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FEBRUARY, 1961
BROADCAST
ENGINEERING
THE TECHNICAL JOURNAL OF THE BROADCAST INDUSTRY
In This Issue
A
GUIDE
FOR
STUDIO
PLANNING
www.americanradiohistory.com
S14
- Your Operating Cost 1,000%
With
the FOTO - VIDEO V-410 Power Supply
$
0
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v °5ee``S
0t
7 7
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42
V-410
V-410
V-410
V-410
V-410
V-410
V-410
V-410
V-410
V-410
V-410
V-410
COMPARE!
Output Current-(235 V DC)
Constant Current for Focus
Centering Supply
Power Input
Rock Space
48 BRAND
"X"
24 A.
16
No
24 A.
Yes
?
Yes
22.8 KW
616 inches
9.6 KW
Extra Power Costs
Extra Tube Costs
Extra Air Conditioning Costs
52,830/yr.
55,760/yr.
Total Extra Costs
54,000 Fixed
v-410
V-410
V-410
V-410
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84 inches
54,000 Fixed
5720/yr
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Yes
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the V-410 's May Be Easily Paid For By Cost Savings in less than
one year - and Save Space Besides!
FIELD
PROVEN ALL -TRANSISTOR V-140 REGULATED POWER SUPPLY SYSTEM
-
Semiconductor rectifier
filter and All -Transistor Regulator provides the following broadcast volrages and currents:
Load current 200 ma. to 1.5 a.
Output voltage
275 to 285 V DC
Regulation vs. Line
± 0.5% maximum
Ripple
5 MV RMS maximum
Source Impedance ._______......... _.._._0.5 Ohms maximum DC to 100 KC.
Regulation vs. Load
-- 0.5°x maximum
Unregulated Output.______ .......... _.._Approx. 350 V up to 200 ma.
Metering
Built-in Voltmeter for output CC voltage and line input selector.
Overload Protection
Built-in.
V-410 MON
Same as V-410, plus centering current. Adequate for centering of a broadcast master monitor or TV camera.
V-410 CAM
Same as V-410 MON, plus metering, plus a constant current supply of ma (metered) with control on front panel.
Overall size: 514 high for rack mounting. Depth 16 W. Weight approx. 35 lbs.
Highest reliability, optimum use of space and equipment, superior regulation, tubeless system means lowest maintenance. Modules available
from Foto -Video easily converts a V-410 to a V-410 MON or a V-410 CAM.
EXTREMELY LOW ON COST, HEAT AND POWER.
--
Foto-Video Electronics, Inc.
Cedar Grove, N.J. CEnter
West Coast Engineering and Sales Office
1317 West 214 St., Torrance, California Phone Spruce 5-1003
-
(Write or Phone for Information)
www.americanradiohistory.com
9-6100
THE TECHNICAL JOURNAL OF THE BROADCAST INDUSTRY
VOLUME 3
FEBRUARY, 1961
NUMBER 2
EDITORIAL
D. E. MEHL, Editor
D. F. BOICOURT, Managing Editor
DUDLEY ROSE, Presentation Editor
E. P. LANGAN, Advertising Director
S. F. WILSON. Production Manager
W. J. SHAW, Circulation Director
Contents
Stereophonic Broadcast Tests by the National
Stereophonic Radio Committee
2
ADVERTISING SALES OFFICES
Flushing 54, New York
PAUL AND DON WEIL
39-01 Main Street
Telephone INdependence 3-9098
Automatic Production Manager Simplifies
Chicago
TV Switching
6
I2
Studio Planning Considerations
1,
Illinois
WILLIAM L. MILLER, .JR.
E. F. LUKENS
C. E. PARKER
307 N. Michigan Ave.
Telephone FRanklin 2-5944
Cleveland 16, Ohio
DAVID H. HERTEL
An Automatic Conelrad Attention
Signal Unit
Wooster Road
Telephone EDison 1-2370
3100
28
Southwest
C. H. STOCKWELL CO.
4916 W. 64th Street
Mission, Kansas
Telephone RAndolph 2-4417
Los Angeles 57, California
MAURICE A. KIMBALL CO., INC.
2550 Beverly Boulevard
Telephone DUnkirk 8-6178
Departments
San Francisco 5, California
MAURICE A. KIMBALL CO., INC.
F.C.C. Regulations
34
Industry News
36
New Products
38
London W. 1, England
Index to Advertisers
38
Tokyo, Japan
Classified Ads
40
681
Market Street
Telephone EXbrook 2-3365
Paris
8,
France
JOHN ASHCRAFT
67 Avenue des Champs Elysees
Telephone Elysees 47-18
JOHN ASHCRAFT
9 Curzon Street
Telephone GRosvenor 7408
INTERNATIONAL MEDIA
REPRESENTATIVES, LTD.
Shadan Ho.1in. 14, 2-chome Marunouchi
Telephone 571-4450
Editorial, Circulation and Advertising headquarters, 1014 Wyandotte St., Kansas City 5,
Missouri: Telephone Victor 2-5955.
Cover
The AM and FM tower on the cover symbolizes the planning series
which begins in this issue with a guide for planning studio installations.
Subscription Price: II. S. $6, one year; Outside V. S. A., $7. Single copies, 75 cents.
Adjustments necessitated by subscription
termination at single copy price.
ERRATA
The January issue of Broadcast Engineering contained an article by
J. Bruce Glaab of the Electro-Plex Company entitled "Multiplex
Demodulator Circuitry." The title was erroneously published as
"Modulator Demodulator Circuitry." Mr. Glaab's name was misspelled
as Glabb. Our apologies are extended to Mr. Glaab and the ElectroPlex Division of Nuclear Electronics
>E3 P<<<1
Corporation.
February, 1961
www.americanradiohistory.com
Broadcast Engineering is published monthly by
Technical Publications, Inc., 1014 Wyandotte St..
Kansas City 5, Missouri, U. S. A.
Corporate Personnel: Robert E. Hertel, President; Frank D. Smalley, Executive Vice -President; E. P. Langan, Vice -President; W. J
Shaw, Vice-President; Kenneth Long, Vice.
President; D. E. Mehl, Vice -President.
Stereophonic Broadcast Tests by the
National Stereophonic Radio Committee
Transmission and reception tests of the various stereo systems were made at
Pittsburgh and Uniontown, Pa., to obtain data which is being used by the F.C.C. to
select a standard for stereophonic broadcasting.
WITH
the Federal Communication Commission's decision on stereo
FM standards anticipated momentarily, broadcasters look toward implementation of the new system as
soon as it is established.
Featured at the eight National
Assn. of Broadcasters regional conferences last fall were reports on the
exhaustive field tests of proposed
stereo FM systems. A. Prose Walker, manager of the NAB engineering
department, presented the reports
and demonstrated the tests. He
earlier had supervised the tests,
which were conducted under the direction of the National Stereo Radio
Committee and instituted for measuring performance of the proposed
systems.
Since the NAB regionals involved
almost split-second scheduling,
Walker found himself dashing from
city to city via commercial air -liner,
usually traveling during the wee
hours of the morning. It was imp possible to have equipment for the
demonstrations set up in advance at
the eight locations. So Walker carried his own-an Ampex PR-10 professional tape recorder and two Ampex SA -10 speaker units-as regular
baggage on the flights. Test tapes
of the stereophonic program material used during the field tests
were played for the NAB audiences
in New York, Atlanta, Dallas, San
Francisco, Denver, Omaha and Chicago.
FCC commissioners recently lis-
tened to the same tapes. They are
now proceeding toward a determination of an acceptable national multiplex standard.
Following its formation by the
Electronic Industries Assn., the National Stereophonic Radio Committee studied the 14 proposed multiplexing systems and reduced that
original number to six considered as
having individual characteristics.
These systems were those proposed
by Crosby Teletronics, Calbest,
Multiplex Services, Inc. (Halstead) , Electric & Musical Industries, Ltd. (Percival) , Zenith and
General Electric.
Arrangements were made for the
field tests by a panel of some 50 engineers headed by Walker and Ross
KDKA-FM
R. F.
IO
INPUT
WATTS
WESTINGHOUSE
X
5052
FM -10
TRANSMITTER
X
EXISTING STATION
MONITOR
KDKA-FM
G.E.L. EXCITER
ELECTRO-PLEX MONITOR
8-A, 22-A
FM
EXCITER
X
SYSTEM
PANORAMIC
I
SB -12A
R. F.
OUTPUTS
X
SYSTEM
2
X
SYSTEM
3
MONITOR
A
B
C
D
MONITOR
I
WATT
FEEDS
500
E
F
Figure I. Transmitter facilities and
R. F.
test equipment.
BROADCAST
2
www.americanradiohistory.com
ENGINEERING
AMPEX
FOR EVERY PROFESSIONAL NEED
/MN
In sound
quality... in features... in lasting economy... these four Ampex professional re-
corders maintain the highest performance standards for broadcasters, recording studios,
educators and other critical users. For 7" reel requirements-the PR -10 series-newest in
studio quality compact recorders, priced from $845. For 10%"
-proven by more than
reels- the 351/354 series
10,000 units in use throughout the world. Other 10%" Recorders
include the 300 series multi-channel Mastering series with up to 8 tracks. Your Ampex
dealer will aid you in selecting the Ampex which best fits your needs. And ask him about
the new Ampex Finance and Lease Plans.
7"
THE PR -10-1
MONOPHONIC,
REELS
THE PR -10-2,
STEREO/MONO
Full or half-track. Single -channel
Two -channel electronics fit same
rack space as PR -10-1. Portable
for remote pickups as well as in
studio use. Split erase permits
stereo recording, half-track mono
recording, cue track, and sound on -sound. Two line inputs convertible (with pre -amps) to two
mikes
one per channel. Additional mike and line inputs possible with MX -10 mixer. Write for
Bulletin 212.
electronics include built-in mixer
to mix line and mike or two mikes
(with plug-in pre -amp). Portable,
or fits 14" of rack space. 33/, and
71/2; or 71/2 and 15 ips speeds.
Exclusive self -threading option.
Alignment controls in front panel.
New frictionless tape handling.
All -electric push-button controls
permit remote control operation.
Write for Bulletin 212.
-
-
10/2"
THE AMPEX 351
MONOPHONIC
Available
in
REELS
THE AMPEX 354,
STEREO/MONO
full or half-track
Two -channel electronics. Compact and portable version os well
os console. Requires only same
rack space as 351. Same heavy
duty tape transport as 351. Two
line inputs, convertible to two
mikes (one per channel) with pre amps. More mike and line inputs
with MX -35 mixer. Convenient
balancing of stereo -channels with
side -by -side VU meters. Split
erase for stereo recording, halftrack mono, cue track, sound -on sound. Alignment controls in
front panel. Bulletin 208.
models. Input switchable to mike,
balanced or unbalanced line.
Takes reels from 3" to 10'/2".
Speeds: 33/, and 71/2 or 71/2 and
15 ips. Available as console, two case portable or mounts in 223/,"
of rack space. All -electric push-
button controls permit remote
control operation. Large 4" VU
meter reads input or recorded
level plus bias and erase current.
For more information, write for
Bulletin 203.
ACCESSORIES AND ASSOCIATED EQUIPMENT
ii
MONITOR SYSTEM
STEREO/MONO MIXER
SA -10,
Console quality, 40
watt speaker -amplifier unit.
provide NAB AME or CCIR
tion, two channels, matches curves as required.
Portable, rack or wall
PR -10
MX -10 or MX -35, Four posi-
or
PLUG-IN EQUALIZERS
AMPEX
PLUG-IN INPUTS
match various inputs. Balanced bridging or mikes.
351354.
mounting. Bulletin 214.
Complete descriptive literature also available on 300 series Mastering Recorder and High Speed Duplicators from Ampex. Write Dept. BE. 4
AMPEX PROFESSIONAL PRODUCTS COMPANY 934 Charter Street. Redwood City, Calif. Ampex of Canada Ltd., Rexdale, Ontario
February, 1961
3
www.americanradiohistory.com
OSC. NO.
OUT
H.P.
206
A
206
OSC. NO.2
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X
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TYPICAL, TO
EQUIPMENT OF
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DISTORTION
METER IN
H.P.
330-B
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IN
NOTE:
K
OUT
X
X
G.E.
8 KC LP
-X
IN
X
OUT
INPUT AND
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IS
OUTPUT
MULT
BE
PROVIDED
WITH
NO.2
OF
MULTIPLE
JACKS.
ONE
TO
SET
X
X
AMPEX
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354
REPRO
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OUT
R
OUT
AMPEX
X
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IN
(MONOPHONIC)
354
X
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(SCA)
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AMPEX
354
Figure 2. Audio test setup at KDKA-FM transmitter.
STEREO RECORD.
v
CHANNEL MASTER
FM
FISHER
LOUDSPEAKER
YAGI
3000
750
302A
330B
ALUN
WAVE ANALYZER
DISTORT. ANALYZ.
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FISHER
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H.H. SCOTT
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2
RECORDER
(MONOPHONIC O
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TAPE RECORDER
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Figure 3. Receiving and test equipment at Uniontown.
BROADCAST
4
www.americanradiohistory.com
ENGINEERING
Figure 4. A.
Prose
Walker (left), NAB
manager of engineering, and Harold L. Kas sens, FCC's chief of
aural existing facilities,
H. Beville of station WWDC-FM,
Washington, D. C. The field test
panel was one of six set up by
NSRC. Others included groups
working on system specifications, interconnecting facilities, transmitters.
receivers, and subjective aspects.
Chief differences between the six
systems tested lie in composition of
the main channel (monophonic) and
subcarrier signals, which differ in
the subcarrier frequency, bandwidth, deviation, and type of modulation, i.e., AM vs. FM.
For the field tests, NSRC's panel
5 was organized into six subcommittees with the following chairmen:
Transmitter and Receiver Site Selection (A. C. Goodnow, Westinghouse Broadcasting Co.), Specifications for Measurement (B. F. Tyson, General Telephone & Electronic
Laboratories) , Transmitters (R. N.
Harmon, Westinghouse Broadcasting Co.) , Receivers (D. R. Von
Recklinghausen, H. H. Scott Inc.)
Data Correlation (Norman Parker,
Motorola) , Recorded Program Considerations (R. A. Isberg, Ampex
Professional Products Co.) .
Facilities for conducting the tests
were provided by KDKA-FM, Pittsburgh. Parameters to be measured
included frequency response, total
harmonic distortion, signal-to-noise
ratio with respect to 400 cycles per
second (cps) and 100 per cent modulation, stereo separation and crosstalk, spectrum requirements of system and subjective listening tests of
tape recorded program material.
