of course, much simpler than systems using switched or pulsed
light sources.
The film feed arrangement of the TP 16A is identical to that
of the standard projector with the exception that the pull down claw works at a greater speed. Film is fed from the
upper reel under a large sixteen-tooth feed sprocket and
through the precision made film gate Light, controlled by a
rotating shutter, is projected through the film at this point.
The film is pulled down through the gate., a single frame at
a time, by the pull -down claw just below the gate.
The mechanism of the Type TP-16A Television Projector is
an adaptation of that used in RCA's outstandingly successful
PG -201 Deluxe 16mm Sound Projector. The film feed arrangement, optical system, and sound pickup unit of the TP -16A
are identical to those of the PG -201. The cast-aluminum frame
and the front part of the projector housing are also the same.
Use of these precision -made components, whose satisfactoriness
is attested by thousands of PG -201's in use, not only insures
trouble -free operation, but also makes it possible to provide
a deluxe -type projector at a price much lower than would be
entailed if these machines were special -developed and manufactured from scratch in the relatively small quantities required for television use.
Since television standards (and proper synchronization) require transmission of 60 fields (30 frame interlaced) per second, and motion picture film is made for projection at 24
frames per second, some means must be provided for conversion from the one rate to the other. In the TP-16A this is
done by "scanning the first frame twice, the second frame
three times, the third twice, the fourth three times, and so on.
The average rate, then is 21/2 scanninga per frame-which,
multiplied by the 24 frames per second, provides 60 scanned
fields per second.
The optical projection system consists of a 1000 -watt air blast
cooled incandescent lamp, a silver-coated pyrex glass reflector,
a large two -element aspheric condenser lens, and a 3 inch,
F.2 "coated" projection lens. This system provides plenty of
157
PROJECTORS
If the "pull-down" coull be accomplished during the vertical
blanking interval-1/750th of a second, every 1/60th of a
equalizer panel is available as an accessory for the
projector sound channel and is identified as MI -26313. The
unit is constructed to be mounted convenient to the audio
control position so that the film sound may be easily adjusted
for proper response. The compensation in frequency response
is necessary because of the wide variation in recording of
and printing of 16mm films. A single control is used in a tilt
circuit with a straight through center position; with three high
boost and three low boost positions of 2.5 db steps each.
A sound
second-no further modifications
of the standard projector
would be necessary. Unfortunately this is not mechanically
possible. Therefore, a further stratagem is employed. This consists in the use of short light flashes so timed that the film
picture is projected on the pickup tube mosaic for only
1/1200th of a second, every 1/60th of a second. These flashes
occur during the vertical retrace time and are provided by
a rotary shutter which consists of an 18-inch metal disc with a
slot cut in its periphery. This disc is driven at a speed of
exactly 3600 rpm by a special 3-phase synchronous motor. This
arrangement is possible because the mosaic of the pickup tube
"stores" the picture during the interval between flashes of
Provision for Remote Control
Controls mounted on the projector include "Standby," "Emergency Run," "Start," "Stop" and "Remote." When the remote
switch is operated, "Start" and "Stop" controls at a remote
location may be used to control operation. These circuits
operate through relays and a master contactor mounted on
the pedestal.
illumination.
Synchronization of the TP -16A Projector with the television
system is assured by virtue of the fact that both the television
synchronizing generator (which drives the beam in the camera
pickup tube) and the motor which drives the projector shutter
have a common source of power. To insure that the shutter
will be in step at all times a large-size motor with a separately
excited d-c field is used. The d -c field, being polarized, makes
the motor always "lock" in proper phase relationship with
the sync generator. The power supply for the motor field is
mounted in the pedestal.
Maintenance Features
Easy and quick maintenance is one of the features of the
TP -16A projector. The field power supply, control circuits
and all external connectors in the pedestal are easily reached
by removing the pedestal side covers. The preamplifier and
exciter filament supply unit are available when the cover
plate, held by two thumbscrews, is removed. The projector
lamp is reached through a hinged door. The film gate assembly
is easily removed for cleaning. All parts of the film feed system
are in the open where they may be constantly observed.
Sound System
A number of unusual features are incorporated in this sound
unit. One is the use of radio -frequency voltage (28 kc) on the
exciter lamp filament. This prevents hum and noise from being
introduced by the lamp itself. Another feature is the fact
that the exciter lamp mounting and sound carriage are diecast in one piece, thereby insuring permanent accurate alignment. Still another is the use of the famous RCA-developed
rotary stabilizer on the sound drive. This maintains smoothly
uniform film speed for sound take-off-a guarantee of sound
reproduction at originally recorded pitch.
Specifications
Film Type
Film Capacity
Film SpeedShutter
Projector Lens Line
Projection Distance (3" lens)
Audio Output Power
Output Impedance
Frequency Response
Speed-
An audio preamplifier is built into the base of the projector.
This amplifier, which is of conventional design, employs an
RCA -1620 as a photo -cell amplifier, an RCA -6J7 as a voltage
amplifier and RCA 6V6FT/G as an output tube. A tapped
output transformer provides output impedances of 250 or
500 ohms. Output level is +4VU at 1000 cycles with less
than 1% total r-m -s harmonic distortion.
Standard 16mm
400' to 2000'
24 frames per second
60 frames per second
48" above floor
+4
40"
VU at 1000 cycles
950/500 ohms
±2 db from 80 to 3000 cycles
±3 db from 80 to 4000 cycles
Hum and Noise Level50 db below output level
Dimensions
Height 68"; Length 32"; Width 163/4"
Weight_ Projector 90 lbs.; Pedestal 135 lbs.; Total 225 lbs.
Tubes Required.l RCA -927, 1 RCA -1620, 2 RCA-6V6GT/G,
4 RCA-5Y3GT/G, Projector Lamp T-12
Power Required
209.220 volts, three-phase
250 watts
105-125 volts, single-phase
1200 watts
-
The audio amplifier is assembled on a small chassis which
can be easily removed from the base housing. Also mounted
on this panel is the 28 kc oscillator which supplies voltage
for the filament of the exciter lamp and a power supply using
a 5Y3-GT/E which supplies plate voltage for the amplifier
and oscillator.
158
PROJECTORS
Film Projector Type TP -35A
Features
Highly efficient pulsed light source, no shutter mechanism
required.
Quiet operation.
Excellent picture definition.
Completely enclosed unit-even to film magazines.
Very little heat on
be projected.
film-stills of any frame
of the film can
Spectral characteristics of light source comparable to natural
light-advantageous for use of color film.
RCA sound head used-response flat out to
6
kc.
Light output of projector favorable for proper operation of
film camera.
Use
The TP -35A 35mm Television Projector is designed for use
in television stations as a means for utilizing standard 35mm
sound motion picture films as program material. The TP -35A
can be used as the single source of program material for the
television station, or it may be alternated with "live" programs
and network shows to add variety to the station's program
schedule.
The TP-35A Projector is designed for use with the TK-20A
Film Camera. In the simplest arrangement, the projector is
mounted in such a position that it projects motion pictures
directly on the pickup tube in the TK-20A Film Camera. The
video signal produced by the camera is then fed to the studio
control room. A single TK -20A Film Camera can serve two
motion picture projectors and a slide projector by using a
Multiplexer. This device employs a slide projector and two
mirrors mounted at the required angle to direct the pictures
from either projector onto the pickup tube of the film camera.
Description
light lamp. Power for this lamp is furnished by a power supply which can be mounted in the studio control room rack
containing the monitoring equipment and remote control panel.
A control box on the rear of the projector contains the necessary switches for starting and stopping. For the use of two
projectors, a changeover panel is provided. This panel, which
is rack -mounted directly below the video monitor in the projection room, contains switches for starting and stopping either
projector, and for changing over from one projector to the
other. The changeover switches control relays which switch
the optical systems (douse and undouse) as well as the sound
circuits.
The TP -35A Projector is entirely enclosed. The housing is
finished in an attractive umber -gray crackle finish, matching
that of other RCA equipment. Shatterproof glass windows permit viewing the operation of the mechanism without removing
any door or cover.
Film is fed from the upper film magazine down through the
film feed sprocket and through the film gate in the picture
head. At this point, light produced by a pulsed -light lamp is
projected through the film. The pulsed -light system eliminates
the need for a shutter mechanism. It consists of an electrically
operated gas -filled lamp which produces short pulses of light
at the required rate of speed. The film then passes over the
sound drum to the lower film magazine in the pedestal of
the projector.
All moving parts of the projector are automatically and continuously lubricated. A pump inside the housing delivers a
continuous flow of oil from the reservoir at the base of the
main frame to the rotary lubricator which throws the oil over
the gears and to every bearing. An oil sight gauge provides an
indication of the amount of oil in the reservoir.
Also contained in the pedestal is a power supply which furnishes d -c voltage for the field of the driving motor, and a
terminal board on which is mounted the relay for the pulsed.
159
PROJECTORS
Film Multiplexer
Type TP-9A
Features
Permits use of a single film camera for two film projectors.
Employs built-in slide projector.
Employs long life front -surface type mirrors.
Aids program continuity.
Introduces negligible optical distortion.
Permits use of a stand-by film projector.
Designed for use with 16mm and 35mm projectors.
Employs no moving parts.
Uses
The Film Multiplexer is a device for use in the television
projection room. It enables television station personnel to
permanently arrange a single film camera and two film projectors so that either projector can be used with the film camera, without need for moving the units about the room.
The Multiplexer employs two mirrors mounted at the required
angle to reflect the image from either projector onto the pickup
tube in the film camera. In addition, a small slide projector
mounted just above the two mirrors provides a means for
station identification. The image from the slide projector is
focused directly on the tube in the film camera.
Using the Film Multiplexer, it is also possible to have a
standby film camera already set up for emergency use. The
four units are then mounted opposite each other with the
Multiplexer in the center. Since the mirror and slide projector
assembly of the Multiplexer swivels on the pedestal mounting,
the Multiplexer can be quickly swung around to serve either
film camera.
Description
The Film Multiplexer consists of a cast aluminum pedestal
which mounts two front -surface mirrors and a slide projector.
The pedestal is fitted with a flange at the bottom for bolting
to the floor. The slide projector is an Eastman Type A-2
Kodaslide Projector with a 100 -watt projection lamp. The
Multiplexer is finished in umber gray to match other RCA
television equipment.
Specifications
Power Requirement (for projector lamp)
110 volts a -c, 50/60 cycles
Dimensions (overall):
Height
54"
Width
13"
Weight
Typical projection installation showing Multiplexer with two
TP16A Film Projectors and TK20A Film Camera
Stock Identification
160
40 lbs.
MI.26318
Studio Camera Switching Equipment Type
TS -10A
Features
System will accommodate six signal inputs.
Manual fading control allows choice of any fading speed.
Remote signals can be previewed before being switched
on -the-air.
Full complement of tally lights.
Tally lights at on -the -air cameras are activated by the
switching system.
Local sync automatically added when remote sync fails.
Private or conference communication can be maintained
between all stations.
Intercommunication can be operated with other equipment
off.
All personnel have access to program sound.
Stabilizing amplifier automatically corrects picture -sync
ratio for transmitter.
Uses
The TS -10A Studio Camera Switching System is designed for
use by television stations obtaining video signals from more
than one line. Briefly, the TS -10A will allow a single video
operator to do these things: (1) Select any signal from six
input lines; (2) switch the desired signal into the on -the-air
line; (3) fade or dissolve two signals simultaneously at any
speed; (4) fade in or fade out any one signal; (5) switch
instantaneously front one signal to another; and (6) superimpose two signals with any desired degree of magnitude for
each signal.
Intercommunication circuits in the TS -10A allow program personnel two-way conversation. In addition, volume -controlled
program sound is supplied to all personnel through one earpiece of their headset.
The controls for the switching amplifier project through the
inclined top panel of the desk. These controls consist of two
banks of pushbuttons from which the on -the-air signal is
selected, two toggle switches for controlling local and remote
sync, gain controls for two remote input lines, a three -position
switch for selecting either the on -the-air signal or one of the
two remote signals for preview display on the monitor, fading
and dissolving controls, and tally lights showing which inputs
are being used.
Description
The TS -10A Studio Camera Switching Equipment consists of
the switching amplifier chassis -type unit, a TM -5A Master Monitor, two WP-33A Power Supplies and a TA -5B Stabilizing
Amplifier. The switching amplifier is mounted in the lower
compartment of an RCA desk -type console section, and the
TM -5A Master Monitor is mounted above it. The TA -5B
Stabilizing Amplifier and WP -33A Power Supplies are also
chassis -type units designed for mounting in a standard equipment rack.
The switching amplifier consists of 3 two-stage picture amplifiers and 2 two-stage sync relay interlock amplifiers. Two of
the picture amplifiers have their inputs connected to separate
banks of camera selector switches. They have common outputs,
however, so that they can serve one camera singly or two
cameras together in a lap -dissolve or superimposition. The
third picture amplifier feeds the monitor input. The two sync
amplifiers automatically add local sync to the video signal when
remote sync fails or when local sync is otherwise required.
Specifications
Power Line Requirements
100-120 volts, 50/60 cycles, 1060 (max.) watts
(includes power required by the two WP-33A Power Supplies)
Input Signal:
Local Input
(video from camera control)
1 5 v. peak -to -peak
Auxiliary Input (as remote)
1.5 v. min. peak -to -peak
video, 18.33% sync
Input Impedance:
Local Input
75 ohms
Auxiliary Input
75 ohms, variable line termination
(as remote)
75 ohms
Output Impedance
Mechanical Specifications (Console Section) :
Dimensions (overall)
41" High, 13" Wide, 6" Deep
46 lbs.
Weight
Dark umber gray
Finish
Close-up of TS10A Control Panel
161
MONOSCOPE
Monoscope Camera Type TK -1A
Features
Description
Useful to television transmitting station, laboratory, factory,
or service bench.
The TK-1A Monoscope Camera comprises the monoscope tube,
the scanning generators, the video output amplifiers, and the
high voltage power supply for the monoscope tube. This equipment is built on the familiar recessed bathtub type of chassis
which fits into a standard nineteen -inch rack. All tubes and
large components are located on the front of the chassis, while
the wiring and smaller components are on the rear. The controls are grouped on a narrow control panel along the bottom
of the chassis. When installed and in operation, the front is
covered by a large cover plate which conceals everything but
the control panel. This cover plate is interlocked to protect
operating personnel from the high voltages present in the
equipment.
Compact construction; bathtub chassis.
Built-in high voltage power supply.
Pattern shows scanning symmetry, vertical and horizontal
resolution, shading, reproduction of isolated details, contrast
and brightness.
Accessible arrangement.
The monoscope tube in the TK-1A is mounted in a vertical
position at the left of the chassis. The upper part of the tube
is enclosed in a mu-metal shield. The magnetic deflecting coils
are mounted within the shield, and are attached to it. By disconnecting the tube socket, anode, and signal leads, the whole
assembly-tube, coils, and shield-may be swung outward. This
arrangement allows the tube to be changed very easily, and,
at the same time, is very economical of rack space.
Uses
The Type TK -1A Monoscope Camera may be used as a convenient means of obtaining an image for video testing of television transmitting equipment, or a "test pattern" to be
transmitted during warm-up and stand-by periods. In the latter
case, the station call letters may be made a part of the pattern,
thereby providing station identification. It may, likewise, be
used in the television transmitting station as a readily available
source of video signal, of known quality, to be used in place
of the studio camera when making tests or adjustments on
other units of the system. In the laboratory, factory, or service
bench, the equipment may be used as a source of video signal
to test or adjust television receivers, video amplifiers, and
picture tubes. With the addition of an IF sweep generator and
an RF signal generator, it produces a complete television picture signal simulating that received off the air, and thus provides a means of testing receivers under conditions equivalent
to actual use.
The monoscope tube ordinarily used in the TK -1A is an
RCA-2F21. This tube provides a pattern which combines the
features of several previously used tubes. It shows the following details of the quality of reproduction in a given television
system: scanning symmetry, resolution in both vertical and
horizontal directions, shading and reproduction of isloated details. In addition it provides a pattern to facilitate proper
adjustment of contrast and brightness.
The Vertical Deflection Generator consists of four tubes and
associated circuits. The first of these tubes amplifies the driving
162
MONOSCOPE
two separate outputs-one of which may be used to feed a
monitor, while the other is usually connected to a distribution
amplifier.
signal received from the synchronizing generator and generates
a sawtooth voltage wave which is amplified in the second,
third, and fourth tubes. The output is applied to the magnetic
deflecting coils of the monoscope tube. Negative feedback is
employed to improve scanning linearity.
Specifications
The Horizontal Deflection Generator includes three tubes and
associated circuits. The first tube is the driving signal input
amplifier and sawtooth voltage generator; the second and third
tubes amplify the output wave and feed it to the horizontal
deflecting coils of the monoscope tube.
Output Voltage
Power Supply Required:
110-120 volts a -c 60 cycles
280 volts d -c
The Blanking Amplifier is used to provide the proper level
and polarity of the blanking pulses received from the synchronizing generator before these pulses are fed into the
Video Amplifier for mixing with the video signal.
Dimensions
Weight
VERTICAL
DRIVING SIGNAL
O
>
VERTICAL
DEFLECTION
GENERATOR
O
>
1
1
1
RCA
RCA
RCA
RCA
8016
6Y6
6V64T
2F21
MI -26960
Accessories
Tube Kit (complete tube complement)
-ML26679
OUTPUT INCLUDES VIDEO
AND BLANKING SIGNALS
>
MONOSCOPE TUBE
VIDEO
AMPLIFIER
)3
-E-.-- - ---->
-E-
L --
TYPE
O
rt... .n+-^
A
J
BLANKING
AMPLIFIER
r
1
HORIZONTAL
DEFLECTION
GENERATOR
KINESCOPEtBLANKING SIGNAL
high, 19" wide, 11" deep
55 lbs.
Stock Identification
SUPPLY
O
watts
950 ma.
- E-1
HIGH
VOLTAGE
HORIZONTAL
DRIVING SIGNAL
volts peak to peak
75
171/2"
Tube Complement:
6 RCA 6AC7
1 RCA 6116
3 RCA 6AG7
3 RCA 6SL7-GT
The Video Amplifier includes six stages of video amplification-together with a clipper stage which is inserted between
the fifth and sixth stages. The monoscope output signal is fed
directly into the first stage of this amplifier, and the blanking
signal is introduced in the output of the fourth stage. The
output of the fifth stage (which contains both video and
blanking signals) is fed to a clipper stage which adjusts the
height of the blanking "pedestals". The clipper feeds an output stage which consists of two tubes having their grids tied
in parallel, but with the plate circuits separate. This provides
1.5
580-C
REGULATED
POWER SUPPLY
BLOCK DIAGRAM OF THE TYPE TK -1A MONOSCOPE CAMERA
Synchronizing Generator Type TG -1A
Features
Special circuits which maintain the timing of the leading
edges of the equalizing pulses, the horizontal synchronizing pulses and the vertical synchronizing pulses, with extreme accuracy.
An improved locking circuit for synchronizing the generator with the 60 -cycle power supply-or with a remotely
generated synchronizing wave form.
Use of circuits which are relatively insensitive to large
changes in tube characteristics, so that ageing of tubes will
not affect operation of the equipment.
Operation of all tubes in extremely conservative manner,
so that a very long, useful life may be expected.
Wiring which has been greatly simplified by carefully
grouping components so that all leads are very short.
A built-in oscilloscope which, by means of a selector
switch, can be used to check the step-down ratio of any
of the frequency -dividing counter circuits.
A regulated plate voltage power supply unit which, with
the other panels, is mounted in place and wired at the
factory. The unit is ready for operation immediately on
installation.
Uses
The TG -1A Synchronizing Generator is designed for use in
television transmitting stations as a source of synchronizing
pulses for the studio and film cameras, the monoscope camera,
the monitoring oscilloscopes, and the mixing amplifier (which
adds the synchronizing pulses to the transmitted video signal).
In laboratories and factories it is used in conjunction with a
monoscope camera to furnish a complete RMA standard video
signal voltage which can be used in the development and
production testing of television receivers.
Description
The Type TG -1A Synchronizing Generator is an integral unit
complete with power supply. It is assembled in a standard
cabinet-type rack which is 84 inches high, 22 inches wide and
18 inches deep. The rack has front and rear doors which open
the full length and width of the unit. This type of rack has
been standardized for all RCA television, broadcast, and communications terminal equipment. Moreover, all RCA Television and FM transmitters are made up of racks which are
similar in appearance, construction and height (although of
greater width). Therefore, the TG-1A Generator, and other
units mounted in similar racks, may be installed as needed,
with assurance that they will match in appearance, other terminal and transmitting units which may be added later.
the back of the panels, and are accessible through the rear
door. All terminals are in the clear, and components are
identified so that circuit testing, when required, is relatively
easy.
The 60 tubes and other components which make up the circuits of the TG -1A Generator are mounted on bath -tub type
chassis which are placed in the cabinet vertically, as shown
in the illustration. A 29% inch chassis at the top of the cabinet
contains the "pulse forming" circuits. Immediately below is a
similar chassis containing the "pulse shaping" circuits. The
101/2 inch chassis near the bottom is a standard Type 580-C
Power Supply Unit, and just below is a 1% inch chassis containing electrolytic filter capacitors.
Electrically, as well as mechanically, the TG -1A Generator is
divided into two main sections. The first section comprises the
"pulse -forming" circuits while the second section comprises
the "pulse-shaping" circuits. The "pulse -forming" unit generates all of the different timing frequencies which are required by the system. It also provides a means whereby these
frequencies (which are all derived from a single master
oscillator) may be "locked in", either with the local 60 -cycle
power line frequency, with a crystal oscillator, or with some
other external source, such as a remotely generated synchronizing wave form The "pulse -shaping" unit forms the pulses into
the proper wave shapes and combines them as required to
All of the controls, tubes and major components are mounted
on the front of the vertical chassis. Thus, all ordinary adjustments, as well as routine checks, can be made by opening the
front door. Since no high voltages are exposed on the front of
the chassis, this door is not interlocked. Wiring and minor
components, such as small capacitors and resistors, are on
164
provide the five different signals listed below. These signals
are fed to ten output connectors located on a subpanel at the
base of the "pulse -shaping" unit.
vertical pulse interval and six more following it. All of these
have the timing and wave shape prescribed by the RMA
Standards.
It is intended that RG11/U or RG59/U concentric lines be
used between these points and the studio cameras, mixing
amplifiers, etc. Two coaxial output connections are provided
for each signal so that output of either negative or positive
polarity is available. When more than one equipment is fed
from a single output, a distribution amplifier, such as the
Type TA-1A, should be employed in order to isolate the
circuits.
(4) KINESCOPE BLANKING SIGNAL
This signal is added to the transmitted video signal in order
to blank out the return trace in the receiver picture tube
(kinescope). It consists of square -wave pulses at horizontal
scanning frequency (15,750 cycles) and vertical scanning frequency (60 cycles). These pulses are of longer duration than
the synchronizing pulses and are transmitted at approximately
"black" level. They form the "pedestals" on which the synchronizing signals are placed.
Regulated plate voltages for the "pulse -forming" and "pulse shaping" units are furnished by the Type 580-C Power Supply.
Filament voltages are provided by transformers mounted on
the units themselves. All a -c power input to the cabinet is
controlled by the circuit -breaker switch at the bottom of the
"pulse -shaping" unit.
(5) OSCILLOSCOPE DRIVING SIGNAL
This signal consists of pulses at half horizontal (7,875 cycles)
and half vertical (30 cycles) frequencies. They are used to
trigger the saw-tooth generator in the monitoring oscilloscope,
thus providing (for "wave form" monitoring) oscilloscope
patterns which are two lines or two fields in length.
The Type TG -1A Synchronizing Generator furnishes all of the
timing pulses required in a complete television system. These
pulses are accurately timed with relation to each other, and
are carefully controlled as to wave form in accordance with
the standards adopted by the RMA. The five different output
signals which are generated will provide all of the timing and
synchronizing requirements of a standard 525 -line, 30 -frame,
interlaced television system. These five output signals are:
Specifications
Output Voltages
Synchronizing Signals (pulses as shown above black level in
the FCC drawing below)
4 volts, peak -to -peak across 75 ohms
Kinescope Blanking Signal (pulses as shown below black
level on FCC drawing below)
4 volts, peak -to -peak across 75 ohms
Horizontal Driving Signal (for actuating camera horizontal
scanning circuits)
4 volts, peak -to -peak across 75 ohms
Vertical Driving Signal (for actuating camera vertical scanning circuits)
_4 volts, peak -to -peak across 75 ohms
Oscilloscope Driving Signal
(for actuating oscilloscope for wave form monitoring)
8 volts, peak-to -peak across 75 ohms
(1) HORIZONTAL DRIVING SIGNAL
This consists of short -duration, square -wave pulses at horizontal scanning frequency (15,750 cycles). These pulses are
used to "trigger" the saw -tooth wave generator (in the camera)
which supplies the horizontal scanning voltage for the pickup
tube.
(2)
VERTICAL DRIVING SIGNAL
This consists of square -wave pulses of somewhat longer duration which occur at vertical scanning frequency (60 cycles).
These pulses are used to "trigger" the saw -tooth wave generator (in the camera) which supplies the vertical scanning
voltage for the pickup tube. The width of these pulses is
sufficient to blank out the vertical return trace of the camera
tube.
Power Supply Required
From 120 volt, 60 cycle, single phase line
Dimensions
Mounted in Cabinet
Unmounted Rack Units
Weight (in cabinet)
(unmounted)
(3) SYNCHRONIZING SIGNAL
BOTTOM OF
PICTURE-.
NTERVAL
VERTICAL
SYNCH
I$INC
----.a-EQUAL
PULSE
PULSE
J
rH.
ª5
MI-26915
Accessories
Front Door
Side Panel (single)
MI.30536-G84
MI -30541.G84
Mí-30596
Monogram
..-TOP OF
PICTURE
7
-MAXIMUM CARRIER
5H
LLILJLM_-11-117l:
1
1
160 lbs.
HORIZONTAL SYNCH.
PULSES
INTERVAL
3H
High, 22" Wide, 18" Deep
-77"84"High,
19" Wide, 12%" Deep
375 lbs.
Stock Identification
This is the signal which must be added to the camera picture
signal before it is transmitted in order to synchronize the
scanning action in the receiver. It is a composite signal consisting of (a) short-duration, horizontal synchronizing pulses
at 15,750 cycles, (b) longer duration, vertical synchronizing
pulses of the "serrated" type at 60 cycles, and (c) a series
of six short -duration; equalizing pulses just preceding each
EQPULIZING
450 watts
SYNCH.
1
-BLACK LEVEL
-
1
PICTURE & BLANKING
e
WHITE
PICTURE -1
VERTICAL BLANKING
HORIZONTAL
b
BLANKING
I
IF-'
..>- t I+
SEC.
TIME
SN
l
1
1
--
BLACK LEVEL
B
-MAxIMUM
WMITE
Comparison of odd -line and even -line synchronizing pulses
165
VOLTAGE
AMPLIFIERS
Distribution Amplifier Type TA -1A
Features
Equally useful as distribution, mixing or isolation amplifier.
Five amplifiers on one chassis.
Bridging inputs.
Excellent isolation between units.
Positive or negative polarity.
Standard "bath tub" type chassis.
A ccessible mounting arrangement.
rack or a standard open type rack. In the latter case a cover
panel may be used, if desired.
Each of the five amplifiers consists of two stages. The two
tubes and other components which make up each amplifier are
arranged in a row across the chassis. Each amplifier is provided with a gain control so that the gain may be varied from
approximately .9 to 1.1. This feature is especially convenient
when it is desired to equalize accurately the levels on the
several output lines.
Uses
The Type TA -1A Distribution Amplifier may be used in any
one of the three following applications: (a) to feed video or
synchronizing signals from a single source to several separate
outlets; (b) to mix video signals from several sources in order
that they may be fed to a single output line; (c) as a straightforward isolation amplifier requiring voltage gain of not over
15 db. The wide variety of possible uses of this equipment
makes it equally adaptable to test bench, laboratory, or television transmitting installations.
The input and output connections on the rear of the amplifier
are designed to accommodate standard fittings for either
RG 11/U or RG 59/U coaxial lines. Two connectors are provided for each input and each output to facilitate interconnecting the sections. This amplifier may be used at any point in
a television system regardless of whether the polarity at that
point is positive or negative. An adjustment is provided for
reducing the low frequency phase distortion to a negligible
value.
built in filament transformer provides filament voltages for
all tubes. Plate voltages are obtained externally, preferably
from a well regulated power supply such as the Type 580-C.
Power connections are made by means of a standard cable
receptacle at the lower left of the chassis.
