44-3/g`7g~0A-d - American Radio History

44-3/g`7g~0A-d - American Radio History
B ROADCAST
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"44-3/g'7g~0A-d
VOLUME N0. 91
OCTOBER, 1956
www.americanradiohistory.com
Into sales tools
turns your recepvers
RCA House Monitoring
...TELLS HOW STATIONS
CAN GIVE SERVICE
THAT RATES HIGH WITH CLIENTS
"Tune in Your Time Sales" describes the benefits of the RCA House
Monitoring System. It points out that with such a system the television station is better equipped for serving clients efficiently.
Your
Off -Air Signal
You can dial any local on -air signal ... any studio signal wherever
yod happen to be in the station. What a service to sponsors this is in
program planning! When a question is asked about other stations ...
competing programs ... you're there with the proof! In special presentation in your own studio, or in viewing commercials, it's a tremendous assist to be as close to the "on -air" result as your nearest monitor.
Up to seven channels are available -tailored to your own special
requirements. You can flip the switch and bring in whatever your
client requires.
Film Preview
Fully rated for color, the RCA House Monitoring System is low in
cost and easy to install and operate. Complete technical description
of the equipment is included in this booklet.
Ask your Broadcast Sales Representative for a copy.
RADIO CORPORATION of AMERICA
BROADCAST AND TELEVISION EQUIPMENT
CAMDEN, N. J.
Special Client Presentation in Your Studio
In Canada: Write
RCA VICTOR Company
Limited, Montreal
www.americanradiohistory.com
Vol.
October, 1956
No. 91
BROADCAST NEWS
published by
RADIO CORPORATION OF AMERICA
BROADCAST
PRICE
&
TELEVISION EQUIPMENT DEPARTMENT
CAMDEN, NEW JERSEY
In continental U.S.A.
- --
In other countries
$4.00 for
12 issues
$5.00 for 12 issues
C O N T E N T S
WWJ-TV--A CUSTOM STUDIO INSTALLATION
6
PROGRESSIVE WHLM AM -FM KEYNOTES QUALITY OPERATION
WEIL -TV PROGRAMS LOCAL LIVE COLOR
.
.
.
.
.
.
RCA NOW USING 750 -MESH SCREEN IN TV CAMERA TUBES
.
.
.
.
.
.
.
.
.
.
.
.
.
.
WRC -TV FIRST STATION DESIGNED SPECIFICALLY FOR COLOR
WRCV -TV NOW BROADCASTING IN COLOR
.
.
.
.
.
WHYY -PHILADELPHIA'S FIRST EDUCATIONAL TV STATION
24
.
TWENTY -FIVE YEARS OF BROADCAST NEWS
THE DEVELOPMENT OF THE COLOR MARKET
1500 MILLIAMPERE POWER SUPPLY
FOR BROADCAST TV USE
.
.
27
28
29
30
31
32
by Thomas F. Joyce
40
by R. T. Ross & I. W. Wentworth
44
by F. E. Talmage
48
by Paul A. Greenmeyer
& Louis T. Iglehart
56
.
.
LATEST DEVELOPMENTS IN VHF
TELEVISION TRANSMITTERS
TV AND THE CRISIS IN EDUCATION
.
Copy lebt P.. :e. nadio Corporation of America. Broadcast
"reo
.
.
.
& Television Equipment Department, Camden. N. J.
Unlimited system
plus superb picture quality...make RCA best
Improved technical quality in your film programs need not require a big investment
ICONOSCOPE CONVERSION
You can start simply and build gradually, if you prefer,
first by converting iconoscope film cameras to RCA
vidicon film cameras. You'll get marked improvement
in gray scale, tremendously increased signal -to -noise
ratio, improvement in resolution, and provision for
automatic black level control ... all with a minimum of
operating attention. The "snap," clarity and live effect
will be immediately reflected in advertiser preference.
NEW STANDARDS OF QUALITY
The RCA Vidicon Film System has established a standard of film reproduction by which all other methods
are judged. You can expect and get the highest quality
reproduction, with protection against obsolescence for
years to come. To give some idea of the wide range
of system possibilities with RCA equipment we submit
four diagrams, at right, from the very simplest equipment to a Dual Color Film System.
MONOCHROME SYSTEM EXPANDABLE TO COLOR
Or, you can start with the superior vidicon film system
expandable to color. Using the RCA TP -15 universal
multiplexer, color and monochrome film equipment
can be completely integrated -by adding a TK -26 color
film camera at any time. This new multiplexer accommodates up to four projector inputs, all of which are
available to two film camera outputs.
COLOR FILM SYSTEMS
To go to color now, you can select from various equipment combinations which use the RCA TK -26 threevidicon film camera. In TV stations where superb
picture quality and operational simplicity count, the
TK -26 is the preferred system for color film programming. It has been selected after careful comparative
evaluation with other systems and found to produce
finer quality film pictures in both monochrome and
color. Superior results arc achieved at minimum cost
with maximum operational simplicity.
LIVE COLOR, TOO
It is possible to use the RCA three -vidicon film system
for pickup of opaques, live commercial products and
demonstrations within a limited area.
See your RCA Broadcast Representative for more details
on Vidicon Film Systems. He will be glad to answer
your questions. Let him help plan a film system that
can start you on the road to the new and additional
revenue that will come from color!
Monochrome film system
expandable to color.
RADIO CORPORATION of AMERICA
BROADCAST AND TELEVISION EQUIPMENT
www.americanradiohistory.com
CAMDEN, N.J.
possibilities...
buy in film equipment monochrome and color
1.
CONVERSION OF ICONOSCOPE FILM SYSTEM TO VIDICON
3. BASIC COLOR FILM SYSTEM
TP-16
16MM
PROJ
TP -6
16MM
PROJ
TP -3
SLIDE
PROJ.
TK-21
VIDICON
CAMERA
TP-16
16MM
PROJ.
TK-26
MULTIPLEXER
Much of the equipment in an
existing RCA iconoscope chain
can be used with TK -2I vidicon
camero. A basic system employs two 16mm projectors and
a
TP -3
SLIDE
TP -12
3V COLOR
CAMERA
PROJ.
Permits two film projectors and
a slide projector to be operoted into a single TK -26 color
film camera. Designed for maxi-
TP 6
16MM
PROJ
mum simplicity and economy, it
can be used for both color and
dual -channel slide projector.
monochrome film.
2. MONOCHROME FILM SYSTEM EXPANDABLE TO COLOR
4. DUAL COLOR FILM SYSTEM
TP -6
16 MM
PROJ
TK -21
VIDI CON
CAMERA
TK 26
I3V COLOR
CAMERA
TP
r.
-I5
P
P3
3
SL,LIE
PnO.1
MULTIPLEXER
TP -3
LFUTURE
mi
SLIDE
PROJ.
TP
35
Combines
a
TK -21
monochrome film
camera
Will handle a large number of inputs and therefore
provides maximum program protection. Two corn pletely independent program channels provide the
ultimate in reliability and assure continuous program-
with
projectors and multiplexing equipment, which are
usable in color as well as monochrome. At any time a
TK -26 color film camera can be added, retaining the
TK -21 for the monochrome channel.
Best
for color and monochrome because it
..
RCA d ., tnp: ...:et
Vidicon storage tube is outstanding from standpoint of high
signal -to -noise ratio, reliability and low -cost operation. It
produces a sharp lifelike picture -equally good in monochrome or color. Replacement involves minimum of equipment readjustment.
iOICtJN
ming. Permits previewing
IUBE
STANDARD -TYPE PROJECTORS FOR 35 and 16MM
Standard of the motion picture industry, the intermittent projector produces a beautiful steady picture. It involves none of
the critical mechanical tolerances of the continuous projector
for 16mm. RCA now offers the TP -6 series projector designed
from the beginning for professional 16mm television use. Provides maximum video and audio quality with operating convenience and dependability. RCA neutral- density -filter light
in
color.
uses proved -in components
!
control makes it possible to achieve satisfactory results with
practically all kinds of film.
NEW TYPE TP-
1
5 MULTIPLEXER
Provides for complete integration of color and monochrome.
Offers flexibility and protection of two -camera system without
the necessity of buying separate projectors for each camera.
Permits preview of one program while another is on -air.
OPERATING CONVENIENCE AND SIMPLICITY
Only two simple controls are employed in "on -air" operation.
Pedestal level and Master Gain. For assuring picture perfection,
all controls, together with waveform and picture monitors, are
located at the operating position.
i
New! Space - Saving
These
Advanced
ujl9!liDf
iüüiirio`
11000000000000
`:.'
0041100000
Features:
Compact- requires only
101/2" rack space.
1500 ma output at 280
volts regulated.
High efficiency. Less
power lost as heat.
Uses only 6 tubes.
New high -efficiency germanium rectifiers.
Two -chassis
construction
for maximum flexibility.
Only $675 complete.
New RCA WP -15 Power Supply
highlights two -chassis construction. The rectifier chassis contains all the
rectifier and filter elements. The regulator chassis contains a full complement of 6 tubes and regulating elements.
System Simplification
By separating the functions of rectification and regulation it has made it
possible to place all the rectifier chassis at one location. Regulator sections
can thus be arranged in a location adjacent to equipment loads. If desired
the rectifier and regulator chassis can be mounted together as a complete
power supply, occupying only 1012" space.
New Safety Features
Heavy -duty on /off switches are provided on both rectifier and regulator.
Both can be remote controlled from regulator, eliminating presence of
high voltage when the regulated voltage may be off. Indicating type fuses
are used in ac power input line. Each regulator tube is individually fused
to prevent overload in case of failure of any other regulator tubes. Indicator lamps on front and rear of both chassis warn of presence of high
voltage. Entire power supply is completely covered to prevent contact with
terminals carrying high voltage.
Two WP-15's (mounted at left)
are equivalent to five WP-33B's.
RCA Power Supply WP -15
Up To 70% Reduction in Rack Space
Priced at Only 45c per Milliampere!
Check and Compare
!
Use this chart to
find out
your own savings potential.
EQUIPMENT
PREVIOUS POWER SUPPLY
POWER SUPPLY AND
WP -15
USED
AND SPACE NEEDED
SPACE NOW NEEDED
SAVING
WP -15
101/2"
171/2"
TK -21
r
MI
Black and White
Film Camera
2 WP -33B's
TK 11/31
2 WP -33B's
580D
381/2"
Black and White
Live Camera
^'L"
t,I;
r
o
1
1
WP -15
101/2"
28"
2 WP -33B's
TK -26
Iiii
1
28"
Color
Film Camera
3
580D's
59'/z"
2 WP -15's
381/2"
21 ""
3 WP -33B's
TK -41
Color
Liv Camera
2
580D's
63"
63
2 WP -15's
21 ""
NOTE: Comparisons are based on the number of WP -33B
and 580D power supplies necessary to provide 1500 ma.
High current capacity, small size, light weight and lowest cost per milliampere
make the WP -15 excellent in television broadcasting, closed circuit and laboratory applications. Your RCA Broadcast and Television Sales Representative will
he glad to supply additional information. IN CANADA: write RCA VICTOR
Company Limited, Montreal.
RADIO CORPORATION of AMERICA
BROADCAST AND TELEVISION EQUIPMENT
CAMDEN, N. J.
42ií
www.americanradiohistory.com
STUDIO INSTALLATION
Plans
for WWJ's impressive studio build-
ing in downtown Detroit were first conceived in 1947, a year after the Channel 4
NBC affiliate received its television CP.
Telecasting operations began in March of
1947, as WWJ broadcast from studios
located in their radio building. The need
for new quarters soon became apparent as
the television operation proceeded to outgrow the available space.
Construction of the new building was
authorized in November of 1951 by the
Evening News Association, owners of The
Detroit News and WWJ- AM /FM /TV.
Shortages of materials, such as copper.
created by the Korean War hampered construction and later equipment procurement.
In spite of this, 1952 saw the completion
of the new home of WWJ -TV. A shotsawn
limestone exterior covers the masonry and
steel structure which is skillfully related
miles of wire, not counting telephone and
light circuits. Cable runs are made through
open ducts to a central vertical shaft running from the basement to the master control room on the second floor. The maze
of conduits, piping and cables required are
concealed in the floor slabs.
Control rooms for the three large studios are located directly beneath the master control room in order to concentrate
all electronic and electrical circuits. The
structural design of the building provides
for two additional floors for possible fu-
FIG. 2. Mr. E.
of
FIG. 3. Downtown studio building
of WWJ- AM /FM /TV.
FIG, 1. WWJ -TV custom -built mobile
unit doing a remote pickup at Detroit's
fabulous
Northland
Shopping Center.
G
--:r_...Ir. _-..lr..
,tttqf/1
Wheeler, General Manager
WWI-AM /FM /TV.
ture expansion.
by glass section to the radio building.
According to E. J. Love, General Engineering Manager, the plant facilities represent a composite team effort in planning.
Their engineering department, composed
of men like R. P. Williams, Chief Engineer
(Studio) ; A. G. Sanderson, Chief Engineer (Facilities); C. H. Wesser, Chief
Engineer (Radio); and H. F. Tank, Chief
Engineer (Transmitter) worked with engineers from RCA to produce one of the
biggest custom installations in the country.
The building has been completely designed around a highly demanding electrical installation. Since the technology of
television is still rapidly developing, wiring
is designed, not only for the present heavy
electrical load, but to provide for future
changes. The building contains about 120
4
K.