Other considerations were such receiver qualifications as ease of tuning, selectivity, capture ratio and
the performance of adapters.
The block diagrams (Figures 1
coordinate
measurements at Uniontown receiving site during field
tests of proposed stereo
FM systems.
Figure 5. In the field
tests of stereo FM systems, Ampex tape recorders at the KDKAFM transmitter were
,
used for reproducing
the test tape, recording the stereo transmission and recording the
monophonic and SCA
transmissions.
(Continued on page 32)
February, 1961
5
www.americanradiohistory.com
Figure I. The above picture shows the simplicity of the control panel.
Presetting is performed with the black knobs.
AUTOMATZ( PRODUCTION MANAGER
SIMPLIFIES TV SWITCHING
By
EDWARD
L
COVINGTON*
IN RECENT YEARS, the desire has increased among television station
operators to simplify, and therefore
increase reliability of switching operations. Such simplification is particularly desirable where the size of
the operating staff is limited, as in
small and medium market stations.
The equipment to be described was
designed primarily for these operations.
Previous efforts along this line
have varied from the use of "total"
automation down to timer operated
"panic -period" switchers. The total
automation systems carry a memory tape or other such device, and
are built to handle all segments of
a day's programming. The job of
the operator is simply to watch that
all operations are properly performed and to take over in emergencies. The cost of such equipment
naturally runs into many thousands
of dollars due to its required complexity.
The panic switchers are designed
with the station break period in
mind. The operator presets all the
operations to take place during the
break and at the desired time gives
control to the unit. A timing device
then controls all the break operations, switches back to network, and
returns control to the operator.
To determine the most usable
system, an analysis of station operation was made. This produced
the following requirements:
(1) Pre-setting adjustments must
be simpler than normal operating
controls. If pre-setting is at all complex, the possibility of human error
is increased. Such complexity may
even cause operators to avoid use
of the device. In one station visited
by the author, an automation system was standing idle because presetting was too involved.
(2) Continuous operation of the
unit should be possible. With the
system on the air, the operator
should be able to preset or change
preset of upcoming program material. It must not be necessary to
switch back to normal operation except at the desire of the operator.
(3) Timer control is to be avoided. Unfortunately, there is often a
variation of several seconds in the
time allocated for an operation. In
addition, many station breaks and
cut -ins from network are made on
cue without a precise time being
specified. Operators with whom the
problem was discussed voiced a desire to retain control of the time
and occurrence of each aired material segment.
(4) Normal projection controls
must be able to override the automatic system. In the event an error
were to occur, it would be possible
to make an instantaneous correction, (i.e., to stop a projector with
a broken film instantly) without
first having to take control from the
automatic unit.
'Chief Engineer. KCMC-TV, Texarkana, Tex.
BROADCAST
6
www.americanradiohistory.com
ENGINEERING
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7
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SERIES N.G.
BUTTON
PAR. N.0.
BUTTON
L_1 _
24
24V
Figure 3. Momentary contactor.
(5) The unit must be simple circuit wise. Only a relatively small
amount of time should be taken
from an already crowded maintainence schedule for fabrication and installation. Circuit simplicity will also
contribute to reliability.
(6) Cost must be reasonable.
All requirements were met in a
preset switcher affectionately
dubbed "The Production Manager"
by the KCMC-TV control room
staff. Of preset switching, it is interesting to note that even total automation proponents have called it
automation's "most important contribution" in simplifying operations.
System Operation
Referring to Figure 1, the simplicity of the control panel is apparent.
A row of six rotary switches functions as the memory for the sequence of sources to be used. Note
the indicated positions of each knob
are identical (net, projector 1, etc.)
and that each has an adjacent pilot
lamp. This indicates which knob is
controlling material on the air.
On application of an operate
pulse, the next knob to the right
will become the "hot" one and
whatever is selected with it will be
put on the air. When a knob to the
right end is hot and an operate
pulse is applied, control is returned
to the extreme left switch, etc. It
is possible to preset the switches for
material to follow, even with the
unit on the air, as long as the hot
knob is not disturbed. In practice,
only a few seconds are required to
preset a complete sequence of operations.
In line with the requirement to
keep the presetting of the system
simpler than normal operations, it
was decided to retain slide changing
as a manual operation (the change
button appears to the lower right) .
Analysis of possible circuitry
showed the inclusion of automatic
slide changing to be the item which
would increase complication of the
control panel many times over.
The tape -tie switch to the right
of the rotary switches functions to
put a tape recorder on the air simultaneously with the slide projector. This feature is provided as
announcers often pre-record station
breaks. The turntable -tie switch
functions in the same manner as the
tape -tie for instances where disc recorded announcements are called
for.
The "operate" button appears at
the front center of the control panel.
This is the only control, excepting
the slide change button, used during
operation-pressing it causes the
system to perform all operations to
put the next pre -selected source on
the air. In this manner, the operator retains control of "when."
Adjacent to the operate button is
the "auto -normal" switch. To put
the Production Manager into operation, the rotary switch indicated by
its pilot to be hot is turned to a
position to coincide with material
on air and the auto -normal switch
is thrown to auto. The pilot lamp
at the front of the panel lights to
indicate the system has control. To
return to manual operation, the
switch is reversed. In either instance, there is no interruption to
the material on the air at the time
of the switch.
Circuit Details
Operation of the Production
Manager centers about the familiar
stepping relay (refer to Figure 2).
One deck is used to supply control
voltage to the hot selector switch.
As corresponding contacts of the rotary selectors are wired in parallel,
the voltage will be routed to the
selected function. This voltage is
available to the stepper only when
S8 is closed. Opening S8 disables
the system.
Pressing the advance button (S7)
energizes the step coil, advancing
control voltage to the next selector.
When the stepper is in the number
six position and the advance button is closed, the wiper arm on the
second deck contacts the reset coil
which returns the stepper to the
number one position.
Control voltage is available at all
times to the step coil and the pilot
lamps. This permits the stepper to
be advanced to a desired position
when not in use and lets the operator know which selector will be hot
when put on the air.
Video and Audio Control
Video switching is straightforward, using coax relays. Relay VK2
follows the action of S8 selecting the
output of either the regular station
switcher or the Production Manager. VK1 closes with voltage from
any hot selector in the net position
and opens in all others.
Since the slide and both projectors all originate from the same
camera, and this device was built
with no live camera considerations,
local video is fed to the relaxed contacts of VKl. If it were desired to
select more than one local video
BROADCAST
8
www.americanradiohistory.com
ENGINEERING
COLLINS CLOSE-UP
no. 3 in a series
PROFILE OF COLLINS AUTOMATIC TAPE DECK
Collins Automatic. Tape Control is available
in console models and 15" or 19" panels for
rack mounting.
Collins Automatic Tape Control bears close inspection. As individual components or as a unit, the quality of Collins automatic tape programming equipment is
unmatched.
Notice, for example, the heavy-duty, aluminum deck plate shown above. It's
guaranteed to keep its associated components in perfect alignment. The Bodine
synchronous motor, solid brass flywheel and steel capstan hold flutter and wow to
less than 0.2% rms. The precision of these components and maximum torque
make possible syllable -splitting cueing and a 99.96% tape speed accuracy.
The sound center of the Collins unit is mounted on the deck plate. A record/playback head is built on a laminated core and provides a uniform resolution of the
complete audio range, with a ±4 db frequency response at 50-15,000 cps (typical
performance ±2 db, 50-12,000 cps) and a signal-to-noise ratio of 55 db or better.
These are just a few of the reasons why there are more Collins Automatic Tape
Control units in U.S. radio stations than those of any other two manufacturers.
Ask your Collins broadcast equipment sales engineer for a demonstration, and
compare Collins
component -for -component, price -for -price
with any other.
You'll see why Collins is the indisputable leader in automatic tape programming
equipment.
-
-
!\
COLLINSj-COLLINS RADIO COMPANY
CEDAR RAPIDS. IOWA
DALLAS. TEXAS
February. 196!
BURBANK. CALIFORNIA
9
www.americanradiohistory.com
source, it would be a simple matter
to connect the appropriate selector
contact to an electronic or relay
video switcher.
Local, network, and automatic
audios are switched with auxiliary
contacts on the coax relays. When
one of the local program sources is
in use, the regular audio console
output is used. Local audio switching is done ahead of the console and
is described later. When network is
on the air, a separate amplifier is
used. This completely frees the audio console for other purposes and
makes it impossible for unwanted
cueing etc. to get on the air acci-
dentally.
Projection Controls
The usual projector remote control consists of three push -buttons
(start, show, stop) of the momentary contact type. A system requirement was that normal controls
be able to take over at any time.
Projector modification being undesirable, it was necessary to duplicate the momentary contact action
of the regular controls using the
continuous voltage from the hot
selector. The basic circuit of Figure
3 was devised for this purpose.
Capacitor C charges to 24 volts
by way of current through R. When
the switch is closed, C becomes a
power source, energizing K. In
about one-half second, C has discharged through the coil to the
point it can no longer hold in the
relay, thus having provided the
momentary contact required. The
voltage drop across R is sufficiently
high that the relay will remain open.
C cannot recharge to the source
voltage until S is opened.
Typical Operation
Assume the stepper in the number one position (Fig. 2) with S8
closed. Network will be on the air
via the energized positions of VK1
and VK2. The advance button (S7)
is depressed advancing control to
selector 2 which energizes K5 and
permits VK1 to relax, selecting local video and audio.
Due to the closing of K5, K6 will
energize momentarily, starting the
projector; the K7 coil circuit will be
opened permitting Cl to charge,
and heater voltage is applied to
thermal delay relay TK3. After a
lapse in "black" of two seconds the
projector will be up to operating
speed. At this time the TK3 contacts close and cause K8 to momentarily energize. As the K8 contacts parallel the show button, the
projector douser will be opened. To
get the audio on the air, a relay
across the douser connects the projector preamp to the console input.
On the next depression of S7, the
stepper will advance control to selector three. K5 relaxes and completes the K7-C2 circuit. Opening
the K7 contacts stops the projector,
closes the douser, and opens the audio relay since these circuits all
"make" through the normally closed
stop button and the K7 contacts. If
the operator returns to manual operation before advancing to selector
three, S8 will open the K7 -C2 cir-
Figure 4. The operator with the only control used during
routine switching at his fingertip. The unit performs all of
the switching and projection control excluding only live
cameras.
cuit to prevent unwanted stopping
of the projector when the control
voltage is removed from K5.
With selector three hot, a slide
will be on the air due to the closing
of K8. When the tape -tie switch is
closed, K10 and KI1 control start
and stop of the tape recorder in the
same manner as the corresponding
projector controls. Contacts are also
provided on K9 to energize a turntable relay.
During its several months of operation, the Production Manager has
proved very reliable and versatile.
A second operate button has been
installed in the projection room in
case the operator is "caught" with
an unexpected break or cut -in. If
completely automatic operation
should ever be desired, it will be
necessary to connect an appropriate
timer to the operate and slide
change buttons.
The unit was built and installed
in less than 80 manhours at a most
reasonable materials cost of slightly over $100. Since very few station operations are identical, the
circuit could probably not be used
exactly as shown in most instances.
However, due to circuit simplicity,
it should be adaptable to the individual case with minor modifications
and will pay for itself in operating
reliability and convenience many
times over.
The author wishes to extend
thanks to Mr. Lloyd Cox of the
KCMC-TV engineering staff for
construction work and helpful suggestions.
Figure 5. Rear view of the rack mounted section of the
Production Manager. The stepping relay is at bottom
center. Cables to control and projection are at upper
right.
BROADCAST
I0
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ENGINEERING
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Note the features of CBS Instrument
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Microelectronics
STUDIO PLANNING CONSIDERATIONS
article outlines the
considerations in choosing
equipment for a new broadcasting studio. Plans are given
for three different sizes of
operation which are intended
This
guide in planning
as a
new facilities.
Material and illustrations courtesy of
Radio Corporation of America.
THE EARLY planning
of a radio station usually involves consideration
of: the market to be served, site
selection, transmitter power, tower
height, station policies, personnel,
the extent of programming, the
hours of operation and available
capital. In this article we confine
ourselves mainly to the selection
and arrangement of equipment to
achieve the desired results. First,
and foremost of the decisions to be
reached, is whether the studio and
transmitter are to be combined
under one roof or to be in separate
locations.
PLAN A
Quantity
1
1
1
1
1
1
2
2
2
2
2
-
Table
1
1
3
3
2
1
I
Quantity
CONTROL ROOM
1
Audio Consolette With Tubes
Dual Headphone
Microphone
Microphone Mounting
XLR-3-11C Microphone Plug
XLR-3-32 Microphone Receptacle
"On-Air" Lights
1
1
100 ft.
STUDIO
1
rated installations, with the transmitter operated by remote control
from the studio-where permissible.
It is generally agreed that wherever practical it is most economical
to combine the studio and transmitter facilities. The initial equipment requirements are less and
more important, is the fact that
day-to-day operating expenses are
EQUIPMENT LIST
Three -Speed Turntables
Transcription Tone Arms
Pickup Heads
Transcription Equalizers or Filters
Tape Recorder
1
Input Transformer for Tape Recorder
1
Output Transformer for Tape Recorder
i
20db, 600 ohm Fixed Pad
1
Monitor Speaker
1
Monitor Speaker Housing
1
Speaker Matching Transformer
i
16 inch Clock
1
100 ft. Interconnecting Cable No. 22 AWG Shielded
Pair, With Cotton -Braided Outer Cover
Tape Cartridge Recorders
2
1
In the past few years there has
been a trend toward combined
studio and transmitter facilities
rather than separated facilities.
More recently, however, there has
again been a trend toward sepa-
AM TRANSMITTER INPUT AND
MONITORING
1
1
1
1
1
1
1
1
1
1
400 ft.
200 ft.