A
Description
The equipment consists of five separate video isolation amplifiers mounted on a single chassis. These amplifiers are of the
bridging type, and have relatively high input impedance, permitting any number of them to be paralleled across a video
line with a minimum disturbance to the driving source. Each
amplifier delivers, to a 75 ohm output line, a signal of the
same level and polarity as it receives.
Specifications
Number of Amplifiers
Voltage Gain, Each Amplifier
Input Signal Level (max )
Output Signal Level (per section)
Input Impedance
Input Polarity
Output Impedance
Output Polarity
Power Supply Required
a -c 110-120 volts, 60 cycles
When the amplifiers are used to feed several output lines, the
inputs being paralleled, there is a high degree of isolation between lines and between any individual line and the source.
Thus, disturbances, short circuits, equipment failures, or the
like on one line will not be reflected onto the other lines.
This is of considerable value to good overall operation in any
television installation.
Five
Adjustable .9 to 1.1
2 volts, peak -to -peak
9 volts, peak -to -peak
Bridging
Positive or negative
75 ohms
Positive or negative
50 watts
960 ma.
d-c 280 volts
Tube Complement
Dimensions
Weight
Stock Identification
The components of the TA -1A are assembled on a chassis of
the recessed, or "bath tube", type. All tubes and other large
components are mounted on the front of the chassis, with the
resistors and other small components on the rear. This type
of construction provides neat appearance, convenient operation
and maximum accessibility. The chassis is standard rack width
and is designed to mount in either an enclosed cabinet type
5 RCA 6AC7, 5 RCA 6AG7
121/" high, 19" wide, 8" deep
98 lbs
MI.26155
Accessories
Tube Kit (complete tube complement)
166
MI.26676
AMPLIFIERS
Stabilizing Amplifier Type TA -5B
Features
Improves the signal-to-noise ratio of the sync signal.
Operates on signal levels as low as 0.25 volts peak -to -peak.
Elimination of these spurious disturbances at their source is
often difficult and sometimes impossible. They must be eliminated, however, because in many cases not only is receiver
operation impaired, but proper modulation of the transmitter
will be affected. The Stabilizing Amplifier is capable of correcting any one or all of these faults simultaneously, thus
producing a signal which is suitable for modulating the
transmitter.
Restores sync to standard 25% levels in signals where sync
is less than 18%.
Description
Combines sync with video signals; separates sync from
video signals.
Corrects defective video signals, eliminates hum and lowfrequency distortion.
The TA -5B Stabilizing Amplifier employs 19 tubes. Nine of
these are used in a 6 -stage picture amplifier which has two
identical output stages for supplying signal to the transmitter
and to a picture monitor. The remaining tubes are employed
as sync separators, keyers, shapers, dampers, and tubes for
adding sync.
Has two identical 75 -ohm outputs.
Power requirements are low.
Bath tub type chassis mounts on standard rack.
A two -position attenuator at the input accommodates a range
of input signals from 0.25 volt to 2 volts, peak-to -peak. The
output of the amplifier is designed to deliver the standard
level of picture and blanking signal (1.5 volts peak -to -peak)
with a maximum sync of 1.5 volts peak -to -peak. The amount
Uses
The TA -5B Stabilizing Amplifier is a unit designed to cor
rect, automatically, faulty video television signals which may
have become defective in their transmission from the pickup
device to the input of the transmitter. It is also used with
the RCA Studio Switching Equipment to combine the sync
signal with the video signals from the cameras.
The common sources of disturbance in any television system
may be classified as follows:
1.
2.
3.
4.
of sync can be adjusted independently to any value between
0.2 and 1.5 volts, peak-to -peak.
The first three stages provide linear amplification of the incoming signal; while the fourth stage amplifies the sync
pulses by a larger factor than it amplifies other parts of the
signal. Three tubes are employed in this fourth stage. One
operates as a normal amplifier and contributes signal throughout the useful portion of its characteristic curve. The second
tube of the trio clamps the black level at a fixed point on the
characteristic curve of the third tube, however, so that it
operates only at grid levels above the blanking signal, amplifying only the sync signals. Since clamping action is independent of the signal, spurious additive components (at low
frequencies) are eliminated from the sync amplifier.
Hum or surges originating in power supplies and other
random disturbances created by high-impedance grounding
circuits, long cable sheaths, etc.
Circuit saturation, with resultant destruction of the proper
sync-picture ratio.
Switching surges, including the shifting of patch cords.
Low -frequency distortion introduced by coupling circuits
with inadequate time constants.
167
AMPLIFIERS
Specifications
Amplified sync thus passes on to the fifth (clipper) stage of
the amplifier which clips off the sync in accordance with its
grid bias adjustment, yielding the desired sync -picture ratio
at the output of the fifth stage. As is the case in the non-linear
amplifier just described, the grid of the clipper is also clamped
at black level so that the absolute amplitude of the sync
pulses is fixed and independent of variations in the average
amplitude of the picture signal. In this stage also, spurious
components are eliminated from the picture and blanking
portions of the signal.
Input Signal Voltage
Min
Max
0 25
2 5
volts, peak -to -peak
volts, peak -to -peak
Permissable Input Signal -to -Noise Ratio
(a) High-Frequency Noise
2
(b) Low -Frequency Noise (hum)
13
Output Signal Voltage
(a) Picture and Blanking
15 volts, peak-to -peak
(b) Sync (Max.)
15 volts, peak-to -peak
Output Impedance
75 ohms
Power Requirements
(a) A -c
100-120 volts, 50/60 cycles, 5 watts, fuse
rating, 1 amp.
(b) D -c
980 volts, 235 ma., regulated
(RCA Type 580-C or equivalent)
Dimensions
Height
101/2"
Width
19"
Depth
8%"
Weight
17 lbs.
Finish (front of chassis)
Light umber gray
Tube Complement
1st Picture Amplifier
1 -RCA 6SK7
2nd
"
1 -RCA 6AC7
ii
3rd
6AG7
The sixth and last stage comprises the two output amplifier
tubes, one for the transmitter and one for the monitor. The
grids of these tubes are in parallel and their plates are coupled
separately to two output connectors for 75 -ohm coaxial lines.
When output higher than the 1.5 volt peak -to -peak is desired,
the two outputs can be paralleled to give almost double the
signal obtainable from either one alone.
fit1-RCA
Filament power for all tubes is provided by a transformer
mounted on the chassis. Plate voltage must be obtained from
an external regulated power supply such as the RCA Type
580-C. All external power connections are made through a
6 -pin plug and receptacle. One side of the primary line to the
filament transformer is fused.
4th
1 -RCA
5th Picture Amplifier (Sync Clipper) -1 -RCA
Sync Amplifier (Picture Clipper)
1 -RCA
Main Output
1 -RCA
Monitor Output
1 -RCA
1st Amplifier-Sync Channel
1 -RCA
Sync Separator
1-RCA
Pulse Former
1 -RCA
Keying Pulse Driver
1 -RCA
Clamp Diodes
3 -RCA
Sync Inserters
1 -RCA
1 -RCA
Voltage Regulator
1 -RCA
The TA -5B Stabilizing Amplifier is mounted on a recessed
chassis for standard rack -mounting. Therefore, it can be
mounted in the transmitter room or studio control room with
other rack -mounted equipment
168
6AC7
6AC7
6AC7
6AG7
6AG7
6AC7
6SL7-GT
6SN7-GT
6AG7
6H6
6SN7 and
6AC7
OD3 /VR -150
POWER SUPPLIES
Regulated Power Supply Type 580-C
(General Purpose)
Features
This Power Supply is assembled on a recessed chassis of the
"bath -tub" type. Tubes and filter condensers project from the
front of the chassis, while transformers, resistors, and wiring
are at the rear. The chassis is standard rack width and may be
mounted either in one of the new enclosed-type RCA cabinet
racks, or on a standard "open -face" rack. In the latter event
a blank panel may be mounted over the Power Supply if
desired. Controls are centralized on a small, plainly -marked
panel at the bottom of the unit. In addition to the power
"on -oft switch there is provision for switching from a load
range of 50-80 ma. to 80.400 ma., as well as a potentiometer
for adjusting output voltage. A meter selector switch and a
meter jack provide for plugging in a meter to read individual
tube plate currents, output current, and output voltage. A
special meter (MI -21200-C) is available for this purpose.
Extremely well-regulated output.
Unusually low output ripple.
Low internal d -c resistance.
Components and connections easily accessible.
Compact and neat in arrangement.
Uses
The RCA Type 580-C Regulated Power Supply fills the need
for a well-regulated source of d -c at loads of 50 to 400 milliamperes. The output is adjustable between 260 and 295 volts,
with variations of less than 0.25 volts from minimum to maximum load. Thus it is suitable for laboratory, industrial, and
communications applications in which an unusually well-regulated source of d-c is required. As a -c ripple in the output
is less than 0.005 per cent, the output voltage may be used
for most purposes without additional filtering.
Specifications
Output Voltage
Output Current
D -C Regulation
Ripple
Power Supply
Power Input
The Type 580-C is especially suited for use with RCA
television equipment, which it matches in appearance and
construction.
A -C
Tube Complement:
2 RCA 0D3/VR150
2 RCA 51346
Description
1 NE 32
Dimensions
Weight
The regulating circuit employed in the 580-C is of the series
type. The d-c internal resistance is less than 0.7 ohms.
-
169
Adjustable 260 to 295 volts
50 to 400 ma.
Less than 0.25 volts, minimum
to maximum load
Less than 0.005 per cent
110-120 volts, 50.60 cycles
370 watts (maximum)
1
RCA 6SL7GT
6 RCA 6Y6G
101/2"
high, 19" wide, 12" deep
58 lbs.
POWER SUPPLIES
Regulated Power Supply Type WP -33A
(Heavy Duty)
Features
The WP-33A is assembled on a recessed chassis of the "bath
tub" type. Tubes, filter condensers, and transformers project
from the front of the chassis, while transformer terminals,
resistors, and wiring are at the rear. The chassis is standard
rack width and may be mounted in one of the new enclosed type RCA cabinet racks or on a standard "open -face" rack. In
the latter event, a blank panel may be mounted over the Power
Supply if desired.
Extremely well-regulated output.
Unusually low output ripple.
Low internal d -c resistance.
Components and connections easily accessible.
Compact and neat in arrangement.
Controls are centralized on a small, plainly -marked panel at
the bottom of the unit. In addition to the power "on -off"
switch, there is a potentiometer for adjusting output voltage.
A meter selector switch and a meter jack make provision
for plugging in a meter to read individual tube plate currents, output current, and output voltage. A special meter
(MI.21200-C) is available for this purpose.
Uses
The RCA WP -33A Power Supply is intended for laboratory,
industrial and communications applications requiring a well regulated source of d-c voltage at loads of 200 to 600 milliamperes. The output is adjustable between 260 and 295 volts,
and varies less than 0.20 volts from minimum to maximum
load. A -C ripple in the output is less than 0.005 per cent, so
that the output voltage may be used for most purposes without additional filtering.
Specifications
Output Voltage
Output Current
D-C Regulation
The Type WP -33A is especially suited for use with RCA
television equipment, which it matches in appearance and
construction.
Adjustable 260 to 295 volts
900 to 600 ma.
Less than 0.20 volts, minimum
to maximum load
i ess than 0.005%
105/125 volts, 50/60 cycles
50 watts (maximum)
A -C Ripple
Power Supply
Power Input
Tube Complement:
4 Type 5V4G
1 Type 6SL7GT
Dimensions
Weight
Description
The regulating circuit employed in the WP-33A is of the series
type. The d-c internal resistance of this Power Supply is less
than 0.5 ohms.
170
Type 6AS7G
Type 0D3/VR150
14" high, 19" wide, 9" deep
82 lbs.
3
2
-
POWER SUPPLIES
Current Regulator MI -26090
T\PE RAG
AMP
OUTPUT
CURRENT
METER
M .2 200
Features
The 6Y6 -G current regulator tube is effectively in series with
the camera focus coil and its 400 -volt source of d -c so that
the internal resistance of the 6Y6-G, which is controlled by the
d -c amplifier, determines the magnitude of current flowing in
the coil circuit. The input of the d-c amplifier is connected
across a small resistor also connected in series with the focus
coil. Thus variations in the voltage developed across the small
resistor (as a result of current changes in the focus coil circuit) are fed to the d -c amplifier which in turn raises or
lowers the conductance of the 6Y6-G to counteract the current
change taking place. Regulation is, of course, instantaneous
and the result is a constant flow of current through the focus
coil of the camera. The Current Regulator will maintain constant current at a preset value over wide ranges of resistance
change in the load and over wide ranges of input voltage.
Counteracts current variations in camera focus coil circuit.
Current can be manually adjusted over
to 85 milliamperes.
a
range from
65
Common tube types are employed.
All tubes easily replaced from front of unit.
Designed for standard racks and cabinets.
Use
The Current Regulator is an electronic device which maintains
constant current in the focus coil of the TK-10A Studio Camera.
Variations in the magnitude of current flowing through the
coil are brought about by temperature changes, which would
ordinarily impair the focus of the camera. The Current Regulator counteracts these variations and also provides a means
for adjusting the focus coil current to the proper value.
Specifications
Power Requirements:
Single phase 117 volts, 60 cycles, 15 watts
A -c
(for fil. transformer)
400 volts from Type 580-C Power Supply
D -c
-
Chassis Dimensions:
Depth
51/2"
Width
19"
Height
Description
8"
Weight
All components of the Current Regulator are mounted on a
recessed chassis designed for rack mounting. The unit employs
an RCA 6SL7-GT twin triode as a d -c amplifier, and an RCA
6Y6 -G current regulator tube. The cathodes of the d-c amplifier are kept at fixed levels by voltage regulator tubes.
9
Tube Complement:
1-RCA OD3/VR150 Voltage Regulator
1-RCA 991 Voltage Regulator
1-RCA 6SL7-GT D -C Amplifier
1-RCA 6Y6 -G Current Regulator
171
lbs.
u
TELEVISION
FIELD and RELAY
EQUIPMENT
Page
FIELD EQUIPMENT
174
RELAY EQUIPMENT
185
MOBILE UNIT
188
FIELD EQUIP.
RCA Television Field Pick-up Equipment
IMAGE ORTHICON CAMERA
IMAGE ORTHICON CAMERA
WITH TELEPHOTO LENS
SWITCHING
SYSTEM
MASTER
MONITOR
REGULATED POWER
[POWER DISTRIBUTION BOXI
PULSE
SHAPER
SUPPLIES
The RCA Television Field Pickup Equipment is designed for
portable or field use in picking up television programs such
as sporting events, parades, outdoor or indoor shows, and
other special events in places where permanent television installations are not available. The design of the equipment is
centered around the RCA Image Orthicon camera tube which
is so sensitive that it may be used with incident illumination
on the scene as low as approximately one foot candle, and
which is entirely free of any blocking or "charging -up" effect
from flashes of excess light which paralyze other types of
pick-up tubes.
PULSE
FORMER
are made with cables and plugs which may be connected or
disconnected in a few minutes.
A general practice of making all electrical connections through
receptacles mounted on the rear panels of the suitcase units
has been followed. An exception exists in the case of intercommunication head -sets which are plugged into jacks on the
front of the Field Switching System. Whenever possible, multiple conductor cables are used so that the number of cable
connections is kept to a minimum consistent with flexibility
of the equipment. With few exceptions, the connectors used
have single -turn locking rings which prevent accidental disconnecting of the cables.
The Field Equipment includes such important features as a
four -position lens turret on each camera, an electronic view
finder in each camera, a complete telephone intercommunication system, accessibility of tubes, components, and circuits
for easy servicing, and many other features.
Careful consideration has been given to conservative design
in the selection of high quality components and in allowing
ample reserve in ratings. Also attention has been given to providing rugged construction and secure mountings so that the
equipment will stand the wear and tear of daily use over long
periods of time.
To facilitate portability, the equipment has been divided into
relatively small units with emphasis placed on keeping the
number of major pieces to a minimum, and at the same time
maintaining high standards of reliability and flexibility in
operation. Wherever possible the major units have the shape
and approximate size of a medium sized suitcase. The camera
and view finder, master monitor, and power distribution box
are the only exceptions. Each unit is provided with one or
more carrying handles, and covers and shock mounts to protect fragile parts during transportation. All interconnections
The Field Equipment is so designed that it may be set up for
temporary operation on a table or desk. A special Field Corp
trol Desk (MI.26960) is available if it is desired to make a
semi-permanent installation of this equipment for studio use.
In such a case, the desk and control units comprise a simple
operating console. The equipment may also be used in conjunction with a mobile television unit in which the suitcases
may be installed to form a mobile television studio.
174
FIELD EQUIP.
The units included with the standard Two -Camera Chain, Field
Pick -Up Equipment are as follows:
2-Type TK-30A Field Camera Equipments
1-Type TG -10A Field Synchronizing Generator
1-Type TS 30A Field Switching Equipment
(All equipments are supplied with tubes)
The Type TS-30A Field Switching Equipment includes:
1-Switching System. This unit provides all the video program,
monitor and intercommunication switching required for
field pick-up equipment using up to four cameras, plus two
auxiliary video program lines. Camera, view finder, camera
control and switching equipment tally lights indicate to performers, cameraman, control operators and program director which camera is supplying program.
The Type TK -30A Field Camera Equipment includes:
1-High Sensitivity Image Orthicon Camera with newsreel -type
tripod, plug-in electronic view finder employing a 5"
Kinescope and three turret -mounted lenses (50 mm and
90 mm and 135 mm focal lengths).
--Field Camera Control Unit. This unit provides the required
control and operating voltages for the Field Camera and
provides picture (on a 7" Kinescope) and wave form (on
a 3" Cathode Ray Oscilloscope tube) monitoring of the
camera signal.
I-Field type Power Supply. This unit contains the heater and
plate supply transformer, rectifiers and plate -voltage regulating circuits.
1-Set of Camera -Camera Control Unit Cables; one 50' length,
one 100' length and one 200' length.
The Field Type Master Monitor (listed below) can be
switched to:
a. The outgoing video signal.
b. Relay equipment monitoring signal.
c. Either of the two auxiliary video program lines.
d. A separate Monitor input.
1
The audio intercommunication facilities provide a flexible
set-up so that the program director can talk to any or all
of the operating personnel and the home station, or various
special and separate intercommunication circuits may be set
up. All operating personnel normally hear program sound
on one headphone, and intercommunication sound on the
other.
1-Field Type Power Supply. This furnishes power to the
switching system and Master Monitor.
The Type TG -10A Field Synchronizing Generator includes:
1-Field Pulse Former
1-Field Pulse Shaper
1-Power Distribution Box. This unit provides for power supply connections to a -c power systems of three types: 3 phase
-4 wire; Single phase-3 wire; Single phase -2 wire.
9 Twist Lok power outlets and 4 convenience outlets are
provided.
OPTIONAL
1-Field Type Master Monitor. This unit provides for picture
(on a 10" Kinescope) and wave form (on a 5" CRO Tube)
monitoring of the Signal selected by the field switching
system.
RCA TELEVISION FIELD PICKUP EQUIPMENT
Max. Number of Cameras, Four
TK -30A FIELD CAMERA EQUIP. #1
MI -26905
Image
Orthicon
Camera
Camera
Control
MI -26010
MI -26065
TG -10A FIELD SYNC. GEN. EQUIP.
M1-26920
Pulse
Former
M1-26105
Power
Pulse
Supply
Shaper
MI -26095
TK
-30A FIELD CAMERA EQUIP.
Image
Orthicon
Camera
F -N,
Power
Dist. Box
MI
--26260
MI -26115
-2
TS -30A FIELD SWITCHING
MI -26950
EQUIP.
To micro -wave
MI -26010
Camera
Control
III
Switching
System
MI -26065
!
M1
Power
-2621
transmission line
-
Power
Supply
Supply
MI -26095
MI -26095
r
I
(
TK
-30A FIELD CAMERA EQUIP.
3
Master
Monitor
(Same units cs above)
L
MI -26295
r
TM -SA -1 MASTER MONITOR EQUIP.
TK
-30A FIELD CAMERA EQUIP.
ä4
(Same units as above)
L___
175
relay
equipment or
FIELD EQUIP.
Field Television Camera Type TK -30A
Features
Highly sensitive at extremely low light levels.
Able to handle enormous light ranges.
No loss of picture after intense flashes of light.
Simplified interconnections providing quick assembly on
location.
Electronic view finder.
Rugged mechanical construction.
A four position lens turret controlled from rear.
Provision for two intercom telephone sets.
Suitable for studio use.
Easy access to all parts.
Uses
The TK -30 television camera is intended to be used in field
television pick-ups of all kinds. It is especially suitable for
use where the lighting conditions are poor, as is frequently the
case at sporting events, in night clubs, and at other remote
pick-up points. While designed especially for field use, it is
also satisfactory for most types of studio programs; and for
many applications the TK -30A has special advantages.
Description
The TK-30A is a portable, field television camera equipment
consisting of camera, tripod, camera cntrol, field power supply, and miscellaneous accessory items; such as: cables, etc.
The camera makes use of the RCA -developed Image Orthicon.
The remarkable sensitivity of the Image Orthicon is so great
that operation is possible with light levels as low as one footcandle with an f 3.5 lens. This is a considerable improvement
over other types of picture tubes, and makes possible field
television pick-ups without elaborate, special lighting installations, and under conditions which hitherto would have been
impossible. In addition, the Image Orthicon is able to adapt
itself automatically to enormous changes in scene brilliance
without serious loss of contrast anywhere in the range. This
characteristic makes it possible to shift instantly from a dark
scene in heavy shadows to another in bright sunlight with only
very slight readjustment. The Image Orthicon is able to withstand extreme peaks of intense illumination, such as photo
flash lamps aimed directly at the lens, without any after effects
requiring the resetting of controls.
The output voltage of this power supply is electronically regulated within very close limits. It is capable of delivering 1
ampere at a maximum of 285 volts. The internal impedance
of the power supply is less than 0.25 ohm. This low impedance
makes it an excellent power supply for amplifiers having
variable current requirements and critical low frequency response such as television amplifiers.
The Field Camera Control is contained in a small easily carried case. On the front, there are located two cathode ray tubes
which serve as indicators of the picture quality. A seven inch
kinescope is used as a picture monitor, and a three inch
oscilloscope is used as a wave form monitor.
The picture signal amplifier performs the following several
important functions:
separate electronic regulator circuit is provided to hold a
constant current flow regardless of resistance changes, through
the focusing field coil in the Field Camera.
A
On the rear panel are two receptacles for a -c input and power
output respectively. In addition there is included a single
It provides a gain control for the picture signal.
It mixes the Picture Blanking signal with the signal from
the Camera.
3. It establishes black level at the beginning of each scanning
line by means of a "clamp" circuit.
4. It provides for the addition of the Synchronizing signal
whenever only a single camera chain is used.
5. Its output stage is a line amplifier capable of delivering
two volts peak to peak composite picture and synchronizing
signal to a 75 ohm coaxial transmission line (or 1.5 volts
of picture only).
6. It includes a stage for introducing a fixed amount of gamma
correction.
7. It includes high level driver stages for feeding the two
monitor tubes.
1.
2.
convenience outlet with fuse.
The complete camera may be disassembled into several parts
for easy carrying. The camera is built into an exceedingly
compact case which mounts on top of the tripod. All controls are conveniently located on the back. The camera assembly includes a picture signal preamplifier and the deflection and camera blanking circuits. A feature of this camera
is the provision of a lens turret in which four lenses of different focal lengths may be mounted. On the rear of the case
is located a large handle which rotates the lens turret. A
trigger switch incorporated in the handle cuts off the picture
during the interval while the handle is turning. Changing from
one lens to another requires only one and a half seconds. This
compares to two or three minutes with prior types of cameras.
Because the plate of the Image Orthicon is much smaller than
that of previously designed pickup tubes, the focal lengths of
the lenses required is only about half as great. This makes it
possible to use relatively inexpensive standard lenses for all
types of pick-up.
The Field Power Supply is a portable unit designed to provide all the d -c required by the circuits in the Field Camera,
Field View Finder, and Field Camera Control in one camera
chain. It may, of course, be used for any other application
where its voltage and current ratings meet the requirements.
176
FIELD EQUIP.
Specifications
FIELD CAMERA CONTROL
Number of Scanning Lines
525
Interlacing
9 to 1
Field Repetition Rate
60 per sec.
Frame Repetition Rate
30 per sec.
Line Repetition Rate
15750 per sec.
Picture Signal Level
2.0 volts, peak -to -peak, max. of which
75% is picture and blank, and 25% is sine. (See RMA
Standards).
Picture Signal Polarity at Output
Black negative
Type of Transmission Line for Picture Signal
Coaxial
Impedance of Transmission Line
75 ohms
Maximum Length of Camera Cable
1000 ft.
Total Included Angle of Lenses (in horizontal plane) :
a. 50 mm f1.9 Extar
34°
b. 90 mm f3.5 Ektar
20°
c. 135 mm f3.8 Ektar
13°
***d. 220 mm f4.5 Ektar
8°
***e. 15 inch
45°
***f. 25 inch
2 75°
Incident Illumination on Scene:
(a) Minimum (approx.)
0 5 ft. candle
(b) Required for First Grade Results10 to 20 ft. candles
(c) Maximum
Bright sunlight
Note: Figure for (a) above is based on the use of an
f3.5 lens or faster.
Primary Volts
98-129 volts, a -c, 50-60 cycles
Primary Voltage Taps:
Nominal
Range
Tap No. 1
125 v.
121.129 v.
Tap No. 2
117 v.
113-121 v.
Tap No. 3
109 v.
105-113 V.
Tap No. 4
102 v.
98.106 v.
Power Outputs:
Regulated d -c Supply 270-285 volts
1 amp.
Constant Current Supply intended to operate into 2000 ohm
load (focusing coil)
50.80 ma.
Dimensions (in inches)
FIELD CAMERA
Field Camera Control Unit and Field Power Supply
The operator focuses the picture by observing the image in
the electronic view finder, constituting the upper section of
the camera assembly, and adjusting a knob on the right side
of the cabinet. This knob slides the Orthicon back and forth
inside the case. This saves having to adjust the lenses themselves for focusing. The use of the electronic view finder with
this camera is a necessity; since at low light levels an optical
view finder would not be satisfactory. It also has the advantage of eliminating the need for additional lenses which would
be required for an optical system. The view finder employs a
five inch kinescope with sufficient brilliance to produce a satisfactory picture under normal outdoor light conditions. Since
the operator sees on the face of this kinescope the picture
which is being transmitted, he is able to focus the picture,
and also to monitor the quality and general operation. Two
different viewing hoods are provided: one straight -on type,
and the other a periscope type, which may be mounted in
either of two positions. This gives the operator a choice of
three different viewing heights. For ease in transporting and
maintenance, the view finder and camera are separate units,
each of which is an integral unit in itself. A streamlined
cover with a carrying handle is placed on the camera unit
when the view finder is removed. It is also possible to operate
the camera without the view finder: as for instance where the
camera is set up in a fixed position and operates unattended.
CASE ONLY
Length
Width
20%
10%
OVERALL
Height
Length
11A
25%*
VIEW FINDER
CASE ONLY
Length
21%
Width
Width
11%
OVERALL
Height
Length
Width
10%
213/a
10%
7
FIELD CAMERA CONTROL
CASE ONLY
Length
Width
241/
8'/s
Height
13%**
Height
7
OVERALL
Height
151/e
Length
Width
Height
271/
8%
18%
FIELD POWER SUPPLY
CASE ONLY
OVERALL
Length
Width
Height
Length
Width
Height
24%
8%
15%
24%
8%
15%
Camera Cable Dimensions:
Diameter
0 840 in.
Standard Lengths
50 ft., 100 ft., 200 ft.
Weights:
Field Camera (less Lenses)
65 lbs.
View Finder (less Hood)
34 lbs.
Field Camera Control
65 lbs.
Field Power Supply
58 lb..
Turret with 3 Ektar Lenses
43/ lb..
Camera Cable (200 ft. with plugs)
80 lbs.
Finish
Two tone umber gray wrinkle with chrome trim
Stock Identification:
Field Camera
Mí.26010
View Finder
MI -26015
Field Camera Tripod__
MI.26045
Field Camera Control
MI -26065
Field Power Supply
MI.26091
f Less viewing hood.
*
Less lenses.
** Including cover.
TK -30A Electronic View Finder and Camera disassembled
for easy carrying
*** Not standard equipment. Available as accessory items.
177
FIELD EQUIP.
Field Synchronizing Generator Type TG -10A
Features
Pulse Former and the Field Pulse Shaper. Also included with
the TG -10A is a Power Distribution Box which is intended
to be used for connecting the 117 volt power source to the
various units of the RCA Field Television Equipment.
The equipment generates four separate signals which are used
in various ways to produce the RMA standard television signal.