--T- '.:f444
www.americanradiohistory.com
OPEN
STORAGE
1140 SOFT
TUBE
STORAGE
ELEVATOR
UPPER
STUDIO
PPER
PART
A
PA+
U STUDIO
CONTROL
STUDIO x
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CONTROL
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STAIR
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ISO
FIG. 4. Floor plan of second floor where
Master Control and Studio "X" are located.
I
OOM
SALES PROGRAM
FRAFFIC OFFICES
STAIRS
TI
ISO'
FIG. 5. First floor plan of WWI studio building
showing the station's three television studios.
Television Studios
Interest on the first floor centers around
the three studios. Largest and most elaborate is Studio A. measuring approximately
58 by 80 ft, or 4,640 sq ft. One of the
main features of this studio is a 25 -ft
diameter turntable built flush to the floor.
Here, automobile commercials are produced to advantage as the rotating turntable presents a continuously changing
product view.
This studio, with 221 ft of wall space
available for stage sets, handles productions that require elaborate settings and
space. For example, a number of different
sets are required to produce such shows as
"Michigan Outdoors ", a program covering
sports, hunting and fishing. Programming,
where two or three shows are lined up back
to back or special shows usually originate
from Studio A.
In order to accommodate visitors, a public gallery measuring 11 by 17 ft, has been
provided at one end of the studio next to
the control room. There are seating facilities here for about fifteen people. either
visitors or clients.
Cinder concrete block walls are used
throughout the building as well as in the
studios, providing good sound absorption
and freedom from pronounced resonances.
No acoustical flats are employed in the
studios -the feeling being that live sets in
themselves provide enough acoustical treatment. 7'his has proven to be a very satisfactory approach.
8
CORRIDOR
Studios B and C are somewhat smaller
than Studio A. Studio B contains approximately 1,900 sq ft with 146 ft of wall
space for sets. Studio C is slightly larger
with 2,288 sq ft and 162 ft of wall space.
Permanent -set shows such as sportscasts
and news programs usually originate from
Studio C.
At the end of each studio is a control
room, designed so that the booth floor level
is 4 ft above the studio floor. The control
rooms were raised for visual reasons to
give complete visibility and avoid clutter
in front of the control room windows.
Each of the three studios at WWJ is a
separate entity. An r -f monitor distribution
system is fed to every studio with three
outlets in the studio and one in the control
room. Four TK -10 image orthicon cameras
are used in the large studio, with Studio
B having three TK -10's and Studio C
equipped with two TK -30 field cameras.
These RCA TK -30's are from the first
production run in 1946 and are still giving
excellent service.
About 150 tons of air refrigeration
equipment are required to handle the tremendous heat load given off by the high
lighting intensities necessary in the studios
and the heat given off by operating equipment in the control rooms. Unusually large
ducts provide air supply at velocities low
enough to be noiseless.
Noticeably longer image orthicon life
has resulted from the installation of the
air- conditioning system which cools the studios down to approximately 68 degrees F.
6. Automobile commercials are done in
Studio A on the large 25 It diameter turntable.
FIG.
FIG. 7. General view or Studio A during a television rehearsal.
www.americanradiohistory.com
FIG. 8. Studio B handles one of the commercials for "Michigan Outdoors" show.
FIG. 9. The motor- driven pipe battens, providing support for lighting
in Studio B, are controlled by wall -mounted push -button switches.
l0
Lighting
At WWJ lighting is a program department function and is of the "off- the -floor"
type. All scoops and spots are hung from
2 -inch pipe battens supported by wire
cables at either end. Thus, with very few
exceptions, the studio floor is not cluttered
by dolly- mounted light units. The pulleys
supporting the cables are attached to
lengths of angle iron anchored in the ceiling. A total of eighteen pipe battens are
used in Studio A. Nine battens are hung
down one half of the studio and nine down
the other half. Wall- mounted push-button
switches control the motor -driven pipe
battens- raising or lowering them as long
as the push- button is depressed. Two control boards make 120 lighting outlets
switchable or dimmable. either individually
or collectively in the large studio. Since
regularly scheduled shows set a pattern, all
lights are set according to lighting tables
with each light individually adjustable.
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IO. Close-up view of one of the
pipe battens illustrates ease with which
lights can be changed or adjusted.
FIG.
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FIG. 11.
make
120
Two Kliegl Bros. lighting control boards
lighting outlets switchable or dimmable.
FIG. 12. Studio A control room
note equipment bays at extreme right. Control rooms
FIG. 13. Close -up showing details of console in control room A. Audio consolette contains no power
supplies or amplifiers - -all of them are rack mounted.
B
and
C
are similar in layout.
Control Rooms
All of the control rooms are located at
one end of their respective studios, affording excellent visibility into the studios.
Equipment layouts are almost identical in
each of the control rooms.
At the main console located in front of
the control room window the director
technical director and audio operator carry
out their program functions. Four camera
monitors and a row of intercom switches
directly in front of the director allow him
to exercise tight control over programming.
An important part of this console is the
push- button control panel of the TS -20
remote control switching system which provides complete facitities for program monitoring, video switching, remote pickups
and network programs. Two master monitors are used-one for previewing and one
for monitoring the outgoing line.
.
A custom designed RCA seven channel
split -mixer audio consolette provides all the
audio switching, control and monitoring
facilities required. Input cutovers are provided on each preamplifier input. Control
of all inputs can be handled by either one
of the two sub -masters. These sub -masters
are in turn controlled by the master fader.
All amplifiers and power supplies for this
audio consolette are rack mounted -no
tubes are mounted in the console housing
itself. Two standard, three -speed BQ-2A
turntables are located immediately to the
right of the audio consolette.
A video console, housing the four camera
control units and a master monitor, is
located just to the left of the control room
window. Monitoring of either local or network color programs is possible in each
control room, since they are equipped with
standard 21 -inch color receivers.
Three bays behind the audio operator's
position complete the equipment layout in
the control room. One is a low -level bay
for program audio- another, the high -level
bay includes intercom facilities. A varistortype limiter keeps the level down on the
intercom from control room to cameras.
Distribution amplifiers and power supplies
for the cameras make up the balance of
chassis in the cabinet racks. The air in all
of the control rooms is used twice -once
to cool the booth and then the equipment
racks. All of the custom -built consoles are
exactly the same in each control room except for numbers of camera control units
and monitors.
The height of the control room floor
above studio floor level permitted the construction of a 4 -ft crawl space under each
control booth. An 8 by 14 -inch cable trench
in the control room floor carries all cabling
from the booth into the crawl space where
the cables are then fed to a main cable
shaft and thence to MCR.
Chief Engineer (Studio) at WWI is
Williams, shown at one of the equipment
bays in control room A.
FIG. 16.
R. P.
FIG. 14.
Video engineer's position faces well to the Lit
of
the main control console.
FIG. 15. A. G. Sanderson is Chief Engineer
of Facilities of WW1.
3 -V System in use at WW] shows lens arrangement for producing opaques on bracket
mounted metal plate. Projectionist can easily switch from opaque to slide-protector input as shown above.
FIG. 17. View of optics of
-
Film Projection Room
Two TK -20 Iconoscope Film Chains
and one TK -26 3- Vidicon Color Film Cam-
era Chain comprise the major equipment
facilities in the film room located next to
master control on the second floor.
Opaques, both color and monochrome,
are playing an important and ever-growing
part in WWJ -TV's 3 -V system. By means
of a simple extension lens system the 3 -V
system can produce opaques or live color
commercials of actual products. According
to Russ Williams, Studio Chief, a breadboard model of the opaque optical setup
had just been completed when the February issue of BROADCAST NEWS came out
with an article on this very subject.
Numerous advantages accrue from the
use of opaques. The large 14 by 17 inch
cards with 3 -inch borders all around are
much easier for an artist to handle and
work on. It is extremely difficult to get
small artwork done quickly-now artwork
on opaques can be done in minutes at the
station's art department. All station i.d.'s
are done in color if possible.
FIG. 13. Each one of the TK -20 Iconoscope Film
Chains has a TP -16 16mm Film Projector and
two slide -projector inputs.
1
4
By using opaques in the 3 -V system for
monochrome operation, instead of employ-
19. Tom O'Toole, Senior Projectionist, is
shown operating the douser which he designed.
FIG.
ing a black- and -white image orthicon camera, work has been taken out of the WWJ
studios resulting in a less costly operation
since a camera crew is not needed and a
studio is not tied up. As a result, image
orthicon operating hours have been reduced
and a worthwhile saving effected.
A bank of six RSP2 500 watt spots
mounted under a metal hood are directed
through a sheet of heat -absorbing glass
onto the color opaque. Cooling is provided
by a blower mounted under the lights as
the airflow is directed out through a vent
in the top of the hood.
Two TP -6 16 -mm film projectors and a
Gray Telojector for 35 -mm slides feed into
the TP -12 multiplexer portion of the 3 -V
system. A unique douser arrangement designed by Tom O'Toole, Senior Projectionist, gives smoother programming to
WWJ's film presentations. The douser,
shown in Fig. 19, (one for each projector)
consists of a flat movable metal plate
mounted on the multiplexer chassis. This
plate is interposed between the multiplexer
optics and the projector lens before the
film is run through the 3 -V system. Thus,
the projectionist can see the end of the
leader and cut the douser out at exactly
the right point, eliminating the annoying
clutter that is sometimes seen on TV receivers just prior to a film presentation.
Each of the iconoscope film chains has
TP -16 16 -mm film projector, one Selectomatic Jr. slide projector and a standard
35 -mm slide projector associated with it.
The projectors can be controlled from any
one of the three studios
push -button
a
-a
control panel being located to the left of
the switcher control panel in each studio
control room. Film sound is also fed to
each of the studio control rooms.
Some film storage as well as editing and
splicing of film is handled in the projection room, but the major portion of this
activity is located in the lower level below
the first floor.
A line of monitors has been placed above
the window separating MCR and the projection room. Here, monitors for both the
iconoscope film chains, preview and outgoing lines are located. The 3 -V system has
two separate monitors, one for color and
the other a black-and -white monitor for
the green channel of the 3 -V film chain.
This arrangement is employed for pro.
ducing opaques, or live commercials using 3 -V
System. Note the product on the turntable (left)
optical setup is mounted on brackets and can
be seen to the left of the TP -6 16mm projector.
FIG. 20.
-
15
www.americanradiohistory.com
FIL M
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29'
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BAY-3
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MODIFIED AS PER RCA TECH.
BULLETIN NO. Eß-149.
DA-7I INPUT MODIFIED AS
PER RCA TECH. BULLETIN
21_0
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-at WW]-TV.
FIG. 21. Pulse distribution diagram of the film facilities -both color and monochrome
16
www.americanradiohistory.com
Eß-149.
FIG. 22. Master Control facilities at this console include audio and video switching panels. master
monitors and an audio ringdown and remote panel. The booth shown is the Studio "X" announce
booth where any or all of the four outgoing audio channels can be overridden.
Master Control
Nerve center of the operation is the large
Master Control area which occupies an
area of approximately 1.144 sq ft on the
second floor of the building. Station operation in this area has been divided into a
master control function and a Studio "X"
concept which can operate as a sub -master
control. A Studio "X" announce booth is
located at one corner of MCR.
At WWJ, a preset switching system is in
effect in MCR which is a direct outgrowth
of the audio preset system used in their
radio operations. In this arrangement, the
push- button switch normally employed for
channel selection is dead and may thus be
set up for the next channel setup to be put
on the air. A trip button will then cause
one or several channels to transfer to the
new preset schedule. Normally, master
control itself is not manned at WWJ-
only unusual or special events requiring
operator attendance.
The MCR video switching panel is
capable of switching 12 inputs to 2 outgoing channels and a preview bus. Each
one of the outgoing feeds has a right
and left bank. One bank can be used for
a preset condition while the other bank is
being used on air. Actual switching is
handled by a transfer switch at the bottom
of the panel. Push -button switches of the
nonlocking, illuminated variety are employed for operating video relays. The preview channel can be punched up on any
one of the inputs.
There are facilities for switching two
outgoing video lines and four outgoing
audio lines. Three master monitors are employed, one for each of the two outgoing
video lines and one for previewing. The
four separate audio switching panels are
located at the extreme right of the master
control console. Usually, audio is locked to
video switching so that the video is followed by audio switching-however, audio
can be switched separately.
Two audio switching circuits are contained in each audio switching panel. Here
12 inputs are switched to 2 outgoing channels. A left and right bank are associated
with each channel. While one is in use, the
other channel can be employed for preset.
Audio relays are operated by mechanically
interlocked push buttons. Switching of
audio is accomplished by a transfer switch
at the bottom of the panel. Each channel
has a VU meter associated with it.
An audio ringdown and remote panel in
the MCR console provides ring and talk
facilities for 12 lines. Mechanically interlocked selection for the 12 incoming program lines are provided on remote busses.
17
www.americanradiohistory.com
ANN
ÌB00T
,
L__J
RROJ
2
FILM
WITCHIN
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FIG. 24. Simplified block dia.
gram
WWJ -TV's Master
Control Switching System.
of
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INCOMING REMOTE
LINES
www.americanradiohistory.com
SPI
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J. Love, General Engineering Manager,
indicates rack space that has been provided in MCR
for future possible additional 3 -V system.
FIG. 25. E.