1
Ribbon Microphone for Desk
Desk Stand for Microphone
Ribbon Microphone for Studio Floor
Floor Stand for Microphone
XLR-3-11C Microphone Plugs
XLR-3-32 Microphone Receptacles
"On -Air" Lights
Studio Monitor Speaker
Monitor Speaker Housing
Speaker Matching Transformer
16 inch Clock
Interconnecting Cable No. 22 AWG Shielded
Pair, With Cotton -Braided Outer Cover
1
1
4
1
1
1
2
1
Cabinet Rack
AM Frequency Monitor
Modulation Monitor
40db, 600 ohm Fixed Pad
AGC Program Amplier With Tubes
Mounting Shelf for Amplifier
20db, 600 ohm Fixed Pad
Limiting Amplifier With Tubes
Double Jack Panel
Single Jack Panel Mat
Interconnecting Cable for Audio Rack Wiring, No. 20 Shielded Pair, Solid Conductor
Interconnecting Cable for AC and Filament
Circuits, No. 18 Shielded Pair, Stranded
Conductor
Terminal Board Mounting Bracket
Terminal Power Strip
Terminal Audio Block
Audio Patch Cords, 2 ft. in length
Switch and Fuse Panel
3H inch Blank Panel
1sá inch Blank Panel
8H inch Blank Panels
5 2 inch Blank Panel
BROADCAST ENGINEERING
12
www.americanradiohistory.com
POWER
WORK
WORK
BENCH
ROOM
TRANS -
MITT ER
RECORD
STORAGE
UTILITY
TABLE
CONTROL
ROOM
TURN
Ù
TA BLE
NO.
r
TURN
TABLE
NO 2
I
TA
E
CART
EQUIP J
RECORD
RACK
RACK
-SPKR.-
CLOCK
CLOCK
-J
SPKR.
SOUND
LOCK
STUDIO
FLOOR
STAND
MIC.
6'-7 V2
8'-4
rr
25'41"
Figure I. Floor Plan A shows a typical arrangement of studio and control room for
a small station with the transmitter located at the studio.
February, 1961
13
www.americanradiohistory.com
TAPE
OUT
NET
REM
REM
2
REM
3
EXT
1
REM
REM
TAPE
TAPE
NET
REM
IN
IN
IN
I
2
IN
4
PGM
OUT
REC
IN
EXT
AUD
OUT
TAPE
CART
IN
CONSOLE
OUT
40DB
PAD
IN
40DB
PAD
OUT
AGC
AMP
IN
AGC
AMP
OUT
20DB LIMITER
PAD
OUT
PAD
IN
IN
111111
LEGEND
dir -+-(rrttit
OPEN JACK
OUT
20DB LIMITERXMITTER
IN
FREQUENCY
MONITOR
1
MODULATION
MONITOR
i
LIMITER
AMPLIFIER
NORMALED THROUGH
BLANK PANEL
Figure 2. The suggested jack panel for the studio and control room of Plan A.
Figure 3. The
lower. With the plant "all under
one roof" there are savings in heating and air conditioning, building
maintenance, travel time and, in
addition, less technical personnel is
required. A "combined" operation,
however, is not always practical.
There are several important con-
siderations:
1. Is the combined location the
best spot for the transmitter site?
(By that we mean is there sufficient room for installation of tower
or towers, and an adequate ground
system? Furthermore, is it more advantageous from a standpoint of
providing the desired coverage?)
2. Is the combined location convenient and accessible for station
personnel and for clients? (A combined location is generally more
practical in smaller cities, since an
accessible and satisfactory location
for both studio and transmitter can
usually be obtained near the city
limits.)
When a combined operation is
not practical, the second most economical approach, where permissible, is to operate the transmitter by
remote control from the studio.
Then one can select a transmitter
site that is most advantageous from
a radiation and coverage standpoint,
and the studio could logically be
placed at its most convenient location. The building requirements at
the transmitter can be the very
minimum, requiring only space for
the equipment, a small work area
and a small room -heating unit. The
studio contains conventional equipment and a remote -control unit.
This type of installation is one of
the most desirable for larger cities.
Control Room
All control -room installations,
large or small, are alike in many
JACK PANEL
BLANK PANEL
AGC AMP
respects. The differences are mainly rack used in Plan
a matter of the number of micro- A contains the
BLANK PANEL
monitors and am phones, turntables, tape recorders fiers. Other opand other program sources to be tional equipment
BLANK PANEL
served. This, in turn, will dictate could be installed
the type of consolette or control in place of the
BLANK PANEL
console that is most suitable. Be- blank panels
yond this, there are various arrange- shown in the illusSWITCH & FUSE
tration.
ments of facilities to suit special
PANEL
conditions and personal tastes. For
economic reasons, most stations locate the control console in front of ing less consideration because fewer
the studio viewing window. They live programs are being originated.
locate the turntables on either side However, we have further discovof the operator's position at the ered that neglect in the planning of
console, a microphone over the con- the studio places a later handicap
sole for control -room announcing, on the average operation, which
and tape-recording equipment with- could have been prevented with
in easy reach of the operator. Such only a small additional expense and
an operating arrangement is shown r. little careful consideration at the
in Fig. 1.
time of construction. Hence in this
article we present plans that proHouse Monitoring
A house -monitoring system is an vide for normal expansion without
important function, and proper undue expense.
planning before construction begins Equipment Planning
will provide a much neater installaThe next most logical step after
tion. Provisions should be made to early plans have been completed is
carry audio to several locations the careful and considered planning
throughout the building, the lobby for the technical equipment. This
area, offices, clients' room, etc. Be- goes hand -in -hand with the buildsides normal program material, it ing design and construction. Equipprovides a convenient closed-circuit ment planning is the proper selecsystem for auditions and special tion and layout of technical equipmonitoring.
ment to satisfy contemplated proDuctwork
gramming requirements.
The careful planning and layout
We are going to cover three verof trenches and ducts for wiring is satile radio station equipment plans,
essential to economical installation which do not necessarily represent
and efficient operation. Once the any existing stations but they do
technical equipment has been accu- illustrate several ways in which the
rately determined, it is then time to very latest equipment may be arplan trench runs. These should pro- ranged to perform efficiently with a
vide for some measure of future ex- minimum of capital and personnel.
pansion. A typical trench layout is
Since programming requirements
shown by dotted lines in Fig. 1.
vary, we present three plans, which
represent three specific categories
Studio Considerations
As we examine present-day op- of operation:
1. Plan "A" covers a typical
erations, we find the studio receivBROADCAST
14
www.americanradiohistory.com
ENGINEERING
"combined" studio -transmitter operation, with programming requirement of records and transcriptions,
control room announce, one studio,
tape facilities, network and remotes.
This is a small station, requiring
minimum investment.
2. Plan "B" also covers a "combined" operation, but incorporates
additional facilities to allow for an
announce booth and other local program material. It is a typical community station of moderate size.
3. Plan "C" covers a fairly large
two -studio station with separate
studio and transmitter locations,
but with optional remote operation
of the transmitter. It is designed for
large city operation, providing a
high degree of flexibility and facilities for extensive programming.
The three plans are considered
adequate for the majority of cases,
and each is so arranged that modification of the plan may be made to
suit individual requirements. The
choice of the equipment layout will
depend to a large extent on factors
which are already determined: type
of programming; area to be served;
station policies and personnel.
Plan
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"A"
Plan "A" is a desirable layout
for the small station that proposes
to start operation at minimum investment. It includes the necessary
technical equipment for handling
the following programs: (1) announcements, (2) record and tape
shows, (3) network, (4) remotes,
and (5) local live originations such
as interviews and newscasts.
It will be noted in Fig. 1 that
the floor plan is separated into:
combined transmitter and control
.IPOOM,
small studio, engineering
work room and parts storage, supply storage and a sound lock.
The major items of equipment required to perform the programming
operation are identified on the floor
plan. A block diagram, Fig. 4, shows
how the system is connected together. An Equipment List, table 1
itemizes the requirements, including
the miscellaneous small items necessary to complete the system. The
rack layout, Fig. 3, further details
the location of the various equipments.
The choice of transmitter, of
course, depends upon the power of
the individual station. Regardless of
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Figure 4. The block diagram showing the connections to the studio console in
Plan A. The console diagram shown is an RCA BC -5.
February, 1961
15
www.americanradiohistory.com
PLAN
B
-
Table
EQUIPMENT LIST
Quantity
Quantity
CONTROL ROOM
1
1
1
1
1
1
2
2
2
2
2
2
1
2
1
1
1
1
1
1
1
100
ft.
1
Audio Consolette With Tubes, and
Additional Speaker Light Relay
Dual Headphone
Microphone
Microphone Mounting
XLR-3-11C Microphone Plug
XLR-3-32 Microphone Receptacle
"On -Air" Lights
Three -Speed Turntables
Transcription Tone Arms
Pickup Heads
Transcription Equalizers or Filters
Utility Amplifiers
Tape Recorder
Tape Cartridge Recorders
Input Transformer for Tape Recorder
Output Transformer for Tape Recorder
20db, 600 ohm Fixed Pad
Monitor Speaking
Monitor Speaker -Housing
Speaker Matching Transformer
16 inch Clock
Interconnecting Cable No. 22 AWG Shielded
Pair, With Cotton -Braided Outer Cover
AM TRANSMITTER INPUT AND
1
1
1
1
1
1
1
1
1
1
400 ft.
200 ft.
1
1
2
MONITORING
Cabinet Rack
AM Frequency Monitor
Modulation Monitor
40db, 600 ohm Fixed Pad
AGC Program Amplifier With Tubes
Mounting Shelf for Amplifier
20db, 600 ohm Fixed Pad
Limiting Amplifier With Tubes
Double Jack Panel
Single Jack Panel Mat
Interconnecting Cable for Audio Rack Wiring, No. 20 Shielded Pair, Solid Conductor
Interconnecting Cable for AC and Filament
Circuits, No. 18 Shielded Pair, Stranded
Conductor
Terminal Board Mounting Bracket
4
1
1
1
1
1
1
1
1
1
1
1
1
1
1
4
4
4
2
2
2
2
150 ft.
STUDIO AND ANNOUNCE BOOTH
Ribbon Microphone for Desk
Desk Stand for Microphone
Ribbon Microphone for Floor Stand
Floor Stand
Uniaxial Microphone
Desk Stand for Above Microphone
XLR-3-32 Microphone Receptacles
XLR-3-11C Microphone Plugs
"On-Air" Lights
Studio Monitor Speakers
Monitor Speaker Housings
Speaker Matching Transformers
16 inch Clocks
Interconnecting Cable No. 22 AWG Shielded
Pair, With Cotton -Braided Outer Cover
RECORD LIBRARY
1
1
2
2
1
1
1
1
1
1
1
100 ft.
Terminal Power Strip
power, all other items included in
Plan "A" remain the same.
Plan "A" incorporates many features to permit operation with a
minimum of personnel. It is designed for a single operator-announcer to work directly from the
control room. The equipment location makes this practicable since
turntables, tape recorder, control
console, and record rack are all
within easy reach of the operator.
The equipment rack is situated for
convenient reading of the frequency
Terminal Audio Block
Audio Patch Cards, 2 ft. in length
Switch and Fuse Panel
Monitor Amplifier With Tubes for House
Monitoring System (Speakers to be select ed as required)
Plug-in Transformer for Amplifier
Mounting Shelf for Monitor Amplifier
3j4 inch Blank Panel
1;L inch Blank Panel
5, inch Blank Panel
832 inch Blank Panel
Turntable
Transcription Tone Arm
Pickup Heads
Transcription Equalizers and Filters
Utility Amplifier
Monitor Amplifier for Audition
Plug-in Transformer for Amplifier
Selector Switch for Input of Amplifier
Bridging Pad for Automatic Turntable
Audition
Monitor Speaker for Audition
Monitor Speaker Housing
Interconnecting Cable No. 22 AWG Shielded
Pair, With Cotton-Braided Outer Cover
easily accessible within the control
room. Furthermore, the small utility
storage rack and table, located directly behind the operating position,
provides a handy place for keeping
the daily program material ready
for use.
Entrance to the control room or
the studio is via the common sound
lock. The small engineering work
room with storage cabinet and
workbench is sometimes neglected
in planning, but will prove its worth
many times over. The wiring trough
meters
monitor
and modulation
without leaving the operating po- shown in dotted lines in Fig. 1
sition. Record storage racks are makes the wiring readily accessible
for service, or making additions to
the system.
Technical Facilities of Plan "A"
The control console is the heart
of the audio system. Considerations
in choosing a control console include operational simplicity, number of inputs and outputs, accessibility of controls and versatility.
The console suggested in Plan "A"
has facilities for the control room
mike, two turntables, tape recorder,
cartridge tape, net, three studio
mikes, and four remote lines. It is
single channel and has line, audition, and recording outputs as well
BROADCAST
16
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ENGINEERING
12'
AUDITION
TURN
TABLE
--f
9"
34' 9"
,
22'-0"
I
POWER
WORK BENCH
UTILITY
TABLE
II
II
II
II
WORK ROOM
II
II
rL
TRANSMITTER
RECORD
JI
1
LIBRARY
UTILITY
TABLE
CONTROL
ANN
BOOTH
a
ROOM
TURN
TABLE
oMIC.
NO.1
0
TURN
TABLE
NO.2
TAPE
CART
RECORD
IEQUIP.
I
RACK
IIJII
RACK
CLOCK
I
SPKR:J
CLOCK SPKR.
SOUND
LOCK
6'-7"
STUDIO
Figure 5. Floor Plan B shows the equipment arrangement of the enlarged plan
which includes a separate record library
and announce booth. This plan is also
a combined studio -transmitter operation.
O
FLOOR
STAND
MIC.
22'-4"
as a monitor amplifier for loudspeakers.
The turntables selected are three
speed units: 33-1/3, 45, and 78 rpm.
A smooth starting, reliable, turntable with a simplified speed changing mechanism and a hysteresis synchronous motor is a must.
The tape recorder should be a
professional model using a synchronous motor. It may either be rack
mounted, console type, or mounted
on a table top if a portable version
is used.
An Automatic Gain Control Amplifier and a Limiting Amplifier are
located in the equipment rack. The
functions of these two units in the
system are related, and a description of their importance follows: It
is a well-known fact that station
coverage, regardless of power, is
definitely related to the ability of
maintaining the highest possible
average level of modulation without
distortion. The use of a limiting
amplifier has been common for several years with reasonably good results, however, it has some limitations. In a Limiting Amplifier, the
gain is constant up to a certain output level. Above this level, there is
February. 1961
reduction that the
output level will be maintained virtually constant. Thus, a limiting
so much gain
amplifier is effective only on high
levels of program material. On the
other hand, the Automatic Gain
Control Amplifier (AGC) will serve
to maintain a relatively constant
output, much in the same manner
that an operator might, by carefully
and constantly "riding gain" on the
program. A gain control amplifier
and a limiting amplifier are sometimes used together to supplement
one another. This combination permits a higher average level of pro 17
www.americanradiohistory.com
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BROADCAST
18
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ENGINEERING
Bauer
Standard Of Quality!
A New
1000/250
WATT
AM TRANSMITTER
If you want the very best
1 kw AM transmitter available today... order the Bauer
Model 707.
Bauer keeps pace with the fast moving field
of electronics to give you a modern transmitter for the "sixties"... at a price that
proves the economy of superior design.