These four signals are those required for a 525 line interlaced
system as recommended by the RMA. The signals are usually
designated as follows:
1. Synchronizing
2. Picture blanking
3. Vertical driving (at field frequency, 60 cycles)
4. Horizontal driving (at line frequency, 15,750 cycles)
The first two of these signals, Synchronizing and Picture
Blanking, are used directly in composing the final picture
signal fed to the output of the system. In other words, they
appear as parts of the composite picture signal. The last two
signals, Horizontal and Vertical Driving, are used in the pickup
equipment only. Their principal function is to trigger deflection
generators in cameras and monitors. They are also used for
keying signals in "clamp" circuits and for blanking signals
in the camera.
FIELD PULSE FORMER
The Field Pulse Former contains the timing circuits required
in the system. Specifically, they include the master oscillator
which operates at twice line frequency (31,500 cycles), a
series of counters for stepping this master frequency down to
line frequency (15,750 cycles) and to field frequency (60
cycles), and an automatic frequency control circuit for locking the synchronizing generator to the power supply frequency.
A crystal oscillator operating at 94.5 kc. is provided as an
alternative means of stabilizing the generator where the power
supply system is not stable enough to serve as a reference.
Controls for the counter circuits, AFC circuit, and crystal
oscillator are made accessible by removing the side cover on
Delivers standard RMA synchronizing and blanking.
Also delivers separate horizontal and vertical driving signals.
Complete in two suitcases, Pulse Former and Pulse Shaper.
Frequency stabilization either by 60 cycle power line or by
quartz crystal.
Built-in cathode ray tube indicator for counter circuits.
Built-in regulated power supply.
Single cable connection between the two suitcases.
All output signals, except synchronizing, on single cable.
Synchronizing on separate cable to provide for single or
multiple camera operation.
Operation over wide range of line voltage.
Built-in line voltage meter and tap switch.
Convenience outlet with fuse.
Uses
The field synchronizing generator is the heart of the field
television pickup equipment. Its function is to provide all the
timing information, in the form of electrical pulse signals, required for controlling and synchronizing the scanning processes
in both the field pickup equipment and the home receivers.
Description
In order to keep the weight and size of the TG -10A within
reasonable limits, the equipment has been divided into two
parts, each contained in a separate case, and called the Field
178
FIELD EQUIP.
Provision is made for connecting this box to any one of three
types of power distribution lines which are normally encountered in the United States. These are:
I. Single phase.
2
Single phase,
3
wire (117 volts).
wire (117 volts from each outer line to
Three phase,
4
wire (117 volts from each outer line to
2.
neutral).
3.
neutral).
link board under a trap door at one end of the box provides easy means for rearranging the circuits to fit any of
these three systems. Outlets are color -coded to indicate phasing on the three phase system, and correspondingly colored
pilot lamps indicate which phases are "hot" in case a main
fuse burns out.
A
Provision is thus made to utilize all elements of any available power distribution system so as to minimize voltage drop.
Specifications
Field Repetition Rate
Frame Repetition Rate
Line Repetition Rate
Power Distribution Box
60
per sec.
30
per sec.
per sec.
Synchronizing Generator Master Oscillator Frequency
31,500 cycles/sec.
Synchronizing Generator Counter Ratios:
First
7.1
Second
5 1
Third
5
1
Fourth
3
1
the tube side of the unit. A cathode ray tube indicator
(RCA 2BP1) for the counter circuits is mounted within the
case and is visible when the cover is removed to make adjustments of the controls.
single cable containing 4 coaxial lines and several other
conductors carries signals and power between the Field Pulse
Former and the Field Pulse Shaper. The a -c power enters the
Pulse Former through a special connector. A convenience outlet, separately fused for 10 amperes, is provided on the rear
panel. No other connections to this unit are required.
The Field Pulse Former also includes a regulated power
supply which provides all the plate current required by both
the Former and the Shaper. The Transformer primary is tapped
at several points to accommodate a wide range of line voltage
(98 to 129 volts). A selector switch for these taps is mounted
on the front panel directly under a line voltmeter which indicates when the proper tap has been selected.
A
15,750
Frequency Stability of Horizontal Sync.
(when stabilized by power supply)_ ±0.15°ío/sec. max.
Frequency of Quartz Crystal
_94,500 cycles/sec. ±50 cycles
Synchronizing Generator Output Signals:
(a) Signal Level (all signals)
4.0 (-0.5, +1.0 volts, peak -to -peak)
(h) Signal Polarity (all signals)
Negative
(c) Waveform -Sync
Defined by "Recomended Sync.
Generator Waveforms", a drawing submimtted January 22, 1946 (Revised October 9, 1946) by the RMA
Sub -committee on Studio Facilities.
(d) Waveform-Picture Blanking
Defined by "Recommended Sync. Generator Waveforms", a drawing submitted January 22, 1946 (Revised October 9, 1946) by
the RMA Sub -committee on Studio Facilities.
(e) Waveform -Horizontal Driving
Rectangular pulse,
15,750/sec. Width 6.3 microsec. (approx.)
(f) Waveform -Vertical Driving
Rectangular pulse,
60/sec. Width 4% or .00067 sec.
Dimensions (in inches) :
FIELD PULSE SHAPER
The Field Pulse Shaper contains all circuits necessary for
shaping, mixing, and pulse width control to produce the four
output signals. Pulse widths are adjustable by means of screwdriver -type controls which may be locked in position.
The outputs are fed to 75 ohm coaxial lines from the plate
circuits- of the final amplifier tubes (RCA 6ÁG7). These outputs are coupled through blocking capacitors to prevent d -c
fl orn flowing in the transmission lines. The normal signal level
on these lines is 4 volts, peak to peak. All four signals are
negative in polarity.
Two separate cables carry the signals to other units in the
system. One multiple cable, consisting of several coaxials, carries the Picture Blanking and the Horizontal and Vertical
Driving signals to the Field Camera Controls. The second cable
is a single coaxial line which carries the Synchronizing signal.
Length
24%
Two filament transformers are mounted in this unit to supply
the tube heaters. Plate current for the tubes is provided by the
regulated power supply in the Field Pulse Former.
CASE ONLY
Width
OVERALL
Height
Length
Width
FIELD PULSE FORMER
151/s
81/8
253ía
Height
81/z
18%
8%
18%
FIELD PULSE SHAPER
241,4
11%
POWER DISTRIBUTION BOX
This distribution box has nine 2 -prong twistlock receptacles
which fit the power cables supplied with the equipment. This
number of outlets is more than sufficient for a four camera
setup, and thus allows extra outlets for operation of associated audio equipment. Two standard convenience outlets are
also provided for soldering irons, trouble lights, etc.
The -power feed line to the box is a four conductor water
proof cable (each conductor #10 gauge, stranded) connected
through 4 -prong twistlock connectors. A total of 200 feet of
this cable is supplied with each equipment.
81,4
87/8
151/8
253%
334
11%
Weights:
Field Pulse Former
Field Pulse Shaper
Power Distribution Box
Finish
877/8
5
67% lbs.
52 lbs.
10 lbs.
Two tone umber gray wrinkle with chrome trim
Stock Identification:
Field Pulse Former
Field Pulse Shaper
Power Distribution Box
179
MI.26105
MI -26115
MI.26260
FIELD EQUIP.
Field Switching System Type
TS-30A
Features
provision of an intercommunication center for the telephone
system which enables all operating personnel to talk with each
other.
Surgeless camera switching (clamp circuit) for four cameras and two auxiliary signals.
Individual level control on each auxiliary picture input.
Switching of Master Monitor for checking the outgoing picture line, auxiliary lines, relay transmitter, etc.
Push button switches for picture signals.
Tally system to indicate "on -the -air" to the camera control
operator, camera man, and performers.
Clamp circuit holds black level constant.
Sync. level adjustable over wide range.
Incoming signal may be with or without sync.
Operation in conjunction with a Master Monitor from a
single external power supply.
Built-in power supply with separate control switch for the
intercom. system.
Complete miniature "central office" for an inter-communication system between all operators in a four camera setup
and the program director, technical director, and main
studio.
Description
The complete equipment consists of the Field Switching unit,
contained in a compact, easily carried case; and the associated
Field Power Supply, likewise contained in a portable case.
The picture signal circuits provide for switching between four
cameras and two incoming auxiliary lines, or in unusual
cases, between six cameras. Communication circuits are limited
to a maximum of four cameras.
Two sets of push button switches are provided for picture
switching. One set, located at the bottom of the front panel,
and marked "CAMERA SWITCHING," switches signal from
any of four cameras or two auxilliary inputs to the outgoing line. The second set marked "MONITOR SWITCHING"
provides for switching the Field Master Monitor to any of
the following five positions:
1. Outgoing picture line.
2. Monitor output of relay transmitter.
3. Incoming auxiliary line 5.
4. Incoming auxiliary line 6.
5. Spare input to monitor.
Each push button has an associated tally. Camera switching
tallies operate in conjunction with tallies in the Cameras and
Camera Controls.
The picture amplifier includes a "clamp" circuit to eliminate
switching transients and other low frequency disturbances
which may have been added to the signal earlier in the system,
and thus provides that smooth switching which adds much to
program technique.
Uses
The Field Switching System, when used in combination with
the Field Master Monitor, is the equivalent, in the Field Equipment, of the director's console in a studio. It provides two
major services in a setup involving more than one camera.
The first is, of course, a means of switching between cameras
and of monitoring the outgoing signal. The second is the
180
FIELD EQUIP.
The three 75 -ohm coaxial outputs from the outgoing line amplifier are as follows:
1. Picture Output (for feeding a relay transmitter or studio
The intercommunication system provides talking circuits between the camera men, the camera control operator, the technical director, the program director, and any assistant production personnel who may be stationed near the cameras. It provides also a circuit for distribution of the program sound to
all the operators of the system. Each operator may be provided
with a telephone set consisting of a double ear phone head
band and a microphone. One ear phone in each set reproduces the program sound, and the other reproduces the oper-
line).
2.
3.
Master Monitor Output.
Auxiliary Monitor Output.
At output 1 appears the signal from the particular camera
selected by the CAMERA SWITCHING push button. The
second output is effectively in parallel with the first output.
ators' conversation.
The third output is provided to supply signal to any auxiliary
equipment which it may be desired to operate such as an additional monitor, a standby link transmitter, or the switching
system of an additional set of field equipment.
Recessed under the front panel of the Field Switching System
is a jack board with accommodations for six telephone sets;
one for each camera, one for the program director and one
without program sound for the relay transmitter operator.
All three of these outputs deliver the same signal level and
polarity, i.e., 2 volts, peak to peak, of picture and sync. with
sync. negative. It is assumed that this level is based on the
standard ratio of 75% picture and 25% sync. However, for
signals from local Cameras, where sync. is mixed with the
camera signal in the Field Switching System, the amount of
synchronizing voltage may be increased above the 25% value
by adjusting the Synchronizing Gain Control.
A group of toggle switches on the
upper part of the front
panel provides means for making several circuit combinations
in the intercommunication system. The following combinations
are available:
Separate circuit to each camera and the relay transmitter.
common circuit to all cameras or any grouping of them.
3. Optional tie-in between operators and program director.
4. Optional tie-in between operators and the engineering PL.
(Private Line).
5. Optional tie-in between engineering PL and production PL.
6. Optional circuit for the program director over the program
line.
1.
2. A
Pulse signals for operation of the clamp circuit are derived
from the synchronizing signal. The clamp operates at black
level so that the output stage always operates over the same
portion of its characteristic.
Filament power for the picture and pulse amplifier tubes is
supplied by a transformer in the Field Switching System. D -c
for plate supply is obtained from an MI-26095 Field Power
The circuit used for the intercommunication system is the
common battery type. The power supply operates fom the a -c
line and is contained in the Field Switching System. A separate power switch, fuse, and tally are provided so that the
intercommunication system may be operated while the rest
of the equipment is turned off.
Supply which is also capable of providing plate current to a
Field Master Monitor at the same time. The power control
switch for the Field Power Supply with an associated tally, is
located on the front panel of the Field Switching System.
A
lAY
GAM FONT. ö
CAM. CONTI
CAM OONT.4
Four separate cables carry the intercommunication and tally
circuits between the Field Switching System and the four Field
Camera Controls. A jack provides means for a 2 wire circuit
to the relay transmitter. Receptacles are provided for connecting the program sound, and the engineering and program
phone lines, or PL's, from the main studio or transmitter.
Controls normally used during show time are located on the
front panel. Others, used rather infrequently, are located under
a small trap door on top of the suitcase. Controls normally
preset are located on the chassis and are made accessible by
removing the cover on the tube side of the unit.
Individual coaxial connectors are provided for all incoming
and outgoing picture and synchronizing lines. All other connections are made with multiple conductor cables to keep the
number of connections to a minimum.
A removable front cover is provided to protect the switches
and other controls from damage during transportation. Removable side covers are also provided. The wiring side is
interlocked and an auxiliary link is supplied to restore power
for servicing.
CAM -CON 1.2
PROD.
CO 00 00
Specifications
Dimensions:
Field Switching Unit
Case Only
Overall
Field Power Supply
Case Only
Overall
Weight:
Field Switching Unit
Field Power Unit
Stock Identification:
Field Switching Unit
Field Power Supply
Front view of Switching Unit
showing panel detail
181
241/2"
261/2"
long, 8%" wide, 15%" high
long, 8%" wide, 181/2" high
241/2"
241/2"
long, 8%" wide, 15%" high
long, 81/2" wide, 15%" high
71 5
58
'lbs.
lbs.
-MI -26215
MI -26095
FIELD EQUIP.
Master Monitor Type TM -5A
Features
Description
Operates with composite picture signal input (synchronized
operation) or with separate picture signal and pulse signal
input voltages (driven operation).
Special 10 inch diameter, kinescope with aluminum backing
makes possible a very brilliant picture.
Special low capacity input connection.
Compact design permits location in operating consoles with
minimum space requirements. Operator can easily look over
the top of the console and can observe at least three
adjacent monitors without difficulty.
Synchronization of the oscilloscope sweep with the kinescope
sweep at half line or half field frequency is completely
automatic.
Operating controls are extremely simple.
Pulse high voltage supply reduces shock hazard considerably.
Tubes and circuits are readily accessible.
Adapter is available for rack mounting and a suitcase type
enclosure available for portable or field use.
Calibration circuit permits quick reference to a fixed voltage
level.
Grid circuit of oscilloscope is available for pulse measuring techniques.
The Master Monitor is furnished in chassis form. It may,
therefore, be placed in a housing and grouped with other master
monitors or camera controls to form an operating console. A
case for table top mounting is available so it can be used
conveniently with field equipment for monitoring purposes,
and in conjunction with the adaptor, MI.26526, it can be used
as a rack mounted monitor.
The unit employs a 10 inch kinescope for direct picture
monitoring and a 5 inch oscilloscope for signal component
analysis. Input circuits are arranged to permit the same or
different picture signals to appear on the kinescope and osciIloscope screens at the same time.
A calibration circuit is included to establish a definite voltage
level on the oscilloscope screen for measuring purposes. The
horizontal scanning frequency of the oscilloscope tube is automatically half that of the kinescope and results in two cycles
of either horizontal or vertical pulses, as may be selected by
the operator, appearing on the oscilloscope screen.
The vertical front panel of the monitor, finished in dark
umber gray is arranged with an opening at the top center,
fitted with a rectangular mask, for the 10 inch kinescope to
present the picture screen. The screen of the 5 inch oscilloscope
is arranged immediately below the kinescope screen in a 5 inch
circular opening. The lower section of the panel carries the
switches and controls, conveniently grouped.
Uses
The Type TM -5A Master Monitor provides in a compact
chassis a complete monitoring unit adaptable to the supervision of composite picture signals at any stage of transmission,
from camera pickup to radio transmitter input. It may be used
for both picture and waveform monitoring of signals from the
relay receiver, the output signal at the master control room,
or any other picture signals it may be desirable to monitor
at the radio transmitter location.
'With the ends of the kinescope and oscilloscope presented to
the panel, the other components of the circuits are mounted
on vertical chassis on both sides of the cathode-ray tubes with
tube sockets and circuit components arranged on narrow shelf
members so that all parts are readily accessible for servicing.
182
FIELD EQUIP.
INPUT FROM CAMERA CHAIN WHEN USED AS
CAMERA OR PROGRAM MONITOR
twelve contact plug at the rear of the assembly provides for
the connection of necessary input power and external synchronizing pulse wiring. A safety feature is included in the
form of an interlock which is attached to the monitor, so that
withdrawal of the chassis from the case opens the high voltage
circuits in the unit to prevent accidental contact with dangerous potentials.
A
Peak to Peak
Voltage
Vertical Drive
Horizontal Drive
*Oscillator Drive
** Bias
* * * Tally Light
The Master Monitor may be operated as either a "synchronized" or as a "driven" monitor. In the synchronized case, the
scanning circuits are operated by blocking oscillators which
in turn are triggered by the sync. pulses contained in the
incoming composite picture signal. In the driven case, the
incoming signal will normally come from a camera chain
without sync. pulses. The scanning circuits are therefore
"driven" directly by separate signals from the synchronizing
generator. Connections to the sync. generator are made through
the multi -contact plug. The switching arrangement employed
for selecting the type of operation cuts off the blocking oscillators by opening the cathode circuits when the unit is operated as a driven monitor. The unit includes three step down
transformers to furnish current for the tube heaters and filaments but d -c currents for the tube plate circuits and centering
circuits must be obtained from an external regulated power
supply.
--
2
2
min.
min.
8
-18
Pulse
Width
Frequency
in Cycles
4%
10%
60
15,750
Mixed 30 and 7875
d-c
6 3 v
Frequency Response:
Kinescope Amplifier
Oscilloscope Amplifier
(Vertical Deflection)
Flat
±1
db to
8
mc.
Flat ±1.5 db to
4
mc.
Input Impedance:
CRO Input
Kinescope Input
CRO Drive Signal
High
High
High
Signal Input Range:
CRO Input
Kinescope Input
Chassis Dimensions
Specifications
0 5
0 5
3
3
volts
volts
173/" high; 13" wide; 201/4" deep
Weight
INPUT POWER WHEN USED AS LINE OR
RELAY RECEIVER MONITOR
From Line for Tube Heaters:
105-125 volts
Line Voltage
50.60 cycles, single phase
Line Frequency
From Power Supply:
985 volts d -c
Plate Voltage_
510 ma.
Plate Current
-7 volts d-c
Centering Voltage
to
to
Stock Identification (chassis only)
68 lbs.
MI.26135
* Use of this signal is optional.
** Used only with camera chain, under which condition fol-
lowing output voltages are available from monitor:
0 to -18 volts d -c
Pedestal Control
0 to -18 volts d -c
Video Gain Control
* * * Connected to switching or monitor heater circuit.
183
FIELD EQUIP.
Television Field Desk MI -26560
Tels
i
ion
field desk with field camera control and
monitoring equipment in place
Features
Uses
The Television Field Equipment Desk was designed expressly
for RCA field camera equipment. It is sturdy and easily
transported, and when used where telecasts are being made,
provides a convenient operating desk on which the units required for controlling and monitoring the television cameras
can be mounted.
Desk is convenient height.
Inclined desk top supports field units at eye level.
Adequate space for all control units.
Stainless steel strips protect mounting surfaces.
Sturdy all -metal construction and durable finish assures long
service and pleasing appearance.
illustration, the field desk will accommodate
the nine units required for operation of two field cameras. The
camera control, switching and master monitor units which require observation or adjustment can be placed in a convenient
position on the inclined portion of the desk top, with the
power supply and sync generator units on a shelf below.
As shown in the
Ample desk space in front of control and monitoring units.
Description
The all -metal desk is sturdily constructed and attractively
finished. Painted surfaces are finished in umber gray color;
the table top is stainless steel. Stainless steel strips prevent
the finished surfaces from being marred by the television units.
Specifications
Dimensions:
Height
Width
Depth
Weight
Finish
Rear view of television field desk
Itt
-
28"
50"
44"
117 lbs.
Umber gray
RELAY EQUIP.
Television Relay Transmitter Type TTR-1A
Features
Complete transmitting system.
(a) FOR STUDIO -TO -TRANSMITTER CIRCUITS where
conditions of terrain, distance, or right-of-way make it more
convenient or economical than a coaxial line. For such use
the transmitter and parabolic antenna units will be permanently
mounted on the roof or other high location near the studio
and the transmitter control unit will be mounted, ordinarily,
on the equipment racks in the studio control room. The receiving equipment will be permanently located at the transmitter site.
Suitable for permanent installation.
Completely portable for field pickups.
Superfrequency operation permits simplified circuits and
small physical size.
(b) FOR FIELD PICKUPS as a means of transmitting the
video signal back to the studio when no coaxial line or satisfactory wire line is available for the purpose. In this case,
the rotatable tripod mounting illustrated will ordinarily be
used. The antenna will be located on some high point, such
as the top of a stadium where there is a line -of-sight path to
the receiving antenna at the studio. The transmitter control
unit will be located with the camera control equipment as,
for instance, in the radio booth or in the field truck or
mobile unit.
Flexibility of operation.
Lightweight.
Optional console operation.
Highly directional antenna.
Description
Uses
The TTR-1A Relay Transmitter is a complete, transportable
transmitting system consisting of (1) a transmitter, (2) a
highly directional antenna, (3) a rotatable antenna mounting
unit, and (4) a transmitter control unit. These unite are designed to work together, and may easily be set up and connected by means of plug-in cables.
The Type TTR-1A Relay Transmitter, when used with a Type
TRR-1A Relay Receiver, constitutes a highly directional wide band relay link especially suited to the transmission of television video signals. Such a link circuit has two important
applications which are:
1115
RELAY EQUIP.
to 400 feet away from the transmitter. It contains all the necessary operating and monitoring controls, and after initial adjustments of the transmitter and antenna have been made, all
operations may be carried on from this unit. It also contains
a regulated B-1-- supply for operation of the transmitter tubes,
The transmitter is contained in a cylindrical weatherproof
housing attached to the rear of a parabolic reflector. It utilizes
a klystron oscillator which is frequency -modulated by variations of the negative voltage on the repeller plate. It has a
power output of approximately 100 milliwatts, operating at
any selected frequency between 6500 and 7050 megacycles.
The normal frequency deviation is 12 mc. with polarity such
that a video signal in the white direction produces an increase
in frequency. The output is fed to the parabolic reflector by
means of a wave guide. Coupled into this wave guide system
are an absorption type wavemeter, and a crystal detector monitor. The wavemeter is preset to any desired frequency. The
d -c from the crystal detector may be measured either at the
transmitter or at the transmitter control unit as a rough indication of relative power output. The a -c component of the
crystal detector output is amplified and fed over a coaxial
line to the transmitter control unit where it serves during preliminary adjustment to indicate the correct frequency, and
during operation, to indicate proper centering of the signal
around the resonant frequency of the klystron cavity. Filament
power for the tubes in the transmitter is supplied from a
small filament transformer on the same chassis. All other voltage supplies are received on the transmitter chassis which are
accessible by removing the protective cover over the cable
input connection. By plugging in a suitable meter in the proper
jack, it is possible to measure the current through modulator
tube, and the oscillator tube. Another jack is provided so that
a telephone handset can be plugged into the unit for communication with the transmitter control unit location.
and a regulated negative supply for the klystron repeller
plate. For greater operating convenience, provision is made
for extending the operation of the controls necessary for
routine adjustments of the transmitter to a monitoring console.
Specifications
6800.7050 mc.
Frequency Range
100 milliwatts
Power Output
Antenna Gain
4,500
4 ft. reflector
10,000
6 ft. reflector
10 mc.
Frequency Deviation for 100% Modulation
75 ohms
Video Input Impedance
60 cycles to 6 mc.
Video Frequency Range-32 db
FM Noise Level Below ±10 mc Swing
-40 db
AM Noise Level Below (Maximum) Modulation
Power Supply Requirements:
150 watts
110 volt, 60 cycles a -c
Tube Complement:
Transmitter
1-6H6
1-6AG7
2-6SL7GT
The parabolic antenna provides a very high gain in the direction of transmission. The four foot size (illustrated) has a
gain of approximately 5000, thereby giving an equivalent power
output of 500 watts. The parabola is also available in the six
foot size, with approximately twice the gain, for use in communicating over greater distances. Transmission is limited to
a line -of -sight path, and under normal conditions, a range of
10 to 15 miles may be expected with a satisfactory signal to
noise ratio.
1-2K26
Transmitter Control Unit
1-6AG7
2-6X5GT
4-VR150
Reflector Dimensions:
1-5V4G
1-6AS7G
1-6SL7GT
Diameter
Focal Length
Depth
4'
14.5"
21"
10"
14"
6'
The antenna and transmitter are mounted on a standard rotatable camera tripod mounting unit. This mounting unit may
be accurately adjusted over wide vertical and horizontal angles.
For fixed installations, a different type of mounting, providing
only small adjustments of angle, is available.
Transmitter
Transmitter Control Unit:
Carrying Case
The transmitter control unit is housed in a small, easily carried, portable cabinet with a convenient handle on the
top. The controls are accessibly located on a control panel on
the side of the cabinet. This control unit may be located up
Weights:
Transmitter and Housing
Transmitter Control Unit
Stock Identification
Standard Rack Space
Finish-
186
13" Diameter, 17" Long
20" Long, 19" High, 13" Wide
101/2"
Two-tone umber grey
96 lbs.
38 lbs.
Mí.26935
RELAY EQUIP.
Television Relay Receiver Type TRR-1A
Features
Complete receiving system.
Suitable for permanent installation.
Completely portable for field use.
Lightweight.
Optional console operation.
Effective automatic frequency control.
Uses
The Type TRR-1A Relay Receiver, when used with a Type
TTR-1A Relay Transmitter, constitutes a highly-directional
wide -band radio link especially suited to the transmission and
reception of television video signals. Such a link circuit has
two important applications which are:
(a) FOR STUDIO -TO -TRANSMITTER CIRCUITS where conditions of terrain, distance, or right-of-way make such a system more convenient or economical than a coaxial line. For
such use the antenna of the TRR-1A is located on a tower or
other high point near the transmitter building in a fixed position directed toward the TTR-1A Transmitter located at the
studio. The receiver control unit and power supply unit are
ordinarily mounted on equipment racks in the transmitter
control room.
(b) FOR FIELD PICKUPS where a TTR-1A Transmitter,
arranged for portable use, is employed to send the video
signal back to the studio (instead of wire or coaxial lines).
In this case a rotatable mounting such as that illustrated will
ordinarily be used (since there will be pickups from various
directions). For temporary use, the tripod mounting may be
used. When the equipment is used frequently, a more permanent mounting is desirable. In any event it must be high
enough to provide a line -of-sight path to the transmitting antenna location.
Description
The TRR-1A Relay Receiver is a complete (transportable, if
desired) FM receiving system covering of frequency range of
6500-7050 megacycles. It consists of (1) a receiver, (2) a highly
directional antenna, (3) an antenna mounting unit which may
be either fixed or rotatable, (4) a receiver control unit, and
(5) a regulated power supply unit. These units are easily set
up and connected by means of convenient plug-in cables.
The signal is picked up on the highly directional, high gain
(4500) parabolic antenna and fed into the receiver. The receiver is contained in a cylindrical, weatherproof housing attached to the back of the parabolic reflector. This housing
contains a klystron tube heterodyne oscillator, a crystal mixer
circuit, and five stages of the receiver i -f amplifier. This provides an output signal of about 50 millivolts at an i-f center
frequency of 120 mc. This signal is fed to a coaxial line leading to the receiver control unit. The receiver has a built-in
transformer which supplies filament power to all tubes. All
other voltages are obtained from the power supply by way of
the ri ceiver control unit. The equipment is provided with an
intercommunication system so that handsets may be plugged
in and operators may communicate between the receiver and
the receiver control unit.
The receiver control unit contains seven additional i -f
stages, the limiter and discriminator stages, and the AFC system. There are two separate discriminator channels fed from
the output of the i-f amplifier. One supplies signal to the main
transmitter and monitoring circuits. The other is used to generate a control voltage for the AFC amplifier. The purpose of
the AFC is to control the frequency of the heterodyne oscillator and keep it in proper adjustment for variations in
transmitter frequency. The receiver control unit is connected
to the receiver by means of a single cable with plug connectors at each end. In operation this cable may be as long as
200 feet. For special cases, however, it may be made as long
as 1000 feet by employing a separate coaxial line carrying the
i -f signal. In addition, a cable connector at the rear of the
receiver control unit permits the connection of an extension
cable so that routine operation may be conducted from a
nearby monitoring console. Both this unit and the power supply are intended to be mounted in a standard equipment rack,
as illustrated. A small control panel is located on the front
from which all adjustments can be made. They may also be
mounted in convenient carrying cases for portable operation,
if desired. This unit has its own filament transformer, but the
other voltages are received from the power supply. All tubes
are accessible from the front of the unit, and all cable connections are made at the rear.