FIG. 23. Studio "X" is handled by Walt Runkel,
MCR technical director and Ned May, audio operator.
Studio "X"
All film- camera outputs appear on master monitors in the Studio "X" control
console -these include the 3 -17 film chain
and the iconoscope film cameras. The 3 -V
output appears in both black and white
and color -hence a color monitor is situated directly above the processing amplifier at the left-hand side of the console.
Two additional master monitors are provided for studio /line and previewing. Gain
and pedestal controls for all the film cameras are located in front of the MCR technical director in Studio "X ". A TS -20
relay switcher panel enables the TD to
handle video switching
noncomposite
video being fed to the switcher from all
studios. Two 24 -dc power supplies with
automatic change -overs are provided for
-
the cl -c relays in the TS -20 remote control
switching system. To date there have been
no failures. Late hour program material,
such as network or film, can also be
handled at the Studio "X" console.
Intercom and additional ringdown facilities control for remotes are also provided.
It is possible for the Studio "X" announcer to override any or all of the four
outgoing audio channels. In control of this
function at WWJ is the audio operator at
the Studio "X" audio consolette. Five
mixer positions are provided on this con solette. A utility position at the extreme
left may be used for any studio, remote
or network. Mixer positions are also provided for the announce booth and film
sound. The remaining two mixer positions
are used for the 70 -D turntables.
19
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FIG. 26. Cable shaft in WWJ studio building runs
vertically the entire height of building -all interfloor cabling is run through this 3 by 10 It shaft.
FIG. 27. Master control area containing a
total of five banks of equipment racks. Work
shop area is located in the far background.
-
20
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Power Supplies and Wiring
A total of 90 ft of relay racks in five
banks are located in the MCR area. An
isolated power supply arrangement is used
here-an entire bank consisting of eight
relay racks being devoted just to power
supplies. This bank is on a separate master
breaker system. All power comes into the
racks overhead, keeping audio and video
lines isolated from the power lines.
Dirt and heat factors decided the station
on air- conditioning. As a result tube life
has been extended by anywhere from 300
to 400 per cent. This represents a considerable saving in a plant that uses a total
of approximately 6,000 tubes in its equipment. Now, a replacement figure of nearly
200 tubes a month is average.
All of the equipment bays in master
control are exhausted out the top by convection, with the exception of the power
supply bank which uses an exhaust fan to
remove air from the entire bank. The exhaust air is then cooled and filtered by
the air -conditioning system.
Patching at WWJ -TV is kept to an absolute minimum. "It is axiomatic," according to A. G. Sanderson, Facilities Chief,
"that a well engineered system uses a
minimum of patching." Video and synchronizing circuits are patched only when
testing or when by- passing is required.
All interfloor cabling is brought into a
3 by 10 ft shaft. Cable trenches then
carry the cable and wiring on each floor to
the various studios and control rooms.
Uni -Strut piping is used for cable lashing
and all cable and wiring in the shaft is
tagged for easy identification. Steel gratings at each floor level permit maintenance
work to be performed. Power lines are run
in conduit both as a means for protection
and for isolation. Boiler plate covers the
top of the shaft, since the whole building
MECHANICAL
with a view towards future expansion (adding two entire floors).
In the MCR area and right next to the
cable shaft is a main terminal frame. Here
all wiring, except coax, is brought in for
maximum plant flexibility. Two 50 -pair
cables and a 26 -pair cable for d -c control circuits terminate here from all three
has been designed
studios.
Building Layout
At the back of the building on the first
floor, garage space has been provided to
house 'v«VJ -TV's mobile unit and associated equipment. Along the front of the
building are the offices of the TV station
manager and the sales department as well
as a
large conference room.
The entire first floor of the building has
been planned so as to give direct passage
for talent from rehearsal and properties
rooms downstairs to the studios. Another
ROOM
ART
DESIGN
ELEVATOR
passage gives the engineers easy access
from MCR upstairs to each studio control
room.
At the far end of M/C is an engineering
workshop of 660 sq ft separated from M/C
proper by relay racks containing an "Antenaplex" system for closed circuit distribution of TV broadcast signals. The
remainder of the second floor level consists
of engineering offices.
The lower level of the building has
around a central storage
area for television properties-an area
measuring 64 by 88 ft. Space has also
been provided for a rehearsal studio with
adjoining dressing rooms. A film library
and a news room are also located in the
lower level, while another section contains
the refrigeration equipment for the air conditioning system and the electrical
equipment which provides primary power
for the entire AM and TV operations.
been designed
CARPENTER SHOP
MAINT.
SHOP
!STAIRS
i
FI
DRESSING
ROOMS
CUSTUME WARDROBE
& LOUNGE
STORAG
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E
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SQ FT
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i
0
JANITORS
REHEARSAL
M
I
e.
LOCKERS
STORAGE
I
OPERATIONS MANAGER
AND OFFICES
FILM
CORRIDOR
FILM
ELEVATOR
LOBBY
STAIRS
EDITOR
PRODUCTION
OFFICES
LOUNGE
NEWS
ELECTRICAL
ROOM
fic
TOILETS
ISO
FIG. 28. Floor plan of lower level of building shows location of art and film editing facilities.
21
www.americanradiohistory.com
FIG. 29. Remote pickup point at
Detroit's Northland Shopping
Center. Two hour broadcast of
fashions and subjects of interest
to women was done every Saturday during the summer.
Mobile Unit
Remote pickups are handled using a
25 -ft television mobile unit, custom built
under the direction of Olin Lapham, Studio
Supervisor. Three field cameras comprise
the live TV pickup gear in the 13,000 -lb
remete truck.
One remote handled on a regular basis
every Saturday during the summer is a
2 -hour pickup from Detroit's
fabulous
Northland Shopping Center. Here fashions
and other topics of interest to women are
picked up and beamed via an RCA TTR -1
microwave transmitter to the transmitter
site 1% miles away. A remote controlled
mount is used for the microwave dish.
Switching facilities are available at the
WWJ transmitter site.
22
Cable runs of 250, 400 and 850 ft are
used to give the necessary flexibility during programming. A TS -30 field switching system permits fades, superpositions,
dissolves or instantaneous switching between the three RCA field cameras.
Audio control is provided by a four channel audio consolette with an auxiliary
mike cut -over box. Two microphone inputs
fed through the mike cut -over box allow
the audio man to cut from one mike to the
other at will.
Color Operations
The entire system at WWJ -TV has been
modified, integrated and checked out for
color. The station has been working with
color since October 1955 when they con-
30. Interior view of the WWJ television
mobile unit. TS -30 field switcher provides flexible
control of the three RCA field cameras.
FIG.
FIG. 31. On location at Northland Shopping Center remote. Microwave dish of upper left has
remotely controlled mount.
ducted a seminar for their production and
engineering personnel in preparation for
the installation of their 3 -V system. The
next step is local live color. As far as
facilities are concerned, all that is required
for live color programming is the installation of live color camera chains.
Probably unique in broadcast operations
are the two separate pulse- distribution
systems in use at WWJ. Non-synchronous
operation of the TV system is a must in
color since the color signal frequency is
controlled by a crystal setting in the sync
generator. Present black-and -white TV
operating standards provide that the system be tied in with the 60 cycle power line.
Since WWJ had brand new iconoscope film
camera chains, they felt that use had to be
made of them-as a result, separate pulse
distribution systems.
At the present time approximately 20
per cent of the artwork produced at
WWJ-TV is being done in color. To satisfy the demands of the 3 -V system for
color material a great deal of use is made
of magazine and calendar color art. Printed
matter is then inserted on these pictures
when and where needed.
In preparation for live color programming the art department is building up
data on color reproduction values on the
grey scale. A luminosity chart which plots
relative response versus wavelength, is
being used as a general guide so that colors
can be selected with a view towards adequate grey -scale separation. There must
be no degradation of picture quality and
contrast on black -and -white receivers
as a result of going to local live color
programming.
January 1st, 1954, saw WWJ -TV telecast the first network color program in the
Detroit area, the Tournament of Roses
Parade from Pasadena, California. On October 9th, 1955. WWJ-TV gave viewers
the first local color television in the State
of Michigan. On that day, the station
transmitted over four hours of station originated film and slide features. Color casts have been on the regular schedule
ever since. Future plans according to Mr.
Edwin K. Wheeler, General Manager, call
for local news coverage and a growing
number of other programs in color video.
23
www.americanradiohistory.com
PROGRESSIVE
WHIM
AM -FM
KEYNOTES
QUALITY OPERATION
Started as a Community Project
Grows
to
Enterprising
.
.
.
Independent
1. "WHLM predicts the weather"
via a large neon sign on the roof of the
FIG.
downtown studio building. Bloomsburg,
a farm area, appreciates this service.
Radio listeners in North Central Pennsylvania are served by one of the nation's most forward -looking radio stations,
WHLM, owned and operated by Harry L.
Magee. Located in Bloomsburg, the station
serves an audience of over 150,000 people
in Columbus, Montour, Northumberland,
Luzerne and adjoining counties. The area
is one of Pennsylvania's richest agricultural
and manufacturing districts. WHLM was
planned and sponsored by Mr. Magee,
owner of the well -known Magee Carpet
Mills, as a community project, but it has
been a notable financial success as well,
almost from the first. The station began
operating with the call letters WLTR in
January, 1948, on a frequency of 690 kc
and a power of 1,000 watts using two towers, daytime. In September, 1952, the call
was changed to WHLM. In December,
1953, WHLM switched to 550 kc, with
500 watts and a four tower array on
day/night operation.
From the beginning, a balanced program
fare of news, music and sports built a loyal
listening audience. Particular attention is
paid in planning the programs to provide
both entertainment and public service
features.
News programs are featured on WHLM.
In addition to a local news reporter, the
station obtains regional reporting service
from the news wires of both Associated
and United Press. The station staff members are proud of several important news
"beats" which were first reported on
WHLM.
Studios
2. One of the spacious, tastefully decorated WHLM studios.
Large enough to accommodate a reasonable -size audience. The studio's
irregular shape prevents multiple reflections . . . improves acoustics.
FIG.
24
www.americanradiohistory.com
The studios and station business offices
are located on the second floor of a building in the center of Bloomsburg. This studio location was chosen both for the con-
FIG. 3. Ray Calabrese, veteran announcer, gives a newscast on the famous RCA.44BX
microphone. In the background, Terry Abrams engineers the program at studio control.
venience of the station staff, artists, and
for the convenience of the public, who are
always welcome to visit the spacious,
tastefully decorated studios. On the roof
of the building the station has erected a
large neon sign which shows the daily
weather forecast and the current temperature. The townsfolk, a great percentage of
whom are agricultural people. appreciate
this WHLbI forecast.
season on the air. Considerable use is made
of tape recordings for delayed broadcasts,
where two or more events occur simultaneously.
Transmitter Site
The transmitter building, constructed of
concrete block, is located approximately
1% miles from the center of Bloomsburg.
Four Stainless 400 -foot guyed towers
comprise the directional antenna system,
"beaming" the station's power in the direction of the major audience, increasing the
effective signal strength in that direction
to many times the value obtainable with a
single antenna tower.
The selection of a suitable site was a
considerable problem, due to the fact that
The main studio, although used primarily for news and special programs, is large
enough to accommodate a small audience
and the performing artists. The acoustic
properties of the large studio were carefully controlled by the designers, and provide a pleasingly balanced sound whether
or not an audience is present. Sound absorbing material is used in such a manner as to cancel or reduce sounds reflected
from the large windows and the doors.
The studio shape is irregular rather than
rectangular, thereby preventing multiple
reflections from parallel walls.
Much of the program material originates
from the control room, which has also
been treated acoustically to provide balanced sound.
Regularly -Scheduled Remotes
The station has a number of regularly scheduled remote broadcasts, both from
Bloomsburg and from nearby cities. Local
sports are emphasized, and every effort is
made to present live broadcasts of all
events of local or regional interest, such as
the county and state fairs, parades, and
the like. The station is also affiliated with
the Phillies baseball network, and has carried major -league baseball since its first
Harry L. Magee, station owner (left), and Mr. Robert R.
Williams, station manager, discuss transmitting equipment functions
at the transmitter site. Transmitter is the RCA BTA -1M.
FIG. 4.
25
FIG. 5. The WHLM transmitter building lies in
the valley between the second and third tower.
It Is constructed of concrete block and has more
than- adequate room for its AM and FM transmitting equipment.
-
Anthony F. Hogg. Chief Engineer, observes meter readings on the AM transmitter. Mr.
Hogg keeps station operating at peak efficiency
as proved by a recent nationwide Conelrad alert.
WHLM, key Conelrad station in Bloomsburg area,
made switch from 550 to 640 kc in 30 seconds.
FIG. 6.
26
the four towers are in a straight line and
are spaced approximately 500 -feet apart.
In the rolling hills which surround Bloomsburg it was not easy to locate a level space
of this size which was otherwise suitable.
It was, in fact, necessary to place one of
the four towers on an embankment opposite the entrance to the transmitter building, and a county road runs between this
tower and the next in line. According to
Anthony F. Hogg. WHLM chief engineer,
the site has proved satisfactory in every
respect.
The lower level of the transmitter building, which opens onto the county road,
provides garage space for WHLM's station
wagon and special -events car. Also on this
level are two 10,000 watt a -c generators
which provide emergency power.
On the upper level are the engineering
office, the operating area, the RCA BTA1M transmitter and associated equipment,
a stand -by transmitter, and the workshop.