These Quality Features Provide Economical And Optimum Performance
SILICON RECTIFIERS
- In all
power supplies ... No more arc back...
longer life ... plus automatic starting
and simplified control circuitry.
CONSTANT VOLTAGE TRANSFORM E R-Maintains all filament and
low voltage supplies within 1% ... thereby eliminating manual adjustment and extending tube life.
VACUUM CRYSTAL Maintains carrier frequency within ± 5 cps without heaters, thermostats
-
or ovens.
VACUUM VARIABLE CAPACITOR-Provides
highly dependable tuning of final tank circuit
.
a Bauer "quality" exclusive.
..
BUILT-IN REMOTE CONTROL - No need to
add metering kits and power control motors with a
Bauer Model 707-they are included at no extra cost.
POWER CUTBACK - Throw the switch (local
or remote control) for 250 watts night-time . .
standard equipment. Instantaneous surge free
efficient.
-
.
-
- Modern cooling
CONTINUOUS METERING - Of all circuits
provided by nine different
PRESSURIZED CABINET
system extends component operating life.
meters. No multi-meters!
BUILT-IN DUMMY ANTENNA-Furnished as
standard equipment. A Bauer feature for many years!
The Economical Approach
The Bauer Model 707 is also available as a kit ... at a substantial savings.
DON'T BUY A 1 KW TRANSMITTER UNTIL YOU HAVE THE BAUER STORY.
WRITE TODAY
13
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!
ELECTRONICS
INDUSTRIAL WAY. SAN CARLOS, CALIFORNIA
LYTELL 3-0800
CORPORATION
AREA CODE 415
February, 1961
1
www.americanradiohistory.com
9
NET
NET
IN
TAPE
CART
REM
TAPE
CART
IN
REM
1
I
IN
REM
2
REM
3
REM
2
REM
CONSOLE
OUT
TAPE
OUT
EXT
PGMOUT
OUT
REC
IN
4
IN
EXT
40 DB
SPARE
PAD
IN
40
DB
PAD
OUT
AGC
AMP
AGC
AMP
OUT
20DB
IN
PAD
IN
20 DB LIMITER
AMP
PAD
OUT
OUT
LIMITER XMITTER
AMP
IN
IN
FREQUE NCY
11fí1
#rar
LEGEND
-4-{
OPEN
MONITOR
MODULATION
MONITOR
LIMITER
AMPLIFIER
NORMALED THROUGH
JACK
Figure 7. The jack panel for plan
B.
BLANK PANEL
Figure 8. The
Plan
Figure 9. The block diagram of the record audition system. The amplifier
may be mounted in the turntable cabinet. A switch is shown for the amplifier input to accommodate other equipment such as tape or other source.
o
AUDITION
AMP.
TURN
TABLE
B
JACK PANEL
BLANK PANEL
rack shown
here is similar
to the rack of
system A except
that a house
AGC
AMP
BLANK PANEL
HOUSE
MONITOR
monitoring amplifier has been
added.
AMPLIFIER
BLANK PANEL
SWITCH &. FUSE
PANEL
AUX. INPUT
grain material, and prevents over modulation on sudden program
peaks, which effectively improves
reception in fringe areas and extends coverage without increasing
transmitter power.
Other major equipment items located in the equipment rack are the
frequency and modulation monitors
(required by the FCC), and a jack
panel. The complete rack layout is
shown in Fig. 3.
Plan "B"
Plan "B" typifies the most desirable arrangement for the community -type radio station. This plan fulfills all the requirements, from a
space and facility point of view, for
handling a very diversified program
schedule. It incorporates technical
features that make for an adequate,
yet economical, operation.
While Plan "B" is identical in
many respects to the Plan "A" station, it includes larger and additional facilities (see Fig. 5) The
major difference is a larger studio,
the addition of an announce booth,
and a record library room. The con .
Technical Facilities of Plan "B"
Three turntables are specified in
more facilities than the one described in Plan A. Provisions for an the Equipment List for Plan "B".
announce booth and an additional The additional turntable, along with
studio mike are provided. It also some accessory equipment, makes
provides loudspeaker monitoring fa- up a small system for auditioning
records. Figure 9 gives the details as
cilities for the announce booth.
to how this system goes together.
be
excan
Now programming
panded to include the origination Plan "C"
Plan "C" approaches the ultimate
of a fairly substantial live studio
show. Another important aspect of for the "larger"type of radio stathis plan is that with the announce tion as we know it today. From the
booth serving as another point of floor plan, Fig. 10, it will be apparorigination, it becomes very practi- ent that a high degree of flexibility
cal to record announcements and is maintained, offering facilities for
other program material while on the handling very extensive programming. Furthermore, it will be noted
air.
Again we have utilized a common that Plan "C" incorporates many of
sound lock, in the interest of econ- the same general considerations deomy, with the announce booth, stu- scribed for the other two stations
dio and control room all accessible but with several additions. There is
from this area. The record library also one significant deletion-the
being separated from the point of transmitter. In this plan we have
program origination makes possible, assumed that the transmitter would
with the facilities provided, au- be located separate from the studio,
ditioning of records, building of with its own building, at its own
shows, cataloging, filing, etc., to be site.
First there is a large studio, the
carried on without interruption durto be determined by just what
size
day.
program
ing the
sole recommended for Plan B has
BROADCAST
20
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ENGINEERING
RCA "Traveling Wave" Antenna
atop world's tallest structure
gives KFVS one of the world's
largest TV service areas
According to KFVS-TV, Cape Girardeau,
Mo., programs beamed from this new 1676
ft. tower should reach more than 2 million
people living in one of the largest TV service areas in the world. Yet, thanks to the
excellent null -fill characteristics of the
Antenna, KFVS's close -in coverage will
not be sacrificed for added tower height.
This new "Traveling Wave" Antenna and
tower 2000 ft. above average terrain represent the world's tallest man-made struc-
ture. Together they are 204 feet taller than
the Empire State Building. They dwarf the
Eiffel Tower.
The RCA "Traveling Wave" Antenna combines excellent electrical characteristics,
with mechanical simplicity and economy.
Here is a VHF high -band antenna that
has inherently low VSWR and produces
smoother patterns. The design, based on
slot radiators, results in improved
circularity.
RCA
Broadcast and Television Equipment
Camden, N.J.
Even if you are not in the market for the world's tallest, if you
want a VHF High -Band Antenna which combines mechanical
simplicity and economy, especially in high -gain, high -power
applications, your RCA Broadcast Representative can help
with your Antenna planning. See him for complete story. Or
write to RCA, Dept. R-367, Building 15-1, Camden, N. J. In
Canada: RCA VICTOR Company Limited, Montreal.
The Most Trusted Name
in Television
RADIO CORPORATION OF AMERICA
www.americanradiohistory.com
Table
PLAN C
-
EQUIPMENT
1
1
1
1
1
2
2
2
2
2
2
2
2
2
2
2
2
2
2
1
4
2
8
1
2
1
1
2
2
2
2
4
1
4
2
2
200 ft.
400 ft.
200 ft.
MAIN CONTROL ROOM
Audio Consolette With Tubes, and Additional
Speaker Light Relay
Dual Headphone
Microphone
Microphone Mounting
XLR-3-11C Microphone Plug
XLR-3-32 Microphone Receptacle
"On -Air" Lights
Three -Speed Turntables
Transcription Tone Arms
Pickup Heads
Transcription Equalizers or Filters
Tape Recorders, Remote Control,
Rack Mounting
Cabinet Racks
40db, 600 ohm Fixed Pads
AGC Program Amplifiers With Tubes
Monitor Amplifiers, With Tubes
Tape Cartridge Recorders
Monitor Speakers
Monitor Speaker Housings
Speaker -Matching Transformers
16 inch Clock
Double Jack Panels
Double Jack Panel Mats
Audio Patch Cords, 2 ft. in length
AM -FM Tuner
Line Equalizers
VU Meter Panel
Sound Effects Filter
Terminal Board Mounting Brackets
Terminal Power Strips
Terminal Audio Blocks
Switch and Fuse Panels
1032 Blank Panels
111 Blank Panel
5-h Blank Panels
8H Blank Panels
3H Blank Panels
Interconnecting Cable No. 22 AWG Shielded
Pair, With Cotton -Braided Outer Cover
Interconnecting Cable for Audio Rack Wiring
No. 20 Shielded Pair, Solid Conductor
Interconnecting Cable for AC and Filament
Circuits No. 18 Shielded Pair, Stranded
Conductor
8
8
3
2
2
2
1
300 ft.
1
1
3
3
2
1
1
1
1
1
150 ft.
1
2
1
1
2
2
Pressure Microphone
Desk Stand for Above
Ribbon Microphones
Floor Stand for Microphone
Microphone Boom Stand
Uniaxial Microphones
Desk Stands for Above
Turntable
Transcription Tone Arm
Pickup Heads
Transcription Equalizers and Filters
Utility Amplifiers
Monitor Amplifier for Audition
Plug-in Transformer for Amplifier
Selector Switch for Input of Amplifier
Monitor Speaker for Audition
Monitor Speaker Housing
Interconnecting Cable No. 22 AWG Shielded
Pair, With Cotton-Braided Outer Cover
MULTI -PURPOSE ROOM EQUIPPED
AS STUDIO
1
1
2
2
2
1
1
1
1
50 ft.
Pressure Microphone
Microphone Mounting
XLR-3-11C Microphone Plugs
XLR-3-32 Microphone Receptacles
"On -Air" Lights
Monitor Speaker
Monitor Speaker Housing
Speaker Matching Transformer
16 inch Clock
Interconnecting Cable No. 22 AWG Shielded
Pair, With Cotton -Braided Outer Cover
MULTI -PURPOSE ROOM EQUIPPED
AS A SUBCONTROL ROOM
1
STUDIO AND ANNOUNCE BOOTH
XLR-3-32 Microphone Receptacles
XLR-3-11C Microphone Plugs
"On -Air" Lights
Studio Monitor Speakers
Monitor Speaker Housings
Speaker Matching Transformers
16 inch Clock
Interconnecting Cable No. 22 AWG Shielded
Pair, With Cotton-Braided Outer Cover
RECORD LIBRARY
1
1
LIST
Quantity
Quantity
1
3
2
2
2
2
1
1
1
100 ft.
Audio Consolette With Tubes
Dual Headphone
Three -Speed Turntables
Transcription Tone Arms
Pickup Heads
Transcription Equalizers and Filters
Tape Recorder
Input Transformer for Tape Recorder
Output Transformer for Tape Recorder
Interconnecting Cable No. 22 AWG Shielded
Pair, With Cotton-Braided Outer Cover
BROADCAST
22
www.americanradiohistory.com
ENGINEERING
BOOM
STAND
MIC.
TRANSMITTER
BUILDING
STUDIO
MAIN
FLOOR
STAND
MIC.
O
U
SOUND
LOCK
MON
SPKR
MON
SPK R
O
MIC
U
ANNOUNCE
BOOTH
CLOCK
MON
MON
SPKR.
NMI
SPKR.
TAPE
CART
TURN
TABLE
NO.
U
I
MAIN
MON
SPK
CLOCK
TURN
CLOCK
STORAGE
-
R.
F
CLOCK
RACK
TURN
TABLE
TABLE
NO 2
--RECORD
U
NO 3
CONTROL
SUB
-
TURN
TABLE
NO 4
CONTROL
RECORD. SHOWS
RECORDING
FM ETC
UTILITY
TABLE
07
EQUIPMENT
!RACKS'
RECORD
LIBRARY
WORK ROOM
ò
AUDITION
TURN
TABLE
è
SPKR
WORK
STORAGE
POWER
12'-4"
21' 0"
3
Figure 10. The Floor Plan C above
BENCH
is a
3'-4"
very complete arrangement which includes
a
large studio
that may be expanded if desired. The transmitter is not installed at the studio in this plan which
for a larger station where a separate transmitter location would be desirable.
February, 1961
is
23
www.americanradiohistory.com
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BROADCAST
24
www.americanradiohistory.com
ENGINEERING
Plug-in reliability
with
ç
250 SU CONSOLE Combining compact simplicity with maximum flexibility through Altec
professional
audio equipment
input devices of uniform size and interchangeability permit free range in number and type of
amplifiers used per console.
Characterized by single unit construction for simplicity (amplifiers and controls within same housing) and economical installation, Altec's 250 SU features an externally mounted power supply for
cool operation and isolation of strong magnetic fields.
Providing complete circuitry for all stereo or universal operating functions, there is no finer, more
reliable control console serving the audio industry. Individual components are available complete
with plug-in trays for custom and rack installation.
An
extemely
simple, highly reliable, low noise preamplifier, the 458A
incorporates a single stage push-pull cross -neutralized
vacuum tube circuit, transformer coupled to source and
load. Maximum reliability with unfailing performance are
achieved through simplified design featuring fewer components, extremely accurate balance of input and output transformers, and premium quality pre -aged, shielded
tubes. The failure of either tube will not cause loss of
program.
SPECIFICATIONS GAIN: 40db unterminated input,
+20 dbm at less
than .5% THD 50 to 15,000 cps. +25 dbm at less than
1% THD at I KC. FREQUENCY RESPONSE: + 1 db 20 to
20,000 cps. SOURCE IMPEDANCE: 150 or 600 ohms
(centertap for 600 ohms). LOAD IMPEDANCE: 150 to 600
ohms (centertap for 600 ohms). OUTPUT IMPEDANCE:
Equal to load impedance. NOISE LEVEL: Equivalent input
noise: -126 dbm. POWER SUPPLY: 15ma at 275vdc and
.7a at 6.3vdc. TUBES: 2-6072/12AY7. DIMENSIONS:
34 db terminated. POWER OUTPUT:
1 3/4" W x 3
15/16" H and 9 11/16" L. COLOR: Cad
plate, dichromate dip. WEIGHT: 3 1/2 lbs. (including
tray). SPECIAL FEATURES: Push buttons for individual
tube test. 40ma dc can be applied to center taps for
simplexing. ACCESSORIES: 13225 Rack Mounting Assembly (for 9 units). 13401 Mounting Tray Assembly. 5981
Tube Test Meter. 535A Power Supply.
ALTEC
THE 250 SU FEATURES:
advanced
design, the new 250 SU Altec has proven to be the ultimate in control consoles for TV, AM, FM,
recording studio or sound system use. Newly designed miniature plug-in preamplifiers, and utility
458A "PLUG-IN" PREAMPLIFIER
"Plug-in" units com-
to 10 mixing
channels
Single channel operation
pletely interchangeable
Two channel operation
Low impedance mixing
Two channel/three
Meets NAB, EIA, and
Speech -music
terminated.