Specifications
Frequency Range
Type of Reception
Video Frequency Range
Band Widtb
Tube Complement:
Receiver
Receiver Control Unit
11-6AK5
3-6J6
2-6AL5
1-6AC7
6800-7050 mc.
Frequency modulation
60 cycles to 6 mc.
15 mc.
1-2K26
1- 6J6
2-6AG7
2-6SL7-GT
1-6SN7-GT
Total Power Consumption -110 volts, 60 cycles
Weights:
Receiver and Housing
Receiver Control
Power Supply
Stock Identification
187
4-6AK5
a -c, 250
watts
35
36
58
lbs.
lbs.
lbs.
MI -26940
'MOBILE
Television Mobile Unit Type TJ-50A
Uses
Features
The RCA Television Mobile Unit is a custom-built vehicle
designed to carry the television equipment needed to pick up
outdoor scenes and relay the pictures to a studio or transmitter room for broadcasting.
Economical and convenient to maintain-standard Chevrolet
school bus chassis.
Modern styling conforms with that of RCA Television
Equipment.
Six feet of head room in interior.
The interior arrangement provides adequate storage space
for three cameras, their tripods and the relay transmitting para.
bola-units which must be set up outside the vehicle for telecasting. Equipment which need not be removed from the
vehicle, such as the relay transmitter control unit, audio amplifier and mixer, monitors and the camera control units, are
shockmounted on an attractively finished, linoleum covered
operating table inside.
Large windows in driving compartment.
All glass is shatterproof.
Complete and convenient stowage facilities.
Cables contained on six convenient reels.
Inside ladder and hatch provides access to roof.
Use of the Mobile Unit greatly simplifies the work of transporting the television equipment required for field pickups.
It also saves considerable wear and tear on the television units
as well as time in setting them up for operation.
Roof covered with special non-skid tread material.
Adequate heating facilities.
Complete control room in rear of truck.
188
MOBILE
Description
The body of the vehicle, built on a standard 1% -ton Chevrolet
chassis, is custom-built to provide an attractive, practical and
compact unit. Finished in two-tone umber gray, it is both
attractive and durable. The roof is reinforced to support the
weight of the field cameras as well as the relay antenna and
the operators. Access to the roof is made easy through use
of an inside ladder and a 24" x 36" rain-tight hatch.
short wheelbase gets the vehicle around sharp turns in narrow streets; large, full -view shatterproof windows facilitate
safe driving in heavy traffic; and a 90 -horsepower engine provides speed on open roads as well as pulling power on the hills.
A
Four cable reels mounted on swinging arms are housed in a
rear compartment accessible through two doors in the back
of the unit. When the rear doors are opened, the reels can
be swung out into the clear to facilitate unreeling the cable.
Each reel can accommodate 200 feet of cable. If additional
cable is required, there is space in the compartment for the
addition of two cable reels.
Inside, the vehicle has adequate heating facilities for cold
weather. In warm weather, the heater fan can be used for
ventilation. The linoleum covered operating table at the rear
runs the full width of the Mobile Unit, and provides convenient operating space for three operators seated side by
aide. Swivel chairs for the operators are permanently mounted
to the floor. The storage lockers for the cameras, tripods and
accessories are built along the inside walls of the vehicle.
Interior view, looking aft, showing ladder to roof,
and operators' positions
Inside Dimensions:
Width
84"
72"
Height
Height (at operators' table)
67"
13,500 Ibs.
Gross Weight
Tire Size
7 50 x 20
Chassis
Standard 1% -ton 160" wheelbase Chevrolet
Finish- Two-tone umber gray (light umber gray inside)
Specifications
Outside Dimensions (overall) :
Length (bumper to bumper)
Width
Height
969"
89"
110"
STORAuE
STEP
REELS
o
L____
1
HATCH"
ENGINE
COMPARTMENT
00
J
STORAGE
0,
w
3
o z
STEP
Q
3
Interior layout plan of TI -50A
189
v
00
U
I
1
I
1
I
I
U
TELEVISION
TRANSMITTING
EQUIPMENT
Page
TRANSMITTERS
192
SIDE BAND FILTER
194
DIPLEXER
195
TRIPLEXER
197
SUPER TURNSTILE ANTENNA
198
TV TRANSMITTER
Television Transmitter Type
a®® 1:2o
TT-5A
el®
®
a,
C2
fil
Features
Low installation costs-flexible cabinet arrangement.
maximum accessibility, for testing and servicing. End trim
and meter panels complete the cabinet enclosure, so that it
presents a pleasing and dignified appearance. A filtered air
supply for each cabinet is provided through individual removable filters in the bottom. Warm air is expelled through
the top. The visual section of the transmitter is located on the
right side and the aural section is on the left, with the power
supplies and control panel for both sections in the center. This
central location of power controls provides a high degree of
convenience and flexibility in the operation of the transmitter.
Low operating cost.
Uses highly efficient RCA 8D21 dual tetrode as power
amplifier.
Power amplifiers require no neutralization.
Quick changing of power amplifier tubes.
High level modulation in visual section.
The transmitter control circuits employ the newest and most
modern techniques. Provision is made for both manual and
automatic -sequence starting. The automatic system provides a
three shot recycling sequence, which automatically returns the
transmitter to the air up to three times in case of momentary
overload. If the overload persists, the transmitter is automatically shut down. A special hold -in circuit permits the transmitter to return instantly to the air in the case of momentary
power line failure, thus avoiding the thirty second delay required for the plate time -delay relay to close. A switch is
provided for each main rectifier to provide a reduced power
position for tune-up and emergency operation. All critical
power supplies are electronically regulated, making possible
stable, high -quality operation under all conditions of signal
or line voltage variation.
Straight -forward "meter tuning" of all r -f driver stages.
Uses highly efficient RCA FM exciter in aural section.
Packaged for convenience in shipping and installation.
All components readily accessible through front and rear
doors.
Description
The TT-5A is RCA's first post-war television transmitter. It
represents the culmination of the many years of RCA Television research and development. Many new features found in
this transmitter are the first applications of the latest RCA
developments.
The transmitter has a nominal power output of five kilowatts
peak visual power, and two and one-half kilowatts peak aural
power. This ratio is in conformance with the RMA standard.
The frequency range is from 54 to 216 mc., which covers the
twelve presently assigned television channels for metropolitan
operation.
The visual section of the transmitter is essentially a crystal
oscillator followed by several r-f amplifier stages, and a grid modulated, power amplifier. The use of final -amplifier, gridntoduation makes possible the operation of all driver stages
as high -efficiency, narrow -band, class "C" amplifiers, which can
be tuned quickly and easily from front panel meter observations.
The entire transmitter is housed in eight steel cabinets which
are fastened to a base frame. This frame is divided in such a
manner that the eight cabinets may be placed either in a
straight line (overall width-208") or in a "U" -shaped arrangement (smallest possible overall width -150"). Each cabinet has both a front and rear door. The front doors are provided with windows for observing the transmitter while in
operation. The components and wiring are arranged to permit
The final power stage uses the new RCA 8D21 water-cooled
dual tetrode operated as a push pull amplifier. The use of
this tube is one of the outstanding features of this transmitter.
Its highly efficient water cooling system introduces a new
principle in tube construction which permits roughly ten times
the power handling capacity of other tubes of comparable size.
It results in exceptionally low output capacitance. This, together with the dual tetrode construction does away with the
192
TV TRANSMITTER
necessity of neutralization. Since small physical size and low
output capacitance are necessary requirements for broad band
operation at television frequencies, this tube is an important
development in the progress of television.
Aural
distortion:***
50 to 100 cycles
1.5%
100 to 7,500 cycles_1.0%
7,500 to 15,000 cycles-1.5%
The aural section of the transmitter utilizes the highly efficient
RCA FM exciter, MI.7015, followed by several amplifier
stages, and a power amplifier likewise employing the RCA
8D21 dual tetrode.
Noise level:
FM noise, below
±25 kc swing_60 db
Coupled into the outputs of both the visual and aural sections
of the transmitter are "Reflectometer" units, which perform
the following important functions:
1.
2.
3.
Amplitude noise,
rms below carrier_50 db
Amplitude variation
over one frame.
Measure the standing wave ratio on the main transmission
line.
Measure the "Peak of Sync" power output (when calibrated
against the dummy load).
Operate as an r-f overvoltage output, thus protecting the
transmission line against rupture due to lightning, bad instrumentation or any trouble which causes excessive standing waves to occur.
Power Line Requirement:
Transmitter
Line voltage
Phase
Frequency
Instantaneous regulation
Power consumption (approx)
Power factor
208/230 volts
3
50 or 60 cycles
-
-
Console, crystal heaters, etc.
Line voltage
Phase
Frequency
Power consumption (approx.)
All high power circuits are doubly protected by highspeed
overload relays backed up by thermal type circuit breaker
switches. Similar circuit breaker type switches are used to
connect water cooler, blowers, filaments, and low power circuits to the power line. All fuses are of the visual indicating
type, and are mounted in a group on the front panel for
easy accessibility and identification.
5% maximum
32 kw
85%
-
115
volts
1
50
-
or 60 cycles
600 watts
Dimensions:
Overall length****
208"
Overall height
t4"
Overall depth (inc. door handles)
38"
Building entrance and elevator clearance requirements
25" x 80"
In order to provide greater convenience in shipping and installation, the transmitter is partially disassembled when it
leaves the factory. The largest unit, uncrated, is 25 x 38 x 80
inches, and no single unit weighs over 1000 pounds. This
facilitates handling in confined spaces and elevators. All connections between units are made from conveniently located
terminal boards on each unit.
Weight:
Transmitter**** (8 cabinets plus
Console
Water circulating system
Finish
Specifications
-2
-72
Less than 5% of
peak to peak signal
amplitude
The power circuits are so arranged that the operator may do
emergency maintenance or servicing work on the aural or
visual section of the transmitter while the other is on the air.
This includes changing the 8D21 tubes without shutting down
the water circulator. The operator is fully protected by proper
interlocking and safety devices. During test periods, either
section of the transmitter may be operated independent of the
other with a resultant saving in overall power consumption.
Aural
Type of emision
A3
Frequency range
Chan. 2 to 13
Power output (into
transmission line)
to 4 kw.
RF output impedance
ohms
Carrier frequency
±0.002%
stability
Modulation capability_±50 kc.
Method of modulation_Frequency mod.
Input impedance
600 ohms
Input level
+12, ±2 db
Frequency response**_Uniform within
±1 db from 30
to 15,000 cycles
Visual
Audio frequency
Stock Identification
Visual
2
PA cabinets)
8000 lbs. (approx.)
600 lbs. (approx.)
1300 lbs. (approx.)
Two-tone umber gray with satin chrome
trim and fittings
MI -19205-A, B
A5
Chan.
2
to
13
2.5 to 5 kw
72
*
peak
ohms
**
±0.002%
90%
Maximum attenuation with respect to idealized rectified
vestigial sideband response.
For
pre -emphasized response the pre.efittphasis filter
(MI -4926A) is provided to be inserted in the 600 ohm
audio input line at the most effective point.
*** Distortion and noise are measured following a standard
de-emphasis network.
Amplitude mod.
ohms
1 volt peak to peak
*0 db at 0.1 mc.
2 db at 0.5 mc.
2 db at 1.25 mc.
2 db at 2 mc.
2 db at 3 mc.
3 db at 4 mc.
75
* ** *
193
facilitate packaging and handling, the equipment
breaks down into its component cabinets (8 plus 2 PA
cabinets) and is shipped accordingly. The larger power
supply components are also removed and packed separately. Thus, the dimensions of the largest unit (unpacked) is 25 x 80 x 38 inches, and the weight approxi.
imately 600 lbs.
To
IIIEZECE31.
Vestigial Side Band Filter MI -19104
Features
Small size-small floor space.
No adjustments.
Low insertion loss.
Constant impedance input over entire double sideband.
Completely enclosed to prevent tampering and admission
of dust.
Description
The sideband filter is a device which is connected directly to
the output of the television visual transmitter to absorb the
relatively small amount of lower sideband energy falling outside of the assigned television channel. Use of a sideband filter
has several advantages: first, the tedious adjustment of tuned
radio frequency amplifiers needed for the rejection of the side band when low level modulation is employed is eliminated;
second, the sideband filter has a constant impedance input so
that the process of sideband elimination is accomplished without a detrimental effect on the picture quality; and third, the
high level modulation system used in the transmitter gives
the visual transmitter a better overall linearity.
Electrically, the sideband filter is a combination of two
M -derived filters. Since filter components of the common coil
and condenser construction would be difficult to manufacture
and uneconomical to use because of the currents, voltages and
reactances involved, the sideband filter has been designed,
using low loss coaxial transmission line elements. The undesired sidebands are passed through one of the filter units
into a properly terminated transmission line that effectively
eliminates reflections of the lower sidebands. The desired sig.
nals are passed through the other filter unit and a notch filter.
The notch filter is incorporated in the design to give positive
insurance against interference with the sound channel of the
next lower television channel. This notch filter is a system
of resonant coaxial transmission line elements that allows the
absorption of a single frequency in a second terminated coaxial
transmission line while the desired television signals are not
Specifications
effected.
Dimensions
Height*
84"
Width
36"
Depth
42"
Weight
1400 lbs.
Finish
Two-tone umber gray
Water connections (connected to transmitter water cooling
system)
"In" union for t/g nominal dia. copper water tubing
"Out" union for % nominal dia. copper water tubing
Electrical Connections
Transmitter interlock of circuit
Radio Frequency Connectins
Input Impedance
72 ohms, 3t/e" coaxial line
Output Impedance
72 ohms, 3t/" coaxial line
Since the filter is completely assembled at the factory, all
tuning adjustments are factory made. It is contained in a completely enclosed metal cabinet finished in umber-gray and
styled to match the associated television transmitter. The sideband filter is designed to stand in a vertical position near the
visual transmitter, with a connecting transmission line preferably not more than 10 feet in length. The transmission line
connecting the filter to the visual transmitter may leave the
filter through the top or bottom or on one side. The output
line passes through the top of the unit. The only other connections are with the station water-cooling supply and the
visual transmitter interlock circuit.
Vestigial sideband filter, MI.19104-A, covers channels 1 to 6
inclusive; and vestigial sideband filter, MI-19104-B covers channels 7 to 13 inclusive. Each unit is tuned for the desired
specific channel at the factory.
*
Height of sideband filter with base taken off for shipment
is 80".
194
DIPLEXER
Television Diplexer Unit Ml -19021, Ml -19022
Features
Permits use of one antenna for both visual and aural television signals.
Enclosed cabinet prevents tampering and admission of dust.
Cabinet sides easily removed for inspection.
Dependable. Electrical networks are composed of conservatively rated coaxial sections.
No adjustment required at installation.
Occupies little floor space.
Description
The Television Diplexer is a device to permit the feeding of
both the telvision visual signal and the television aural signal
to the same turnstile antenna without detrimental cross talk.
This eliminates one of the two transmitting antennas that
would otherwise be required and thereby saves the expense of
an additional antenna with its associated supporting tower.
There are two types of Television Diplexers: one for low
frequencies and one for high frequencies. MI.19021 covers the
television channels 1 through 6, and MI.19022 covers channels
7 through 13. The low frequency diplexer is larger than the
high frequency unit because of the greater physical size of
the components.
The diplexers are completely enclosed in steel cabinets finished
in umber-gray, and styled to match the apparatus with which
they are associated. The cabinet sides are easily removed for
routine inspection. The unit is shipped complete, and no
adjustment is required during installation.
In a simplified form, the diplexer may be considered to be a
balanced bridge circuit in which there are four legs, as illustrated in the accompanying diagram. The visual and the aural
Low-frequency Diplexer, MI -19021
signals are fed to alternate diagonals of the bridge. Since the
aural signal is fed into the circuit moss the mid -points of the
antenna and the reactors, no visual signal can go into the
aural transmitter. In like manner, the visual signal is fed to
the circuit between two points of equal potential with respect
to the aural transmitter so that no aural signal can get back
io the visual transmitter.
The Television Diplexer is installed in the station room, as
near as possible to the vestigial sideband filter. In this way,
it is convenient for inspection and maintenance, and no wind
or weight load is added to the tower. Because of the upright
cabinet type of construction, it occupies very little station
floor space.
High-frequency Diplexer, MI -19022
Iqs
DIPLEXER
TURNSTILE ANTENNA
E -W RADIATORS
TURNSTILE ANTENNA
N -S
RADIATORS
AURAL
TRANS
Simplified Schematic Diagram of Television Diplexer Unit
Specifications
LOW FREQUENCY DIPLEXER MI-19021
Dimensions
Height
Width
Depth
Weight
Finish
Radio Frequency Connections:
Input
Visual
Aural
Output
Two
Cross Talk
HIGH FREQUENCY DIPLEXER MI -19022
Dimensions
Height
Width
Depth
Weight
Finish
Radio Frequency Connections:
84"
281/8"
22%"
450 lbs.
Umber gray
17"
11"
26%"
110 lbs.
Umber gray
Input
72
72
ohms,
ohms,
31/8"
31/8"
coaxial line
coaxial line
Visual
Aural
Output
Two
Cross Talk
515 ohms, 3%" coaxial line
Below 40 db.
196
72
72
ohms, 1%" coaxial line
ohms, 1%" coaxial line
51 5
ohms, 1%" coaxial line
Below 40 db.
Television Triplexer MI -19023
Features
Permits use of one Super Turnstile antenna for both FM
and TV services.
Styled to match other transmitting equipment.
Simple, compact design.
Requires no elaborate accessory items.
Small floor space requirement.
Uses
The RCA Triplexer is designed to permit feeding three independent signals to the Super Turnstile Antenna from where
they can be radiated with good efficiency. The need for such
a system might be found by the broadcaster planning television plus FM service. In this case all three, FM signals in
the 88-108 me band, the TV picture signal and the TV sound
signal can be fed through the Triplexer to one Super Turnstile Antenna, saving the broadcaster the expense of separate
antennas. The broadband characteristics of the Super Turnstile
make such a system very practicable.
Description
The Triplexer consists of a number of rigid coaxial line segmente tuned to the frequencies of the three signals fed into it.
These tuned segments act as wave traps to prevent any one of
the three signals from feeding back into the feed lines of the
other two.
The usual arrangement is to have the TV picture and sound
transmitters feed through a Diplexer to the Triplexer. The
FM signal is fed directly to the Triplexer as shown in the
diagram.
The FM power that can be handled by this system is limited
by the standing wave ratios appearing on the lines. This is,
of course, determined by the operating frequencies used. In
general, the following combinations apply: TV channels II
and III with an FM input up to 3 kw; channels IV -VI with
an FM input up to 10 kw; and channels VII-XIII with an
FM input up to 3 kw.
The coaxial line assembly of the Triplexer is contained in a
completely enclosed steel cabinet the same size as the standard
low -frequency Diplexer unit. The Triplexer, which is installed
adjacent to the Diplexer, is finished in umber -gray to match
the other television units.
SUPER TURNSTILE
TELEVISION
PICTURE
TRANSMITTER
DIPLEXER
_
_
_
_
II
Triplexer with all covers removed to
show system of tunable coaxial lines.
Two output connectors are made near
the bottom, as shown. The two input
lines are at the rear and are not
j
=11=
TELEVISION
SOUND
TRANSMITTER
FM
TRANSMITTER
l
TRIPLEXER
visible.
Specifications
Input and Output Impedances
Height
84"
Width
22%"
Depth
281/4"
Weight
197
51% ohms
475 lbs.
Super Turnstile Antenna For Television
Types
TF -3A, TF -3B, TF -6A
and
TF -6B
Features
Extremely broad frequency characteristic
High gain for given height.
Permits diplexing of visual and aural signals into same
antenna.
No critical field adjustments-no coupling networks at tower
top.
Furnished complete with all fittings and hardware.
Grounded for lightning protection.
No weight supported by insulators.
Attractive appearance-adds to appearance of tower struc
tures.
Description
The new RCA Super Turnstile for television broadcasting is a
multi-element antenna system radiating horizontally polarized
waves with a circular radiation pattern. An increased gain is
accomplished by concentrating the radiation in the horizontal
direction at the expense of radiation in the vertical direction.
This gain increases with the number of sections, or layers, used
in the antenna; however, practical considerations establish a
maximum limit.
Each section of the antenna consists of four radiators mounted
at intervals of ninety degrees around a steel pole. The individual sections are mounted approximately a wavelength apart,
center to center. These radiators are attached to the steel pole
at both the top and bottom so that the complete structure is
grounded for lightning, and no weight is carried by endseals
or insulators.
The radiators are fed by means of coaxial transmission lines.
Each set of opposing radiators may be considered as comprising a horizontal dipole antenna. The outer conductor of the
transmission line is connected to one radiator, and the inner
conductor is connected to the opposite radiator. Connection is
made at the center of the inner member of each radiator. In
the event of icing, therefore, only the central part of each section is subject to impedance change. Ice formations can be
prevented, however, by the use of sleet melting resistors,
which will be provided, if specified. The sleet melting elements
are inserted into the vertical tubing of the radiating elements
which are adjacent to the pole. This will prevent ice formation
between the radiator and the pole-this being the only place
where ice formation will have a detrimental effect.
Three Section Super Turnstile. The
ing and may be mounted on top of
tain or a supporting tower similar
band broadcasting
center pole is self-supporta suitable building, mounto that used for standard
antennas.
The individual radiators consist of frameworks of narrow
diameter seamless steel tubing with cross members of cold
rolled steel rods. This open construction results in an antenna
with a rather low value of wind resistance, and the somewhat
triangular shape of the radiator forme a structure which is
198
and all associated fittings and hardware. The pole is painted
one coat of red metal primer and tone exterior coat of CAA
international orange paint. It is shop drilled and tapped for
accommodating standard steel steps at required points on the
pole. A circular plate, properly drilled, is welded to the top
of the pole for the mounting of a 300mm. code beacon. The
radiating elements, steel brackets, transmission line support
assemblies and all required bolts and lock washers are either
electro -galvanized or cadmium plated. The radiating elements
with attached steel fittings are packed for domestic shipment
in crates. The cross feeds, the brackets, clamps, pole steps and
transmission line assemblies are packed in separate containers.
Inherently rigid and well able to stand mechanical loads, vibration, wind force, etc.
The outstanding feature of this antenna is its broad frequency
characteristic, which makes it ideal for use in television broadcasting. This important feature has eliminated the need for
critical field adjustments, so common with antennas operating
in the higher frequencies. It has further made possible a degree of standardization heretofore out of the question. Only
three antenna designs are required to cover television channels
two through thirteen. Finally, it permits efficient diplexing of
the visual and aural signals into the same antenna.
The complete antenna installation consists of a tubular steel
pole, the radiating elements, the transmission line assemblies
Engineering Data For Super Turnstile Television Antenna
The antennae are designed to withstand a maximum wind
velocity of 85 miles per hour when coated with %" radial
ice and a maximum wind velocity of 95 miles per hour when
there is no ice. The antennae are designed for total transmitter
power of 20 KW.
.e-
Maximum Unit Stress, 20,000 lbs./in 2
Type No.
No. Sections
Power Gain
Channels
Frequency
W"
Band-
Lbs
A Ft
B Ft
TF -3A
3
3.45-4.1
II, III
54-66 Mc.
3,800
8' 10"
0"
0"
5"
0"
D2 Ft
44'
3'
24'
12'
R1* Lbs
R2* Lbs
R3* Lbs
H1 Ft
H2 Ft
1,144
2,330
3,474
61' 0"
49' 0"
C Ft
D1 Ft
Dia. of Pole at
Guide Flange
Projected Areas
With %" Ice
Without Ice
Max. Dim. of Tower
Top***
Stock
TF3A
3
3.64.5
IV, V & VI
66-88 Mc.
2,650
7' 23/4
36' 4"
2' 2"
18' 0"
10' 0"
980
1,746
2,744
50' 0"
40' 0"
103/4"
8%"
94.6
62.8
71.8
44.4
TF -6A
6
7.2-8.6
VII to XIII
174 to 216
2,300
3' 21/4"
32' 2%"
2' 6%"
18' 0"
10' 0"
925
1,711
2,636
46' 3"
36' 3"
B
C
R
8%"
75.34
48.1
6'0"x6'0"
5'5"x5'5"
5'5"sq.
Identification- MI -19012-A
MI.19012-B
MI -19013
Reactions R1, R2 and R3 as shown in table are for estimating purposes only and are figured on the basis of
20 lbs./Ft 2 of projected area without ice. All sections are
rounds.
1." W-Total weight, including pole, guide flange, pole socket,
30 mm Beacon, pole steps and miscellaneous hardware.
* * * Figures are for installation without railing on tower top.
If railing is to be used, pole is extended as required.
Super Turnstiles designed for mounting atop FM Pylon
antennas are designated Types TF-3B and TF -6B.
*
12
TOWER
199
TOP
D2
fik
AND
MEASURING
EQUIPMENT
TEST
Page
MONITORS
202
AUDIO & VIDEO MEASURING EQUIP.
211
OSCILLOSCOPES
217
SERVICE TEST EQUIPMENT
224
MONITORS
AM Modulation Monitor Type WM -43A
cation of the peak modulation, and (3) a trigger circuit which
flashes a light whenever the modulation momentarily exceeds
any previously set value.
The linear rectifier is designed for operation at a low power
level, which greatly simplifies the coupling to the transmitter.
In the output of the linear rectifier is a d -c meter, which indicates the carrier level at which the instrument is operating and
also shows any carrier shift during modulation.
addition, two auxiliary audio output circuits operating from
separate diode rectifier are provided. One of these at 600
ohms, is intended for audible monitoring; the other, a highimpedance circuit, gives a faithful reproduction of the carrier
envelope with less than 0.1% distortion. The high impedance
output circuit can be connected directly to the RCA WM -71A
Distortion and Noise Meter, enabling overall fidelity and noise
mea"urements to he made on the transmitter.
In
a
Specifications
Carrier Frequency Range
05
MODULATION PERCENTAGE RANGE
Negative Peaks
Positive Peaks
Features
75
0
to 110%
±2%
+4%
AUDIO FREQUENCY RESPONSE
Meter Indication, 30 to 15,000 cps
±0.25 db
Meter Circuit, 50 to 15,000 cps
±0.1 db
Audio Monitoring Output, 30 to 45,000 cps
±1.0 db
Measuring Output, when used with RCA Type WM -71A Distortion-Noise Meter and Coupling Cable, 30 to 15,000 cps
±1.0 db
R -f Input Power (over entire frequency range)
approximately
0 5 watts
R -f Input Impedance, broadcast band, approximately
ohms
NOTE: Input impedance increases at higher frequencies. Actual
impedance varies with coil position and input tuning.
ohms).
Indicates either positive or negative peaks in percentage
modulation and in decibels.
Meets all FCC specifications for modulation monitors.
-75
Carrier amplitude shift with modulation can be measured.
High impedance, low distortion output circuit permits use
of RCA WM -71A Distortion and Noise Meter.
WARNING LAMP CIRCUIT
The overmodulation lamp will flash whenever the negative
modulation peaks exceed the setting of the MODULATION
PEAKS dial by approximately 2% modulation, for audio frequencies between 30 and 7500 cps. For higher audio frequencies, the percentage overmodulation required to flash the lamp
increases slightly.
Low impedance, low distortion output circuit for aural
monitoring.
Terminals for connecting
indicator.
mc
0 to 100%
ACCURACY, of full scale at 0 and 100%
of full scale at any other percentage
Wide frequency range (0.5 to 60 mc).
Operates at low r -f input power (05 watt in
to 60
remote percentage -modulation
AUXILIARY OUTPUT
A multipoint connector at the rear of the instrument provides
a means of connecting:
1. A remote percentage modulation meter.
2. Line for 600 ohm monitoring.
3. The RCA WM -71A Distortion and Noise Meter.
Uses
The RCA Type WM-43A Modulation Monitor is designed to
give continuous direct reading indications of percentage modulation in the carriers of broadcast or other transmitters operating in the range of 05 to 60 mc. This modulation monitor performs the following specific functions:
TUBE COMPLEMENT (shipped with
2 Type 6SN7-GT
1
2 Type 6SJ7
2
1 Type 6116
1
Dimensions
width 19",
Weight (unpacked)
Finish
FCC Approval Number
Stock Identification
Measurement of percentage of modulation on either positive
or negative peaks.
2. Overmodulation indication.
3. Program level monitoring.
4. Measurement of carrier shift when modulation is applied.
5. Measurement of transmitter audio -frequency response.
1.