A control desk, placed conveniently in
front of the equipment, permits the operator to maintain constant supervision of
the transmitter and phasing equipment. In
addition to these facilities, a small studio
is kept in readiness at the transmitter site,
and may be used should the telephone
lines from the studio become inoperative.
WHLM is the key Conelrad station for
the rich Susquehanna Valley area. During
a recent nationwide alert, WHLM demon-
FIG. 7. Four Stainless 400 -ft guyed towers comprise the WHLM directional antenna system.
-
strated the efficiency of their operation
making the Conelrad transition from 550
to 640 kc in 30 seconds.
FM Service, Too
In line with its continuing policy of
public service, WHLM is now in the
process of installing an RCA BTF-3B 3
KW FM transmitter atop a hill near the
AM transmitter site. The FM programs
will originate from a second studio and
control room to be added to the present
studio facilities, and will be programmed
separately. The FM antenna will be
mounted atop a 400 -foot tower on the hilltop, and will be approximately 1,000 feet
above the average terrain. It is expected
that excellent FM program service will be
available to listeners within a 75 -mile
radius of Bloomsburg. The FM transmitter will be unattended, and will be controlled by means of an RCA BTR -5F Remote Control unit, permitting the engineer
on duty at the AM transmitter building to
maintain supervision of the FM equipment
more than a mile away.
According to Harry L. Magee, the station owner, future prospects for WHLM
are excellent. The area is growing and prospering. There is every indication that
WHLM's policy of offering excellent entertainment and public service will continue to build both an increasing and a
loyal audience.
broadcast
WFIL -TV PROGRAMS LOCAL
LIVE COLOR
0
July 23rd, WFIL -TV startled the
Philadelphia area by announcing the inception of regularly scheduled colorcasts,
thus becoming the first Philadelphia station
to present local live programs in color.
Color telecasting plans called for at least
one local live color program each week.
This schedule has now been expanded to
include more than fifteen hours a week of
local live color. The Channel 6 station k
now doing one of its top shows. "Bandstand" in full color every day, Monday
through Friday.
The move is bound to provide a strong
stimulus on the growth of color television
in the area. With more than two and one half hours of color coming their way each
day, televiewers are given increased incentive to make the move to color.
Foresight and faith in the future of color
television have led to the step to local live
color. it is axiomatic that color will soon
be big business. WFIL took the step to
anticipate the big swing to color and to obtain the experience that will enable the
station to take advantage of the opportunities offered by color.
Although the station's intention to start
regularly scheduled color programming was
a highly guarded secret, station technicians were fully prepared for the change
over. For several months prior to the start
of live color programming, operating personnel had been briefed on the operation
of the new equipment. Closed circuit demonstrations provided full opportunity to
study the problems associated with the
change. As a result, the first show was very
successful and unmarred by unexpected
technical or production problems.
The big emphasis in the months prior
to live color telecasting was on lighting.
As the color medium became more familiar
two things became apparent. Lighting had
to be much more uniform and more of it
was required for color. For the "Bandstand" show a lighting level of 300 foot
candles is used as contrasted with the 70
foot candles required for this same program in black and white.
For the past four years WFIL has been
making lavish use of color in sets and
scenery. Their program people feel that
George A. Koehler. WFIL.TV station manager (left), and Henry
with their newly acquired TK -41 Live Color Camera Chain.
color has a positive and desirable effect
on performers. Thus, when live color became a reality, the station found itself in
the fortunate position of not having to
make any changes in the "Bandstand" set.
As other color shows come up, the station feels that it will probably have to do
some testing on grey scale rendition of
various colors to assure adequate contrast
on black- and -white receivers. With over
one million black- and -white receivers in
the Philadelphia area, no compromise with
E.
Rhea. chief engineer are shown
quality of black and white reception can
be tolerated.
Since announcement of the move was
withheld until shortly before air time, the
opportunity for viewer reaction was of
necessity limited. However, a surprisingly
large number of calls were received by
WFIL asking for confirmation of the color
move. One delighted appliance dealer reported that a large crowd had gathered in
his store as word of the live color program
spread throughout the area.
27
broadcast
John D. Herrington, foreman in charge of mesh master development is shown at the ruling engine developed at Lancaster.
RCA NOW USING 750 -MESH
SCREEN IN TV CAMERA TUBES
Two
improved image orthicon television
camera tubes-the RCA -5820 for black
and white and the RCA-6474 for three tube color cameras-are now being quantity produced for the broadcasting industry
with Micro -Mesh, a 750 -line per inch mesh
screen, replacing the 500 -mesh screen heretofore standard in both tube types.
The 750 mesh eliminates all traces of
bothersome noise patterns. Although mesh
up to 1,000 lines per inch has been produced by RCA, requirements of the present
525 -line television system are exceeded
with camera tubes employing the new 750
mesh. Laboratory and field tests have
shown that mesh of 750 lines per inch is
more than adequate.
To achieve the goal of a 750 -mesh
screen, it was necessary for RCA to develop its own mesh -making techniques and
equipment. Included in the work was the
design of an amazingly accurate ruling en28
gine to produce the "master" matrices
from which the gossamer -like screen can
be produced in quantity.
These meshes are made by an electrodeposition process, using grooves ruled in
a glass master as a form. An acid- resistant
wax coating is first applied to optically
flat glass. Using a suitably shaped stylus
or tool, the wax is then ruled with perpendicular sets of parallel lines. When the
ruling has been completed, the glass is
etched, cleaned and covered with a thin
metallic layer using a sputtering process.
The surface layer is then removed by rubbing with a plastic material. This leaves
only the metal in the etched grooves. An
electroplating process forms the mesh
which is then removed from the glass
master.
Obviously, the ruling of the mesh master is a critical step in mesh manufacture
and is accomplished using the new ruling
engine. Operation of the ruling engine involves the shuttling motion of a diamond
stylus moving back and forth on lubricated crossways. As the stylus shuttles
back and forth, it presses very lightly on
the glass mesh master. The stylus cuts
only in one direction, lifting when a cutting stroke has been completed and returning for the next stroke. A lead screw moves
the glass mesh master the required distance laterally during the return stroke.
The width, depth, contour and spacing of
these ruled lines must meet very exacting
requirements to insure that each line will
be identical with the next.
So fine is the grid forming the mesh that
the minute openings represent more than
60 per cent of the total area of the screen.
It is through these openings that electrons
must pass to reach the vital "target" of
the image orthicon and create the television signal.
WRC -TV FIRST STATION DESIGNED
SPECIFICALLY FOR COLOR TV
The
nation's first television station designed and constructed "from the ground
up" specifically for local and network color
programming will soon be built by the
National Broadcasting Company in Washington, D. C., for its owned and operated
stations WRC and WRC -TV.
Approval by the NBC Board of Directors of the new station's plan was recently
announced by Robert W. Sarnoff, President of NBC. Completion of the plant is
scheduled for the Fall of 1957. The cost
of the new plant will be approximately
four million dollars.
These new facilities will make it possible to show to the whole nation, in living color, the events, personalities and
scenes of our Capital City. They will also
provide Washington audiences with an exceptional local color programming schedule
to supplement network color service.
Carleton D. Smith, NBC Vice President
and General Manager of WRC and WRC TV, pointed out that the new plant, representing the last word in RCA electronic
engineering, will have outstanding significance to "official Washington." Members
of the Cabinet, members of Congress and
other government dignitaries, will be able
to participate directly in the new TV era
by appearances before WRC color cameras.
With the start of operations in the new
plant, the majority of all local live pro-
grams will be telecast in color. The plant
will be equipped to expand the schedule as
rapidly as local interest in color develops.
Color will have a powerful impact upon
the advertisers and consumers in our nation's capital. which is the ninth largest
retail market in America.
The site for the new WRC, WRC -TV
building is a seven -acre tract on Nebraska
Avenue in Northwest Washington, located
near Ward Circle Avenue, adjacent to the
Naval Communications Center. The ground
level at the point is 385 feet elevation.
The top of the \VRC -TV antenna will be
849 feet above sea level, making it the
highest structure in Washington.
The exterior of the rectangular two story broadcast center will be contemporary
in style. consisting of gray modular brick,
limestone and colored porcelain enamel.
Because of the sloping topography the
basement will be entirely above ground at
the rear of the building where landscaping
will provide areas for programs requiring
an outdoor setting. The seven-acre tract
will include room for parking 150 cars.
The building plans call for three television studios, 60 by 100 feet, 60 by 40
feet, and a small TV- commercial studio.
Control and viewing rooms, and service
and set assembly areas are located immediately adjacent to the studios. The two
large studios are accessible by truck and
auto for ease in handling equipment, sets
and large advertising displays. Carpenter
and paint shops are also nearby.
First floor offices provide accommodations for news editors and commentators,
producers, directors, and traffic and program departments. Also on the first floor
level are a kitchen and employees' dining
room. The second floor will contain the
executive and sales offices.
In the basement there will be three
radio studios. rehearsal and recording
rooms. announce booths, the small TVcommercial studio, and TV and radio technical areas. Also to be included are engineering offices and shops, talent lounges
and dressings rooms, and a garage.
The interior of the new building will be
modern in all respects, employing materials chosen for efficiency, attractiveness
and ease of maintenance. The marble and
glass lobby will feature show windows for
the displaying of the latest RCA broadcast
equipment. The entire building will be
acoustically treated and equipped with
fluorescent lighting. The power requirements of the building will exceed 2,000
kilowatts of electricity. The air conditioning system will be individually controlled
in each one of the many studio and office
spaces to be served.
Architects drawing of new WRC -TV plant to be located on a seven acre tract in northwest Washington,
D.
C.
broadcast
W
WRCV-TV NOW BROADCASTING IN COLOR
LIVE LOCAL PROGRAMS COLORCAST ON REGULAR BASIS
On
September 24, WRCV -TV, NBC's
owned station in Philadelphia began local,
live color telecasting with the airing of the
station's top local Monday -through- Friday
programs. According to Lloyd E. Yoder,
NBC Vice President and General Manager
of WRCV and WRCV -TV, the station will
telecast a total of 15 hours of local color
programming per week.
WRCV -TV local shows colorcast on a
Monday-through- Friday basis include the
"Let Scott Do It" show, featuring Alan
Scott and Mr. Rivets, the mechanical man,
9 -10 a.m.; "Newsroom," 2:25 -2:30 p.m.,
with Pat Landon reporting late local and
world -wide headlines direct from the
WRCV -TV newsroom; and Pete Boyle's
popular 6:00 -6:30 p.m., "Funhouse," featuring cartoons and film features for the
kiddies. Channel 3's entire 11:00 to 11:30
p.m. strip of news, weather and sports may
also be seen in color. Mr. Yoder, in announcing Channel 3's color lineup, said
that weekend color -schedule plans were
being formulated and would be announced
in the near future.
Preparation for WRCV -TV's switch to
color has been going on in the NBC building in downtown Philadelphia since early
summer. Walls were torn down and new
ones went up, new equipment was installed
and tested, training periods for technical
personnel were set up, and studios were
modified for the station's extensive color
programming.
The fifth floor of the WRCV -TV studios
has been completely revamped, with a
video -central set up. This video -central
encompasses master control as well as individual studio controls and a color control
room. One of the station's main studios has
undergone a complete "colorization." This
includes entirely new lighting which has
increased the studio light intensity by at
least three times its former value. The
former Studio K has been converted into
a training studio where all necessary instruction, rehearsal, etc., take place.
Equipment additions for conversion to
color included two live color camera chains
and a 3 -V color film chain capable of projecting 16 -mm color film, and 2 by 2 inch
color slides, as well as having an opaque
attachment. In order to accommodate this
new color equipment, modifications and
special construction throughout the building were necessary. By using the new RCA
WP-I5 regulated power supplies, a considerable saving in valuable rack space has
been realized.
Channel 3's master control setup was
modified to include eight color monitors.
Two additional color monitors were installed in the master control while three
units were placed in studios and three in
the video color control room.
An entirely new projection room was
constructed. It contains not only the 3 -V
color film chain, but also a staging area
for live commercial presentations. There
are, in addition, two modified and completely modern black- and -white chains.
All of the technical work at Channel 3
is under the direction and supervision of
William A. Howard, Supervisor of Television Technical Operations for WRCV TV. Mr. Howard has been with the NBC
Engineering Department since 1946, having worked in Development and Staff Engineering in New York and served as supervisor of a Cleveland radio and television
station. He has stayed close to the development of color television since its early
days, having trained in New York as well
as attending many of the RCA seminars.
The Philadelphia area is benefitting from
an increasing variety of local live color
programs as WRCV -TV's colorcasting
schedule provides additional impetus to the
nationwide swing to color.
.its
FiG. 1. Bill Howard, WRCV Supervisor of Television Technical Operations (right) explains circuit details of new WRCV -TV color camera.
30
FIG. 2. Final cheek Is made on 3 -V color film
chain multiplexer. An input for opaques has
also been provided in this equipment.
Mr. W. Laurence Le Page (right). Chairman of the Board of the Metropolitan Philadelphia Radio and Television Corporation and Mr. Samuel Barbour, WHYY chief engineer. examine a newly acquired image orthicon studio camera.
WHYY - PHILADELPHIA'S FIRST
EDUCATIONAL TV STATION
INSTALLATION
OF
RCA
UHF
BROAD-
CAST EQUIPMENT NEARLY COMPLETED
The
first community- sponsored educational television station in Philadelphia.