"Stereo" operation
Illuminated meters
for tape -disc -line networks, etc.
Color coded controls
16 connected inputs
Microphone level or
"high level" on any
input
Tube testing provisions
Expandable to jack
fields, equalizers, etc.
GAIN: 56 db unterminated input, 50
+30 dbm at less than
535A POWER SUPPLY Compact, highly
reliable, the 535A is the
DC
power supply for
furnishing the operating voltages to the
Altec 458A and 459A amplifiers used together
with the Altec 250 SU Console. Externally
mounted to preclude hum, the 535A employs
silicon rectifiers in both the filament and
"B" supplies. The 535A connects to the 250
SU by means of a 4 -foot multiple conductor
cable terminated in a type P306CCT Jones
plug which "mates" with a Jones receptacle
in the 250 SU Console. A single screw frees
the power supply unit from its mounting
bracket for inspection.
POWER OUTPUT:
A subsidiary of Ling-Temco Electronics, Inc.
POWER OUTPUT: 275vdc
at 275ma. At 275ma ripple is .02v peak to
peak max. 6.3vdc at 13a. At 13a evc ripple is
1.5v peak to peak max. POWER INPUT: 117v
50-60 cps 245 watts at full load. RECTIFIERS:
Silicon. CONTROLS: 1. Power Switch. 2. Circuit Breaker (Push to reset). 3. 4 Position tap
switch (provides adjustment of voltage by
SPECIFICATIONS
2 to 1
range of loads). COLOR: Dark Green. WEIGHT:
16 pounds. SIZE AND MOUNTING: 7 3/16" W
autoformer action to accommodate
x 9
5/8"
H
x
7"
D
overall.
technical literature on
ALTEC Professional Audio Equipment, write Dept. B-2.
For FREE
ALTEC
IAM01M0 CO0/UMAr1OM
161
channel operation
Utility input devices
.5% THD 30 to 20,000 cps. +35 dbm at less than 1% THD
at 1 KC. FREQUENCY RESPONSE: ±1 db. 20 to 20,000 cps.
SOURCE IMPEDANCE: 150 or 600 ohms (centertap for 600
ohms). LOAD IMPEDANCE: 150 or 600 ohms (centertap for
600 ohms). NOISE LEVEL: Equivalent input noise: -126
dom. POWER SUPPLY: 40ma at 275 vdc and 1.6a at 6.3vdc.
TUBES: 1-6072/12AY7, 2-12BH7. DIMENSIONS: 1 34" W
x 3 15/16" H x 9 11/16" L. COLOR: Cad plate, dichromate
dip. WEIGHT: 3 1/2 lbs. (including tray). SPECIAL FEATURES: Push buttons for individual tube test. 40ma dc can
be applied to center taps for simplexing. ACCESSORIES:
13225 Rack Mounting Assembly (for 9 units). 13401 Mounting
Tray Assembly. 5981 Tube Test Meter. 535A Power Supply.
LANSING CORPORATION
1515 Manchester, Anaheim, Calif.
filter
D.C. heater supply
large power capability, the 459A consists of a 2 -stage
push-pull circuit with a balanced negative feedback loop.
Push-pull operation of all stages provides reliability, interchangeability with preamplifiers for added gain and power.
Superior overall performance results from special input and
output transformer design of ultrafine balance combined
with premium quality pre -aged shielded tubes. Program
transmission is not interrupted by failure of either output
tube.
db
Up
recording requirements
459A "PLUG-IN" PROGRAM AMPLIFIER A highly
reliable, low noise program amplifier with exceptionally
SPECIFICATIONS
ALTEC
Sixth Avenue, New York 13, N.Y
©1960 Altec Lansing Corporation
25
February, 1961
www.americanradiohistory.com
type of programs one wants to originate. The associated technical facilities suggested will handle choral
groups, full orchestra, audience participation programs, etc.
Then there is the main control
room equipped with a dual -channel
control console. These two full
channels, each with its own monitoring amplifier and power supply, provide maximum flexibility and reliability. Two three -speed turntables
are employed. Two remote -controlled tape recorders and two monitor speakers, together with miscellaneous amplifiers and accessory
items are included.
A highlight of this plan is the inclusion of a multi -purpose room. It
may be a small studio, or, as it is
shown equipped (Fig. 10) , may
serve many purposes as follows:
1. A subcontrol room serving the
main studio for regular programing auditions or recording.
2. For disc-jockey type shows.
3. For separate programming of
another channel such as FM or to
another AM station.
4. As a recording control room.
5. Announce booth.
ß. Auditioning special programs.
BLANK PANEL
AM
- FM
TUNER
REM. CONT.
TAPE
RECORDER
BLANK PANEL
LINE
EQUALIZER
TWO DOUBLE
JACK PANELS
BLANK PANEL
7. Standby, or
8. As a program
command as: a master control, a
"combo" or operator-announcer's
control board; a program on one
channel while running an audition
or recording on the other. Figure 12
shows the rack layout for Plan "C."
At the beginning of this series of
plans it was stated that they did not
necessarily represent any existing
stations, but that they illustrated
several ways in which the equipment could be arranged, and the
plans or combinations of them
would satisfy a majority of cases.
As Plan "C" is examined, it becomes
"make-up" facility for automatic program utilization in the future.
The announce booth, record library, engineering work room and
storage area follow closely the preceding plans.
Technical Facilities of Plan "C"
The major equipment item new to
this plan is the dual -channel control
console. A block diagram of the unit
is shown within the system diagram
in Fig. 11.
As used in the Plan "C" system
this consolette is made to serve on
(Continued on page 31)
C.R.
MIC
ANN.B
MIC
MIC
MIC
TT
TT
TAPE
1
2
3
MIC
4
MIC
MIC
5
1
2
1
2
OUT
PRE
PRE
AMP
PRE
AMP
PRE
PRE
PRE
AMP
AMP
AMP
AMP
PRE
AMP
-A
2-A
PRE
AMP
1-B
2-B
3-A
4-A
OUT
PRE
AMP
5-A
I
TAPE
CART
TAPE
CART
1
2
PRE
AMP
PRE
AMP
3-8
4-B
SUB
TAPE
CONT CONT
3
SPARE PRE-AMPPREAMP
I -B
3-B
OUT
SUB
SUB
NET
CONTET
SPARE
PRE AMP LINE
SUB
SUB
CONT
REM-I
IN
SUB
2-B
IN
RÉM
IN
I
X
2
AGC
AMP -1
AGC
AMP -2
SUB
CONT
MON
OUT
SUB
SUB
CONT
CO
ÚNT
D
OUT
7-B
CONSOLE
OUT
40DB
PAD
IN
6-A
40DB
PAD
OUT
AGC
AMP
IN
7-A
AGC
AMP
OUT
20DB
PAD
IN
5-B
20DB
PAD
OUT
TAPE
3
IN
XIX
i I
I
Y
i
Y
Y
Y
Y
Y
z
z
z
z
I
z
Y
Y
Y
Y
Y
Y
XXXII'
YYYrrY
REM
REM
REM
REM
REM
LINE
LINE
LINE
LINE
LINE
3
4
5
Y
Y
Y
VU METER
PANEL
BLANK PANEL
REM. CONT.
TAPE
RECORDER
SOUND EFFECTS
FILTER
TWO DOUBLE
JACK PANELS
BLANK PANEL
MON.
MON.
AMP -1
AMP -2
BLANK PANEL
BLANK PANEL
BLANK PANEL
BLANK PANEL
BLANK PANEL
BLANK PANEL
SWITCH 8c FUSE
SWITCH 8c FUSE
PANEL
PANEL
PRE
AMP
SUB
CONT
OUT
PRE
AMP
"
1
2
REM
REM
INPUT
REM
INPUT INPUT
2
1
3
REM
REM
INPUT
4
INPUT
AM FM HOUSE
MON SPARE
SPARE TUNER
-OUT
OUT
HOUSE HOUSE
SPARE MON
SPARE
MON
5
LINE
NET
I-
NET
IN
IN
Figure 12. The Plan C rack includes
optional features which may be desired in a larger broadcast operation.
-IN
CKT
CUE
-IN
2 -IN
i
1
LINEI
PAD
OUT
OUT
AGC
AMP
I
SPARE SPARE SPARE
CUE
2 -IN
LINE
LINE 40DB
EQ-ZR EQ-ZR PAD
-OUT 2 -OUT
IN
CUE
3 -IN
z1
II1.
tit
I
LINE CONSOLE 40DB
LINE EQ-ZR EQ-ZR
I
BLANK PANEL
PRE
AMP
6-B
TAPE
IN
AGC
AMP
OUT
PAD
IN
EXT
z
z
Y
PAD
OUT
LINE
20DB
HOUSE
MON SPARE
2 -OUT
HOUSE HOUSE
MON SPARE
MON
CKT
2 -IN
SPARE
20DB
MON
1
TO
X
MTR
CONSOLE
LINE -2
OUT
EXT
SPARE
MON
LINE TO
2
XMTR
z
z
z
Y
Y
Y
z
z
z
II
YYYYxYYYYYYY
z
z
z
z
z
z
z
Figure 13. The jack panels for Plan C show how the additional facilities of the
larger installation are arranged.
BROADCAST ENGINEERING
26
www.americanradiohistory.com
GG
We Do More
Jobs... Be tier
with Videotape* Recording. Business
is better than it's ever been and we have a smoother, more efficient operation," sums up Al Beck.
"For us, Ampex VTR is a basic piece of equipment that fit into our operation right from the
start. It's no `sacred cow' to us; everyone here operates it. And essentially, it gives us a whole
crew of operators plus announcers ... a real problem -solver when it comes to scheduling personnel. From an operating standpoint, it's tremendous. Today, for instance, the boys are
knocking out 15 1 -minute commercials. And we have scheduled as many as 63 recordings in
Ask
one operating day. I wouldn't want to go back to operating without an Ampex."
Ampex today for specific station histories of the Videotape Television Recorder as a basic
money -making component of any competitive TV facility. Ask, too, about Ampex financing
and leasing arrangements. Write Department EB.
AMPEX
AMPEX PROFESSIONAL PRODUCTS COMPANY
934 CHARTER ST., REDWOOD CITY, CALIF.
AMPEX OF CANADA LTD., REXDALE, ONTARIO
(2/
MR. AL BECK. CHIEF ENGINEER,
*TM Ampex Corp.
KGBT-TV, HARLINGEN. TEXAS
(73.100 TV HOMES: 180TH MARKET)
February, 1961
27
www.americanradiohistory.com
An Automatic Conelrad
Construction details of
a
Attention Signal Unit
Conelrad actuating device are described which automatically
provides the carrier interruption cycles and tone transmission.
By
EUGENE SEIER*
THE
UNIT described in this article
does not perform all of the functions
necessary in switching to the Conelrad frequency; however, it does relieve the operator of the critical operations involved, namely, the 5 second off, 5 second on, 5 second off,
back on and 15 second 1000 cycle
tone sequence. It can be built at
nominal cost with tools and materials readily available in the average radio station. The only tools
used, beyond the ordinary hand
tools, were a quarter-inch electric
drill and a sabre saw. The last mentioned item, although handy for cutting sheet metal, is not absolutely
necessary.
The switching unit is built around
a 1 -rpm motor rotating a shaft on
which four notched discs are mounted, with the notches so arranged as
to actuate micro -switches to perform the necessary switching functions. This unit is built on a 5" x 9"
sheet metal (16 gauge) sub -chassis,
details of which are shown on the
detail drawing (Fig. 1) . Note that
the bracket which supports the far
end of the shaft must be a separate
piece bolted on, to facilitate assembly and alignment. This is in turn
mounted on a standard 5" x 17" x
Q" chassis as shown in the photo. A
large square hole was cut in this
chassis to clear all bolts protruding
from the bottom of the sub -chassis
and was fastened by a bolt on each
corner. The main chassis also contains a 1000 -cycle RC oscillator and
one stage amplifier with power supply.
The 1 -rpm motor was obtained as
a surplus item from Barry Electronics, New York, N. Y., at a cost
of $1.95; however, if these are no
longer available, a Hurst Type SM 1 motor available at most large electronic supply houses may be used
with only slight modifications in the
mounting needed.
The particular motor used in this
model had a small gear just slightly
over 3/8" in diameter mounted on a
Motor Bracket
Bent
Base
9"
Detail Drawing Subchassis
Figure
I
.
Up
From
Scale
1/a.'"=
Detail drawing of subchassis for Conelrad device.
1"
shaft. It was decided to leave
this gear intact and a 3/8" shaft
bushing was reamed out slightly
with a rat tail file to fit over this
gear and fastened with a set screw.
A 1/4" shaft bushing was then
ground down on one end to fit into
the 3/8" bushing by inserting a 1/4"
rod, chucking in a drill clamped in
a vise, and using a file as a lathe
tool. This then gave a fitting for a
1/4" rod which is used as the shaft
to rotate the discs.
The rod was obtained from a local
hardware store and threaded its entire length except for the inch or so
which is inserted in the 1/4" bushing
on the motor. The shaft was cut approximately one inch longer than
necessary so that the excess length
could be chucked in a drill and the
far end turned down to 3/16" using
the file method. The excess length
was then cut off. The outer bearing
is a 3/16" bushing salvaged from an
old filament rheostat.
The discs were fashioned from
1/8" aluminum and were first cut out
using a 2-1/2" circular hack saw.
Each disc was then fastened to a
short 1/4" bolt, chucked in the drill,
and trued with a file, after which
all four discs were fastened on the
bolt together and turned to the
same diameter. The notches to operate the microswitches were made
with a rat tail file and are approximately 7/16" across and 1/8" deep.
The first disc has only one notch
and is used to control the power to
the motor. When the microswitch
1/8"
*Technical Supervisor, KMMJ,
Grand Island, Neb.
BROADCAST
28
www.americanradiohistory.com
ENGINEERING
%"
Dícx
Hole
Detai
I
On w
Off Disc,
Figure 2. Disc which operates the cam
operated switch and interrupts the
Detai Tone Disc
I
Figure 3.
Disc which
keys the tone
transmitter carrier.
signal.
roller is in the notch, the circuit to
the motor is broken and the motor
is started by either the push button
or the remote relay. As soon as the
microswitch climbs out of the
notch the motor will continue to
rotate until the switch again drops
into the notch or when it completes
one revolution.
The two middle discs control the
carrier off and on operations respectively and are identical, with
notches 10 seconds or 60 degrees
apart, the only difference being the
relative position of the notches with
respect to the rotation of the shaft.