Description
The RCA WM -43A Modulation Monitor consists of three essential elements: (1) A linear diode rectifier which gives an
instantaneous output voltage proportional to the carrier envelope, (2) a peak voltmeter which gives a continuous indi-
instrument)
Type 2050
VR-150-30
Type 6X5
height 83/ ", depth 10"
31 lbs.
Umber gray
1557
MI -30043A
single set of coils (either 0.5 to 8 megacycles or 3 to 60
megacycles) is supplied with each instrument. unless both
sets are specifically ordered.
A
202
MONITORS
AM Frequency Monitor Type WF-48A
amplified, its peaks are clipped to produce an essentially
.quare waveform, and the square waves are applied to an audio
frequency meter.
The indicating element of the frequency meter is calibrated
to read zero when the audio beat is exactly 1000 cycles per
second. Deviations from 1000 cycles (Af) are indicated directly
a. Frequency deviation of the transmitter in cycles per second.
The monitor is a -e operated and is mounted on a single relay
rack panel. Coupling to the transmitter is obtained from a
short length of wire attached to the input terminals to art
:1 :nl anlenna.
Specifications
Frequency Deviation Range (readable to
Carrier Frequency Range
1
cycle)
±30
cycles
500 to 2000 kc
±10 parts per million
Stability (under normal operating conditions)
Better than one part per million
Approx. 100 millivolts to 1 volt
R-f Input Voltage
Power Requirements
cycles, 105-120 volts or 210-240 volts
Heater 25 watts; monitor circuits 100 watts
Power Input
Short antenna
Coupling to Transmitter
Tube Complement (supplied with instrument) :
1 Type 5V4 -G
3 Type 6SJ7
1 Type 6B4 -G
2 Type 6AC7
1 Type VR -105 (0C3)
2 Type 6H6
1 Type 2051
2 Type 6SQ7
1 Type 6V6 -GT
19" wide x 153/" high x 12'/2" deep
Dimensions
Umber gray
Finish
1468
FCC Approval Number
Accuracy
Features
Continuous Reading Deviation Meter.
Modulation of transmitter does not affect frequency indication.
Direct connection to transmitter not required.
Simple pickup antenna supplies r -f excitation.
Warning Lamp System indicates failure of either transmitter carrier or monitor crystal oscillator.
Reliable--minimum of attention required from operating
-60
-
MI -30048-A
Stock Identification
staff.
Uses
VOLTAGE FROM
TRANSMITTER
The RCA Type WF-48A Frequency Deviation Monitor is FCC
approved for use in standard broadcast stations. It indicates
continuously, and directly in cycles-per -second, the magnitude
and direction of any departure of the carrier from its assigned
channel frequency.
ltinr
R
-F
AMPLIFIER
MIXER
R
-F
A
AMPLIFIER
Description
r
f 31000v
-F
AMPLIFIER
f
The elements of the monitor are shown in the accompanying
schematic block diagram. Voltages from a temperature controlled piezo-electric oscillator (frequency f ±1000 cycles)
and the transmitter to be monitored (frequency f ± Af) are
amplified and fed to a mixer from which their difference frequency (1000 ± Af) is obtained. This audio frequency is
STANDARD FREQUENCY
OSCILLATOR
PEAK CLIPPING
AMPLIFIER
1000...= Gt
Schematic Block Diagram of Type WF-48A
Frequency Deviation Monitor
203
MONITORS
Frequency Monitor
Frequency Meter
Type WF-50A
Type WF-49A
Frequency Monitor
Type WF-50A can
be purchased and
used separately.
'
Features
Frequency Meter
Type WF-49A can
be purchased and
used separately.
Features
High sensitivity.
Two buffer stages.
Deviation direction test.
Stand-by operation.
Jack for audio output.
Panel terminals for crystal output.
Direct reading scales.
Single range selector switch.
Individual scale calibration for each range.
Provision for connection of an external meter.
Reading independent of input voltage over wide range.
Accuracy unaffected by input wave shape.
Regulated power supply.
Uses
The RCA Type WF-50A Frequency Monitor is designed to
monitor the carrier frequency of AM radio transmitters in the
HF range, and is particularly suitable for police, fire and other
municipal departments. Because it is a high-sensitivity monitor
it can be used to monitor the frequencies of mobile transmitters from a distance as well as for monitoring the main
Uses
The RCA Type WF-49A Audio Frequency Meter is a general
purpose instrument which may be used in determining the
frequency of an unknown source or for continuously monitoring the frequency of a system.
The electronics laboratory will find it a convenient means of
measuring audio and supersonic frequencies up to 60 kc, regardless of waveform. For monitoring radio transmitters, it
can be used in conjunction with an RCA Type WF-50A Frequency Monitor to indicate continuously the deviation from
assigned channel frequency.
transmitter.
Airlines and airports will find that the WF-50A Frequency
Monitor, used either singly or in groups, provides an excellent
means of monitoring their frequencies.
Where a continuous indication of frequency deviation is desired, the WF-50A should be used in conjunction with the
Type WF-49A Frequency Meter.
Description
The circuit consists of an input amplifier, followed by a series
of clipping and limiting amplifiers, and a frequency indicating
circuit composed of a capacitor, a diode and a d-c micro ammeter. The clippers and limiters convert the input signal
to a square waveform so that the indication is not affected
by changes in amplitude or waveform. A well regulated power
supply eliminates effects of line voltage changes. Two sets of
input terminals are provided on the panel, while at the rear
of the instrument a multi -point connector provides a means of
making connections that are more permanent. Plugging into
the panel jacks automatically disconnects the rear terminals.
Description
The monitor consists of a temperature -controlled piezo-electric
oscillator with mounting facilities for four crystals; two buffer
amplifiers, one for the crystal and one for the transmitter frequency; a mixer; and an AF amplifier.
The audio output is available at a telephone jack on the panel,
and the output of the crystal buffer stage is available at panel
terminals for calibrating or adjusting other equipment, such
as receivers and mobile transmitters. By means of a switch
the monitor can be kept in a stand-by condition in which the
vacuum -tube circuits are not operating but temperature control is maintained.
Specifications
Specifications
Range
Accuracy
1500 kc to 150 me
Carrier Frequency Range
105 /125 or 215/250 volts, 50/60 cycles
Power Supply
_75 watts (including temperature control)
Power Input_
Standard 19-inch relay-rack panel
Mounting
RCA umber gray
Finish
(With Type 376-M Quartz Plate) 0.002%
Accuracy
(Crystals are supplied separately)
Length 19"; depth 111/"; height 7"
Dimensions
92 lbs
Net' Weight
Input Voltages
Power Supply
Power Input
Mounting
Finish
Dimensions
Net Weight
204
_25
to 60,000 cycles per second in 6 ranges
scale, for all ranges
60,000 cycles when
input becomes less than 0.5 volts)
0 25 to 150 volts
105/125 or 215/250 volts, 50/60 cycles
Approximately 50 watts
Standard 19-inch relay-rack panel
RCA umber gray
±2 cycles, ±2% of full
(±3% of full scale for
I ength 19"; depth 111/"; height 51/"
19% lbs.
MONITORS
Phase Monitor Type WM -30A
Features
Phase angles can be read to better than ±0.5 degree.
No complicated preliminary adjustments.
Oversize components insure long life.
Accurate and quick field pattern checking.
Direct reading phase angle scale.
Plug-in resistors to match sampling line impedance.
Instantaneous quadrant indicator.
Uses
The RCA Type WM -30A Phase Monitor provides a simple
means of accurately measuring phase differences between currents in the various towers of an antenna array. It is particularly useful in checking directional arrays to insure proper
phasing and hence proper field pattern. All phase angles up
to 360 degrees at any frequency between 225 and 1800 kc can
be measured.
The WM -30A can be used to adjust phase -shifting networks, to
measure impedances of arrays, and to facilitate calculation of
mutual impedances of antennas. Another important application
is the measuring of phase characteristics of television i -f circuits (this requires the use of an i -f signal generator, two mixer
stages and a variable frequency oscillator).
The RCA Phase Monitor can be used for remote indication of
both relative amplitude and phase of antenna currents in arrays
employing up to three elements. Used in conjunction with the
MI -8216-C Remote Meter Panel correct relationships can be
maintained between phase and magnitude of currents in directive arrays having as many as six elements.
Remote Meter Panel
REMOTE ANTENNA METER PANEL
Description
This unit is designed to give relative indications of the currents in antenna arrays employing up to three elements, thus
insuring correct current relationships and proper field patterns. The unit is complete with power cord and tubes but
does not include sampling coils or meters. It is furnished with
a standard rack mounting panel. (This is the same unit that
forms an integral part of the WM -30A Phase Monitor.) Dimensions: 7" high, 19" wide, 51/" deep.
Two identical amplifiers are used to drive the two pairs of
plates of the 3 -inch Cathode ray tube. One of the amplifiers
incorporates a network which permits a manual phase shift of
90 degrees by means of a potentiometer. Thus, if two out-of phase voltages are impressed on the two amplifier units, it is
only necessary to adjust the potentiometer until the ellipse on
the tube screen becomes a straight line. Then the two voltages
are in phase and their original angular differences can be read
directly on the scale.
A unique circuit is incorporated for producing a keying impulse for correct quadrant indication. By means of a push
ANTENNA SAMPLING KITS
A single element Sampling Kit is recommended for each tower
to be monitored. Two Kits are available, one of which employs a tuned sampling coil, while the other employs an un tuned sampling loop. The Antenna Sampling Kit, MI -8217,
comprises one Antenna Sampling Coil (MI -8217-A) and one
Antenna Current Meter (MI.7184-A-150). The Antenna Sampling Kit, MI -8217-B, comprises one Antenna Sampling Loop
(MI.8217-C) and one Antenna Current Meter (MI.7184-A-150).
button the proper impulse is selected and modulates the
Cathode ray tube so that a spot appears in that quadrant on
the screen in which phase balance occurs.
The RCA Phase Monitor can accommodate three self-contained
meters for remote indication of antenna currents. The unit is
complete with power cord and tubes but does not include
sampling coils or meters. It is designed for rack mounting and
is finished in RCA umber gray.
The WM 30-A is supplied with three 79 -ohm plug-in resistors
for each of the three input circuits, to provide termination
impedance for the commonly used type of sampling line
which has a characteristic impedance of between 75 and 80
ohms. Resistors of other values may be substituted to match
sampling lines of 50 to 100 ohms impedance.
Specifications
Frequency Range
225 to 1800 kc
Phase Angle Range
0 to 360 degrees
Monitoring AccuracyFor small angles (up to 30 degrees)
±1 degree
±2 degrees
All other angles
R -F Input Impedance
ohms (other impedances obtainable)
R-F Input Voltage Range
3 8 to 12 volts
Power Supply
105/125 volts, 50/60 cycles
Power Consumption
115 watts
Tube Complement:
-79
4
1
RCA-6AC7
RCA-2Y2A
Dimensions
Weight
Remote Meter Panel MI -8216-C
*
205
Will not
fit 9AX6
,11I(`ÇA-5R4GY
)i;CA-6AG7
RCA-6AB7
RCA-3AP1A
171/" high, 19" wide, 15" deep'
80 lbs.
1
1
rack but can be used in Type BR -1A rack.
MONITORS
Accessories
for Phase Monitor WM-30A
.
PtutltNrvf»tNnLisu
CtaREnrp
SAMPLING COIL, MI -8217-A
The antenna current Sampling Coil comprises a tuned circuit
constructed with an internal double electrostatic shield, so
that the user need provide magnetic shielding only. It is
normally mounted in a weatherproof housing between the
tuning cabinet and the antenna. It feeds a sampling current to
the WM-30A Phase Monitor.
ANTENNA CURRENT METER, MI -7184-A-150
The Antenna Current Meter is a special high -frequency thermocouple, expanded scale unit calibrated 0.150 per cent of antenna current. This meter has been designed for use with the
WM -30A Phase Monitor for remote antenna current monitoring.
ISOLATION COIL, MI.7327.4
The Isolation Coil is an inductor consisting of a 110 micro henry coil wound with %" copper concentric line. It has an
impedance of 70 ohms. It is recommended for carrying the
sampling line across the base insulator of the tower, when
employing the MI.8217-C Antenna Sampling Loop. The dirt meter of the coil is 191/2". Approximate dimensions are:
height, 30"; depth, 16"; width, 21".
SAMPLING LOOP, MI -8217-C
The antenna current Sampling Loop comprises a rectangular
metal loop approximately two by four feet, together with
associated mounting hardware. The loop is designed for mounting directly to the tower. It feeds a sampling current to the
WM30A Phase Monitor.
206
MONITORS
Field Intensity Meter Type 301-B
(High Frequency)
Features
Measures AM and FM carrier strength.
Range
18-125 Mc.
Sensitivity
10 microvolts per meter at
Complete with power supply and antenna.
--
phones. Noise meter readings may be taken of the noise level
to indicate interference which may be encountered from various
industrial sources.
The power supply unit contains a storage battery and regulated vibrator system designed to operate continuously for
8 hours.
The accessory case contains an insulated tripod on the top
of which is mounted a dipole adjustable in length for the
frequency being measured.
18 Mc.
Uses
The Type 301-B Field Intensity Meter has been designed for
measuring field intensities of FM or AM stations operating in
the frequency band of 18 to 125 megacycles. It is ideal for checking antenna efficiency, directivity and service range and for
research and propagation studies. It provides either linear or
logarithmic output and may be used in conjunction with a
standard recording meter for making records of variation in
signal intensity. It is intended particularly for field use and
is arranged for convenient operation and for carrying from
one location to another.
Specifications
Field Intensity
Meter-Height
13"; width 20%"; depth 91/";
weight 38 lbs.
Accessory Case
Length 39"; height 12"; depth 7%";
weight 24 lbs.
Battery Unit
Height 144"; width 131/4" depth 71/4";
total weight 36 lbs.
Frequency Range
18 to 125 megacycles
Field Intensity Range at 18 Mc
10 to 500,000 u.v. per meter
Field Intensity Range at 125 Mc_50 to 2,500,000 u.v. per meter
Description
The RCA High -frequency Field Intensity Meter consists of three
units-the field intensity meter unit-the power supply-and
an accessory case.
It contains a local oscillator providing a source of calibrating
voltage. Calibration curves on the line and doublet antenna
are supplied so that readings may be converted into field intensity values. The frequency range of 18 to 125 megacycles is covered in three bands. The minimum readable
field strength varies from 10 microvolts per meter at 18 megacycles to 50 microvolts per meter at 125 megacycles. The output indicating meter is a four-inch instrument and will provide
indications which are either linear or logarithmic.
A separate FM detector is provided for identification of FM
stations without detuning the instrument.
A recording milliammeter having a sensitivity of 5 milliamperes
and a resistance up to 560 ohms maximum may be operated
directly from the instrument. A jack is provided for head -
Output Scales
Linear
Logarithmic
Output
Audio
Recorder
10 to
1
100 to
1
or 20 db
or 40 db
Phones or noise meter
Operates any recorder of 5 ma and 560 ohm
maximum resistance
Antenna
Doublet in 6 sections
R -f Transmission Line
Length 30'
Vibrator Power Supply
6 volts at 4 ampere load
207
MONITORS
Field Intensity Meter Type 308-B
Features
Direct readings in microvolts -per -meter.
An accuracy independent of non-linear detectors and panel meter scales.
Wide frequency and amplitude ranges.
Shielded loops for magnetic pickup.
Simplified tuning by ganged controls.
Uses
The 308-B, an entirely portable instrument, measures field
strengths from 20 microvolts -per -meter up to 20 volts -per -meter.
This wide range enables field surveys to be made practically
anywhere, from the very shadow of the transmitting antenna
to the most "down -in -the -noise" location-a welcome advantage in adjusting directive arrays and exploring radiation
patterns.
Description
The 308-B is a sensitive superheterodyne receiver with a
built-in calibrating oscillator for standardizing the receiver
sensitivity. A shielded, unbalanced loop picks up the signal to
POWER REQUIREMENTS
"A" Battery Circuit
6 volts, 1.5 amperes
"B" Battery Circuit
135 volts, 45 ma.
"C" Battery Circuits (two)
7.5 volts each
TUBE COMPLEMENT
1 RCA 6J5
1 RCA 6R7
1 RCA 6L5 -G
1 RCA 6L7
3 RCA 6S7
Dimensions (loop unmounted)
131/2" x 131/4" z 201/4"
Weight (unpacked)
48 lbs.
Finish
Gray wrinkle
Stock Identification
_ MI -7505-E
(Includes Field Meter and #2 Loop less 93-A Power
Supply and storage batteries.)
ACCESSORIES
Type 93-A Power Supply
MI -7519-A
(Mounted in case but less storage battery.)
Note: 93-A Power Supply Dimensions are 131/" x 131/2" x 8"
and its weight with storage battery is 29 lbs.
MI -8204-A
Storage Battery for 93-A
MI.8223-A2
Loop #1 (120-550 kcs )
Loop #3 (3 mc. to 18 me )
MI.8223-A3
MI.6214
High Impedance Headser
-
be measured.
Due to the design of critical components such as the r-f and i -f
attenuators and the mutual-inductance coupler, which couples
the calibrating signal to the input circuit of the receiver,
measurements can be obtained with an accuracy that is considerably better than has been obtained in the past. For example, it is not necessary to know the exact frequency of the
incoming signal in order to measure it accurately; moreover,
the instrument can be calibrated on a frequency somewhat removed from that of a very strong, incoming signal, to prevent
the strong signal from interfering with the low-level calibrating signal.
A series of readings can be obtained conveniently, with field
strength indicated in microvolts -per -meter on the scales of the
built-in attenuators; no involved calculations are necessary.
Special precautions have been taken in the RCA 308-B to obtain maximum oscillator stability and effective shielding. In
addition, the i -f stages are selective enough to prevent interference from signals on adjacent channels.
The wide frequency range of this instrument is covered in six
bands; no plug-in coils are used. Three loop antennas cover
the entire frequency range.
Shielded loops are used to minimize distributed capacitance and eliminate "antenna effect", thus further reducing error.
The loops require no balancing adjustments.
Specifications
Frequency Range
(3 loops)
Field Intensity Range
120 kc.-18,000 kc.
-20
microvolts to
volts per meter
±5% at 180 kc.-7,000 kc.
±10% at any frequency
20
Accuracy
Loop Antennas
120 kc.-550 kc.
Loop #1 (Accessory)
Loop #2 (Furnished)_550 kc:3,000 kc.
Loop #3 (Accessory)
3,000 ke:18.000 kc.
Output Indication
Linear and logarithmic scales
(Provision made for standard 5 ma.
recording meter and headphones.)
208
MONITORS
Visual Monitor Converter Type WM-12A
which forms the input to the control grids of the push-pull
triode r -f amplifier. The plate circuit of the r-f amplifier is
connected to a thirteen channel tapped transmission line type
circuit which is coupled to a similar circuit at the grids of
the r-f converter tube. The mixer is a dual triode with pushpull input to the control grids; the plates are connected in
parallel and form the input to the i -f amplifier. The oscillator
employs a dual triode in a thirteen channel circuit coupled
to the mixer input.
A two stage stagger -tuned i-f amplifier employing pentodes is
used in the instrument. Sound interference rejection of 20 db
is accomplished by means of trap circuits coupled to the i-f
stages. A crystal rectifier is used as a second detector. This
is followed by a pentode video amplifier. The output video
stage is connected as a cathode follower operating into a 75
ohm load.
The picture information provided by means of the WM -12A
approaches in quality the best which can be obtained by the
use of the present picture transmission standards. The output
of the WM -12A is connected through a 75 ohm transmission
line to the Master Monitor. The signal supplied to the Master
Monitor includes both synchronizing pulses and video. The
pulses so provided are used to synchronize the scanning system of the monitor kinescope.
Specifications
Features
Radio Frequency Ranges
13 RMA channels
Fine Tuning Range (approx. )___From ±300 kc on channel 1
to ±750 kc on channel 13
Continuous check on quality of picture transmission.
Picture information is comparable to ideal receiver.
Compact, well -shielded instrument.
Comes complete with r -f pickup device and r -f cable.
Operates on all of the 13 RMA channels.
Intermediate Frequencies:
Picture Carrier Frequency
Trap Frequencies
95 75 mc
21 25 mc, 26.5 mc, 26.75 mc
30 cps to 4.5 mc
Video Response
Sound Rejection
At least 20 db
Output Voltage
1 5 volts peak -to -peak (max)
Output Polarity
Sync negative
Output Impedance
75 ohms unbalanced
Input Impedance
50 ohms unbalanced
Input Voltage
01 volt (max)
Power Requirements (Note : Use RCA MI.8262 Regulated
Power Supply) :
Plate
200 volts d -c at 80 ma
Filament
6 3 volts a -c at 3 amp
Tube Complement:
3 RCA -6J6
1 RCA -6AÚ6
2 RCA-6BA6
1 RCA -6V6 -GT
1 IN34 (crystal rectifier)
Dimensions
8" High, 8" Wide, 9t/" Deep
Weight
12 lb.
Finish
Two tone umber gray
Uses
The Visual Monitor Converter, Type WM -12A, is designed for
use with Television Master Monitor to permit visual observation of the quality of the signal delivered to the antenna of
a television transmitter operating in any of the 13 standard
television -broadcast channels. The picture information supplied by the instrument is equivalent to that which would be
obtained from an ideal television receiver located remotely
from the station. This signal is free from interference by the
accompanying aural transmitter.
Enclosed in an attractive aluminum case, the instrument is
well -shielded, compact, and sturdy. It can be clamped to the
ungassed transmission line to which it is electrically connected, or it may be mounted on some other equipment or
on a shelf near the line.
Description
Essentially a superheterodyne receiver designed for vestigialsideband reception, the WM-12A samples a portion of the television transmitter r-f output and delivers to the Master Monitor a video signal which is applied to the monitor kinescope.
A simple attenuator is used for setting the r-f input of the
instrument to the proper level. The r-f section of the instrument is similar to that used in RCA television receivers. The
response of the video section extends from 30 cycles to 4.5
megacycles. The cathode follower stage which is used for
Video output supplies approximately 2 volts peak across
75 ohms to the Master Monitor input circuit. A standard output polarity with sync "down" is furnished to the Master
Monitor.
The r -f pickup circuit is coupled to the transmission line at
the output of the VSB filter. A variable attenuator is provided
for adjusting the voltage level to the double -ended circuit
TO VESTIGIAL
SIDE BAND FILTE
34 DIA.UNGASSED LINE
-
TO DIDLEXER
PICKUPaF
J
R F
I
CONVERSION
F
SECOND
VIDEO
AMPLIFIER-. DETECTOR., AMPLI FIE
UNIT
VIDEO
OUTPUT
-
I
TO MI-8262
'POWER SUPPLY
WM -12A VISUAL MONITOR CONVERTER
209
MONITORS
Visual Modulation Converter Type WM -13A
flip-flop multivibrator the symmetry of whose output may be
controlled. The rectangular wave output from this stage may
be adjusted to appear as a rectangular pulse of duration equal
to the flyback time of the monitor-oscilloscope sweep. This
pulse is used to key the local oscillator plate voltage, and succeeds in stopping this oscillator during the time of its application. Since the monitor -oscilloscope sweep circuit is set to half
the picture frame frequency, the result of the keying pulse
will be a horizontal line on the screen of displacement equivalent to zero power output from the transmitter.
The germanium crystal detector is used to determine the frequency vs. amplitude response of the transmitter and its asso
ciated circuits. This test is accomplished by connecting a video
sweep generator into the video modulation input and receiving the response in a suitable oscilloscope employing a 60
cycle properly phased sinusiodal sweep.
The WM -13A output is connected through a 75 ohm transmission line to the input of oscilloscope in the Master Monitor.
Synchronism for the horizontal sweep circuit in the oscilloscope
is derived from the signal which appears on the monitor
kinescope.
Specifications
Features
13 RMA channels
Radio Frequency Ranges
Fine Tuning Range (approx.)-From ±300 kc on channel 1
to +750 kc on channel 13
Intermediate Frequencies:
95 75 mc
Picture Carrier Frequency
2125 mc, 26.5 mc
Trap Frequencies__
10 cps to 3 mc
Video Response
At least 20 db
Sound Rejection
15 volts peak-to -peak (max)
Output Voltage
Sync negative
Output Polarity
75 ohms unbalanced
Output Impedance
50 ohms unbalanced
Input Impedance
Less than 2% of peak -to -peak
Maximum Nonlinearity
output voltage
O1 volt (max)
Input voltage
Power Requirements (Note: Use RCA MI.8262 Regulated
Power Supply):
200 volts d -e at 230 ma
Plate
6 3 volts a -c at 5.3 amp
Filament
Tube Complement:
1 RCA -6V6 -GT
5 RCA -6J6
Continuous check on waveform of transmitted television
signal.
Provides check on frequency response of transmitter.
Operates on all of the 13 RMA channels.
Comes complete with r -f pickup device, crystal pickup, and
r -f cable.
Compact and well shielded.
Uses
The Visual Modulation Converter, Type WM -13A, provides
the Television Master Monitor or equivalent unit with a video
signal which is a replica of the modulation envelope of the
television transmitter r -f output. In addition to the video information, the instrument supplies a signal corresponding to
100% modulation in the white direction (zero carrier level)
during the decay time of the monitor -oscilloscope sweep. The
picture signal is observed on the monitor oscilloscope as a
composite video and sync waveform, plus a reference line
representing zero transmitter output. Information for composite
signal -component analysis is thus made available to the transmitter operating engineer.
A separate broad -band detector is included to allow measurement of the frequency response of the transmitter and its
auxiliary equipment.
This instrument, although larger than the WM -12A, is similar
in appearance and construction. It may be mounted near the
WM -12A on the transmitter transmission line or on a shelf
nearby.
2
2
2
Dimensions
Weight
2 RCA-6SN7-GT
RCA-6BA6
1 RCA -6C4
IN34 (crystal rectifier)
RCA-6AU6
8" High, 121/2" Wide, 91/4" Deep
18
TO
3 'DIA. UNGASSED LINE
VESTIGIAL.,_(
TO DIPLEXER
SIPE BAND FILTER I)
I
Description
The WM -13A employs r -f, i -f, second detector, and video circuits similar to those in the WM -12A. Two stages of sync
separation and four stages of keying control are included in
the unit. A germanium crystal rectifier with its input connected
to the r-f pickup and its output circuit connected through a
low-pass filter to the video amplifier input is provided for
observation of transmitter frequency response characteristics.
A simple switching system employing a remotely controlled
relay allows selection of either the superheterodyne or the
crystal outputs.
The sync separater circuits are provided with a sample of
the composite -video signal and provides vertical sync pulses
which are used to synchronize the keyer circuits. The first
keyer control circuit consists of a blocking oscillator operating at one-half the vertical frequency. This is followed by a
rRF
CONVERSION
UNIT
NEVER
-`
-w
*RF
PICKUP
IF
,
SECOND
30 CYCLE
SHAPER
AND
_. 6LOCKINO
DRIVER.
OSCILLATOR
_
CRYSTAL PICKUP
VIDEO
VIDEO
DETECTOR
AMPLI FI ER
`
-"
0.S
SYNC
OUTPUT
AMPLIFIER
SYNC
SEMRATD&__4_, AMPLIFIED
I
NOMI -82621
POYVERSRPPLYI
L
WM-I3A VISUAL
210
lb.
Two tone umber gray
Finish
MODULATION CONVERTER
MEAS. EQUIP.
Beat Frequency Oscillator Type 68-B
Features
Very low distortion -0.2 to 0.3 per cent total arithmetic sum.
electronically coupled to obtain the maximum of stability.
Push-pull detector and amplifier stages are employed, thereby
eliminating the second harmonic distortion frequently found in
these stages, and providing linearity.
The instrument has sufficiently good waveshape to supply tone
for distortion measurements at all frequencies. It has a range
of 20 to 17,000 cycles throughout which optimum performance
is obtained, and has useable output of good waveshape down
to 5 cycles. The output is flat over the whole audio range,
while the distortion content in the output is of the order of
0.2 to 0.3 per cent, total arithmetic sum. Precautions taken in
design insure the low background level of -50 vu or 70 db
below maximum output.
Output impedances of 250, 500, and 5000 ohms are obtainable
from taps on the output transformer, which has a center tap
to provide for balanced outputs at all impedances.
Low background level-70 db below maximum output.
Wide frequency range.
Electron -coupled oscillators.
Push-pull detector and amplifier stages.
Large direct -reading hand -calibrated frequency scale.
Balanced outputs of 250, 500, 5000 ohms.
Magic-eye tube for checking 'calibration.
Standard double-jack output connections.
High output level -125 milliwatts (max.).
Frequency stability.
Uses
The Type 68-B Beat Frequency Oscillator is designed for
easy and fast fidelity masurements with laboratory accuracy.