Pa., will soon make its on -air debut. The
installation is being rushed to enable the
non -commercial UHF station to initiate
television service with cultural and instructional telecasts by late Autumn, according to W. Laurence LePage, Chairman
of the Board of the Metropolitan Philadelphia Radio and Television Corporation,
which will operate the channel -35 station.
The installation involves more than
$300,000 of RCA UHF broadcast equipment. Included are a 12% kilowatt UHF
television transmitter, a transmitting antenna, three monochrome image-orthicon
studio cameras, a monochrome film- camera
system, a kinescope photorecorder, and
associated power, switching and control
equipment.
The RCA transmitter -antenna combination will enable station WHYY to go on
the air with an effective radiated power
ample for primary broadcast coverage
throughout a 25 -mile radial area from its
center -city studios in Philadelphia. The
broadcast area represents 10 counties surrounding the Quaker City.
The non -commercial community station
supported by the City of Philadelphia,
the Philadelphia Board of Education, local
colleges and schools, business organizations
and individual donors. It is the first new
television station in Philadelphia in more
than eight years.
is
In addition to augmenting the Philadelphia Board of Education's television
programs transmitted into classrooms for
in- school use, Station WHYY plans to
originate adult education courses, children's
programs for out -of- school hours, public
affairs programs to interpret community
services and activities. cultural and instructional programs and local special events.
31
IN INK
MIA
SIAl10N
KFI,
LOS ANGELES
Bs1
R
B.^
PLACING
MICROPHONE Yid
"COVERAGE"1
,I HAT
IS
POLICE
YOUR
P
Cover of the first issue of BROADCAST
NEWS, which was mailed in mid October 1931 to the engineers and
managers of the 700 -odd stations then
on the air.
Isla
ALARM
BROADCAST
EOUIPMENI
BROJÑDtoST
NEWS
NUMRFR
OCTOBER
OUR BIRTHDAY
TANNOUNCEMENT
who <n
,csPOn,ibk
'OChBu
I!
Iof
for lh<w <.mr
An, -to those
who devote
Broadcasting
time end attention
to the ad aocemen
on end high
/y useful
modestly
Ì
the exchange
will bring
triumph
eh
ornm t tait
will pros .de
os
e
end
pleasant
of An tax
°
iner
of radio sop.
we
in the hope
that it
and convenient
medium lo.
of ideas and
,nloemetion,
and
that il
benef,r and Io. the
he o lices
own
benefit of
the American
whom e
Ame,ic
all se
people
n this
for
mk.wise_
Title page of the first issue expressed hope
that BROADCAST NEWS would "provide
a pleasant and convenient medium for
the exchange of ideas and information ".
A
I
h.
.,si,
.YULE,
v
"V.
¡....
mg Abducts
Comp,
+d
RCA VICTOR
COMPANY
CAMDEN,
INC.
N
32
www.americanradiohistory.com
In.RCA
1931
YEARS OF
BROADCAST NEWS
Established to Provide Equipment Information for Station Engineers, BROADCAST NEWS Has
Recorded the Technical Progress of the Broadcasting Industry Through a Quarter of a Century
by JOHN
P.
TAYLOR
Manager, Advertising and Promotion. Commercial Electronic Products
BROADCAST NEWS Number One, the cover
and title page of which are reproduced on
the opposite page, appeared in mid -October
1931. Since that date BROADCAST NEWS
has been published continuously (and
regularly, except for the war years) by
the Broadcast Equipment Department of
RCA. In this 25 -year period BROADCAST
NEWS has grown with the industry -from
12 pages in the first to 72 pages in the
present issue. And, like the industry, its
interests have broadened to include FM.
television, UHF, and now color television.
However, during the whole quarter century
there have been only minor changes in
format, and no changes at all in editorial
policy.
started to proinformation on
RCA equipment, its uses, its advantages
and its operation, to the broadcast station
engineers who are RCA's customers. That
was, and still is, the primary purpose of
this publication. However, it was recognized from the first that the magazine
could at the same time serve the broader
purpose of providing (as was noted on
the title page of the first issue) "a pleasant and convenient medium for the exchange of ideas and information" among
broadcast engineers everywhere. To this
end the articles printed in BROADCAST
NEWS have not been limited to those
authored by RCA personnel but, from the
first, have included articles by station engineers, consultants and others. Moreover,
the subjects discussed have included many
other than those directly related to RCA
equipment. The happy result is a publicaBROADCAST NEWS was
vide a means of bringing
tion which serves our engineer -customers
(by helping them in their work) while at
the same time serving us by publicizing
our products.
As a result of this policy, broadcast engineers early accepted BROADCAST NEWS
as an ally in their work, and have supported it not only with letters of approval
but. more importantly, by contributing to
its pages. Other members of the industry
-including some of the best-known consultants and designers -have done likewise.
The subject matter, over the years, has
touched almost everything of interest to
station engineers. Only one limitation has
been imposed. It was early decided that
BROADCAST NEws was properly concerned
only with broadcast equipment design, installation and operation. While broadcast
engineers certainly have other-and wider
-interests. it was felt that these were adequately covered in general magazines. On
the other hand, broadcast equipment per
se, received relatively little attention in the
radio journals existing in 1931. And even
today, there is no magazine which devotes
a major part of its content to the technical side of broadcasting. The reason, of
course, is that the field is too specialized
and too limited to support a paid-circulation magazine devoted exclusively to the
field. BROADCAST NEWS, at least to a degree, fills the gap. By strictly limiting its
coverage to the subject, it is able to print
far more information on broadcast equipment than can be found anywhere else.
During its twenty -five years BROADCAST
NEWS has had four editors, numerous as-
sistant editors, and literally scores of editorial advisors and consultants. Many of
these have lavished on it time and effort
far beyond the possible return in either
pay or glory. Were BROADCAST NEWS a
private publication, this twenty -fifth anniversary issue would nostalgically note their
names and credits. But BROADCAST NEWS
is not a personal organ- rather it is the
symbol of a very special business -the
broadcast equipment business of the Radio
Corporation of America. Thus the important thing in its twenty -five year history
is not the names of the many individuals
who contributed to it, but -almost con trariwise -ths. fact that despite individual
comings and goings, depression and boom,
freeze and unfreeze, war and near -war, it
has held steadfastly to a policy set down
a quarter of a century ago.
In doing so it has reflected the continuity. the stability, the foresight of the
RCA Broadcast Equipment Department.
Only for this reason is the twenty -fifth anniversary of BROADCAST NEWS important.
On following pages are reproduced the
lead pages of some of the articles which
have appeared in BROADCAST NEWS over
the years. Many of these mark milestones
in broadcast equipment development. Some
were described for the first time in BROADCAST NEWS. Together these pages form a
sort of capsule history of the technical
progress in our industry. BROADCAST NEWS
is proud of the fact that in bringing these
articles to broadcast engineers the world
over, it has served the industry as well
as RCA.
33
Station KFI, Los Angeles
What
Microphone Placing
Is
Your "Coverage"?
S-
October 19.Zí
FIRST 50 KW WEST OF TEXAS is the way KF1's
then brand -new RCA 50B Transmitter was described in the lead article of the first issue of
BROADCAST NEWS. Author was I. R. Baker,
manager of RCA's transmitter business from 1930
'tit his death in 1943. It was "Bake" who set the
high standards by which RCA has built and sold
broadcast equipment for 30 years. BROADCAST
NEWS. too, was Bake's idea, and it was he who
formulated its policy of "service to the industry ".
October 1931
MICROPHONE TECHNIQUES were discussed in
the second article of the very first issue. Micro-
phone around which the article was written was
the now long- departed (but not much regretted)
condenser type. Simplified diagrams indicated
placement of various musical instruments for best
pickup balance. Author of this article was Ted
Smith, then an RCA Broadcast Salesman, later
manager of transmitter sales, and now Executive
Vice President. Defense Electronic Products.
RCA Victor 100 250 Watt Broadcast
Police Alarm Broadcast
Transmitter
New,
I)rrubrr 1931
INTENSITY SURVEYS, which were just
then coming into general acceptance, and which
were still unfamiliar to most station engineers.
FIELD
were the subject of the third article of the first
issue. Use of surveys in determining coverage
and interference was briefly described as was
the RCA TMV -21 Field Intensity Meter -first commercial instrument of its kind. Author was John
P. Taylor, then sales engineer, now Advertising
Manager, Commercial Electronic Products.
Directional Broa^ci.,
WFLA WSUN
C`:N' GOv'.h
Y
.-IAril
amplifier efficiency of previous models. It was
the first "250-watter "
size which soon thereafter became, and has remained, the standard of
the industry. Author of this article was W. L.
(Larry) Lyndon -who for thirty years has been
helping to develop and design RCA transmitters.
"
34
-a
July
1932
CLASS B MODULATION was used for the first
time in a commercially -built broadcast transmitter
in the RCA Type 100 /250-w transmitter described
in this article. This transmitter doubled the power
19.32
EQUIPMENT produced for general
commercial use was the RCA ET -5000 Transceiver
described in this early article. Previous to this
time all police radio was in the 1600 kc band.
The ET5000, designed specifically for municipal
police use, established a trend which eventually
led to the transfer of all 2 -way radio services to
the VHF bands. Development was considered of
such interest it was included even though the
subject was not strictly broadcast engineering.
FIRST VHF
Jul..
1'r:;_
DIRECTIONAL ANTENNA at WFLA -WSUN, sub.
ject of this article, was the first directive array
used by a broadcast station. Suggested by Comm.
T. A. M. Craven (then the station's consulting engineer) and designed by Raymond Wilmotte, it
was installed under the direction of Walter Tison,
station director. Bed Adler, who as RCA sales
engineer in the area helped the station with
equipment problems, wrote this article one of
the very first reports on the directional operation.
Thé Velocity Microphone
Pioneer "Live -End, Dead -End" Studios
WCAU A Modern
to the
Artof
Monument
Broadcasting
`_....,.
(October 19a'
VELOCITY MICROPHONE, progenitor of a long series of RCA high.quality
microphones, and grand -daddy of today's widely
popular 44 -BX, was described for the first time in
this article by its inventor, Dr. H. F. Olson. Used
for the first time in the "new" WCAU studios
(which opened on Christmas Day 1932) it immediately swept the boards and has ever since
been the most widely -used microphone in high
quality broadcast stations the world over.
THE
RCA 44A
-
-
of the Ekc;n,:
f:I
Unique One Kilowatt Transmitter
The Iconoscope
A M,,dr.11 V.m,o^
.Iunum
LIVE -END. DEAD -END STUDIOS were first used
on a station-wide scale by WNAC Boston in
February 1932. This development in studio acoustics, together with the introduction of the velocity
microphone late in the same year, resulted in a
large improvement in the quality of sound pickup
and led to establishment of new standards of
audio quality. This BROADCAST NEWS article
was written by Gordon Jones, then director of
operations of WNAC and the Yankee Network.
E,:
4.1
,
rx.,.., ,
+ww,
'-.w. ,.....
n.... a, r
I pril 1933
NEW -TYPE STUDIOS, built by WCAU, Philadelphia, in 1932, started a trend in deluxe studio
buildings. Designed specifically for broadcasting
this building housed seven large studios each
with its own independont control room. First with
velocity microphones and other deluxe gear, it
established a new standard. 14 -page article by
Jock Leitch was first "long station story printed
in BROADCAST NEWS. It set a pattern for
picture- stories about outstanding new stations.
Program
Amplifier -1934 Design
..v.v..
v.v...
__.µ-
.
::
I
ueu..I 193:;
was described in detail for
paper by its inventor, Dr. V.
Laboratories. Prepared origProceedings (and reproduced
by permission) this paper appeared as an article
in BROADCAST NEWS some six months before it
was published in the Proceedings. The iconoscope
was the first true "electronic eye" and its development made possible the first all electronic
television system, -developed by RCA.
THE ICONOSCOPE
the first time in this
K. Zworykin of RCA
inally for the I.R.E.
\ ramb,-r
19:;.;
AIR -COOLING. all -A.C. operation. and modern
styling were incorporated in a broadcast transmitter for the first time in the RCA Type I-D
Transmitter described in this article. Previously
all broadcast transmitters employed motor generators to furnish d.c. for tube filaments. And all
1000 -watt transmitters used water-cooled tubes in
the output stage. The 1-D, first transmitter built
in RCA's Camden plant, revolutionized the styling
as well as the design of broadcast transmitters.
I Armin I9:; I
ALL -A.C. OPERATED studio equipment became
practiccl in 1934 when RCA introduced the first
A.C..operated "studio" amplifier -- the famous
RCA Type 40 -C. All previous equipment of this
type had operated either from batteries or from
an oversize plate rectifier. The 40-C was provided
with a built-in power supply which also provided plate voltage for Type 41 -B Preamplifiers.
Used with a 94 -B Monitoring Amplifier, it formed
the first "all -A.C." audio channel.
"
35
Five Hundred Kilowatts
K,...
>r._
..a,,.
.
Tube Consideration
.
in Class B
Ampffication
A
Brief Survey of the Characteristics of
Broadcast Antennas
... ,,
OM
11
RA._,.Ono
r.
-.u.
...
LW
Jo
Iwo
Jaa.