It was found easier to cut one notch
in these discs, mount them in position on the shaft and with the
microswitch also in position, finding
the correct spot for the second notch
by running the motor and timing
with a stop watch. The notches can
then be touched up with a file and
the microswitch adjusted to get
exactly ten seconds between actuations. When one disc is completed
it can be used as a pattern for the
second disc. The details on this can
be seen by referring to the drawing
(Fig. 2) .
The fourth disc has a notch 15
seconds long or 90 degrees between
actuations and is used to control the
length of the tone by grounding the
grid of the amplifier stage until the
microswitch drops into the notch.
This notch was made by making
two notches 15 seconds apart using
the same method described above
and then filing out the material in
between as shown in Fig. 3 of the
drawing. All discs were then mounted on the shaft in their proper positions, as shown in the photo, by
using a hex nut on each side. By
loosening one nut the discs can be
rotated to obtain the proper relative
positions necessary to turn off the
carrier for 5 seconds, on for 5 seconds, off for 5 seconds, back on and
transmit a 1000 cycle tone for 15
seconds.
The microswitches used were Acro
Type RD -70-1S, Roller Type,
SPDT, and at $1.88 each are the
most expensive item in the unit.
They are mounted on right angle
brackets fashioned from 16 -gauge
sheet metal. Tht brackets are fastened to the sub -chassis by tapping
a hole for a No. 6 screw in the sub chassis with the hole in the bracket.
being slotted so that the position of
the microswitch relative to the
discs can be adjusted. Although this
system has been satisfactory so far
it could be improved upon by making the bracket wide enough so that
two screws could be used.
The tone oscillator, as can be seen
from the schematic diagram, is a
straight forward RC oscillator using
one section of a 12AX7, the other
section is used as an amplifier. The
parts arrangement is not critical,
however it is a good idea to mount
the middle condensers in the RC
network in an accessible location so
that the value can be changed to
adjust for proper frequency. The
values shown were determined by
zero beating against an audio oscillator. The maximum output of the
amplifier is plus 10 dbm and can be
varied over a wide range with the
gain control to cover most input ar-
rangements.
The power supply is not critical
and almost any booster or preamp
type power transformer with a
selenium rectifier and the necessary
filtering should be sufficient.
It will be noted that the micro -
switches are wired to actuate other
on and off relays. In our case these
are the Rust momentary type relays used in the Rust remote control system. This was a matter of
convenience since this then only involved the running of one low voltage cable between the transmitter
and the unit. Since the micro switches are SPDT, the contacts
can easily be arranged to work with
most momentary push-button
transmitter control systems by
changing the connections on the
"off" microswitch and connecting
in series with the "Plate Off" button on the transmitter. The "on"
microswitch with the connections
as shown can be connected across
the "Plate On" button.
Another little innovation incorporated into the unit as a safety
factor is the use of a DPST on -off
switch. As can be seen from the
schematic, when the switch is
turned off it not only opens the ac
to the tone oscillator but also
breaks the control circuit while the
motor circuit remains completed.
This is in case the actuating button
should be inadvertently pushed.
The unit can be immediately deactivated before it goes through the
entire cycle. The motor will continue to run until it completes its
revolution after which the on -off
switch may be turned back on. This
arrangement would have to be
changed slightly if the unit were to
be used to control the plate on -off
circuits directly instead of with the
Rust relays.
Final adjustment of the unit was
made with the unit hooked to the
transmitter and with the plate circuit -breakers open, the relay operation was timed with a stop watch.
It was necessary to make some
slight adjustments by rotating the
on -off discs on the shaft to compensate for the delay caused by relay
operation in the transmitter. When
adjusted the timing of the five second sequences was plus or minus
0.25 seconds. The tone level was
adjusted during the experimental
period for 75 per cent modulation
by temporarily removing one wire
from the tone microswitch and adjusting the main control. In our
case the audio is fed into the system through a spare channel in a
four-channel mixer which is part of
29
February, 1961
www.americanradiohistory.com
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On
Relay
-
Remote
Actuate
-IIR7
Sa.
C7
Motor
Winding
Figure 4. Schematic diagram of Conelrad unit which includes the
tone oscillator. Parts values are as follows.
R
R
R
R
I-47000
2-47000
ohms
ohms
3-270000 ohms
4-2200 ohms
R
5-2
R
6-47000
megohms
ohms
the audio system at the transmitter
and this channel is left switched in
at all times.
The remote actuating relay, if
desired, can be any relay which will
fit under the chassis with the coil
voltage determined by the control
voltage available.
This unit has been tinder weekly
CZ- ,Oaci
C
I,
C3-.001
-
mfd
C 4-25 mfd
C 5, C 6, C 7
.5 mfd
C 8, C 9-20 mfd
C 10-50 mfd
C II -.01 mfd
test for several months with one
failure due to a defective oscillator
tube.
Although this unit was first built
as a noble experiment and no further functions were contemplated
at the time, it readily lends itself to
further modifications by adding
extra discs and more microswitches
Figure 5. Panel view of Conelrad Attention Signal
shown mounted above limiting amplifier.
TI-Stancor A3250
T2-TV booster transformer
FSI-3
SRI
ampere
-50
ma selenium rectifier
47 pilot lamp
b, DPST toggle switch
PLI-No.
S
I
a, S
I
S2-Pushbutton actuate switch
S3abcd-SPDT microswitches
RYI-Remote operated relay
on the upper side to perform additional functions in conjunction with
Cone l ra d. For instance, another
microswitch mounted exactly opposite the motor control microswitch
can utilize the same notch in this
disc to actuate a tape playback
machine to broadcast a short Civil
Defense message.
Figure 6. Rear view of unit shown mounted in rack above
30
limiter.
BROADCAST
www.americanradiohistory.com
ENGINEERING
rr...
an additional phase
operation significant
of
..."
STUDIO PLANNING starts on page 12
evident that some of these features
would readily adapt themselves to
Plan "B." With the cross -application possibilities of these plans,
practically all programming requirements can be met.
Now that we have covered the
station's plant facilities, there is an
additional phase of operation that
is a very significant revenue producer in many markets, and that is
"on -the -spot" program origination.
This phase of operation may be di"ided into three categories:
1. "On -the -spot" tape recordingaccomplished with a portable tape
recorder for playback at a later
time.
2. Direct pickup at a remote location, using a remote amplifier and
telephone lines.
3. Direct pickup at a remote location using a radio link between
the remote point or program origination and the radio station. This
method of remote pick-up warrants
some discussion.
Remote Pickup Via Radio Link
Presently there is authorized by
the FCC several remote pickup
channels for use by the broadcaster.
Categorically, they fall into three
different frequency bands identified
as the 26 -mc band, the 150 -me band
and the 450 -mc band. Recently, the
450 -mc band has become the most
popular for this application. In this
frequency range there is less interference from man-made noise. The
equipment, especially the antenna,
is much smaller physically, so higher gain antennas can be conveniently used. The channels authorized in
this band are not shared by other
TRANSISTORIZED TUNERS AND AMPLFIERS
JE 100 MT
1
crystal controlled
automatic muting
14 Transistor Tuner
Sensitivity -2 microvolt at 20 db quieting
300 ohm balanced 70 ohm
Input
25000 ohms
Output
0.2 Volts RMS
88 to 108 MC
Frequency Range
Sub Carrier Frequencies 41 KC, 67 KC, etc.
All transistor construction and rugged
reliability. Cuts service calls as much as
-
Hum level reduced to absolute
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80%.
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Harmonic Distortion -_
Tone Control 0 to 35 db @ 7,500 cycles
-62 db
Noise and Hum ___
4, 8, 16, 400, 1600
Output Impedances
9"x7"x41/2"
51/4 lbs
117V - 60 cy
Frequency Response
Fully transistorized for infinite life expectancy and practically no maintenance.
Power requirements are minimal for low
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MA
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JE 25
Lo Z
1
microphones
25 Watt Amplifier
services.
It is necessary to file an applica Von with the FCC for authorizatio.ì
to use this service. At this time FCC
Form 313 is to be used for this purpose. With a little imagination
Rugged
many revenue-producing applications can be readily recognized. A
few well known ones are: sporting
events, special events, on -the -spot
accident and other newsworthy reports, traffic information during
rush hours, farm programs and origination of special shows directly
from sponsor locations.
action.
circuit
transistorized
-
eliminates microphonics
300-7,500 ± 3 db
Frequency Response
less than 1.5%
_
Harmonic Distorition
Bass Control -11 db to +12 db @ 50 cy
_
-13 db to -I- 15 db
Treble Control
@ 7,500 cy
4, 8, 50, -200
Output Impedances
(Minus 55 db)
Gain
(Hi Z micro 105 db)-(Lo Z micro 120 db)
14"x7"x41/2"
121/2 lbs.
117V 60 cy
completely
practically no
_
to replace-low maintecost-low power consumption-ex-
hum. No tubes
nance
tremely long
bass
life.
Separate
tone controls with
Protected by
3
_
treble and
boost and
cut
year warranty
-
6
months free service guarantee.
X1L.f OX1L
0lectronics,
Zc-
PRODUCTS DIVISION
62 so. Hiway 17-92 Casselberry, Florida (suburban Orlando)TErrace8-211
1
3I
February, 1961
www.americanradiohistory.com
".
JOHN SILVA,,
Chief Engineer
Paramount
Television
Productions:
w.....
i
..11...._..4._
fis
s-s ss
d f 4 4 411 4i..
4
4
In planning the new control
room for their famous Stage 6,
Paramount Television specified
only the best equipment manufactured. Included in this choice,
naturally, were Conrac video
monitors. Why Conrac? "Because of their unfailing ability
to display all the information
just as it is, without distortion,
and do it dependably day after
day after day," is the way John
Silva put it. Whether you're
building a new facility or expanding your present operation,
it will pay you, too, to select
Conrac - the finest in video
"For our new
control room,
CON RAC
MONITORS
were the
natural
choice..."
monitoring equipment.
EVERY CONRAC MONITOR FROM 8" THROUGH 27" BROADCAST
OR UTILITY includes these
important features:
*
*
Video response flat to 10 megacycles
*
Provision for operation from external
sync with selector switch
*
Video line terminating resistor and
DC restorer
- with "In -Out" switch
-
switch
Conrac Monitors Are Distributed by
cowrSP.4c, INC.
-
RCA
GENERAL ELECTRIC
AMPEX and
VISUAL ELECTRONICS
Makers of Fine Fleetwood Home Television Systems
Dept. K, Glendora, California
TELEPHONE:
COVINA,
CALIFORNIA,
EDGEWOOD 5.0541
site selected offered a
good receiving location . . ."
.
.
STEROPHONIC starts on page
and 2) show the facilities and
www.americanradiohistory.com
I
st
equipment used at the KDKA-FJI
transmitter in Pittsburgh. Figure 3
shows the facilities used at the
Uniontown receiver site.
Selection of the Uniontown Motel in Uniontown, Pa., for the reception test site was based on its
affording a good receiving location
for the three field strength conditions (1,000, 200 and 50 microvolts
per meter) and living accommodations. For 1,000 microvolts field
strength levels a Channel Master 5 element FM Yagi antenna (furnished by General Electric) was used
at a height of approximately 20 ft.
above the ground. The low field
strength levels were obtained by
lowering the antenna height to 10
ft. and 40 inches above ground level,
respectively. It was originally intended to utilize a dipole antenna
at the receiving site. But initial tests
resulted in such great inultipath effects because of the terrain surrounding Uniontown that a more
directional antenna proved necessary in order to measure accurately
such parameters of the system as
distortion, crosstalk, etc.
In addition to the measurements
already mentioned, recordings of
each system were made at both the
transmitting and receiving site for
subjective evaluation of the monophonic main channel, the simultaneous stereophonic transmission
and an unrelated program on the
67 kc. SCA multiplex channel.
Representing the FCC at the
tests were Harold L. Kassens, chief
of aural existing facilities branch of
the broadcast facilities division;
John T. Robinson, office of chief engineer, and Commissioner Robert T.
Ba rtley.
For subjective program quality
evaluation of the systems, panelists
used a 4e -minute test tape prepared
by F. K. Harvey under the direction of Dr. M. R. Schroeder of Bell
Telephone Laboratories. The test
tape included signals for adjusting
the azimuth of the reproduce head,
reference level tones, white noise
and stereophonic recordings of representative types of music at widely
separated dynamic levels.
BROADCAST
32
2
ENGINEERING
Reproduction of the test tape and
all related recording was handled by
Ampex Model 354 two -channel recorder/reproducers, featuring electronic circuitry specifically designed
for recording and reproducing stereophonic programs.
At the KDKA-FM transmitter,
three Ampex 354's were used-one
for reproducing the test tape, one
for recording the stereophonic transmission and one for recording the
monophonic and SCA transmissions.
At the Uniontown receiving site,
one Ampex 354 was used to record
the stereophonic program while a
second 354 recorded the monophonic
main channel as well as the SCA
reception.
One wing of the motel served as
the receiver laboratory as well as
living quarters for some of the field
test personnel. The Yagi receiving
antenna required to reduce multipath effects was mounted on an adjustable mast situated on a small hill
behind the building. This antenna
fed an impedance matching transformer and a 200 -ft. length of 75 ohm coaxial line which terminated
in a distribution -attenuation box in
the receiver laboratory. This box, in
turn, fed the RCA field strength
meter directly, whereas baluns again
were used to feed the respective 300 ohm receiver inputs.
A Fisher and a Graneo FM tuner
were used for receiving all compatible monophonic main channel transmissions. The 67 kc multiplex program was received by a Bogen SCA
receiver. The outputs of the stereophonic receivers were measured
through isolation amplifiers supplied
by H. H. Scott, Inc.
All of the receivers had been calibrated previously in the H. H. Scott
laboratory as an assignment of the
receivers subcommittee. Although
this materially reduced the work of
the field test group, more than 3200
measurements were made at Uniontown to evaluate the respective systems.
Once the FCC establishes a standard and compatible monophonic and
stereophonic broadcasting becomes
a reality, present day FM receivers
will receive a monophonic rendition
of stereo programs, while new FM
receivers, or older FM receivers
fitted with inexpensive adapters,
will receive the full stereo broadcast.
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UNIVERSITY..
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33
February, 1961
www.americanradiohistory.com
ITA...
AMENDMENTS AND PROPOSED
WORLD LEADER
CHANGES OF F.C.C. REGULATIONS
IN FM BROADCAST
REQUIREMENTS FOR FREQUENCY
TRANSMITTERS
OFFERS YOU
...