This instrument is required for frequency response, audio distortion, noise level, and other measurements which must constantly be made on broadcast station equipment in order to
maintain high fidelity transmission.
Specifications
Frequency Range
Output Power
Output Impedances
Frequency Characteristics:
5000 ohm tap
The Type 68-B plus the 69-C Distortion Meter forms the combination necessary for making all types of fidelity observations. This equipment can be used to advantage by broadcasting stations and laboratories, and serves well in experimental work. Additional applications of these two units are:
equalization of lines, receiver measurements, a source of sine
waves for oscilloscope work or modulated oscillators.
20 to 17,000 cycles
(good waveform down to 5 cps)
125 mw. (max.)
250, 500, 5000 ohms
±0.5 db
±1
±1
500 ohm tap
250 ohm tap
Distortion (total arithmetic sum)
Below 100 cycles
Above 100 cycles
Hum (max. output)
Power Input
db
db
:
3%
2%
-70 db
110/120 volts, 25/60 cycles, 70 watts
0
0
Tube Complement:
Description
6
1
1
The Type 68-B BFO employs the usual two r-f oscillators, one
fixed and the other adjustable to produce a beat note of the
desired frequency. In the 68-B, however, the oscillators are
Dimensions
Weight
211
RCA-6C5G
RCA -45
RCA -5Z4
3
1
1
83/4"
RCA -6J7
RCA -874
RCA -6E5
high, 19" wide, 10" deep
50 lbs
MEAS. EQUIP.
Distortion and Noise Meter Type 69-C
Features
Wide frequency range for
f-m
The meter can be connected by means of a patch cord to any
point in the speech input system. A linear r -f rectifier stage
in the 69-C provides for measurements of overall transmitter
distortion. The r -f input terminals may be connected through
a twisted pair from a pick-up coil in the transmitter.
Noise levels and distortion percentages can be read directly
from the large -size meter.
applications.
Electronic output meter improves stability.
Wide range distortion measurements.
New bridging transformer for wider frequency band.
Noise level measurements from
-75
db.
Direct reading, large -size meter.
Gain standardized on 1 milliwatt, 600 -ohm level.
Specifications
Self-contained power supply.
Frequency Range for
30 to 15,000 cycles
Distortion Measurements
(harmonics to 30,000 cycles using bridging input)
(harmonics to 45,000 cycles using unbalanced high
impedance input)
500 to 2000 kc
R -F Range
Uses
The Type 69-C Distortion and Noise Meter has wide application in the broadcast field for measuring harmonic distortion,
obtaining frequency response characteristics, and measuring
background noise levels. It is designed for the accurate measurement of distortion over the entire audio range of 30 to
15,000 cycles, thus enabling the broadcaster to obtain a true
picture of the fidelity of his station.
The RCA 69-C is capable of accurately measuring very low
level distortions. It gives a precise indication of distortion
from 0.3 to 100 per cent, rms.
Modern transmitters have noise levels 60 db below 100 per
cent modulation. The Type 69-C can accurately indicate noise
levels as low as 85 db below 100 per cent modulation. In
addition, background noise levels down to -75 vu can be
measured.
Frequency Response:
30 to 45,000 cycles ±1 db unbalanced
1 db bridging
30 to 30,000 cycles
±
input
input
0 3 to 100%
Distortion Measurement Range
Noise Level Measurement Range:
Any level down to 85 db below 100% modulation
Any level down to -75 vu
Input Levels:
Modulated r -f
10 to 80
9 to 4
A -F Level from Oscillator
A -F from System under Test
Bridging Input
Unbalanced Input
Description
Audio Input Impedance:
Bridging Input
Unbalanced Input
Power Input
Tube Complement:
The Type 69-C employs a simplified switching arrangement for
making distortion measurements over the entire audio range.
The input and output fundamental signals from the equipment
under test are balanced against one another by means of the
amplitude and phase controls on the front panel, leaving the
harmonics to be measured by a vacuum tube voltmeter. Noise
voltages are measured directly by the voltmeter.
The Type 69-C has three alternative inputs so that measurements can conveniently be made at either the output of the
transmitter, any 500 ohm termination in the speech input system, or at any point where no appreciable load may be drawn.
2
2
2
RCA-6C5G
RCA-6SJ7
RCA-6X5G
Dimensions
Weight
212
-15
volts
volts
to +22 vu
0.12 to 8 volts and 1.2 to 80 volts
by means of high -low taps
90,000 ohms
200,000 and 20,000 ohms
watts, 105/125 volts, 50/60 cycles
50
1
1
1
RCA-6F8G
RCA-VR150
RCA-VR105
834 high,
1 Amperite
Ballast Tube
6-8
19" wide, 10" deep
44 lbs.
(net)
MEAS. EQUIP.
Distortion and Noise Meter Type WM -71A
In measuring distortion, the a -f signal is applied to the instrument and the null point is obtained to balance out its
fundamental frequency, leaving only its harmonics and other
distortion components which are indicated in percentage directly on the panel meter. When the modulated output of a
radio transmitter is to be measured, a linear rectifier is required
to produce the audio envelope. Any linear detector system
having an undistorted output of 1.5 volts can be used.
switch on the front panel provides for switching out the
null circuit so that the instrument can be used as an extremely
sensitive voltmeter for measuring noise and hum levels.
A
Since the WM -71A has only one tuning control plus a small
trimmer, it can be quickly set to any frequency over its
range. This is a time -saving feature in making a series of
Features
measurements.
Continuous coverage of audio range for distortion, noise
and hum measurements.
Distortion measurements, as low as .1%, quickly and easily
made by one tuning adjustment.
Specifications
Audio Frequency Range-_50-15,000 cycles (fundamental) for
distortion measurements; 50-45,000 cycles for VU and
noise measurements.
Distortion measurements independent of phase shift.
Requires no direct connection to audio oscillator.
Audio oscillator distortion can be measured.
100% to 0.1% in six ranges.
Distortion Range
Full-scale meter deflection for values of 100%, 30%,
10%, 3%®, 1%, and 0.3%.
Can be used as a wide range highly sensitive voltmeter
or VU meter.
Tapped power transformer permits operation on either
125 volts or 210-250 volts.
Range-Extends from 0 to -80 db below a reference
level of one milliwatt in 600 ohms, in seven ranges; and
to -80 db below 100% modulation when at least one
volt is available from the modulation monitor at 100%
modulation level.
Noise
105-
Uses
Accuracy_For distortion measurements, accurate to within
±5% of full-scale ± residual distortion level which will
Distortion and Noise Meter RCA Type WM -71A is a compact
precision instrument of new design. It permits continuous
coverage of the audio frequency range, indicating directly the
percentage of a -f distortion in modulators, speech amplifiers,
a -f generators, receivers and other equipment employing audio
frequencies. The instrument will give full-scale readings for
distortion percentages as low as 0.3%, and is capable of
measuring noise components at frequencies from 50 to 45,000
not exceed .05% to .1%. Noise measurements accurate to
within ±5% of full-scale (residual noise level is less than
-80 db). Effect of line -voltage variations from 105 to 125
volts, negligible.
Range-For distortion and noise, 1.2-30 volts
at 100,000 ohms input; 0.8-30 volts at 10,000 ohms (bridging) input.
Input Voltage
cycles.
Innovations in circuit design permit distortion measurements
to be made easily and rapidly. Direct connection to the audio
oscillator is not required, making it easy to measure at places
remote from the oscillator. Moreover, the flat response and
wide frequency range of the internal amplifier make the instrument useful for accurately measuring noise and VU levels.
Input Impedance-100,000 ohms unbalanced; 600 ohms bridging input (10,000 ohms) balanced or unbalanced to ground
Audio Frequency Response
Flat within
1
db from
30-45,000 cycles
Tube Complement
5 Type 6J5, 1 Type 6H6, 1 Type 6X5,
1 Type 6SN7-GT, 1 Type 6K6 -GT, 2 Type VR -150-30
Description
Power Requirements_A tapped primary provides for operation on a -c line voltages of 105-125 volts 50/60 cycles, or
210-250 volts 50/60 cycles. Approximately 60 watts is
required.
Essentially, the WM -71A consists of a high -gain amplifier, an
r -c interstage coupling unit, a calibrated attenuator for adjusting the sensitivity, and a panel meter to indicate amplifier
output.
Dimensions-Rack mounting typeheight 7", width 19", and depth 12" (approx.)
The r -c interstage coupling unit balances to a sharp null at
the frequency to which it is tuned, the null frequency being
controlled from the panel. Degeneration is employed to maintain high stability in the amplifier and to provide flat transmission characteristics (except within an octave of the null
Weight
Finish
point).
Stock Identfication
213
35t/ lbs.
Umber gray lacquer
MI.30071-A
MEAS. EQUIP.
Attenuator and Measuring Panel Type 89-C
Features
Description
Simplifies fidelity measurements.
The Type 89-C Panel consists of a volume indicator meter, an
input and output attenuator, an impedance matching system.
and jacks for convenient connections.
Wide range.
Convenient switches allow the volume indicator to be connected
to the input of the attenuator system or to a pair of jacks for
external connection. Other switches control four balanced "H"
pads having 5, 10, 20, and 40 db. attenuation, respectively.
These pads may be inserted between the input and output
jacks in steps of 5 db. from zero to 75 db. An output impedance switch allows matching to 600, 250, or 30 -ohm circuits.
An input switch for the Distortion Meter permits a choice of
high or low signal level.
Levels can be read directly in db.
Useful for taking frequency response curves.
Output impedance switch for matching.
Input switch for high or low level.
Uses
Specifications
The Type 89-C Attenuator and Measuring Panel has been designed for facilitating measurements with the Type 68-B Beat
Frequency Oscillator and the Type 69-C Distortion and Noise
Meter. It will serve equally as well for general measuring
work.
Impedance Values:
Input
600 ohms
Output
600, 250, or 30 ohms
Volume Indicator
By use of the 89-C suitable attenuation can he introduced to
90,000 ohms
Volume Indicator Range
feed the equipment being measured from the 68-B Oscillator.
Also, the voltage fed from the Oscillator to the Distortion
Meter can be conveniently controlled.
(1 mw.
below zero level)
Attenuation
0
0
to
75
to
+22 v.u.
db. in steps of
5
db.
Operating Limits:
The volume indicator is useful for measuring levels as well as
for taking frequency response curves when the 68-B Oscillator
is employed alone.
Input Level
O
to
+22 v.u.
-75
-85
-95
to
to
to
+22
Output:
600 ohms
250 ohms
The 89-C Panel saves considerable time in setting up apparatus
for measurement and provides for a wide range of conditions.
It is particularly useful for laboratories and for broadcasting
stations in the master control room or at the transmitter.
30
ohms
Dimensions
Weight
214
51,4"
+ 12
+ 2
v.u.
v.u.
v.u.
High, 19" Wide, 7" Deep
16
lbs. (approx.)
MEAS. EQUIP.
Audio Voltmeter Type WV-73A
Features
Unusual sensitivity (0.001 volt a -c).
Wide range (0.001 to 1000 volts a -c).
Can be connected across high d -c potentials (1000 volts).
May be used as an a-f amplifier with high gain and good
fidelity.
Unvarying meter readings despite line voltage changes or
tube replacements.
Logarithmic scale and overlapping attenuator provide accuracy even when pointer is at either end of scale.
Excellent frequency response over the audio range (20
cycles to 20 kc.) .
Uses
The RCA Type WV -73A Audio Voltmeter is a sensitive electronic instrument designed to measure a-c voltages over wide
ranges of frequency and amplitude. An input circuit with low
capacity and high resistance makes the instrument particularly
suitable for measuring voltages in high -impedance circuits. It
may be used to measure the response of a -f power amplifiers and loudspeakers without disturbing their frequency
characteristics.
The main components consist of a precision attenuator, a
3 -stage high -gain stabilized amplifier, a balanced diode rectifier, a special d -c microammeter, and a well-regulated power
supply.
The voltage to be measured is fed to the attenuator through
a shielded cable attached to a jack on the front panel. The
attenuator consists of an 11 -position switch and high-quality
noninductive resistors designed so that consecutive ranges
overlap by 10 db.
For testing radio receivers and sound systems, the WV-73A
may be used to measure gain and noise level in power amplifiers, and ripple voltage in power supplies. It can be used to
locate sources of frequency distortion and faulty amplifier components in receivers, phonographs, and public address systems.
Because of its unusual sensitivity, the instrument can well
serve to measure the electrical conductivity of switches, circuit breakers, relays, buses, grounds, etc. In addition transmission losses on lines and circuits, as well as the response
of special filters, compensators, and other apparatus, can be
measured.
From the attenuator the voltage is fed to the high-gain amplifier, which employs a conventional feedback circuit to obtain
stabilization. The feedback circuit also greatly reduces input
capacity of the first tube. Output voltage from this amplifier
is fed to a balanced diode rectifier to produce d -c for energizing the meter.
The high-level rectifier is designed to produce an output that
is proportional to the average value of the full wave, thereby
giving a meter reading that agrees very closely with an rms
meter for all usual distorted waveforms. Because a balanced
diode rectifier is used, the meter indicates the true value of
both halves of the wave, avoiding the polarity or "turnover"
error of half-wave circuits.
If desired, the WV -73A can be used as an a -f voltage amplifier. It will give high gain with essentially perfect fidelity, and
its sensitivity readily adapts it for use with microphones having
low output.
For making bridge measurements the Audio Voltmeter is
ideal, readily indicating the null point at either high or low
audio frequencies. By connecting the WV-73A to the output of
a phototube, it will indicate extremely slight variations in
light intensity to which the tube is exposed.
Specifications
Voltage Range
Frequency Range
Input Impedance
Power Supply
Dimensions
Weight_
Finish:
Cabinet
Panel
Description
The WV -73A Audio Voltmeter was developed to fill the need
in industry and in the laboratory for a high -impedance vacuum tube voltmeter of good sensitivity and stability. It is also well
suited for use in broadcast studios and for servicing public
address systems.
215
0 001
to 1000 volts a -c
20 to 20,000 cycles
1 megohm and 25 mmf
105/125 volts, 50/60 cycles
131/2" Wide, 93/4" High, 71/" Deep
Approximately 15 lbs.
Dark cobalt gray Metalustre
Scratch brushed aluminum
MEAS. EQUIP.
Video Sweep Generator Type WA -21A
Features
Sweep or CW signals up to 10 mc.
Uniform sweep rate-no crowding at either end.
Entire CW and Marker signal range covered in one con-
tinuous band.
Unusually flat response.
Built-in output metering circuit.
Continuous control of output.
Built-in mixer system eliminates spurious marker signals.
Uses
The RCA Video Sweep Generator, Type WA -21A, is designed
to facilitate rapid testing of video frequency networks by permitting visual observation of the frequency response characteristic. It permits direct viewing of the envelope of the output wave of a video circuit while the input signal sweeps
through a range from 100 kc to 10 me, at the rate of 60 complete sweeps per second. It is generally used in conjunction
with a suitable detector and oscilloscope to observe the output
voltage vs frequency curve. In this use the deflection voltage
source provided in the instrument furnishes a convenient system for synchronizing the horizontal deflection of the oscilloscope with the frequency excursion of the video input signal.
The WA -21A also embodies a CW generating section that produces sine wave signals tunable from 100 kc to 10 me for
point -by -point or steady-state tests. The beat -frequency principle
is employed, and the entire range is covered in one continuous
band. The CW section is also valuable for detailed analysis
of a narrow portion of the video frequency spectrum, for example, in adjusting infinite rejection traps in television circuits.
The section of the circuit which produces the CW signal is
separate from that which generates the sweep signal, thereby
allowing the CW signal to serve as a calibrating marker on
the sweep trace. When the marker is employed, a clearly visible
"pip" appears on the trace and the frequency at which this
pip occurs may be read directly from the dial.
In testing video amplifiers this instrument is useful for adjusting peaking circuits and for checking overall performance.
In setting up transmitters, it can be used for adjusting the r-f
networks to insure proper frequency response, and can also
be used in conjunction with a field intensity meter for checking sideband energy distribution. For special applications, the
sweep width may be reduced and the center frequency adjusted
(by means of screw -driver adjustments) to permit detailed observation of the response of narrow band -width circuits within
the range of 100 kc to 10 mc.
incorporated. The marker is visible on an oscilloscope screen
either when using a video detector or when viewing the video
waves directly. The pip is uniform in size over the entire
range of adjustment, and the full range from 100 kc to 10 mc
is covered by a single dial scale.
The CW output is supplied through the same coaxial line as
the sweep signal, while a panel switch permits selection of
sweep, sweep plus marker, or CW. The output feeds into a
75 -ohm terminated coaxial cable. An output metering circuit
is provided to indicate the RMS value of the signal voltage.
This circuit consists of a diode VTVM with a step attenuator.
Continuous control of the output from 1 millivolt to 1 volt
is achieved through the use of a fine control in connection
with the step attenuator. Distortion and spurious outputs are
less than 5% of the fundamental signal voltages.
built-in source of supply -frequency voltage is provided for
connection to the horizontal deflection circuit of an oscilloscope. This voltage is adjustable in phase. It is useful for
synchronizing the oscilloscope sweep rate and phase with the
frequency sweep rate of the WA -21A. Stability of the WA -21A
sweep signal is insured by use of an electro -mechanical sweeping capacitor.
A
The instrument is designed for either table top or rack mounting. It is normally furnished in a table model cabinet. For
rack mounting, suitable protective enclosures are provided, the
panel space required is 83/ by 19 inches, and standard relay rack mounting slots are provided in the panel.
Specifications
Sweep frequency Range
CW Range
Calibration Accuracy
Sweep Frequency Rate
Marker Accuracy
Description
The output of an FM sweep oscillator and a heterodyne oscillator are combined in a mixer to produce a sweep signal
covering the range from 100 kc to 10 mc at a rate of 60 complete sweeps per second-when using a 60 cycle power supply.
Output is uniform within 1 db of the midrange response over
this range. A blanking circuit is provided to eliminate the
signal during the return portion of the trace (from 10 mc to
100 kc) if desired, and this feature also furnishes a zero output base line on an oscilloscope screen.
100 kc to 10 me
100 kc to 10 mc
2%
Line frequency
7%
Output Voltage
1 millivolt to 1 volt
Output Impedance
75 -ohm terminated coaxial line
Output Characteristic-Flat within 1 db of mid -range response
from 100 kc to 10 mc
Power Supply
105/120 volts, 50/60 cycles, 180 watts
Tube Complement:
5-6AG5
2-955
1-6SQ7
1-VR150
The CW circuit utilizes two oscillators, the outputs of which
are combined in a mixer tube to produce a beat output that
can be continuously adjusted from zero to 10 mc.
Dimensions:
Cabinet
Relay Rack
Finish
Weight
The CW generator and the sweep generator may be operated
simultaneously to produce a fluctuation or pip on the output
of the sweep, where it crosses the frequency at which the CW
generator is set. In order to produce this marker without any
spurious by-products, a special built-in mixer system has been
216
2-6Y6G
1-6BA6
1-6AS6
1
-5U4 -G
1-6C4
1-6BE6
1-6SJ7
22" wide, 10%" high, 15" deep
83/" high, 19" wide, 131/2" deep
Umber gray
80 lbs.
OSCILLOSCOPES
Cathode Ray Oscilloscope Type 155-C
Features
versatile, since critical observations can be made unobscured
and various filter and limit screens can quickly be substituted
by hand.
Light-shield with removable graph screen facilitates critical
observations.
High-fidelity amplifiers and improved wide -range timing
oscillator insure accuracy and dependability of results.
The timing axis oscillator is of an improved design allowing
synchronization with low voltages in the audio, supersonic and
low r -f ranges. Linearity is practically uniform through the
range of 10 c.p.s. to 60 kc.
Three-inch cathode-ray tube provides a large, easily read
image with sufficient detail for practically every application.
Direct deflector connections accessible through door in
side of case.
The 155-C has provisions for direct deflector -plate connection
through a side opening in the case. It is housed in an attractive grey -wrinkle lacquered metal cabinet which provides adequate protection. A snap handle makes it conveniently portable.
Uses
The RCA Type No. 155-C Oscilloscope has been designed to
meet the requirements of field service, industrial testing, commercial and university laboratories. Although practically unlimited in application, some of its more common uses include
the study of wave shapes, measurement of modulation of transmitters, adjustment of radio receivers and transmitters, and
determination of peak voltages.
Specifications
1 volt rms per inch
Deflection Sensitivity with Amplifiers
Sine Wave Response-Flat 10 cycles to 40 kc; useful to 200 kc
10 cycles to 60 kc
Timing Oscillator Range
Input Impedance
5 megohms in parallel with 22 mmfd.
Power Rating
110.120 volts; 50-60 cycles; 50 watts
Dimensions
14%" High, 8" Wide, 1411/4" Deep
21 lbs.
Weight
Description
This instrument was the first to have a built-in, deep, light shield which permits general observations at lower intensity
and makes many high speed transients visible in lighted rooms.
A removable graph screen makes the Type 155-C still more
217
OSCILLOSCOPES
Cathode Ray Oscilloscope Type WO -79A
(Wide -Range Portable)
Features
Small size and light weight.
Wide frequency range -10 cycles to 5 mc.
Wide horizontal deflection -2 X screen diameter.
Triggered sweep for examination of pulses and transients.
Calibrated meter for voltage measurements.
High voltage for photography.
Wide range centering controls.
Simplicity-multiple functions assigned each control.
Direct and easy connections to deflecting plates.
Time base voltages and 6 volts a -c available for external use.
Uses
The RCA Type WO -79A Wide -Range 3 -Inch Oscilloscope is
designed to fill the need for an inexpensive and portable instrument which will permit close examination of extremely
short, sharp -fronted pulses. It is ideal for detailed observation
and accurate measurement of voltages produced by television
synchronizing and deflection circuits, ignition systems, pulse
generators, radar equipment, and other electronic devices. Centering controls permit expansion of the waveform over a distance twice the diameter of the screen without visible distortion, thus any portion of a complex waveform can be centered
for study. Television servicemen, for example, will find this
innovation in a small instrument to be very helpful. Voltage
amplitude of a signal can be determined by means of a calibrated voltmeter on the instrument.
The triggered sweep feature makes the WO -79A particularly
suitable for photographic study of transients, for television
signal expansion, for checking square wave rise time, and for
checking irregularly timed pulses. Signal triggered deflection.
60 -cycle deflection, and blanking are some more of the unusual
features of this instrument.
Specifications
Vertical Amplifier:
Frequency Range-Flat within ±2 db. from 10 cycles to 5 mc.
Deflection Sensitivity:
With 1000 volts on Second Anode
0.5 peak to peak volts/in.
With 1500 volts on Second Anode
0.75 peak to peak volts/in.
Horizontal Amplifier:
Frequency Range
Flat within ±2 db. from 10 cycles to 500 kc.
Deflection Sensitivity:
With 1000 volts on Second Anode
1.3 peak to peak volts/in.
With 1500 volts on Second Anode
2 peak to peak volts/in.
Description
The Type WO -79A Wide Range 3 -inch Oscilloscope is a general purpose portable precision instrument incorporating features for the study of electrical phenomena which have heretofore been available only in more elaborate and expensive
laboratory-type equipment. Wide frequency range and high
gain characteristics permit high speed transient and pulsed
voltages in the order of 1 microsecond with frequency components up to 10 mc. to be displayed and accurately measured.
Leading edges of short pulsed voltages are clearly and sharply
reproduced so that all details stand out distinctly for either
minute examination or photography. A retractable light shield
provides easy viewing of faint traces.
Major electrical componets include calibrated horizontal and
vertical input attenuators, high gain horizontal and vertical
amplifiers, a sync. amplifier, a time base oscillator and sweep
generator, an intensifying amplifier, low voltage and high
voltage power supplies, and a 3 -inch high-contrast cathode-ray
tube.
There are three types of internal voltages: (1) a sawtooth time
base voltage, (2) a triggered linear time base voltage, and
(3) a 60 -cycle sinusoidal voltage supplied through a phase
shifter circuit.
Input Impedance:
Vertical Amplifier:
With Attenuating Cable
With Direct Cable
Direct (No Cable)
Horizontal Amplifier
Sync. Amplifier
Sawtooth Time Base
-1_1
meg. in parallel with
meg. in parallel with
1 meg. in parallel with
1 meg. in parallel with
1 meg in parallel with
20 cycles to 250
15 mmf.
70 mmf.
30 mmf.
50 mmf.
50 mmf.
kc./sec.
Triggered Time Base:
Max. Speed_
1 microsecond per in.
From single sweep to 50 kc./sec.
Repetition Rate
Blanking
Return trace blanked on triggered deflection
Power Supply
105/125 volts, 50/60 cycles
200 watts
Power Consumption
Tube Complement:
4
The intensifying amplifier increases the brilliancy of the spot
after the time base generator is triggered, to permit examination and photography of small, faint and extremely short signals. The circuit also extinguishes the stationary spot.
2
1
4
RCA-6AC7
RCA-6SN7
RCA -2X2 /879
RCA-6AG7
1
1
1
1
1
Dimensions
The instrument comes complete with both direct and attenuating cables, probe and alligator clips, as well as power
supply cord.
Finish
Weight
218
RCA 6SH7
RCA -5Ú4G
RCA -6H6
RCA -0D3 /VR150
RCA-3KP1 (C-R tube)
14'/2" High, 81/" Wide, 1614" Deep
Light blue -gray wrinkle
(including cables)
42 lbs.
OSCILLOSCOPES
Cathode Ray Oscilloscope WO -60C
Features
Industry can make widespread use of the WO -60C because of
the inherent advantages of this electronic measuring instrument. It operates from almost zero input, has zero inertia,
and practically unlimited speed of response. It has wide range,
smooth and stepless control, and no moving parts It is suitable
for measuring very small quantities, for very rapidly changing
quantities, and for very short time intervals,-those beyond
the range of conventional measuring instruments.
Combines ruggedness and accuracy for heavy-duty continuous service.
Linear sawtooth sweep with uniform rise.
Useful range of 0.5 to 300,000 cycles.
Especially suitable for measuring phase relations.
New
5 -inch
C -R
For testing of electrical components and for A-M, F-M, and
television receiver production the WO -60C is economically
quite efficient. On the production line, this general purpose
instrument, will usually show a savings because of a decrease
in cost per test.
tube gives clearer trace.
Faster changing of
C-R
tube gives unusual flexibility.
Description
Special circuits for steady signal.
The RCA Type WO -60C Oscilloscope is designed for applications that require accuracy and long life despite rugged use.
This instrument will maintain high sensitivity and precision
under conditions of prolonged service, violent shock and vibration, in the presence of damp atmospheres and fumes, and
over wide ranges of temperature. Results are reliable even
when operating with the widely fluctuating line voltages often
encountered in industry.
Uses
The RCA Cathode Ray Oscilloscope, Type WO -60C, is a general purpose, completely portable instrument, especially suitable for industrial applications. It will measure mechanical
movements as low as 60 rpm., assist in the testing of servo
mechanisms, aid in design of sonar and other supersonic equipment. Instantaneous pressure indications, vibration studies, and
strain gage measurements can be made. Also it can be profitably employed to trace distortion in audio systems, to develop
sound systems, to measure modulation characteristics. Industrially it is further applicable to testing and adjusting thyratron, ignitron and similar electronic control circuits used in
modern machines. It also serves as a sensitive voltmeter for
a -c or d -c measurements. In some of these applications the
WO -60C is used directly, while in others a suitable pick-up
device is also employed.
Controls are simplified and grouped for ease of operation.
Connections are few and convenient to make. The WO-60C is
quickly set up. There is no complicated terminal board, no
difficult diagram of connections.
The instrument is entirely self-contained, comprising high gain amplifiers, calibrated attenuators, sweep oscillator, and
internal high and low -voltage power supply. An improved c -r
tube of the zero -first -anode -current type gives better-than -usual
sensitivity, sharp focus from one end of the 5 -inch screen to
the other, and less trapezoidal effect.
219
OSCILLOSCOPES
Horizontal and vertical amplifiers have practically identical
electrical characteristics including sensitivity, frequency response, phase shift, and input impedance. The sweep oscillator
easily synchronizes with the phenomena to be observed, the
sawtooth sweep is exceptionally linear with uniform rise time,
and the trace is faithful reproduction of the input signal.
synchronized with the voltage applied to the grid of the first
triode section of the sweep tube. The "sync sel" control permits selection of sync voltage from the vertical amplifier, power
line or external source. A "sync adj" control makes it possible
to adjust sync voltage amplitude to the desired value.
Both amplifiers employ a 2 -stage r-c circuit featuring an unusual first stage. A cathode -coupled input stage results in low capacity high -impedance input which permits rapid change of
gain without surges. Thus the signal is prevented from shifting or bouncing off the screen, which is a decided aid to visual
examination and, especially, to photographic recording.