AJJ
moo
Ilnv 1931
designed by RCA engineers and installed at WLW. Cincinnati. in 1934,
is described in this article by Loren F. Jones, then
manager of RCA Broadcast Transmitter Engineering. This mammoth "super-power" transmitter
was operated (under experimental license) by
WLW for several years. It successfully proved
the possibilities of super -power AM broadcasting
by bringing radio programs to thousands of rural
homes which were without primary service.
500 KW TRANSMITTER,
B
The Specific Transmitter Performance
De Luxe Transcription Turntable
Required for High Fidelity
Equipment
Februnr
1935
HIGH FIDELITY standards for transmitters were
discussed for the first time in this article. The
term "high fidelity" was first used to denote high quality audio reproduction by Dr. Irving Wolfe
of RCA Laboratories in 1931 and it had been
the subject of considerable attention in BROADCAST NEWS and elsewhere. However, this article
stated, for the first time, the specific transmitter
performance required for high fidelity broadcast
transmission of the full audio range.
36
.1 ugusl 1934
AMPLIFICATION considerations were
discussed in this article by Loy Barton who developed the "Class B" modulation system while
at the University of Arkansas. Soon after he
joined RCA and helped RCA engineers design
the first broadcast transmitters using Class B modulation. This is one of several articles on Class B
modulation which Mr. Barton wrote especially for
BROADCAST NEWS -typical of many advanced
engineering stories in BROADCAST NEWS.
CLASS
June 1935
TRANSCRIPTION TURNTABLES came of age with
the RCA 70-A introduced in this BROADCAST
NEWS article. The 70 -A was the first practical
high -quality turntable designed specifically for
broadcast station use. In a very short time after
this article appeared the 70 -A became the almost
unanimous choice of stations large and small.
During the two decades since then thousands of
70 -A's, 70 B's, 70 -C's and 70 -D's have been manu.
Iactured and a large number cre still in use.
December 1934
ANTENNA CHARACTERISTICS were discussed in
this first of numerous articles written for BROADCAST NEWS by Dr. G. H. Brown and H. E.
Gihring. Dr. Brown's studies of current distribution on various types of towers, and the relation
cf current distribution to radiation pattern, established the basis on which the design of directive
antenna systems rests. Many
of his articles were
published in BROADCAST NEWS along with
descriptions of station antenna installations.
FOURTH ESTATE VIEWS TELEVISION
December I93/i
TELEVISION PROGRESS REPORTS began in the
fall of 1936, when RCA showed its first full -scale
installation to newsmen, broadcasters and the
industry. In the address printed in this issue
General David Sarnoff, speaking to the assembled
newsmen, said "we have invited you here to
witness an experimental television test so that
progress in this new and promising art may
be reflected to the public factually rather than
through the haze of conjecture or speculation ".
A TURNSTILE ANTENNA FOR USE AT
ULTRA -HIGH FREQUENCIES
TELEVISION
SPACE BECOMES A FACTOR
IS HERE
T
1
9,4
.,.2.....,...,,.._..
rro 6
1)v'cO tnber
\.(,)ember
0.10
1
TURNSTILE ANTENNA was described for the first
time in this article by Dr. G. H. Brown of RCA
Laboratories (reprinted by permission from ELECTRONICS). This first of many turnstile antennas
developed by Dr. Brown and other RCA engineers was intended for VHF AM broadcasting
(Apex), which at the time was enjoying some
attention. Later it was adapted for FM. and -as
the superturnstile- -for VHF television where it is
almost universally used in present-day stations.
NAT.
embodying an entirely
new concept was described in this article by
C. M. Lewis (now Manager. Communications
Products Department of RCA). Earlier studio control consoles incorporated controls only-- amplifiers and power supplies were mounted on nearby racks. The RCA 76 -A Consolette. described
in this article was completely self -contained. It
eliminated racks from the studio control booth and
established a design pattern followed ever since.
STUDIO
CONSOLETTE
S:...,..
.tall 19(0
TELEVISION IS HERE, said the signs and the
newspopers. And it was, if only for a short time.
Simultaneously with the opening of the New York
World's Fair in 1939 RCA began commercial telecasting. The July 1939 issue of BROADCAST
NEWS for the first time offered commorcial television equipment for sale. Included were the
TT-IA Transmitter -first of an illustrious line a field-type camera chain using an iconoscope
as the pickup tube and accessory equipment.
RCA TELEVISION FIELD PICKUP EQUIPMENT
SUPPLY
GMlM
dYG
<üiu
\t
44w1
TRIM
WPM
SNIML
KAY
SCOGLI
CMIA
PERFORMANCE
DESIGNED
OF
WITH CONVEX
BROADCAST
SURFACES
STUDIOS
OF
TELEVISION
PlfW000
PROGRESS
POWFR
4451
,...s
c..l,.
.YsTl,.
talc
1949
described in this article was
the first television camera equipment to be produced commercially. It employed an iconoscope
tube in the camera but was otherwise very similar in arrangement and appearance to field -type
equipment in use today. Equipments of this type
were used by NBC for television development
work during the war. At war's end they became
the pattern for RCA post -war equipment and the
some arrangement of units is still used.
TV CAMERA CHAIN
January
Derernber
194.5
POLYCYLINDRICAL DIFFUSERS for control of
sound were first used on a large scale in the
WFAA (Dallas) Studios constructed lust before
the war. These studios were designed by Dr. C.
P. Boner of the University of Texas using information supplied by RCA engineers who hcd used
this treatment in several RCA Recording Studios.
Dr. Boner's work, reported in this BROADCAST
NEWS article, led to widespread use of poly
-
cylindrical diffusers in radio broadcast studios.
1947
GENERAL SARNOFF'S "ATLANTIC CITY
SPEECH as it is now referred to, appeared in
the December 1947 issue. This is the speech,
mode to the NBC Affiliates Meeting in Atlantic
City in September 1947, in which he strongly ad.
vised the NBC affiliates, and indirectly all stations, to get into television. Those who took his
advice found themselves on the high road. It
was an historic address - and BROADCAST
NEWS broke its "no speeches" rule to print it.
37
PRACTICAL
EQUIPMENT
TELEVISION
LAYOUTS
FOR
STATIONS
BASEBALL
N
UP
TELEVISION
10 DM! SURVEY Or
TOUIRMINT SITUPS
:
OPTIETiNG
1949
TICHNIOVIS
r.
.9'/ri/a/r%in .I7rr
lu.ust
Ilereat ber
1918
IIi1H
CONVENTION TELEVISION came into prominence at the National Republican and Demo-
TELEVISION EQUIPMENT PLANNING has been
discussed in many BROADCAST NEWS articles.
cratic Conventions in Philadelphia in 1948. In
a 20 -page picture- article entitled "Philadelphia
Story - --How TV Stole the Show" the editors of
BROADCAST NEWS described in detail the
equipment setups of the "pool" and of each of
the networks, together with a summary of how
they operated during the convention. Probably no
setup has ever been more thoroughly covered.
One of the first and probably the most comprehensive was this 28 -page article which appeared
in the December 1948 issue. It included block
diagrams, floor layouts, and photographs of six
basic equipment setups. Because of its completeness it became the station engineers' chief planning reference. The basic equipment arrangments
portrayed in it are as good today as in 1948.
.September 1949
BASEBALL TELEVISION was a mainstay of the
programs of many of the first television stations
on the air --and it was one of the things that
helped
to
publicize the new medium
HIGH
GAIN
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September 1949
WPIX BASEBALL was covered in a second article
in the September 1949 issue. Purpose was to
show, in detail, how one station did baseball
pickups. Article included eight pages of "pictures from the monitor" showing typical scene
sequences for various plays. Information for story
was furnished by Tow Howard (then WPIX Chief
Engineer, now Vice -President and Technical Director, WBTV, Charlotte) and Otis Freeman (then
assistant engineer, now Chief Engineer, WPIX(.
38
.,,
Mt.
ANTENNAS
BROADCASTING
WPIX Baseball
..,
tcrlN,
MIN
DIRECTIONAL
by
The
AND
TELEVISION
Case Of The
Five Baseballs
..,. of
entertain
-
The Strange
y.
of
ment. Methods of camera placement and switching were of greet interest to station engineers.
BROADCAST NEWS did a lengthy story on
"Baseball Pickup" in the September 1947 issue
followed it with this very comprehensive "roundup" story in the September 1949 issue.
February 1950
ENGINEERING DISCUSSION has often been
prompted by articles appearing in BROADCAST
NEWS, and this exchange of engineering opinion
is, of course, one of the "services to the industry"
in which BROADCAST NEWS takes great pride.
The discussion note reproduced here resulted
from a letter written to BROADCAST NEWS by
an engineer of the Japanese Broadcasting Corporation about the baseball article which appeared in the September 1949 issue (see left).
.A pril 1950
HIGH -GAIN TV ANTENNAS became of great im-
portance when the "defreeze" set new higher
maximum powers for all TV stations. RCA engineers. anticipating the eventuality of this action,
had been working on the development of such
antennas for several years. Although directional
TV antennas have, so far, been used only in a
few instances, RCA engineers have also been
working on these. This article is one of many
on this subject printed in BROADCAST NEWS.
NEW "Itedgtee
PRESSURE
e-
RIBBON
-
THE
MICROPHONE
REQUIREMENTS
NSW
r.
OF
TELEVISION
Ia
STATION DESIGN
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01 Iv
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ender. Uri. Urre
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HOW TO PLAN FOR COLOR
L
If
"UNOBTRUSIVE" MICROPHONES, of which there
are now a number of types, were introduced for
the first time in this article by Dr. Olson and
John Preston of RCA Laboratories. The microphone described in this article was a laboratory
model of a small -sized pressure- operated ribbon
microphone. This is the microphone which in production became the famed -Starmaker ". It led to
a whole new technique in TV sound pickup, and
to the development of a family cf microphones.
)11111er 1'150
L .1110101011
Jnnunrc
TELEVISION STATION DESIGN has been discussed in many BROADCAST NEWS articles.
from many different viewpoints. One of the most
ccmprehensive and interesting discussions--especially in its forward looking view -was the four
part article written by Dr. Walter J. Duschinsky,
cf which the first appeared in the October 1950
issue. Important basic concepts, such as the
overall approach to - traffic flow" were clearly
enunciated for the first time in this series.
-
'NKY-TV's
experience
with
live color
I03I
COLOR TELEVISION was "covered " by BROADCAST NEWS for the first time in the January 1954
issue. It was not discussed previously because
the standards were so controversial there was
little a station engineer could do about color in
a practical way. However, in December 1953 the
FCC finally approved compatible color. BROADCAST NEWS was ready, and within weeks the
January 1954 issue -devoted exclusively to color
-was in the hands of station engineers.
COLOR
L
ri
EQUIPMENT PLANNING
i.,
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COLOR
Sy
FILM
CAMERA
N. 1107Anowslo
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was described
3.V COLOR FILM CAMERA
IL'rember
in de.
tail, for the first time, in this crti le by Dr. H. N.
Kozanowski, whose advanced development engineering group was responsible for the develop.
ment of this truly revolutionary color film camera.
Previously used film pickup equipments- using
the fly spot technique -had required unwieldy
special -type projectors. The 3.V Camera, because
it could be used with standard TV film projectors,
made color film transmissions practical.
1951
COLOR STATION INSTALLATIONS stories began
with exhaustive descriptions of color installation
and operation at WKY -TV, Oklahoma City;
WBAP -TV, Ft. Worth: and WTMJ -TV, Milwaukee.
These were the first three non-network stations
to start regular color programming. Because their
experience with color was of great interest to all
stations BROADCAST NEWS -wrote up" their
color operations in detail, including not only tech-
nical operation, but also programming experience.
,
,........
-i
-- ---
MAHN/
3- VIDICON
S.Y.
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143.7
COLOR EQUIPMENT PLANNING was discussed at
length in this 32 -page article by L. E. Anderson.
Supervisor of RCA's Studio Systems Engineering.
Describing a "three- step" program for getting into
color it showed by photos, block diagrams and
rack layouts exactly how a station could pro-
gressively add equipment units
to
gradually step
up its color facilities to "all- color " operation. A
large number of stations are following this plan
-it provides for expansion without obsolescence.
39
THE DEVELOPMENT OF THE
COLOR MARKET
vision sets -not at a rate of 3'/z million
a year -but at a rate of 5 million a year.
by THOMAS F. JOYCE
President, Raymond Rosen & Co.. Philadelphia*
What are the keys to the mass color
television market? There are five keys.
First, people don't buy color television sets
just to have an electronic gadget around
the house. Second, the color television set
priced for the mass market. Third, proper
service to insure customer satisfaction.
Fourth, credit facilities to enable people
to buy it on a budget program. And fifth,
the market.
(Excerpts from talk before the NARRA**
Institute. Washington. D.C., August 18, 1956)
You
have heard, or read, any number of
prophecies on when color will arrive. Most
of these predictions have been made by
representatives of TV manufacturers who
have consistently taken a negative approach to color TV. Many of these gloomy
"Gusses" represent the same radio manufacturers, whose business is now predominantly TV, who took a decidedly negative
approach to black- and-white TV before
the war and for a number of years following the war. Therefore, when I make the
statement to you that color is really beginning to move I know I must be prepared to back this statement with facts.
I think I can do that.
At Raymond Rosen our color billings
were $288,000 in July, will run about
$190,000 in August, $400,000 for September. Within a year or so, color TV should
represent a $25,000,000 annual business
for our company alone
we can get the
delivery of the merchandise.