MONITORS
Order Extending Time for Filing Comments
lu the matter of amendment of Part
of the Commission rules governing
TV Broadcast Stations concerning requirements for frequency monitors.
3
The Commission has before it for
consideration a request of the National
Association of Broadcasters (NAB)
filed on December 20, 1960 for an extension of time within which to file
comments in the above -entitled proceeding from December 26, 1960 to
March 13, 1961.
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on
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For detailed information on any of our FM transmitters call collect or write us.
AINDUSTRIAL TRANSMITTERS
AND ANTENNAS, INC.
LANSDOWNE, PA.
PHONE: CL 9-8200
NAB states that it contemplates submitting the proposal outlined in the
proceeding to its Engineering Advisory
Committee but that, due to the holiday
season, this cannot be done in time to
submit comments by the date set by
the Commission. It urges that the grant
of the additional time will enable it to
submit information which will assist the
Commission in reaching a final decision in this matter.
The Commission is of the view that
the public interest would be served by
granting the requested extension of
time in order that parties may have the
fullest opportunity to submit meaningful and useful data on the proposal
which would have an impact on the
television broadcast industry. NAB
points out further that the present
rules waive the requirement for television broadcast stations to install
type -approved frequency monitors to
February 28, 1961 and that a grant of
the instant request would require an
extension of the waiver. This may,
however, be accomplished at a later
date by separate order.
In view of the foregoing: it is ordered,
This 21st day of December, 1960, that
To Keep -Up -to-Date
on the Latest Developments
in Broadcasting
Are a
Subscriber to
Be Sure You
BROADCAST
ENGINEERING
the request of National Association of
Broadcasters for an extension of time
is granted, and that the time for filing
comments in response to the Notice of
Proposed Rule Making is extended
from December 26, 1960, to March 13,
1961, and the time for filing reply comments is extended from January 6, 1961,
to March 23, 1961.
CONELRAD DRILLS AND TESTS
Operator Requirements
1. The Commission has before it for
consideration a proposal to amend the
operator requirement rules insofar as
they pertain to standard broadcast station operation in the Emergency Broadcast System.
2. The Commission, on January 26,
1953, in Docket No. 10214, amended
Parts 3 and 13 of its rules to provide
that a person holding any class of radio
operator license (or permit) who is authorized to perform limited operation of
a standard broadcast station, may
make adjustments "when a CONELRAD Radio Alert is called * * *" provided that the station's responsible
radiotelephone first-class operator shall
have previously instructed such person
in the adjustments to the transmitter
which are necessary to accomplish
CONELRAD operation.
3. Under the provision of the above
rules, a holder of a restricted radiotelephone operators permit may switch
the broadcast transmitter to the Emergency Broadcast System frequency, in
the event of a real CONELRAD Radio
Alert, but does not permit such an operator to make the necessary transmitter adjustments in order for the station
to take part in a test or drill of the
Emergency Broadcast System.
4. Emergency Broadcast System drills
have been conducted during the past
years in accordance with the provisions
of § 3.971. There is reason to believe
that such drills will continue to be held
in the future under the provisions of
§ 3.970. Many stations conduct tests of
the Emergency Broadcast System on a
local basis as well as on state and
regional basis.
5. Many of the CONELRAD tests
have been called when the required
radiotelephone first-class operator was
not available and thus authorized stations were unable to participate in the
necessary tests. The same situation occurred in many instances during the
once a year drills.
BROADCAST
34
www.americanradiohistory.com
ENGINEERING
6. In order to properly train lesser
grade operators and to keep them
familiar with the necessary Emergency
Broadcast System operating procedure
as well as to insure operation by all stations having a National Defense Emergency Authorization, it appears necessary to amend the rules to provide that
the lesser grade operator may make the
necessary transmitter adjustments in
order to participate in tests and drills
of the Emergency Broadcast System, as
well as during a real CONELRAD
Radio Alert.
7. The Commission is of the view
that a rule -making proceeding should be
instituted in this matter in order that
interested parties may submit their
views on the proposed amendments as
set forth below.
8. Authority for the adoption of the
proposed amendments is contained in
sections 4 (i) , 301, 303 (b) , (c) , (f) ,
and (r) of the Communications Act of
1934, as amended.
9. Pursuant to applicable procedures
set out in section 1.213 of the Commission's rules, interested parties may
file comments on or before January 23,
1961, and reply comments on or before
February 3, 1961.
10. In accordance with the provisions
of § 1.54 of the rules an original and 14
copies of all written comments shall be
furnished the Commission.
1. It is proposed to amend that portion of § 3.93 (b) , which precedes subparagraph (1) , to read as follows:
4
3.93
previously instructed such person in the
adjustments to the transmitter which
are necessary to accomplish operation
in the Emergency Broadcast System.)
Adjustments of transmitting equipment
by such operators, except when under
the immediate supervision of a radiotelephone first-class operator, shall be
limited to the following:
2. It is proposed to amend § 13.62 (d)
to read as follows:
§
Special privileges.
13.62
*
*
(d) When a CONELRAD Alert, or a
drill, or test of the Emergency Broad-
FROM
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MODEL AM -5116-B
Interchangeable as High
Gain Preamplifier, Regular
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FOR PROFESSIONAL RECORDING
TV -BROADCAST AND MUSICASTING
Use only one amplifier for all purposes up to buss level of +24 dbm.
Operator requirements.
*
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LOW NOISE
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(b) A station which is authorized for
non -directional operation with power of
10 kilowatts or less may be operated by
persons holding commercial radio operator license of any class when the
equipment is so designed that the stability of the frequency is maintained by
the transmitter itself within the limits
of tolerance specified, and none of the
operations, except those specified in
subparagraphs (1) through (4) of this
paragraph, necessary to be performed
during the course of normal operation
may cause off-frequency operation or
result in any unauthorized radiation.
(A person holding any class of radio
operator license or permit who is authorized thereunder to perform limited
operation of a standard broadcast
station may, when a CONELRAD
Radio Alert is called, or for the purpose
of participation in a drill or test of the
Emergency Broadcast System, make
adjustments necessary to effect operation in accordance with a National Defense Emergency Authorization: Provided, That the station's full-time radiotelephone first-class operator shall have
*
*
cast System is called a person holding
any class of radio operator license or
permit who is authorized thereunder to
perform limited operation of a standard
broadcast station may make any adjustments necessary to effect operation
on an Emergency Broadcast System
frequency in accordance with the station's National Defense
mergency
Authorization: Provided, That the station's responsible first-class radiotelephone operator (s) shall have previously
instructed such person in the adjustments to the transmitter which are
necessary to accomplish operation in
the Emergency Broadcast System.
-123
transformers
UNIFORMITY Each amplifier identical through precision printed
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NO OSCILLATION Phase shift only 85° at 20 kcps
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FREE Write Today! $1.00 Value -84 Page Professional
Audio Equipment Catalogue covering Low -Level Amplifiers,
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and Low Pass Filters, VU Meters and Panels, Plugs, Patchcords.
Jacks and Jackstrips, Telephone Keys, Transformers, Precision
Instrument Switches and complete line of new Langevin Attenuators, Pan -Pots, Straight Line and Rotary Mixers, VU Range
Extenders and many others.
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A Division of Sonotec
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AVENUE
February. 1961
SANTA
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pr'+.,
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CALIFORNIA
35
www.americanradiohistory.com
NAB Asks Rule Making
On Automatic Logging
Ind.uathy Neure
Altec Advances Sales Executives
Effective Jan. 1, 1961, Altec Lansing Corp.'s president, A. A. Ward,
announced the appointment of H.
S. Morris as marketing director for
the corporation. Concurrent with
this appointment is that of G. L.
Carrington, Jr., as general sales
manager.
H. S. Morris has served as product sales manager for Altec for the
The National Assn. of Broadcasters has filed a petition for rule making with the Federal Communications Commission asking that electro -mechanical automatic logging
devices be allowed in lieu of manual
logging for the required recording
of operational measurements in radio and television stations.
Under current FCC rules, operating logs must be kept manually.
Granting of the request for rule
making would give licensees the au-
thority to maintain their operating
logs either manually or with new
automatic logging systems.
H. S. Morris
G. L.
Carrington, Jr.
past 18 years and will direct the
enlarged sales activities from the
corporate offices in Anaheim, Calif.
H. S. Morris has had extensive field
sales and marketing experience and
is an alumnus of the Graduate
School of Sales Marketing and
Management at the University of
Syracuse.
G. L. Carrington, Jr., has served
with Altec as commercial and marketing manager for the past eight
years with prior experience in both
its engineering and production de-
partments.
THE FINEST OF ITS
KIND
SINGLE FREQUENCY AND BROAD-
BAND FM RECEIVING ANTENNAE
HIGH GAIN YAGI, CUT TO YOUR FREQUENCY FOR LONG DISTANCE PICKUP.
HEAVY DUTY DESIGN FEATURING ALL
STAINLESS STEEL HARDWARE.
Literature
on request.
Send 304 for booklet
on FM Antennae and
FM Reception.
00
APPARATUS DEVELOPMENT CO.
WETHERSFIELD 9, CONN
A. Prose Walker, manager, and
George Bartlett, assistant manager
cif the NAB engineering department,
cited specific examples of superior
accuracy by the automatic systems
over manual methods in exhibits
made a part of the petition. Many
of the exhibits were in the form of
automatic and manually kept operating logs submitted by those stations participating in the experiment for the NAB. Among those
stations were: WSJS, Winston-Salem, N. C.; WTOP-AM-FM-TV,
Washington, D. C.; WIP, Philadelphia, Pa.; and KFI, Los Angeles,
Calif.
The petition was filed after many
months of experimental operation
of the equipment. Members of the
NAB engineering staff followed the
progress and success of the automatic loggers with an eye to adoption of this system by member stations, and the broadcast industry as
a whole.
The logging apparatus, manufactured by the Broadcast Division of
Radio Corp. of America, Texas Instruments Inc., and the Brown Instrument Division of Minneapolis Honeywell Regulator Co., was successfully operated at several radio
and television stations, at both the
transmitter site, and through remote lines at the studio site. In the
case of remote operation, the automatic logging equipment used existing control lines to the transmitter
site, so the need for additional lines
was eliminated.
The automatic loggers can be installed to record all parameters normally entered manually. It records
such readings as output current,
final stage plate current and voltage.
obstruction lighting, frequency deviation, operating hours, and any interruptions to the carrier. In tests,
all readings were recorded with an
unusually high degree of accuracy,
and all at the precise times called
for by the operating logs or sooner.
The petition said this logging system is an extension of actual remote
control of equipment, and this control has not brought about any degradation in the technical operating standards of stations. It added
that this system would virtually
eliminate improperly maintained op-
erating logs, the most cited category
of violation of FCC rules.
Included within the petition for
rule making was a request that the
FCC relax its rules concerning frequency deviation readings for AM
broadcast stations. More than 1700
stations reported to NAB that a
six-month average deviation rarely
exceeded plus or minus three cycles
per second. The NAB had asked in
an earlier petition that AM broadcast stations be permitted to make
entries of frequency deviation only
at the beginning and end of each
broadcast day, or in the case of 24
hour stations once in each 12 -hour
period. In reviewing the earlier petition, the Commission left the door
open to further consideration when
the information on automatic logging was filed by NAB.
ITA, Inc. Appoints
New Sales Director
Bernard Wise, president of ITA,
Inc., Lansdowne, Pa., one of the
world's largest manufacturers of
broadcast transmitters, has announced the appointment of R. Paul
Comstock, Jr., as director of sales.
In his new position, Comstock will
direct and coordinate the activities
of the company's three sales divisions
broadcasting, government
and industrial, and export. Joseph
Novik continues as manager of
broadcast sales and Eliot Baker as
manager of government -industrial
-
sales.
Comstock comes to ITA, Inc.,
from Schafer Engineering, a division
of Textron Electronics, where he
was marketing manager.
-
Try Classified Ads
They Get Results!
BROADCAST ENGINEERING
36
www.americanradiohistory.com
NAB Opposes FAA
Hearings on Tall Towers
The National Assn. of Broad-
casters has opposed as unnecessary
and tremendously wasteful in time,
money and manpower a proposal
for formal hearings by the Federal
Aviation Agency in determining
whether new broadcast towers
would constitute a hazard to air
safety.
The association also suggested
several modifications of other FAA
proposals concerning heights and
locations of tall structures. NAB
said the modifications would assure
"fair and equitable" treatment for
all parties concerned.
NAB's position was outlined in
testimony by Charles H. Tower, its
vice-president for television, at an
FAA hearing.
Mr. Tower was accompanied by
A. Prose Walker, NAB manager of
engineering, and Douglas A. Anello,
NAB chief counsel.
Mr. Tower said broadcasters believe that a procedure which would
produce a decision on tower structures "quickly and informally"
would be advantageous not only to
their industry but to aviation as
suggested modifications in FAA's
proposed rules for evaluating the
aeronautical hazards of proposed
towers and other tall structures. If
adopted, he said, the procedures
then would be "fair and equitable."
It would work this way:
Applicants and those who might
have objections should appear in
person at an informal hearing in
the area prepared to cite the facts
and to answer questions posed by
others.
Findings should be sent to Washington within 20 days, with copies
mailed to each participant.
Participants would have 20 days
after receipt of the findings to file
their comments with the Washington office.
FAA's Office of Airspace Obstruction Evaluation would issue its
findings to the FCC and, in case of
an adverse recommendation, would
recite the facts used in reaching its
conclusion, cite changes in air operations necessary should the construction go through, and state the
maximum height and location the
FAA would approve, along with
suggested alternate locations.
1961 IRE
International
Convention Set for March 20-23
March 20 through 23 have been
selected as the dates for the 1961
IRE International Convention,
which will again be held at the Waldorf-Astoria Hotel and New York
Coliseum in New York City. More
than 70,000 engineers and scientists
from 40 countries are expected to
attend what has become the world's
largest technical meeting and exhibition.
A comprehensive program of 275
papers, covering the most recent developments in the fields of all
IRE Professional Groups, will be
presented in 54 sessions at the Waldorf-Astoria and the Coliseum. The
high point of the program will be a
special symposium on new energy
sources to be held Tuesday evening,
March 21, at the Waldorf. The complete program will be announced in
e
January.
The IRE Show, filling all four
floors of the Coliseum, will accomodate approximately 850 exhibitors.
Some $15,000,000 worth of the latest
electronic equipment will be on display, most of it for the first time.
well.
Noting that the Federal Communications Commission is the final
authority on granting broadcast licenses and must hold a hearing on
the evidence before denying an application, he said an "elaborate and
extremely formal" hearing by the
FAA on the very same issue would
be an unnecessary duplication of
effort.