Specifications
Deflection Sensitivity:
Vertical Amplifier
0.056 peak -to -peak volts per inch
(0.020 rms. volts)
0.067 peak-to -peak volts per inch
Horizontal Amplifier
(0.024 rms volts)
peak -to -peak volts per inch
Direct to Horizontal Plates
(15 rms. volts)
34 peak-to -peak volts per inch
Direct to Vertical Plates
(12 rms. volts)
-42
Provisions are made for using either sawtooth or sine wave
(line frequency) timing. Filament supply of 6.3 volts a -c is
available at front -panel connections for use with auxiliary
apparatus. A regulator tube stabilizes critical voltages. Gain
control is of the voltage divider type compensated with
capacity, uses fixed carbon resistors, and gives gain control
over a range of 10,000 to 1. Direct connections to deflection
plates are controlled by switches so that leads can remain in
place.
The WO -60C is designed for fast changeover from one type
of c -r tube to another. Tubes can be changed in 10 seconds or
less. This is helpful for those applications requiring long or
short persistence screens. The c -r tube supplied is of medium
persistence which is most suitable for general applications.
For the lowest frequencies, a long persistence screen is often
held desirable. For the very best in photographic recording the
short persistence screen with its highly actinic radiation is
more desirable.
Controls and connections associated with the vertical amplifier
channel are located on the left side of the front panel, those
associated with the horizontal channel are on the right. Sync
input jacks, sync and sweep controls are located in the center
of the panel.
All connections are terminated with jack bodies that will accommodate either binding -post pin plugs or locking pin plugs.
Use of threaded type plugs eliminates the inconvenience caused
by leads pulling out during tests.
The sweep rate can be varied from 3 to 30,000 cycles per second
by adjusting the sweep controls. Sweep oscillations can be
Input Impedance:
Vertical or Horizontal Amplifier
1.0 megohm shunted by approx.
Direct to Vertical or Horizontal Plates
1.0 megohm shunted by approx.
0.5 megohm shunted by approx.
External Sync
22
mmfd.
22
30
mmfd.
mmfd.
Frequency Response:
Flat within ±10%a from 5 to 80,000 cycles
Sine Wave
Flat within ±20% from 2 to 100,000 cycles
Useful range 0.5 to 300,000 cycles
No tilt or overshoot from 20 to 5000 cycles
Square Wave
Rise time less than 5 microseconds
from 10 to 90% of total rise
to 30,000 cycles per second
Sawtooth Time Base_
105/125 volts, 50/60 cycles
Power Supply
64 watts
Power Consumption
Tube Complement:
1 RCA-0D3/VR150
1 RCA -5ÚP1
1 RCA-5Y3GT
3 RCA-6SL7GT
--3
2
1
RCA-6SH7
RCA -0C3 /VR105
1
RCA-2X2A
14" High, 9t/2" Wide, 19t/z" Deep
Dimensions
Finish:
Panel
Brushed aluminum anodized
Blue -gray "Metalustre"
31 lbs.
Case
Weight
120
110
z
100
V
90
80
70
Z
60
50
40
30
20
10
0
10
1,000
100
FREQUENCY
IN
CYCLES
PER
10
000
SECOND
TYPICAL FREQUENCY RESPONSE OF WO -60C OSCILLOSCOPE
220
100 000
1,000 000
OSCILLOSCOPES
D. C. Oscilloscope Type
WO -27A
Features
power rectifier systems can be conveniently investigated with
the WO -27A, because the nature of the arc and its time relation to other events in the system may be studied. In this
connection, it is also of interest to circuit breaker designers
and users.
-0
to 100,000 cycles.
Response-flat down to zero cycles.
Internal direct -coupled balanced amplifiers.
Timing range from 1 to 30,000 cycles.
Range
Single
sweep and
recording.
Faster changing of
a veritable host of applications in which the WO -27A
can be employed as a time- and labor-saving device. Strain
measurements can be quickly and easily made by employing
There is
blanking-excellent for photographic
c-r
tube gives unusual flexibility.
standard test specimens and conventional auxiliary equipment.
Lightning actions and vacuum tube characteristics may be
studied. The instrument is not less than ideal for picturing a -c
components of rectifier currents and their relation to the d -c
value, in the study of grid current effects and other endless
inter -related reactions. It will be found useful for locating discontinuities in transmission lines by recording the time interval between the application of an impulse to the line and
the arrival of the reflected signal. It is widely employed in the
design and servicing of servo mechanisms, sonar and other
supersonic equipment.
The single sweep feature can be employed in the investigation
of transients and other actions which occur at one time only.
For example, flash-backs of any sort in electrical systems, onetime vibrations in mechanical systems, and pressure surges in
hydraulic systems can be readily portrayed. By means of
photography these transients can be permanently recorded for
detailed study and for filing. A camera is set up and focused
on the cathode ray tube. Since the return trace is blanked off,
the shutter of the camera may be left open. When the transient
occurs, it triggers the sweep and the trace is permanently
recorded.
The WO.27A is highly suitable for studies in the field of
medical science. Its low -frequency response, to cite but one
example, enables it to be employed in the analysis of heart
action as a visual stethoscope.
Uses
The RCA Direct Current Oscilloscope, Type WO.27A, is especially designed for observation of low-frequency a -c and d -c
phenomena and, in addition, permits simultaneous observation
of both a-c and d -c components.
Since the internal amplifiers of the WO -27A have flat frequency
response down to zero cycles, it is useful in the study and
servicing of extremely low-frequency actions such as occur in
many mechanical, hydraulic, or electrial systems. This instrument may be employed for rapid adjustment of rotating
machinery, for precise setting of relay contacts, and for measuring instantaneous air and water pressures that ordinary gages
do not detect. Used in conjunction with a piezo-electric transducer, the WO -27A may be used to analyze and to correct
vibration conditions in machinery or any other device or equipment. The d -c oscilloscope has proved to be very helpful in
the development of internal combustion engines because, when
used with suitable auxiliary apparatus, the pressure developed
in a cylinder can be visually displayed on the screen. The
instrument has also proved expedient in velocity measurement
of projectiles, employing light screens to trigger the sweep and
to apply vertical deflection, which allows the traverse time
to be portrayed on the screen. The problem of arc -back in
221
OSCILLOSCOPES
Description
Specifications
The oscilloscope is probably the most useful of measuring
instruments because of inherent versatility and unique freedom
from limitations. It operates from almost zero input, has zero
inertia, and practically -unlimited speed of response. It has
wide range, smooth and stepless control, and no moving parts.
ft is suitable for measuring very small quantities, for very
rapidly changing quantities, and for very short time intervals
-those beyond the range of conventional measuring instruments. The Type WO -27A Oscilloscope is an RCA development
using direct -coupled amplifiers having a low -frequency response characteristic good to zero cycles per second, or direct
current. This makes it useful in portraying the slowest changes
and movements and also serves to eliminate low -frequency
phase distortion.
Frequency Range:
Vertical and Horizontal Amplifiers
Timing Axis Oscillator
to 100,000 cycles
0
1
Blanking Amplifier
to 30,000 cycles
30 to 100,000 cycles
Deflection Sensitivity:
Vertical Amplifier
0 084
Horizontal Amplifier
0 105 d-c
d-c
volts/in
volts/in
Direct to Deflection Plate:
Vertical
The horizontal and vertical amplifiers are identical and have
an essentially flat frequency response characteristic. Connection
may be made to the output of either amplifier, or directly to
either pair of deflecting plates.
54
Horizontal.
67 5
peak -to -peak volts/in
peak -to -peak volts/in
Amplifier Characteristics (vertical and horizontal amplifiers
are identical) :
The timing axis oscillator is of the Potter type, employing
nongaseous tubes and operating down to 1 cycle per second.
Provisions are made for converting the normal timing axis
to a single sweep circuit for the study of transient phenomena.
Triggering may be either externally or internally controlled.
Input Resistance (approx
Input Attenuator
500,000 ohms
)
4
Coupling Capacitor
Input (max )
The circuits used are ideal for high-speed photographic work
in that a combined blanking circuit provides an increased
intensity and illumination only during the sweep. Push-button
switches are provided for all ranges, allowing rapid manipulation. Meter-calibrated comparison input is provided for both
amplifiers. An improved c-r tube of the zero -first -anode -current
type gives better-than -usual sensitivity, sharp focus from one
end of the 5-inch screen to the other, and less trapezoidal effect.
The WO -27A is designed for fast changeover from one type
of c -r tube to another. Tubes can be changed in 10 seconds
or less. This is helpful for those applications requiring long
or short persistence screens. The c -r tube supplied is of medium
persistance which is most suitable for general applications.
For the lowest frequencies, a long persistence screen is often
held desirable. For the very best in photographic recording,
the short peristence screen with its highly actinic radiation is
more desirable.
500 volts
Input (max.)
250 volts
Calibration Voltage
Metered d -c voltage
Synchronization:
Internal, external, or line frequency
Positive or negative
Method.
Polarity
Power Supply.__
105/125 volts, 50/60 cycles, 130 watts
Tube Complement:
1
RCA -5ÚP1
1
12 RCA-6SF5
4 RCA-6SN7-GT
This instrument combines in one compact unit the features
that are usually associated only with larger, multiple unit and
more expensive equipment. Extraordinary features of the
WO -27A include a frequency range from zero cycles (or dc)
to 100,000 cycles and a timing range from 1 to 30,000 cycles.
Heavy duty components that give long life despite rugged
service and high voltage input, together with convenience of
connection and push-button control make the WO -27A what
is probably the best buy in a d -c oscilloscope.
1
1
2
RCA -6N7
Dimensions
2
RCA -2X2 -A
RCA -5V4 -G
RCA -6X5 -GT
RCA-0D3/VR150
20" high, 13" wide, 25" deep
Weight
80 lb
Finish
Two tone umber gray
izo
110
100
90
80
70
60
40
30
20
10
100
10
FREQUENCY
N
1
10 mfd
A -C
D -C
steps, each 10 to
1,000
10,000
CYCLES PER SECOND
TYPICAL FREQUENCY RESPONSE OF WO -27A OSCILLOSCOPE
222
100,000
1,000 000
OSCILLOSCOPES
Cathode Ray Oscilloscope Type 715-B
(Laboratory Type)
Features
Extended frequency range-flat to
11 mc.
High vertical deflection sensitivity.
Low input capacity and high input resistance.
Precisely compensated attenuator for vertical amplifier.
Calibration meter.
Triggered sweep.
Adjustable phase.
Time base marker.
Uses
The RCA Cathode Ray Oscilloscope Type 715-B fills the need
for a laboratory instrument that will permit detailed study of
extremely short, sharp -fronted pulses, and other unusual waveforms. Recurring and transient phenomena can both be observed and measured with the Type 715-B; the waveform need
not be repeated at regular intervals because even a random
recurrence produces a clear, steady trace.
The wide -band amplifier, triggered sweep, blanking, and high
accelerating voltage features make this instrument particularly
well-suited to the photographic study_ of transients. Heavyduty, ball -bearing swivel casters, and a conveniently located
front handle make it easy to move the unit.
Description
The 715-B Oscilloscope is a console type instrument especially
designed for close examination of high-speed transients as well
as regularly occurring phenomena. The cathode ray tube is
operated with a high accelerating voltage in order to produce
the intense spot necessary for many applications. A removable
metal shield prevents direct external light from striking the
surface of the cathode ray tube. A peak -to -peak a -c voltmeter
is included. It may be used to check signal amplitude by pressing a convenient sw:.ch at the probe end of the input cable.
The sweep can be triggered either from the signal causing
vertical deflection or from an external signal. The speed with
which the spot moves is completely independent of the repetition rate, being continuously adjustable by panel controls to
give time calibrations from less than 2 microseconds per inch
to over 100,000. Thus, pulses almost invisible on a standard
oscilloscope can be expanded to reveal their true waveform
on the 715-B. The aperiodic circuit will work satisfactorily
when triggered by a single isolated impulse, or by pulses
having any repetition rate up to 10,000 cps. When desired, a
special built-in oscillator will superimpose clear, steady, microsecond peaks on the curve to facilitate the determination of
time intervals.
With the control in the PERIODIC position a sawtooth deflection is produced, having the exceptional frequency range
of 5 cps. to 100 kc. This can be synchronized with very high
frequency signals or with pulses of extremely short duration.
Triggered Sweep Speed
(continuously adjustable)
Time Interval Markers
1 0 microsecond
Blanking-Return line blanked on aperiodic deflection only
Power Requirements
105/125 or 210/250 volts,
50/60 cycles, 500 watts
Dimension.
941" High, 21" Wide, 27" Deep
Finish:
Cabinet
Two-tone gray enamel
Panel
Brush chrome
Tube Complement:
Specifications
VERTICAL AMPLIFIER
Frequency Range-Flat within ±1 db from 5 cycles to 11 mc
Deflection Sensitivity:
With 2600 volts on Second Anode_0.17 rms volts per inch
With 1500 volts on Second Anode -0.10 rms volts per inch
INPUT IMPEDANCE
Vertical Amplifier:
With Attenuating Cable
With Direct Cable
Horizontal Amplifier
Sawtooth Frequency Range
-2 to 100,000 microseconds per inch
9-6AC7
2-6H6
1-6SH7
11 megohm + 15 mmf
10 megohm + 150 mmf
10 megohm + 50 mmf
5 cps to 100 kc
2-VR150.30
1-5VP1
Weight
223
4-6AG7
1-6SJ7
1-2X2/879
2-807
2-6U6
2-6SL7-GT
4-6L6=G
2-866/866A
350 lbs.
IMIZMEM
VoltOhmyst Type 195-A
Features
Electronic-nonburnout meter.
Measures
10
1
meg
a -c
and d-c to 1000 volts, resistance to 1000 meg.
de input insures greater accuracy.
nteg d-c probe for dynamic testing.
Flat
a -f
response from 30 cycles to
10
kc.
Zero center scale for FM discriminator alignment.
Uses
The VoltOhntyst is an unusually accurate vacuum tube voltmeter designed for measuring both a -c and d -c voltages up
to 1000 volts, and resistance up to 1000 megohms. A -F and
supersonic voltages can be measured up to 100 volts within
a range of 30 to 100,000 cycles and with linear reading at any
frequency. The 195-A serves as an output meter for direct
reading in decibels, or in volume units across 600 -ohm audio
circuits with standard zero level of 1 milliwatt. The VoltOhmyst is also designed to serve as an FM alignment indicator and indicates positive or negative deviation from balance.
The 195-A is used for maintenance of modern machinery
embodying electronic control circuits, because it is ideal for
oscillator grid voltage testing and trigger control voltage
measurements. For servicing of sound systems, it is useful for
level checking-and is a handy, all-purpose meter. For radio servicing, the VoltOhmyst is the one indispensable instrument
for AVC, AFC, FM discriminator and bias voltage readingsplus audio fidelity indication, *supersonic and low r -f testing.
Specifications
D -C Voltmeter:
Six Ranges
0-5, 0-10, 0.50, 0-100, 0-500, 0.1000 volte
10 megohms (constant)
Six Ranges
0-5, 0.10, 0-50, 0-100, 0.500, 0-1000 volte
Input Impedance
A -C Voltmeter:
Ohmmeter:
Six Ranges
0-1000, 0-10,000, 0.100,000 ohms;
0-1, 0-10, 0-1000 megohms
Description
A -F
The extreme versatility and usefulness of the VoltOhmyst
stems from the use of electronic measuring circuits. Additional advantages of the d -c VTVM circuit include high input
resistance (which makes it possible to test radio receivers with
the signal present), ability to measure high values of resistance, and protection against meter burnout. The 195-A also
features a self -balancing diode for a -c measurements, a plastic
meter case with one-piece unbreakable front, and a shielded
a -c cable and probe.
FM Alignment Indicator:
Voltmeter:
Four Ranges
0-5, 0-10, 0-50, 0-100 volts
Frequency Response
Flat from 30 cycles to 100 kc
Input Impedance
200,000 ohms, 170 mmfd
Output Meter:
Six Ranges
-20 to +16, -14 to +22, 0 to +36,
+6 to +42, +20 to +56, +26 to +62 db
(When used for measurements across 600-ohm audio
circuits, the readings are equivalent to Volume Unite
for a reference level of 1 milliwatt)
Provision for zero center adjustment meter reads plus or
minus for alignment of FM discriminator circuit
Power Supply:
A -C Power
105/125 volts, 50/60 cycles, 14 watts
Battery
2-1% volt flashlight cells
Tube Complement
RCA -6K6 -GT, 1 RCA -6H6, 1 RCA -6X5 -GT
For d -c measurements the 195-A has high resistance input of
10 megohms constant on all ranges, 1-megohm isolation resistor in d-c probe for dynamic socket voltage readings, a
polarity reversing switch which eliminates time and trouble
of reversing leads, and individual calibrations for positive and
negative indications.
-2
Dimensions
For measuring resistance up to 1000 megohms with absolute
safety the 195-A applies only 3 volts to any circuit; one scale
is used for all ranges from 0.1 ohm; and no zero resetting is
Weight
93/" High, 6%" Wide, 6%" Deep
14
lb.
Finish:
Case
necessary.
Panel
224
Gray wrinkle
Brush chrome
Voltohmyst Type WV-75A
(High Frequency)
Features
Measures a -c voltages up to 250 mc.
Reads positive and negative peaks.
One megohm isolating resistor in d -c probe for dynamic
voltage checking.
megohms constant input resistance provides low drain
and greater accuracy for all d -c ranges.
11
Polarity reversing selector switch eleminates need of switch.
ing leads.
Zero center selector switch for FM and AVM applications.
Uses
The RCA WV -75A Advanced Voltohmyst is designed for the
convenience of radio and electronic service men, being especially helpful in making FM and television measurements as
well as routine measurements. A newly developed diode probe
makes it possible to read peak-to -peak voltage at frequencies
up to 250 mc. Circuit innovations provide for readings of both
positive and negative peaks. The WV -75A possesses all the outstanding characteristics of its well-known predecessor, the Type
195-A. It will measure d-c resistances up to 1000 megohms, a -c
voltages up to 1000 volts, and d -c voltages up to 1000 volts.
In radio service work the WV -75A is very convenient because
practically all a -c and d -c voltages can be measured. The high
input resistance makes it possible to accurately measure d -c
voltages directly at the grid, plate, sreen or cathode terminal.
A -C measurements in the average radio receiver include all a -c
and audio voltages between the power transformer primary and
the output transformer or voice coil of the speaker.
Other uses of this versatile voltohmyst include the measurement of d -c value of AVC voltages; bias -cell voltages; AFC
and FM discriminator voltages; d-c resistance and insulation
leakage in oscillator and amplifier coils, audio and power transformers; leakage through the dielectric and insulation of condensers; and checking for gassy tubes.
Frequency Response:
Using diode probe directly
30 cycles to 250 mc
Using diode probe with supplied leads
cycles to 30 mc
Using diode probe and multiplier
30 cycles to 15 kc
Input Impedance:
Equivalent Shunt Equivalent Shunt
Resistance, ohms
Capacity, mmi.
Using Diode Probe Directly:
At 1 mc
625,000
15.6
Description
-30
The WV-75A employs a push-pull d-c VTVM circuit characterized by excellent linearity and stability.
An outstanding feature of the Advanced Voltohmyst is the
full wave diode rectifier which is built into the a -c probe.
With this probe, the instrument is capable of measuring voltages at frequencies up to 250 mc. Accurate mechanical construction to close tolerances makes this probe a durable, dependable device. Measurements at high frequencies are made
by direct contact with the central pin and the ground ring at the
end of the probe, while an alligator clip for the central pin
and a short ground lead serve as adaptors for voltage measurements at lower frequencies. An external multiplier can be
screwed into the probe for measurements in the highest a -c
voltage range at the lower frequencies.
At 10 mc
32,000
At 250 me
100
Using Diode Probe with A -C Multiplier:
At 1 kc
1,650,000
At 10 kc
1,650,000
Resistance,
Ranges
A -C, 6
ranges:
0
to 3,
0
Ranges
-0 to
Power Supply:
A -C Power
Battery
Tube Complement_
Specifications
D -C, 6
6
to 10, 0 to 30, 0 to 100,
0 to 300, 0 to 1000 volts
14.5
13
2
2
1000, 0 to 10,000, 0 to 100,000 ohms;
0 to 1, 0 to 10, 0 to 1000 megohms
105/125 volts, 50/60 cycles, 15 watts
9-1% volt flashlight celle
2 RCA -6K6 -GT, 2 RCA-6AL5,
1
Dimensions
Weight
Using diode probe directly or with adapters
0 to 3, 0 to 10, 0 to 30, 0 to 100 volts
(Measures r-f voltages to 100 volts rms. up to 17 mc. Above
that the maximum allowable input tapers to 10 volte at
250 mc.)
Using diode probe and multipliers
to 300, 0 to 1000 volt.
9%" High;
RCA-6X5GT
6h" Wide, 63/" Deep
9
lbs.
Finish:
Steel Case
-0
P
225
Gray wrinkle lacquer
Etched brush chrome
Battery VoltOhmyst, Type WV-65A
Features
Power supply completely self-contained.
Measures voltage, current, and resistance.
11-megohm input resistance for all d -c ranges.
1-megohm isolating resistor in d-e dynamic probe.
..4TNOn1( voumeTen
ro
Electronic circuit-meter protected against burnout.
Polarity reversing selector switch.
Uses
The RCA Battery VoltOhmyst is a combined voltmeterammeter-ohmeter of the electronic type for use in places when
the conventional a -c outlet is not available. Internal battery
operation of this VoltOhmyst makes it entirely independent
of external power sources. It can be used in automobiles, boats,
airplanes, rural areas and any other place when the regular
a -c power supply is either difficult or impossible to obtain.
The Battery VoltOhmyst may be used for accurate measurements of a -c and d -c voltage, for d -c current and for resistance.
In radio and audio applications it may be used for measuring
AVC, AFC and FM discriminator voltages; d -c supply and
bias cell voltages; oscillator strength; and resistance of coils,
resistors, and insulation. This VoltOhmyst is quite helpful for
measuring the d-c voltage developed across the picture channel
of a television receiver when making antenna adjustments. It
also is applied to determining when gassy tubes are present.
D -C measurements may be made when a -c is present. In addition, this Battery VoltOhmyst is a useful tool for the servicing
of all types of modern industrial electronic equipment.
When used with the inexpensive RCA Crystal Probe, the
Battery VoltOhmyst may be employed to measure a -f and r-f
voltages, thereby extending its usefulness to include applications that ordinarily would require the use of more elaborate
and expensive equipment.
Specifications
D -C
Voltmeter:
Six Ranges
Input Resistance
Sensitivity (max.)
Description
Voltmeter:
Five Ranges
Sensitivity
0-3, 0-10, 0-30, 0.100, 0-300, 0.1000 volte
11
megohms constant for all ranges
per volt on 3-volt range
3.7 megohms
A -C
The Battery VoltOhmyst is a push-pull VTVM with 2 -tube
bridge circuit, possessing excellent linearity and stability
characteristics. Circuit innovations that include zero grid current and controlled inverse feedback produce accurate readings
over all ranges.
A high degree of self regulation is obtained without sacrifice
of sensitivity. D -C input resistance has the unusually high
value of 11 megohms
A 1-meg. shielded signal -tracing probe makes possible dynamic
voltage measurements in signal -carrying circuits. The WV-65A
is exceedingly stable in operation, requires no adjustment of
zero controls when changing ranges and is essentially independent of changes in both tube characteristics and battery
voltages during normal life.
A neon lamp mounted on the panel flashes whenever the battery is on. This serves two purposes. It indicates the condition
of the battery, telling when replacement is necessary. It reminds the forgetful one that the instrument is on and that
the battery is being drained.
The a -c circuit using a copper oxide rectifier is isolated from
the case. The d-c circuit for current measurements is also
isolated from the case.
Ohmmeter:
Six Ranges
D -C
0.10, 0-30, 0-100, 0-300, 0-1000 volts
1000 ohms
per volt
0-1000, 0.10,000, 0-100,000 ohms,
0-1, 0.10, 0-1000 megohms
Ammeter:
Six Ranges
Voltage Drop-
milliamp.
and 0-10 amp.
450 mv. for full scale deflection
0-3, 0-10, 0-30, 0-100, 0-300
Power Supply:
Batteries
Four
11/2 volt RCA -V5036
Two 45 volt RCA-VS055
Tube Complement
2
RCA-1C5GT,
1
GE-NE51
Finish:
Etched brush chrome
Gray wrinkle
Panel
Case
Dimensions
Weight
226
91/2"
high, 61/" wide,
9
51/2"
deep
lbs. (incl. batteries)
Crystal Probe, MI -8263
Makes Any VoltOhmyst a V -H -F Voltmeter
Features
Reads rf flat to 100 mc.
tal which rectifies the applied a -c voltage so that it can be
measured by the d -c circuit of the VoltOhmyst. The reading
is proportional to the positive peak of the applied a -c voltage.
Since this half -wave crystal rectifier involves no heater, it
eliminates a possible source of hum and provides a rectifier
which is operated far above ground potential. Use of a crystal
rectifier means simplicity, compactness, and durability. The
Probe is lightweight and rugged, it will withstand abuse from
shock and vibration.
For fm, television, and other h -f applications.
Low -capacity input and high impedance.
Good frequency characteristics.
Excellent linearity over entire range.
Withstands d-c loads of 250 volts.
A detachable phone plug is used at one end of the cable for
connection to the older models of the VoltOhmyst and Chanalyst. The phone plug may be unscrewed and the cable can
then be attached to the single wire microphone connector used
Highly accurate, even with low -resistance loads.
Rugged but simple construction.
on the later models.
Fits any RCA VoltOhmyst.
The probe point is long and narrow for easy testing in crowded
places. The front part of the probe body is made of insulating
material while the back part is made of metal for shielding
hand capacity effects. A detachable ground lead with an alligator clip is provided for use at high frequencies where the
lead length becomes an important factor in the overall accuracy. The regular VoltOhmyst ground lead can be used
with the Crystal Probe for low frequency measurements. A
shielded cable with durable plastic coating is provided with
this probe.
Uses
The RCA Crystal Probe is designed for converting the d -c
circuit of the VoltOhmyst to read a -c so that voltages up to a
frequency of 100 megacycles or more can be indicated directly
on the d -c scale. The Probe may be used with any model
VoltOhmyst, including the original Senior and the Junior, and
it may also be used on the Voltmeter channel of the RCA
Chanalyst.
The Crystal Probe adapts the VoltOhmyst for fm, television,
and other h -f testing requirements, within the sensitivity range
of the instrument. It gives excellent linearity even at both ends
of the scale. Because of its low input capacitance and high
impedance, this Probe is especially suited for accurate reading without regard to load resistance.
Specifications
Input Voltage
Frequency Range
Overall Accuracy
Input Capacitance
The RCA Crystal Probe is an accessory for all models of the
Frequency Characteristics
VoltOhmyst and connects to the d-c input for measurement
of a -f and r-f voltages. The Probe employs a Germanium crys-
Description
227
20 rms volts (max.)
1000 cycles to 100 mc (gives useful
readings up to 175 mc)
±7.5% at full scale
3 5 mmf
Flat within ±10%
from 1 kc to 100 mc
Audio Oscillator Type WA-54A
The pure fundamental tones of the WA -54A can be used to
determine the frequency of any constant audible sound. Extreme accuracy can be obtained when used with tuning forks
and a cathode ray oscilloscope, therefore, it is excellent for
studies of the physical science of music. It may also be used
to advantage in determining mechanical speeds by stroboscopic
methods.
Description
The RCA Audio Oscillator is a temperature -compensated heat
one
frequency oscillator incorporating two r -f oscillators
in
heterare
combined
a
The
outputs
fixed, the other variable.
odyne detector to produce the desired audio frequency. This
signal is amplified and then fed to a load matching output
-
transformer.
Features
Continuous coverage-20 to 17,000 cycles per second.
The instrument can be conveniently calibrated at line frequency using the electronic eye to indicate zero beat exactly.
This method of calibration affords exceptional accuracy as well
Electronic eye calibrator and output indicator.
as the utmost in convenience. The eye also functions as an out-
Load -matching output transformer.
put voltmeter for approximation of response measurements. In
addition, it serves as a pilot light to indicate whether power
Low distortion.
is
being supplied to the unit.
Low hum level.
The tapped output transformer makes it possible to obtain
load matching between the oscillator output and the most fre-
Uniformly high- or low -power output.
quently encountered impedances, namely, 250, 500, and 5000
ohms. The transformer is center -tapped for proper operation
on balanced -to -ground lines. For unbalanced measurements,
Temperature -compensated oscillators.
additional impedances of 62.5, 125, and 1250 ohms are obtainable from the center tap to either side of each winding.
Built-in voltage regulator.