-if
Translated into national business what
does this mean? At the opening of the RCA
Traveling Color Exposition at Gimbels
in Philadelphia on October 15th, General
Sarnoff said, "We expect to manufacture
and sell 200,000 color television sets in
1956, as we originally estimated, and it
estimate that RCA alone
will produce and sell 500,000 color television sets in 1957."
is a conservative
* Raymond Rosen & Co. is the distributor for
RCA Victor Television Receivers (as well as
other RCA products) in eastern Pennsylvania
and southern New Jersey. The market potential
for the market they service is 3.6% of the national potential.
** National Appliance & Radio -TV Dealers
Association.
40
Let's see what we've got. First, color
television broadcasting facilities. You have
to have broadcasting facilities first. When
black- and -white television got going after
the war, there were only five cities in the
United States with black -and -white broadcasting facilities. It was a local service
wasn't a national service.
-it
Thomas F. Joyce
Now you might well ask the question,
"Who is smoking opium ?" Well, let me
tell you, it isn't RCA. General Sarnoff and
Frank Folsom and their associates didn't
build RCA into a company that last year
did over a billion dollars worth of business
by smoking opium. They built it into that
kind of a business by having vision for
the future and the guts to make investments ahead of the future to be prepared
for the future when it arrived.
Let's take a look at the record. Back in
1943, talking before the Federal Communications Commission in an attempt to
get the FCC to give the go -ahead for
black- and -white television after the war,
and although at that time there were only
5 thousand black-and -white television sets
in use, RCA said, "Within 5 years after
the war the industry will be selling 3'/a
million black -and -white television sets a
year."
Now back in those days RCA wasn't just
handing out a lot of propaganda. It was
making plans for investments immediately
after the war
television research. plant
and broadcast facilities to make what they
said was going to happen come true. Again,
the record.
-in
Within five years after the war, the industry was selling black- and -white tele-
It was five years after the war, 1950 to
be exact, before there was coast -to -coast
television broadcasting. What do we have
today? We have 215 television stations
equipped for color in 137 cities. American
Telephone and Telegraph Company has
converted 52,000 of its 75,000 miles of
television interconnecting facilities for
color. We have color broadcasting coast to -coast and border-to- border. It is no
longer a local service. We have two color
television broadcasting networks: The National Broadcasting Company and the
Columbia Broadcasting System.
What about color television programming? NBC, starting in September, a minimum of 80 hours a month, a minimum
of 1 hour a night between 7:30 and 10:30
p.m., 7 days a week. Thirty -nine Spectaculars of
hours, in addition to the
above, between September 1 and June of
next year. CBS
times more color TV
programming than they had a year ago.
1/
-3/
Key No.
to the color television market
at budget prices -not
next year, or 2 years from now, but right
now with BIG COLOR Television at $495
2
is color television
by RCA.
Now, RCA not only has a color television set at $495, but more importantly,
it has a complete line of color television
sets, 10 models to be exact. RCA stylists
have done a wonderful job on the cabinets
1"1"
Thomas
F.
iiiÉri¡iïitKt;
Joyce
Merchant of Television
Article by Mr. Joyce in
January 1944 issue of
BROADCAST NEWS.
BROADCAST NEWS is celebrating its twenty -fifth anniversary this month (see Pg. 32). During all of this twenty -fiveyear period we have adhered closely to our original premise :
namely, that we could best serve the industry by limiting
ourselves to articles about equipment planning, equipment
installation and equipment operation. However. there occasionally comes to our attention an article or paper which;
while not dealing directly with broadcast equipment, is.
nevertheless, so closely related to the interests of broadcasters, and so important to them, that we feel impelled to
bring it to their attention. Tom Joyce's NARDA talk, which
we are printing here, is just such an article. In it Mr. Joyce
forthrightly presents his feelings about the prospects for
color. Certainly this is a subject of great interest -and
importance -to all television broadcasters.
To most of the industry Tom Joyce needs no introduction. A born merchandiser he has spent practically his whole
business life in the marketing end of the radio and television industry. He started with what is now the RCA
Tube Division at Harrison, N. J., in 1922, and rose through
the ranks to positions as advertising manager of the Tube
Division, advertising manager for all of RCA's manufacturing divisions, and, finally, manager of the Radio, Phonograph, and Television Department. At the time of the
World's Fair in 1939 he played an important part in planning RCA's participation in the Fair. as well as the simultaneous announcement of the beginning of `commercial"
television and of TV receiver sales to the public. In 1945,
after 23 years of service, Mr. Joyce left RCA to become
Vice President of Raymond Rosen and Company of Philadelphia. In 1952 he was named President.
Raymond Rosen and Company is the distributor for RCA
Victor Television Receivers (as well as other RCA products)
in eastern Pennsylvania and southern New Jersey. Under
Mr. Joyce's direction the company has been one of the
nation's outstanding distributors of black -and -white television receivers. When color receivers became available
Raymond Rosen and Company immediately recognized the
new opportunity and launched an intensive campaign designed to bring color to the public as fast as possible. As a
result the company quickly became, and has remained, the
nation's number one distributor of color receivers. It was
because of this success, as well as because of his own personal enthusiasm for color, that Tom Joyce was invited
to tell the NARDA Institute about the color market as
he saw it.
This is not the first talk of Mr. Joyce's which we have
published. The first appeared in BROADCAST NEWS, Vol.
No. 38, January 1944. Entitled "The Development of the
Television Market in the Postwar Period" it was delivered
by Mr. Joyce, then manager of RCA's Radio, Phonograph
and Television Department, before the American Television
Society in November, 1943. In it Mr. Joyce plotted in
detail the course which he believed the television receiver
boom would follow.
Let's read what \Ir. Joyce said in his 1943 address:
"Ten per cent (of the homes in areas receiving TV signals)
would represent 741,000 homes with television
in my
opinion this could be attained in two to three years after
the full commercialization of television."
According to RETMA records 975,000 television receivers
were sold in 1948, the third year after -commercialization ".
Thus Mr. Joyce was almost exactly right in his prediction.
Further on in his 1943 talk he said: "In approximately five
years
receiver sales should be at the rate of approximately 2,500,000 units per year." Here again he was close
this rate actually being attained near the end of the fourth
year. In similar fashion, and with almost as great accuracy,
he predicted the growth of the TV networks and the increase in number of stations.
...
...
-
In 1943 Mr. Joyce was able to make these close estimates
because he had made careful surveys in eleven cities across
the country and had studied the whole situation in minute
detail. Similarly, in 1956, he is not talking through his hat.
His firm has conducted test selling campaigns in its own
area, has its own color set sales figures to go on. In addition he has obtained, and carefully studied, the results of
other surveys which have been made. There is probably no
one in the industry who is better qualified than he to forecast the future of color set sales.
-each a beauty
to behold. They are priced
in logical step -ups of $50 from $495 up
to $850. Here is a color TV line to suit
tion. When you sell a color television set
you want to be able to know with complete
confidence that the purchaser is going to
every taste, purpose and purse.
be a happy customer.
Key No. 3 for the mass color television
market is color television installation and
service that guarantees customer satisfac-
In the market served by Raymond
Rosen & Company alone, RCA Service
Company maintains 11 branches, 210
trucks, 250 technicians and $75,000 worth
of color test equipment. All for one reason, to make sure that these color sets are
properly installed and to make certain that
customers are satisfied.
Within the past few months RCA reduced the price of its Color Television
41
Service Contract, including installation and
service for one year, from $139.50 to
$99.50. Now, actually, a Color Television
Service Contract costs less on a price-ratio
basis than a black- and-white contract does.
For example, the average retail price for
a black- and -white television set is about
$254. A one -year RCA Service Contract
is $59.95; therefore, the cost -ratio is
roughly 25%. RCA estimates the average
color sale around $600 retail. With a oneyear contract at $99.50 this is 16%%,
about 1/3 lower to service a color set than
a black- and -white set on a cost ratio basis.
After all, if you buy a Cadillac you expect to pay more for service dollar -wise
but not percentage-wise than when you
buy a Chevrolet.
Key No. 4 to the mass color television
market is credit. The great industries of
America, consumer industries, have been
built on credit-the auto, appliance, and
the furniture industry. The big boom in
home building since the war has been made
possible by credit. A few months ago we
got after the First Pennsylvalia Company,
Philadelphia's largest bank, because they
wanted 25% down with 18 months to pay
on color as against 15% on black-andwhite with 24 months to pay. We sold
Mr. Kelly, the President, on the idea that
a color television set actually was a better
investment than a black- and-white set from
the standpoint of the consumer and, therefore, represented better collateral to the
bank. With the result that the bank reduced the down payment from 25% to
10% but kept the black- and -white at 15%
with 24 months to pay. In other words, for
a lower down payment they are willing to
finance a color television set. When RCA's
1957 color TV line with substantially lower
prices was announced, we asked for 36
months to pay on a color television. In
June the Executive Committee of the First
Pennsylvania Company of Philadelphia
approved 30 months to pay on color as
against 24 on black -and-white with the inducation that at a later date the bank
might go to 36 months on color.
Now, what is the significance of this action by the First Pennsylvania Company?
The significance is this: last year there
were about 2 million television consoles
sold in the United States for more than
$300 retail. We did a tremendous job in
our territory and RCA did a tremendous
job nationally on a console which sold
for $329.95. Now, using the same down
payment across the board with 24 months
to pay on a black- and -white set and 30
months to pay on color, the monthly payment charge is $14.62 on a black -andwhite set and $16.15 on a color set -mak-
42
ing the differential $1.53 a month. I was
taught in school that there were 30 days
in a month. If you divide that into $1.53,
it gets down to the fact that for only 50
a day more your customer can have a color
television set. Now, in talking to a customer a dealer can say, "Look- wouldn't
you spend a nickel to get color, a nickel a
day more to get a color set -the set of
the future -today ?"
The Commercial Credit Corporation of
Baltimore, Maryland, has gone even further than the First Pennsylvania Company.
It has approved 36 months to pay on color.
So have other banks in our area.
Now, why are cold -blooded bankers willing to give 30 months and now 36 months
to pay on color television, but only 24
months on black- and-white? Believe me,
it's not out of the kindness of their hearts.
It's because a color television set is a better investment from their standpoint than
a black- and-white.
If you were operating an airline and
you went in to see one of the big bankers
in the United States-and said, "Look, I
want a loan of 30 million dollars in order
to buy 15 propeller- driven passenger aircraft," the loan officer of that bank would
think you were crazy. Even though all of
the passenger craft that are flying in the
United States are propeller- driven. And
why? Because he knows that jet planes
are on the way; that a jet plane will
carry more passengers faster and at a lower
cost than a propeller- driven plane. You
wouldn't be able to liquidate your investment before the new propeller- driven
planes would be obsolete. The same thing
goes for color. It's tomorrow's TV set
available today.
Now the 5th thing we need is a market.
The estimate is that within the next 12
months, 7 million television sets will be
sold. So, we already have a market. We
have a market that has been conditioned
to buy something that is unnatural;
namely, a picture of something that is the
way it isn't -in black- and-white. Everything we see in life is in color -the clothes
we wear, the food we eat, all the things
we see outdoors and in our homes are in
color. Now, through the miracle of electronics, it becomes possible for the first
time on a mass basis, at an economical
cost, to deliver color pictures to the people
at a price they can afford to pay.
Recently, Daniel Starch was making a
survey of consumer buying intentions of
major appliances, automobiles, etc. In answer to the question, "if you are planning
to buy a television set now, what will it
be, black- and-white or color ?" 53% said
color.
In May we conducted a test campaign
in Wilmington. We said to our dealers,
"Look-we want to put on a concentrated
selling effort on color. We want to work
with the RCA Service Company. The RCA
Service Company has in its Wilmington
shop 15 outside servicemen. They make
hundreds of calls a week. What better time
to talk about a color television set than
when you're in fixing up a broken down
black- and -white set? Let's make these
people color conscious."
So, we gave the servicemen some sales
training. We equipped them with line
folders on color television sets. We put
them in a position to say that if the customer would like to have a free home demonstration without obligation, it would be
arranged. With what results? With the
result that in the last 2 weeks in May,
when we got this program going, we made
more home demonstrations of color television receivers than in the previous
months in Wilmington.
4/
The second thing we accomplished was
to sell more color television sets to the
public in a two -week period than we had
sold in the previous
months. Third,
we had more solid sales prospects unearthed for the future, color television
salesmen reported, than for the previous
4/
4/
months.
Sixteen per cent of all the homes visited
in connection with these regular service
calls said that they wanted a color demonstration now. People don't ask for a home
demonstration unless they are interested
in buying because they know there is an
obligation implied that goes with a free
home demonstration. Sixteen per cent of
them secured home demonstrations during
that period; 35% additional said that they
would be interested in a home demonstration of color television some time this fall.
If you add 16 and 35 together, you get 51.
Remember that Starch figure of 53?
To sum it up: we have color broadcasting facilities, we have color programs, we
have the under $500 big- screen color TV
set, we have service facilities, we have
long -term credit, and we have a demonstrated market. All the five keys to the
mass color market. That's why, with these
factors, plus our demonstrated sales experience, that I make the predictions I do
concerning the buildup in our color TV
sales rate. We are sold on color TV-and
we find that being sold on color TV makes
it easier for us to sell our dealer organization-and through these dealers, the public.