"The requirement that two hearings be held," he added, "would
only serve to make even longer an
already time-consuming procedure
and would seem to be a tremendous
waste of manpower, time and
money from both the governmental
and industry point of view."
Mr. Tower also suggested elimination of an FAA proposal to require broadcasters to notify the
FAA administrator of any proposed
construction or alterations that
might involve a hazard to air navigation. He said the proposal is unnecessary since such notice to the
FCC already is required and the
FCC never acts on such applications until it receives the FAA's
views.
The
NAB
vice-president
Let This Emblem Be Your
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February, 1961
37
www.americanradiohistory.com
THE REMARKABLE
SONY RADIO
WIRELESS
MICROPHONE
The convenience and variety of uses for
this remarkable instrument are almost
beyond the imagination. The Sony CR -4
mike and radio transmitter can be
slipped into a coat pocket for completely
wireless on -the -street interviewing,
studio audience interviewing or on -thespot broadcasting from awkward places.
It gives complete freedom to active
singers, dancers, comedians, performers
with electric instruments and actors,
eliminating the need for cumbersome
mike booms and entangling wires.
Microphone, transmitter, receiver and
carrying case, $250. For information or
literature, write: Superscope, Inc., Dept.
E, Sun Valley, California.
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for your tower
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check
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SYSTEMS
complete tower
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ENGINEERING
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NEW AUTOMATIC TAPE UNIT
A new model of Collins Radio Co.'s auto-
SERVICE
matic tape programming equipment was introduced to broadcasters during the 1960
NAB Fall Conferences. The equipment, now
in production, features an improved record/
playback assembly superior to the original
model introduced to the broadcasting industry by Collins 11/2 years ago.
The record/playback assembly of the
new Collins automatic tape programming
equipment is mounted on a machined, cast
aluminum deck which increases the precision of the unit. An adjustable capstan
sure to obtain price quotations and engineering assistance for your complete tower
needs from America's foremost
tower erection service.
Be
Advehtieems Index
Altec Lansing Corp.
Ampex Professional Products Co.
Audio Div.
25
:3
Apparatus Development Co., Inc..
27
36
Bauer Electronics Corp.
Burke & James, Inc
39
CBS Electronics
11
Video Div.
19
Collins Radio Co.
Conrac, Inc.
Continental Electronics Mfg. Co
9
32
38
39
Continental Mfg. Co
Ford, Paul Dean
Foto -Video Electronics, Inc.
Industrial Transmitters
Antennas, Inc.
SON
SUPERSCOPE
7hr Tupewuy lu .Slerea
M AGNtPHASE
MAGNI
PHASE
y
40
IFC
&
34
James, Vir N.
Jampro Antenna Co
Johnson Electronics
40
40
31
Langevin, Inc. Div. of Sonotec, Inc.
35
Radio Corp. of America
Rohn Systems, Inc.
38
Sarkes Tarzian, Inc
Sonocraft Corp.
Superscope Inc.
Telechrome Mfg. Corp.
Visual Electronics Corp.
University Loudspeakers Inc.
21, IBC
37
LINE PROTECTION SYSTEM
-
MAGNIPHASE
protects antenna system
from damage caused by static discharge or
transmission line faults.
MAGNIPHASE
will instantaneously
squelch transmitter output, preventing arc
from being sustained by RF energy.
Immediately self -restoring, transmitter
interruption goes unnoticed on the air.
40
38
BC
40
33
MANUFACTURING COMPANY
4212 SOUTH BUCKNER BLVD.
gi
BROADCAST
38
www.americanradiohistory.com
DALLAS 27, TEXAS
SUBSIDIARY OF LING-TEMCO ELECTRONICS. INC.
ENGINEERING
pressure roller and its linkage system are
powered by a heavy duty solenoid that has
withstood two million test activations without showing any appreciable wear.
The unit is powered by a Bodine synchronous motor driving a balanced, solid brass
flywheel. The tape speed of 71/2 inches per
second is 99.6 per cent accurate with less
than 0.2 per cent wow and flutter. The driving torque of the flywheel permits syllable splitting cueing and a start and stop time
of less than 0.1 second.
Frequency response is ±2 db at 70-12,000
cps, with a signal-to-noise ratio of 55 db or
better. Silicon diodes are used throughout
in the power supplies. Various auxiliary
connections are built-in for remote operation and sequencing of multiple units.
Cueing is a completely automatic process.
Tone bursts recorded on the bottom half of
the endless tape, contained in a cartridge,
cue it for the next play or for activating
other units.
NEW TELEPHOTO LENS
Zoomar, Inc., of Glen Cove, N. Y., and
Hollywood, Calif., originators of the first
zoom lens for motion picture cameras, has
announced its latest development in high
precision optics-the F/4 -20 -inch Zoomar
Reflectar. The new lens is light, compact,
and apochromatically corrected. It has an
internal focusing device like all the high
precision Zoomar lenses, has great resolving power, brilliance, and easy adaptability
to all types of motion picture and ITV cameras. All lens elements are anti-reflection
coated.
Several of the most important features of
the lens include: Adaptability to all types
of 16mm and 35mm motion picture and TV
cameras; high resolution resolving power;
compactness and light weight
. distance
from front to film plane -14 inches; outside
diameter
61/4 inches; weight
approximately 7 lb.; closest focusing distance -500
ft. A filter frame or filter wheel is available
as optional equipment.
-
precisely in proper sequence, handling a
number of spots that can range from five
second to five minute duration. Engineered
for simplicity of operation, Quick-Q requires
only insertion of desired cartridge and depressing of a conveniently placed starting
lever to become "airborne."
For further information write to the C. H.
Alvord Co., 1000 Farmington Ave., West
Hartford, Conn.
-
TAPE CARTRIDGE UNIT
The C. H. Alvord Co. announces Quick-Q,
a compact, packaged instrument designed
to speed and simplify radio stations' use of
spot commercials.
A tape cartridge unit, Quick -Q performs
NAGRA III B RECORDER
Shown above is a view of the Nagra
portable recorder. The tape is driven by a
dc motor, speed is electronically stabilized
by a transistorized FM tachometer and
servo-amplifier. Response at 15 ips is 30
to 15,000 cps plus or minus 1.5 db. At 7.5
ips the response is 40 to 12,000 cycles. Further information is available from Electronic Applications, Inc., Stamford, Conn.
The -Shelf
IMME-ORTHICON,
VIDICON
SENSES
L,
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FOR MULTIPLEXING!
If you are looking for the multiplex receiver that provides
the greatest sensitivity ... is the most dependable ... look
to McMartin,the standard of the industry.
Continental's advanced engineering... rigid quality
control ... special manufacturing techniques assure receiving equipment that will deliver the finest in sound
over the greatest distances. What's more, McMartin
guarantees your satisfaction. Send back any unit that
does not function properly (at McMartin's expense) and
it will be repaired or replaced free of charge.
Image Orthicon Lenses
from World's Greatest Selection ...
choose from 28mm focal length to
60"
delivered right " Off-TheShelf' at B & J World's Lens Headquarters!
Here, you'll find the lens you need
for practically ALL T.V. Cameras,
...
R.C.A. (TK -41, TK -11); G. E. Black
and white or color; Du Mont, etc.!
Rely on the Industry's Prime Optics -Source . . . Pioneers in T.V.
Optics Since 1936 and currently
serving such stations as WGN,
VJNBQ, ETC.
Our Instrument Shops and "Knowhow" offer you Special Mountings,
Calibration and Custom Fittings!
(Also Cine' & Slide Equipment for
your News Dept.!)
Write for New T.V. Optics Catalog.
BURKE & JAMES, INC.
321 S. Wabash, Chicago 4. III.
Carl Schultz and McMARTIN Receiver
Says Carl Schultz, of Business Music, Inc., Meriden, Con-
necticut, "We have found that the McMARTIN receiver
surpasses any other in overall reliability and fringe area
reception."
CONTINENTAL MANUFACTURING, INC.
1612 California Street
February, 1961
Omaha, Nebr.
39
www.americanradiohistory.com
Pkdii
New
eto,44
BUY, SELL OR TRADE
-
Advertising rates in the Classified Section
are ten cents per word. Minimum charge is
$2.00. Blind box number is 50 cents extra.
Check or money order must be enclosed
with ad.
EQUIPMENT FOR SALE
Brand new dehydrators, with spare parts
kit. Take your pick of Dielectric Products
Model 22 for $150 or Andrews 1910 for
$135. P & O Sales, 1236 - 40th Avenue, Sac1-61 3t
ramento 20, California.
Magnecord 8 hour automatic players $350,
brand new, originally $800, make excellent
spare machine for Multiplex operators.
Station KCFM, 532 DeBaliviere, St. Louis,
1-61 2t
Mo.
PARABOLIC ANTENNA PROTECTOR
Tower Construction Co., Sioux City, Iowa,
has devised an inexpensive means of protecting parabolic antennas from the buffet-
ing of severe winter weather.
Protection can now be obtained with a
parabolic antenna cover, which is cone
shaped and made with molded fiberglas.
According to Tower engineers, the fiber glas Para -Dome costs from 35 to 50 per cent
less than other protective type covers.
The Para-Dome has been designed to
withstand wind force of 50 lb. per square
foot. Tests have proved that signal attenuation between 2000 and 6200 megacycles
is within .1 db.
Officials at Tower pointed out the Para Dome is available for use with reflectors
of 4 ft., 6 ft., 8 ft., and 10 ft. sizes. Special
sizes are available on request.
Additional information can be obtained
by writing Tower Construction Co., 2700
Hawkeye Drive, Sioux City, Iowa.
MICROWAVE BROCHURE
Electronic Systems, a division of Mechanical Products, Inc., Jackson, Mich., offers a
descriptive brochure describing its new line
of microwave equipment. The microwave
systems operate in the 10,500 to 13,200
megacycle range for point-to-point FM
transmission of television signals, one-way
voice communications channels and data
channels. Power output is 0.1 watt and the
baseband width is 5 megacycles.
Perfect Condition Fairchild 524A two speed
Lip -Sync turntable, Presto RC -10-24 studio
tape recorder, Altec M-11 condenser microphone system, RCA 44BX microphone.
Original cost $2,500, will sell $1,200. Reco Art Sound Studios, 212 North 12th St.,
1-61 2t
Philadelphia, Pennsylvania.
Commercial Crystals and new or replacement crystals for RCA, Gates, W. E. Bliley
and J -K holders; regrinding, repair, etc.
BC -604 crystals. Also A.M. monitor service.
Nation-wide unsolicited testimonials praise
our products and fast service. Eidson Electronic Company, Box 31, Temple, Texas.
12-60 tf
Motorola Mobile 152-174 MC System. Two
sixty watt base stations, with sensicon receivers, Models PA8491BP, and TA -192
(with AC and DC power supply) PA -8270
remote control console. Three bay, high
gain Coaxal antenna, 100 ft. of Coaxal system presently operating on 166.25 MC, for
broadcast remote pickup. Only two hundred hours operating time. Priced low. Call
or write chief engineer, WWOK, Charlotte,
2-61
N. C.
It
HELP WANTED
EDITOR.-Technical magazine in communications field offers real opportunity to
man with knowledge of AM, FM and TV
industry operations. Engineering background desirable but not essential. Industry experience counts most. Should be
able to write and to enjoy editorial work.
People with experience in editing industry
house organs will find this position of particular interest. Salary commensurate with
ability. Steady advancement. Send complete resume and indicate salary desired.
Broadcast Engineering. Dept. 77, 1014
Wyandotte St.. Kansas City 5, Mo. 2-61 lt
Major TV and FM Transmitter Manufacturer seeking representatives to sell TV
and FM Transmitters to the Broadcast Industry. Only those selling to the Broadcast
Industry with companion items need apply.
Good opportunity! Broadcast Engineering,
2-61 2t
Dept. 76, Kansas City 5, Mo.
S
Our thanks to the 63 broadcasters who purchased
ONOC
Will buy or trade used tape and disc reAmpex, Concertone,
cording equipment
Magnecord, Presto, etc. Audio equipment
for sale. Boynton Studio, 10 -BE Pennsyl11-60 4t
vania, Tuckahoe, N. Y.
SERVICES
Cambridge Crystals Precision Frequency
Measuring Service. Specialists for AM -FM TV. 445 Concord Ave., Cambridge 38, Mass
3-60 12t
Phone: TRowbridge 6-2810.
NO.
Record Playback Combo Unit.
For Details or Demonstration,
Write
VISUAL ELECTRONICS, CORP.
,
.
,-
a:,r\\, loth St.,NewYorkl8,N.Y.
Classified Ads in
BROADCAST ENGINEERING
Get Results!
pitairQaeiunae Sentic,al
PAUL DEAN FORD
Broadcast Engineering Consultant
4341 South 8th Street
in 1960.
Specialty
Directional Antennas
232 S, JASMINE
DExter 3.5562
DENVER 22, COLORADO
QFT
MN6 PRO FSSIONAIOURCE
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PROGRAM EQUALIZERS
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MONITOR AMPLIFIER 680
TRANSCRIPTION TABLES
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ENGINEERING
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LONGER LIFE
RCA -6166-A/7007
To replace RCA
EXPECTAN
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THAN EVER
BEfOR
First there was the RCA-6166. It gave, and is still
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technology demanded more:
It demanded more rugged construction
It demanded longer life expectancy
It demanded higher voltage and plate dissipation ratings
To meet these demands-to fill these needs-we proudly announce the new RCA -6166-A/7007, a forced -air-cooled beam
power tube.
Designed for vhf service in television and as an rf power amplifier in cw applications, this new tube features: Maximum plate
dissipation of 12KW Coaxial -electrode construction Large area, low -inductance rf electrode terminals And efficient
external radiator for forced -air cooling.
The RCA-6166-A/7007 can deliver a synchronizing-level
power output of 14KW in broad -banded television service at 216 Mc; a carrier power output of 6KW in plate modulated telephony service using conventional grid drive circuits operating at 60 Mc; and a power
output of 12KW in class C telegraphy service
using grid-drive circuits operating at 216 Mc.
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RADIO CORPORATION OF AMERICA
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ADVANTAGES
Easily broad -banded
Improved life expectancy
Ceramic -metal construction
provides extra safety factor
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Has a higher voltage and plate
dissipation rating (with lower
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Wide terminal contact surface
Silver plating for superior rf
conductivity
For more information, contact
your RCA Broadcast Tube
Distributor, or write Commercial Engineering, RCA
Electron Tube Division,
Harrison, N. J.
cr
CD
UCa
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