Large, easy -to -read drum dial.
Specifications
20 to 17,000 cycles
Frequency Range
Uses
Under 5% (rms) over entire range
60 db below max. output (approx.)
Distortion
The RCA Type WA -54A Audio Oscillator is a portable, completely self-contained a -c operated instrument for generating
audio frequencies within the range of 20 to 17,000 cycles per
second-more than the range of most fine radio receivers. Because of its continuous coverage of the audio spectrum, it is excellent for rapidly testing loud speakers and audio amplifiers,
locating cabinet rattles, and running fidelity curves on radio
receivers. It is also a reliable low distortion signal source for
oscilloscope studies, transmitter adjustments, and industrial
electronic testing. The WA -54A output may be applied to
balanced or unbalanced lines.
Hum Level
Power Output
Power Supply
125
milliwatts
105/125 volts, 50/60 cycles
Tube Complement:
2-6AG5, 1-6BE6, 1-6J6, 1-6E5, 1-0A2, 1-6X4
Finish
Case
Blue -gray Metalustre
Panel: Satin Alumilite
Dimensions
Weight
228
9t/a" high, 131/2" wide, 71/2" deep
Approx.
22
lbs.
SERVICE TEST
Sweep Generator Type WR -53A
Features
I -F
center frequency range,
8.3 to 10.7 mc.
Adjustable I -F sweep width.
R -F continuously variable, 85 to 110 mc.
Wide attenuation of output voltage.
Low distortion FM.
Excellent frequency stability.
Phasing control for oscilloscope.
Use
The RCA Sweep Generator, Type WR -53A, is especially designed to furnish all signals needed for the complete alignment of FM receivers. The instrument provides a signal tunable over the 88 to 110 mc FM band. Both CW and AM
signals are available for local oscillator alignment. For i -f
alignment, the instrument provides an FM center frequency
signal from 8.3 to 10.7 mc, the sweep width of which can be
varied to suit the requirements of wide -band reception. Step
and fine attenuation give the WR -53A the wide range essential
to proper servicing. The signal may be made strong enough to
operate completely misaligned sets, and it can also be reduced
to that minimum essential for high -sensitivity adjustments.
buffer amplifier between the oscillator and the output eliminates frequency pulling with changing load. An i -f output
from 1 microvolt to 0.1 volt can be selected by a suitable
combination of "step" and "fine" attenuators. Attenuation
to less than 1 microvolt can be effected by use of the switch
in the output cable.
A
By use of the
i -f sweep section of this instrument, it is possible to align i-f stages by the variable -frequency or visual
method, which presents an easy -to -read picture of the circuit
characteristics. Stability and accuracy of the WR -53A are such
that use of the conventional "marker oscillator" is unnecessary. Rapid interpretations of band-pass characteristics are
possible.
The r -f oscillator consists of a conventional Hartley circuit
with frequency continuously variable from 85 to 110 mc. Output can be controlled over two ranges: from approximately
5 to 10,000 microvolts and from 300 microvolts to 0.1 volt.
Terminals are provided for obtaining deflection voltages for
an oscilloscope, in order to assure convenience and efficiency
when employing the visual method of adjustment. A phasing
control is included to position the scope pattern properly.
The discriminator circuit of an FM receiver can be efficiently
adjusted by either the visual method, employing the WR -53A
in conjunction with an oscilloscope, or by the single-frequency
method, using a VoltOhmyst as the indicator. Alignment of the
ratio detector circuit is also made a routine task, using either
the visual method or a VoltOhmyst to observe overall characteristics. R -F and local oscillator circuits of FM receivers can
be aligned by use of the WR -53A as an r-f oscillator. In addition, r-f and mixer circuit alignments are also simplified.
The "band -spread" dial permits accurate setting of the center
frequency and also provides a means for estimating the band
width of a given receiver by moving the center frequency from
one side of the response trace to the other and noting the
frequency difference on the dial.
Specifications
Receiver fidelity measurements may be made when the instrument is used in conjunction with an audio oscillator and the
VoltOhmyst. Since the modulation characteristic of the WR-53A
is essentially flat up to 17,000 cycles, accurate response curves
can be plotted.
I -F Oscillator:
Frequency Range
8 3 to 10.7 me
Output (approx.)._1 microvolt to 0.1 volt (Attenuation to
less than 1 microvolt using cable switch)
Modulation Frequency (internal)
Power line frequency
±200 kc at 8.3 me
Sweep Width
Because the frequency dial has an accuracy of ±2% or
better, the WR-53A is quite satisfactory for the great majority
of calibration applications.
±400 kc at
10.7 me
R -F Oscillator:
Frequency Range
85 to 110 me
Output
300 microvolts to 0.1 volt (using cable switch:
from approximately 5 to 10,000 microvolts
Modulation Frequency
Double line frequency
Power Supply
105/125 volts, 50/60 cycles, 30 watts
Tube Complement:
Description
The i -f circuit of the WR -53A consists essentially of an electron coupled oscillator which is frequency modulated by
reactance tube modulation. This provides wide -range low-distortion FM consistent with excellent center -frequency stability.
Modulation level, or maximum frequency deviation, is controlled by the "sweep width" knob. Modulation frequency may
be determined either by the line frequency or the frequency
of an external source, depending upon the position of the
"selector" switch. Direct generation of the output frequency,
without use of beats or harmonics, eliminates spurious output
signals.
1
1
RCA-6AK5
RCA -6C4
3
1
RCA-6AG5
RCA -6X4
Finish:
Case
Panel
Dimensions
Weight
229
Blue -gray Hammeroid
Brushed aluminum, anodized
131/2" Wide, 93/" High, 71/2" Deep
15
lb.
Audio Chanalyst Type 170-A
Features
There are several other units included which operate in collaboration with the above mentioned principal channels to extend the facilities of this instrument. They are: An impedance
measuring device, a distortion indicating device, a loud speaker
for audible testing, and a monitoring electronic indicator which
also serves as a trouble-shooting device.
Portable test bench with facilities for checking all makes
of sound equipment.
Self-contained audio signal source.
Electronic vacuum tube voltmeter for a -c (a -f), d-c, ohms,
Calibrated signal tracing amplifier.
High speed electronic indicator and impedance tester.
Channel monitoring facilities.
Uses
The RCA Audio Chanalyst, type 170-A, is in itself a complete
sound system testing laboratory. It can be set up in any convenient location to do a conclusive job of diagnosing trouble
in audio amplifier, loud speaker systems, and pick-up devices.
Specifications
Description
Oscillator Channel
20 to 10,000 cycle beat frequency oscillator with direct low
level output or high level when used with amplifier channel.
Automatic 10 second audio sweep for multiple speaker testing.
Height 14"; width 21"; depth 10%"; weight 47 lbs.
Voltmeter Channel
A -c Diode and d-c Vacuum Tube V.M.0.1000 v. in 6 ranges
0-1000 megohms in 6 ranges
Ohmmeter
The instrument is portable, weighing approximately 45 pounds
and it is furnished complete with a cover which contains all of
the necessary cables and test leads, packed in neat carrying
order.
Amplifier Channel
4 stage high gain with power output of 1 watt at 10, 250, 500
or high output impedance. Calibrated in db and voltage
ratios. Each stage can be used separately or in cascade.
The Audio Chanalyst itself consists of three principal sections
or channels; namely, a complete volt -ohmmeter, a complete
signal source, and a calibrated audio amplifier. Beside its
basic use as a testing unit, the audio amplifier section can be
used as an emergency replacement unit or as an auxiliary
amplifier for communications and entertainment.
General
Also has speaker channel, electronic indicator, impedance
tester and polarizing voltage supply.
230
DATA
SECTION
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TO EXTEND RANGE MULTIPLY 'VOLTAGE RATIO'
BY 1000 AND ADD 60 TO DB
1000
900
800
700
600
500
400
TO EXTEND RANGE MULTIPLY 'IMPEDANCE RATIO'
BY 1000 AND ADD 30 TO DB
----_-_
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235
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ralOOENC
0
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000
5000
M CYCLES 0E0 SECOND
Loudness level contours.
Courtesy of the Acoustical Society of America
236
10000
FIELD INTENSITY VS. RADIATOR HEIGHT
FOR SEVERAL LENGTHS OF GROUND WIRES
28
THEORETICAL FIELD
INTENSITY OVER PERFECT EARTH
260
24
220
200
180
160
/r
MEASURED FIELD NTENSITY 113
RADIALS 150° LONG
113
RADIALS, 100°LONG
--`113 RADIALS, 50°
LONG
140
120
100
80
ABOVE BASED
60
SINUSOIDAL CURRENT DISTRIBUTION IN ANTENNA
ON
40
20
80
90
100
11O
120
130
140
150
160
170
180 190
200 210
220
230
ANTENNA HEIGHT (DEGREES)
EFFECT OF GROUND WIRES ON FIELD STRENGTH
RANGE FOR PROPAGATION OVER OPTICAL
HORIZON CALCULATIONS
Di -K\5-11
K
=1.22 WHERE
K= 3.57 WHERE
THE
ABOVE
"D" 15
FORMULAE
DT=D1+D2=KfH1+ H2
Hz
D2 = K
PATH
MILES AND 1-f IS IN FEET
IN KILOMETERS AND 6.1-f IS IN METERS
"D
IS
IN
NEGLECT REFRACTION
237
AND
DIFFRACTION
FM RANGE CHART
The ground wave signal range chart, shown on the opposite page, is intended
to be used for determining approximate coverage of FM broadcast stations operating in the 88-108 me band. The effect of transmitting antenna height and radiated
power on field strength is indicated, and field strength vs. distance from the trans-
mitting antenna is also shown.
To find the approximate radius of an area within a given field strength con-
tour, proceed as follows:
1.
Determine field strength in uv/m required and find this figure along extreme right-hand vertical column.
2. Follow the diagonal line corresponding to required field strength until it
intersects with the vertical line representing radiated power.
ruler or straight edge across the chart and along
the vertical line corresponding to antenna height, read distance in miles
to the µv/m contour selected.
3. From this point, lay a
The chart may also be used
cover a given area.
o
find the value of radiated power required to
For example:
Find radiated power required to produce 1000 pv/m signal at
of 30 miles with an antenna 500 feet high.
1.
a
distance
From the 500 foot mark on the "antenna height" scale, follow the vertical
line upwards and locate the 30 mile point.
ruler or straight -edge across the chart from this point, taking care
that the ruler is parallel with the bottom edge of the chart.
2. Lay a
ruler intersects with the diagonal line representing 1000 µv/m and then from this point, place the ruler vertically on the
chart and read approximately 18 KW radiated power on the scale at the
upper right of the chart.
3. Mark the point where the
238
I
1,000,000,
I
I
I[
I
I
L
I
I
IoDuoap,
I
I
\
1
_
-
100,000
,000,000
OOp00
`
-
:M5
10,000
-i
IONILES
-
10411LES
-
-
IONILES
-
_
-
-
-
101IILES
20
-
-
30
_
^
2
50
60
-^
^
-
-
^
-
-
eo
_
--
90
-
e0
--
60
90
110
_
90
120
160
130
100
170
^
140
\
190
150
190
,-
200
_
-
130
120
110
-
^
00
130
120
I
I
s
1{0
18p
150
1
r
.
I
I
s
s
1.000
ANTENNA HEIGHT IN FEET
FIGURE
GROUND WAVE
SIGNAL RANGE
[
.
I
.
O'
I[
r
0.1
1
In
non
I
FOR
FM
BROADCASTING
10 "e.m. u., E = 15
RECEIVING ANTENNA HEIGHT 30 FEET
FOR HORIZONTAL (AND APPROX. FOR VERTICAL) POLARIZATION
98 mc,
1,000
10
90
i
\
ISO
190
110
00
-
00
-
100
-
-
10,000
90
,_
_
0.1
1,000
e0
_-
t20
90
100
_
-
-
70
_
_
_
60
110
-
-
_
70
eo
-
i0
_
i0
70
-
-
e0
70
10
i0
10
-
-
50
70
-
_
SD
-
100,000
30
-
^
{0
-
{O
SO
--
0
90_-
40
_
-
30
30
120
-
20
{0
30
-
2C
--
\
IoA00
IO
--_\
-
-
-
--
= 5
239
83911
18
16
14
12
IO
8
I
/
/
2
/
0
2
re'
"1".
4
50
CYCLES
STANDARD
FREQUENCY
10,000
1000
100
PRE -EMPHASIS
RESPONSE
CURVE
LIMITS
PER
15,000
SECOND
TIME
CONSTANT
75
MICROSECONDS
COAXIAL
LINE
EFFICIENCY
100
90
80
50
C
-
IMC
70
60
z
\\
10MC
,`
50
I- 50
MC
cc
á 40
w
5
3-
g
100
2004i
30
-
-L.......
w
--,
200
w
MC
20
a
10
0
`_``
-``
`_-_200
0
400
600
LENGTH
100
o 90
F-
i
H
80
a
Z
I
800
-
'qn. _`_
P=95%, ACS=95%, I.72x I03
70
1
ABOHM-CM.
Z-,= 51.5^
50
,
'
+___.,s
L -T
200
0
w
a
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Va
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é
34
6é
IN.
1400
1600
w
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JJ
5
O
=
C
200MC
,
IOOMC
200MC
-
x
~ 68
ó
Ó
o
H
-, 31
4
E
8w
o
O
F
400
LENGTH
SIZE
1200
, D,
Y
w 40
1000
LINE - FEET
1111
INSULATOR DIELECTRIC CONSTANT =6.0
INSULATOR LOSS FACTOR =.004
DERATING FACTOR= IO%
f/ _L
3
o
a
ó
CALCULATION:
IN
o
-f-(7,
1-o
CONSTANTS USED
N
8
w
=
o
COAXIAL
OF
7
600
.3125
PER
ioo
TEEF50MC IOOMC
.785 6 .187 .318
.460
1.527 12 .193 .161
.234
D1
.625
1.200 3.027
2.500 5.981
IN.
COAXIAL
OF
DB
D,
800
IN.
S
12
.375 .096
.039
1200
1400
LINE - FEET
FEET
200MC
.673
145
.346
.230
.056
.081
.
1000
IN. IN.
241
P -
728591
1600
1.0
A
0.5
63X`°
0.05
LOSS
(DB/1000')=0.224
vf
fox
-
G
=1000 KC S
G;=100 x 0-15 e.m.u.
fo
0=5x 10-1
0.01
1
(SEA WATER)
1000
200
2000
FREQUENCY IN KILOCYCLES
TRANSMISSION LINE
LINE HEIGHT 12', WIRE SPACING 15", WIRE SIZE '8, Zo=230.íL
LOSS (DB
PER
1000
FT.) OF RCA 6 WIRE
2 2
INDEX
L
.mmw.ww«Rr
INDEX BY TYPE NUMBER
Type
BA -1A
BA -2C
BA -3C
BA -4C
BA -5A
BAF-4A
BCS-1A
BCS-2A
BE -1B
BF -Series
BI-lA
BI.2A
BN -2A
BPA-1A
BPA-10
BPA-50
BR -2A
BR -84
BTA-1L
BTA-5F
BTA-10F
BTA-50F
BTA-250L
BTC-1A
BTF-1C
BTF-3B
BTF-1OB
BTF-50A
BTF-250A
Description
Preamplifier
Booster Amplifier
Program Amplifier
Monitoring Amplifier
Recording Amplifier
AM -FM Isolation Unit
Switching System
Switching System
Line Equalizer
Pylon Antenna
Meter Panel
Meter Panel
Remote Amplifier
1 KW Antenna Tuner
5-10 KW Antenna Tuner
50 KW Antenna Tuner
Panel and Shelf
Standard Cabinet Racks
1 KW AM Transmitter
5 KW AM Transmitter
10 KW AM Transmitter
50 KW AM Transmitter
250 W AM
Transmitter
Transmitter Console
1 KW FM Transmitter
3 KW FM Transmitter
10 KW FM Transmitter
50 KW FM Transmitter
250 W FM Transmitter
Radio Microphone
BTP-1A
Power Supply
BX-1C
KB -2C
Microphone
KN -1A
Microphone
KS -1A
Microphone Stand
KS -3A
Microphone Stand
KS -4A
Microphone Stand
KS -5A
Microphone Stand
LC -1A
Monitoring Speaker
OP-6
Remote Amplifier
Remote Mixer
OP-7
Recorder
OR -1A
RS-1A
Recording Suction Equipment
TA -1A
Distribution Amplifier
TA -5A
Stabilizing Amplifier
TF-3A/B-6A Super Turnstile Antenna
TG -1A
Synchronizing Generator
Field Sync Generator
TG -10A
TJ-50A
TK -1A
TK -10A
TK-20A
TK -30A
TM -5A
TP -9A
TP -16A
TP-35A
Mobile Unit
Monoscope
Studio Camera
Film Camera
Field Camera
Master Monitor
Multiplexer
Film Projector
Film Projector
I) Pe
Page
TRR-1A
TS -10A
TS -30A
38
40
41
TT-5A
42
43
TTR-1A
WA -21A
142
WA -54A
WF-48A
WF-49A
WF-40A
WM -12A
WM -13A
WM -30A
WM -43A
WM -71A
WO -27A
WO -60C
WO -79A
WP -33A
34
33
62
130
60
60
47
114
115
116
57
52
96
WR -53A
WV -65A
WV -73A
WV -75A
98
100
104
94
132
124
9 -AX
126
33-A/D
33-AW/BW
128
44-BX
130
56-C
122
56-E
51
57-C
68
59-B
16
68-B
18
69-C
22
70-D
Description
Relay Receiver
Switching System
Field Switching System
TV Transmitter
Relay Transmitter
Video Sweep Generator
Audio Oscillator
Frequency Monitor
Frequency Meter
Frequency Monitor
Visual Monitor Converter
Visual Modulation Converter
Phase Monitor
Modulation Monitor
Distortion and Noise Meter
D.C. Oscilloscope
Cathode Ray Oscilloscope
Cathode Ray Oscilloscope
Power Supply
Sweep Generator
Battery VoltOhmyst
Audio Voltmeter
VoltOhmyst
Cabinet Rack
Jack Panels
Jack Panels
Microphone
Line Equalizer
Line Equalizer
Switch and Fuse Panel
Microphone Stand
B.F. Oscillator
Distortion and Noise Meter
86
Turntable
72 -D/72 -DX Recording Attachment
Recorder
73-B
74-B
Microphone
Consolette
76-B4
48
76-C
49
77-D
78
86 -Al
84
88-A
23
24
20
166
89-C
167
90-A
198
91-A
164
91-B
178
92-A
188
115-C
162
170-A
153
195-A
155
301-B
176
308-B
182
580-C
160
715-B
157
A-1971
159
A-2101
245
Consolette
Microphone
Limiting Amplifier
Microphone
Attenuator Panel
Microphone Stand
Microphone Stand
Microphone Stand
Antenna Lighting Choke
Cathode Ray Oscilloscope
Audio Chanalyst
VoltOhmyst
Field Intensity Meter
Field Intensity Meter
Power Supply
Oscilloscope
Austin Tower Lighting Transf.
Austin Tower Lighting Transf.
Page
187
161
180
192
185
216
228
203
204
204
209
210
205
202
213
221
219
218
170
229
226
215
225
54
58
53
14
63
63
59
23
211
212
70
75
76
17
30
32
12
44
15
214
22
20
20
118
217
230
224
207
208
169
223
117
117
INDEX BY MASTER ITEM NUMBER
Description
MI Number
41
42
43
49
62
63
63-A
64
65
4027-D
4036 -AA
4045-A
4048-D
4058-C
4068-D
4092-C
4093-B
4094-B
4095-A
4096
4162
4168
4171
4196
4309-B
4388 -C/D
Cable
Cable
Cable
Cable
Cable
Cable
Cable
Cable
Cable
Microphone
Microphone
Microphone
Microphone
Microphone
Microphone
Microphone
Microphone
Microphone
Microphone
Microphone
MI Number
Page
26
6229
6333-C
26
6381/2
26
26
6425
6427
26
6784/5
26
7014
26
7015
7016
7017
7020
7037
7050
7083-E
7084-A
7085-A
7085-C
7112
7157-D
7184-A-150
7186-B
7187-A
7188-A
26
26
11
17
12
15
Stand
Stand
Stand
Stand
Stand
Stand
Stand
20
23
20
23
23
20
21
4652
Equalizer
Equalizer
Pads
Equalizer
Audio Power Change Panel
Meter Panel
Switch Panel
Cabinet Rack
Jack Panel
Jack Panel
Power Block
Audio Block
Terminal Bracket
Cable Support
Blank Panels
Ext. Cord
Receptacle
Plug
Jack Panel
Jack Panel
Patch Cords
4842
Stylus
81
11050
4875-G
Pickup Kit
72
11052
4878-D
Stylus
Stylus
81
11088
81
11089
65
11090
65
11096
82
11099
64
11100;1
63
11202-A
4926-A
Transformer
Transformer
Recording Filter
Sound Effects Filter
H.F. Compensator
Pre -emphasis Filter
4928
Microscope
84
11213
4975
Filter
Microphone
Microphone
Microphone Stand
72
11214
18
18
11216-B/C
11218a1
23
11223-B
4395-A/B
4519-C/E
4534-C
4536-B
4568
4569
4570
4571
4589/99
4620-B
4624-A
4630-B
4645-A
4646-A
4879-A
4901-A
4902
4916-A
4917-A
4925-A
6203-C
6206-G
6208
63
63
66
7242-C
62
136
60
59
7245-B
7260-C/D
7266 -C/D
54
7267-A/B
58
7303
58
7318
55
7320
55
7327-4
55
7485-E
55
7485-F
55
19
7488-A
19
8217
19
58
8217-C
58
10253
58
11001
11210-D/E
137
246
Page
Description
21
Microphone Adaptor
89
Speaker Mechanism
88
Wall Speaker Housing
21
Microphone Stand
21
Microphone Stand
67
AM -FM Tuner
Tower Lighting Isolation Transformer
118
134
Spare FM Exciter Equipment
FM Exciter Unit
134
Power Supply
134
Tube Kit for MI.7016/7017
127
60/50 Cycle Conversion Kit for BTA-50F.. 105
104
50 KW AM Transmitter
Tube Kit for BTA-5F
99
101
Tube Kit for BTA-10F
60/50 Cycle Conversion Kit for BTA-5F.... 99
60/50 Cycle Conversion Kit for BTA-10F.. 101
118
Lighting Choke
114
Remote Ammeter
Remote Antenna Current Meter
206
96
1 KW AM Transmitter
1 KW AM Amplifier
96
Power Change Kit, 1 KW Transmitter
97
94
250 W AM Transmitter
Tube Kit for BTA-250L Transmitter
95
98
5 KW AM Transmitter
100
10 KW AM Transmitter
103
5/10 KW Conversion Kit
103
5/10 KW Conversion Kit
97
Tube Kit for BTA-1L Amplifier
97
Tube Kit for BTA-1L Exciter
206
Isolating Coil
Right Wing Audio Cabinet for
99
BTA-5F/10F
Left Wing Phasing Cabinet for
99
BTA-5F/10F
115
Monitor Rectifier
206
Sampling Coil
206
Pickup Loop
65
Transformer
16
Microphone
22
Microphone Stand
24
Microphone Stand
19
Receptacle
19
Plug
19
Connector
19
Receptacle
22
Cable Hook
82
Recording
Equalizer
Automatic
48
Remote Amplifier
78
Recorder
49
Remote Amplifier
50
Battery Box
44
Limiting Amplifier
38
Preamplifier
42
Monitoring Amplifier
Type
11224-E/F
11226-B
11227
11230
11251
11256
11257/8
11265
11274-A/B
11275
11280
11301-B
11301-B
11303
11304
11305-B
11401
11411
11500
11501-4
11598-9
11606
11613-C
11616
11622
11623
11624
11625
11625-A
11704
11705
11706
11707
11708
11710
11711
11801/2
11825/6
11827
11850-C
11851
11853-A
11855-A
11857/8
11900/1
12051
12053
12057/A
12063
12065
12066/A
12081-B/C
12236
12370
12371
12373
12422
12435
12449
12775
13225
19012/3
19021/2
19023
19104
19205-A/B
19404-B
19406
Description
Program Amplifier
Booster Amplifier
Recording Amplifier
Remote Amplifier
V. U. Meter and Kit
Fabric Cover
Fabric Cover
V. U. Meter Panel
Remote Volume Control
Meter Panel
Voltage Regulator Transf.
Power Supply
Power Supply
Power Supply
Power Supply
Power Supply
Monitoring Loudspeaker
Monitoring Loudspeaker
Cabinet
Jack Mats
Panel and Shelf
Filament Transformer
Consolette
Transmitter Control Console
Switching System
Monitor and Amplifier Rack
Consolette
Master Switching Console
Studio Switching Console
Dividing Networks
Bridging Pad
Studio Warning Lights
Speaker Filter
Speaker Attenuator
Ringdown Panel
Speaker Accessory Kit
Turntable
Recorder
Recorder Base Cabinet
Recording Head
Advance Ball Kit
Recording Head
Heater and Compensator Kit
Recording Suction Equipment
Recording Attachment
Microphone Adaptor
Microphone Adaptor
Microphone Adaptor
Microphone Stand
Microphone Stand
Microphone Stand
Microphone
Monitoring Amplifier
Speaker Transformer
Speaker Transformer
Speaker Transformer
Speaker Mechanism
Speaker Mechanism
Monitoring Loudspeaker
Wire Recorder
Wall Speaker Housing
Super-Turnstile Antenna
Diplexer
Triplexer
Side-Band Filter
TV Transmitter
Remote Metering Kit
Entering Insulator
Page
Type
41
40
43
47
19413.1
19421
19654
26010
26015
26045
26065
26090
26095
26105
26115
26135
30951
26155
26215
26260
61
48
49
61
39
60
136
30
32
69
69
68
86
86
56
58
51
66
30
102
26256-1/2
26560
26574
26915
26935
26940
26960
28010
28011-A
33
136
76
28012-A
28012-B
28013
28014
28015
28154
28156
28157
28158
28161
28162
28163
28217
77
28221/8
80
81
81
80
84
75
21
21
21
21
22
20
18
28231
28316-A
28401-1
28401-2
28403-1
28404-1
28410
28420
28425
28901-A
32
34
34
66
66
36
87
87
59
87
70
28902A/B
28903-A/B
28905
28911
28912
28913
28914
28920
28921
28922
28923
28926
28950
30043-A
46
90
90
90
89
89
88
83
88
198
195
197
194
192
114
118
3004ßA
30071-A
30566-G84
30568-C84
247
Description
Entering Insulator
Trans. Line Insulator
Tube Kit for MI-7085-A
Field Camera
View Finder
Tripod
Camera Control
Current Regulator
Power Supply
Pulse Former
Pulse Shaper
Master Monitor
Standard Racks
Distribution Amplifier
Switching Unit
Power Distribution Box
Desk End Sections
Field Desk
Boom Stand and Perambulator
Sync Generator
Relay Transmitter
Relay Receiver
Monoscope Camera
Trans. Line Wire
Trans. Line Lead-in Kit
Trans. Line Dead-end Kit
Trans. Line Dead-end Kit
Trans. Line Pole and Cap
Trans. Line Bayonet Acc.
Lead-in and Ground Acc. Kit
BTF-10B Power Cut Back Eq.
Tube Kit for BTF-250A Trans.
Tube Kit for BTF-1C Trans.
Tube Kit for BTF-3B Trans.
Tube Kit for Mí.28920
Tube Kit for MI.28921
Tube Kit for MI -28922
AM -FM Isolator
Pylon Antenna
Pylon Antenna
Code Beacon Kit
Page
118
112
99
176
176
176
176
170
176
178
178
182
52
166
180
178
133
184
25
164
185
187
162
112
112
113
113
113
113
113
129
123
125
127
125
125
127
142
138
138
140
133
Basic Desk Section
90° Desk Section
133
Blank Turret
133
Blank Turret for 90° Section
133
Audio Control Turret
133
Transmitter Control Turret
133
Limiting Amp. Ext. Meter 4"
133
1 KW Antenna Tuner
114
5.10 KW Antenna Tuner
115
50 KW Antenna Tuner
116
Power Change Kit for BTA-50F
105
250 W FM Transmitter
122
1 KW FM Transmitter
124
3 KW FM Transmitter
126
10 KW FM Transmitter
128
1 KW to
3 KW FM Conversion Equip. 125
1 KW to 10 KW FM Conversion Equip. 125
3 KW to 10 KW FM Conversion Equip. 127
Radio -Microphone
51
50 KW FM Transmitter
130
Universal Transmitter Console
132
Modulation Monitor
Frequency Monitor
Distortion and Noise Meter
Cabinet Rack Trim Strip
Cabinet Rack Trim Strip
202
203
213
53
53
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