A. R. HOPKINS NAMED MANAGER OF NEW
RCA
COMMERCIAL ELECTRONIC MARKETING DEPARTMENT
Appointment of
A. R. Hopkins to the
newly created post of Manager, Commercial Electronic Marketing Department,
Radio Corporation of America, has been
announced by Arthur L. Malcarney, Vice President and General Manager, RCA
Commercial Electronic Products.
Formerly the Manager of the Broadcast and Television Equipment Department, Mr. Hopkins now assumes broad
administrative and functional responsibilities for the marketing of all RCA commercial electronic products.
The new marketing department will have
functional responsibility for all marketing
activities within the Commercial Electronic
Products organization, and also will administer new product, advertising, sales
promotion, contract, and market research.
The RCA Commercial Electronic Products organization comprises four major
product departments- Broadcast and TV
Equipment, Communications Products,
Theatre and Sound Products (which also
embraces RCA industrial and scientific
equipment) and Bizmac Marketing.
The new Marketing Department has
been established to provide improved customer service for all RCA commercial electronic products. The Department will centralize the planning, direction, and action
essential to meet customer needs promptly
and efficiently.
Mr. Hopkins has been associated with
RCA sales, merchandising and engineering
activities for more than 27 years. He joined
RCA as an engineer in 1929. In 1935, he
transferred to RCA broadcast sales activities and shortly was advanced to Manager, Broadcast Audio Sales. In 1937, he
was assigned to the company's Chicago
office where for nine years he was Broadcast District Manager. then Regional Manager for the former RCA Engineering
Products Department.
In 1946, Mr. Hopkins was advanced to
Sales Manager, Broadcast and Industrial
Department, with headquarters in Camden,
EDWIN C. TRACY APPOINTED MANAGER,
RCA BROADCAST AND TV
DEPARTMENT
Appointment
of Edwin C. 'l'racy as Manager. Broadcast and Television Equipment
Department, Radio Corporation of America. was recently announced by Arthur L.
Malcarney. Vice- President and General
Manager. RCA Commercial Electronic
Products.
Formerly Sales Manager of the department, Mr. Tracy succeeds A. R. Hopkins.
who recently was advanced to the newly
created post of Manager, RCA Commercial Electronic Marketing Department.
As Department Manager. Mr. Tracy
assumes responsibility for all activities
relating to the development, engineering,
marketing, and sales of RCA transmitting
and studio equipment for radio broadcast
stations, color and black -and white TV stations, and closed- circuit TV applications.
N. J. Subsequently, he was advanced to
General Sales Manager, Engineering Products Department; Manager, Broadcast
Marketing Department; and Manager,
Broadcast and TV Equipment Department.
Mr. Tracy has been associated with
RCA engineering and sales activities for
more than 17 years. He joined the RCA
Service Company in 1939 as a television
engineer and shortly thereafter was assigned to RCA's television operations staff
at the New York World's Fair.
During World War II, from 1941 to
1945, he was assigned to numerous field
projects, in this country and abroad, involving the testing, installation, and
maintenance of RCA electronic equipment
developed for the U. S. military forces.
He was honored, in 1942, with a Presidential Citation, presented by President
Franklin D. Roosevelt, for the development of portable test equipment for aircraft altimeters which made possible important time reductions in test procedures.
In 1945, Mr. Tracy transferred to the
RCA broadcast equipment activity as a
field sales engineer, assigned to the Chicago regional office. In 1950, he was
advanced to Field Sales Manager, Broadcast Equipment Sales, with headquarters
in Camden, N. J. Three years later, he
was named Sales Manager for broadcast
equipment.
43
www.americanradiohistory.com
by
J.
W. WENTWORTH and
R.
T.
ROSS
TI" Terminal Equipment Engineering
1500 MILLIAMPERE
POWER SUPPLY
FOR BROADCAST
TV USE
New High Performance Regulated Power
Supply Offers Up to 70 Per Cent Reduction
in Rack Space and
Low Cost Per Milliampere
Considerable interest has been aroused by
RCA's new WP -15 Regulated Power Supply, which was demonstrated at the 1956
NARTB Convention, and announced in
the June, 1956 issue of BROADCAST NEWS.
This article is intended to provide additional information on this significant new
explain why cerpiece of equipment
tain features were included in the design,
and to show how some of the high performance specifications have been achieved.
-to
Objectives of the
WP -15 Design Program
As a first step in the development of a
new power supply to supplement or replace the "old reliable work -horses" in the
RCA line (the WP -33B and the 580-D,
supplying 600 and 400 milliamperes, respectively), a study was undertaken to
yield an up -to -date view of the technical
and economic significance of power supplies in typical broadcast stations. This
study indicated that the power supply
characteristics of greatest importance are
the following:
(a) Basic performance -The main objective of a regulated power supply in a
broadcast station is to provide highly
stabilized +B power to the station's
operating equipment. A good degree
of regulation under varying conditions
of load, line voltage, and temperature
is vital to the proper operation of the
entire plant.
(b) Initial cost.-Power supplies are relatively simple electronic devices, and
hence are relatively inexpensive. The
fact that a rather large number of
supplies is required for a typical
broadcast plant means, however, that
the fraction of the total capital investment required for power supplies
is large enough to justify considerable
emphasis on initial cost.
(
6000000a00000
.yddrdr.sra..
sNlNw!l0lsssti
,
.'
04000000111000609
000414000000004,
0000000000000,.
.
New regulated power supply has two-chassis
construction. The regulator (top) chassis contains only
6 tubes -rectifier chassis contains all the rectifier and
filter elements.
FIG. I.
44
www.americanradiohistory.com
c) Direct operating cost. -The direct operating cost for the tubes and other
limited -life components in power supplies is also quite significant because
of the relatively large number of supplies required for a broadcast plant.
(d) Reliability.-As in the case of most
broadcast equipment, the reliability of
a power supply is probably even more
important than its cost, because a sudden failure can result in a substantial
loss of revenue. It is therefore important that broadcast power supplies be
designed for high reliability, and that
adequate fuses and other safety devices be used to minimize possible
damage and to permit rapid restoration of service in the event of trouble.
.-o
AC
POWER
INPUT
TRANSFORMER
FIG. 2. Simplified block diagram for a regulated power supply.
Performance Stability
The basic circuit configuration for regulated power supplies. shown in block diagram form in Fig. 2, has remained essentially unchanged for a great many years.
Power supplies of various types differ substantially from each other in terms of
performance, however, because of differences in the amount of attention given to
the many small design details that spell
the difference between a run -of- the -mill
design and a truly outstanding one. The
WP -15 is able to provide voltage stabilit
within 0.2 volt (out of 280 volts) with a
ripple voltage of less than 0.002 volt peak to -peak because each circuit and component has been carefully engineered for
optimum performance. Some of the electrical design highlights are described below.
The series amplifier and d -c amplifier in
a regulated power supply comprises a feedback loop, which gives the power supply
its inherent stability. It is a basic principle
in the design of feedback circuits that the
overall performance is best when the feedback loop is called upon to do the least
work. In other words, it is good practice to
make a design as good as possible without
feedback, and then add feedback to get a
substantial bonus in performance.
As applied to power supplies, this means
that IÌ is desirable to design the power
supply with the best possible regulation
even in those circuits which precede the
series regulator. In the WP -15. such good
performance has been achieved by proper
design of the power transformer. by the
use of a high -efficiency germanium rectifier,
and by the use of a choke -input filter (in
preference to the cheaper but less effective
capacitor -input filter used in many power
supplies)
The stability of a regulated power supply can never be any better than that of
the voltage reference against which the
output voltage is compared in the d -c
amplifier. In the WP -15, the voltage reference is provided by a Type 5651 voltage
reference tube, which is the most accurate
.
46
FILTER
RECTIFIER
VOLTAGE
REFERENCE
and stable gaseous -discharge tube commercially available.
Even the mechanical design of a regulated power supply can have a surprising
effect on its stability. The major features
of the WP -15 mechanical design will be
reviewed later in this article, but it should
be observed here that particular care has
been taken to locate the voltage reference
tube and the d -c amplifier well away from
all sources of heat so that they can operate
under stable temperature conditions.
Excellent Regulation
A plus feature in the WP -15 that makes
possible excellent regulation even in cases
where the load is supplied over a long
length of cable is an optional provision
for sampling the output voltage at the load,
rather than at the supply itself. To accomplish this. the connection to the cl-c
amplifier shown at point A in Fig. 2 is
transferred to the load by means of an
additional lead in the power supply cable.
The resistance of the wire carrying current
to the load is thus included in the feedback loop, and is properly compensated for.
The resistance of the return lead conveying the sampled voltage for the d -c amplifier is not significant, because this lead
carries only about one milliampere.
Another significant characteristic of the
WP -15 electrical design is the absence of
a low- frequency resonance problem. In
many power supplies, the filter which precedes the regulator has a natural resonant
frequency at about four or five cycles per
second. A relatively high impedance at this
frequency can cause a supply to "bounce ",
particularly when it is used with an intermittent load. This bounce problem has
been eliminated in the WP -15 by designing
the filter with sufficient capacitance to
make the natural resonant frequency so
low that its effect is negligible.
Mechanical Design Features
The most striking feature of the WP15's mechanical design is its two -package
construction : the transformer, rectifier, and
SERIES
REGULATOR
D C
AMPLIFIER
A
UNREGULATED
OUTPUT
REGULATED
OUTPUT
f-
filter are mounted on a chassis which can
be separated from a second chassis which
contains the regulator tubes, the d -c amplifier, and the voltage reference tube. The
total rack space required for both units is
only 10/ inches, the same space required
for the older 580 -D supply which delivers
only 400 milliamperes!
The use of separate chassis provides considerable flexibility in systems arrangement, and adds to reliability by greatly increasing the number of applications where
trouble -free convection cooling can be used
instead of forced -air ventilation. Since the
regulator tubes are the greatest source of
heat in a power supply (especially where
highly efficient germanium diodes are used
as rectifiers), it is a definite advantage to
be able to mount all the regulators in a
given installation near the tops of their
respective racks, and to mount the rectifier
units near the floor level where the air is
coolest.
It is also desirable in many cases to be
able to locate all the rectifiers for a given
plant in a centralized location, but to locate the regulator units near the equipment
to be powered for greatest operational convenience. Such equipment arrangements
are easily achieved with the WP -15 supply.
To reduce both size and weight, the
transformer and filter chokes for the rectifier unit are of open -core construction.
They are mounted on the back of the
rectifier chassis so as not to interfere with
the ventilation of the germanium stack,
the electrolytic capacitors, or other equipment units mounted above or below the
supply. For personnel safety, the entire
back of the rectifier chassis is fitted with
a perforated metal cover, which is readily
removable for servicing. As an additional
safety feature, indicator lamps are used
on the front and back of both chassis to
indicate the presence of high voltage.
A unique feature of the regulator chassis
is its "split level" construction, which
serves to elevate the fuse holders, meter
jack, and controls so that they can be
(e) Efficiency. -The efficiency of a power
supply affects the indirect operating
cost in two ways-high efficiency
helps to reduce the total power bill
for the station and minimizes the air
conditioning requirement for the
equipment racks.
(f)
-It
is desirable
Space requirements.
to minimize the space required for
power supplies for two reasons: (1)
space costs money in either new or
old buildings, and (2) a reduction in
the space required for power supplies
can make possible room for expansion
in existing installations when rack
space is at a premium.
(g) Personnel safety. -A basic requirement for any equipment is that it be
safe to operate and to service. This
is particularly important in the case
of power supplies providing high
voltage at low source impedance.
(h) Flexibility.-To minimize the number
of equipment types used in a broadcast plant, it is desirable that a power
supply be adaptable to a wide range
of applications. This implies, among
other things, suitability for mounting
in a variety of locations.
The general characteristics of the WP -15
Regulated Power Supply were established
TABLE
I
by giving appropriate weight to each of
the significant characteristics listed above.
It emerged from the design program as a
supply of 1500 milliampere capacity built
in two sections
rectifier unit requiring
7 rack inches. and a regulator unit requiring 3'/z rack inches. Modern components
and design techniques have been used
throughout. In particular, the transformers
and filter choke use modern high- temperature insulation, the rectifier is a high efficiency germanium diode stack and the
regulator tubes are double triodes.
-a
Why 1500 Milliamperes?
A maximum capacity of 1500 milliamperes was decided upon as optimum
for the WP -15 after a careful consideration of the factors of cost, space and systems requirements. In general, the cost per
milliampere for a power supply is reduced
as its maximum capacity is increased. The
reason for this is that the number of corn ponents required for a power supply does
not increase in proportion to its capacity.
Certain functions, such as the d -c amplifier, have much the same requirements for
a supply of any size, while other major
components like transformers and chokes
are increased in size but not in number.
It normally costs less to build one large
transformer or similar component than to
build several smaller ones with the same
- Equipment
total rating. A larger supply also results
in a saving in space relative to a group of
smaller supplies.
The practical upper limit on power supply size is determined primarily by systems requirements, particularly with respect to reliability and flexibility for expansion. If a power supply is large enough
to supply an appreciable fraction of the
total power requirements for a broadcast
plant, it is usually necessary to provide
emergency spare facilities with fairly elaborate switching means (preferably automatic) to achieve the necessary reliability.
An overly large power supply also makes
it difficult to provide for future expansion
without economic waste.
The RCA study of power supply requirements led to the conclusion that 1500
milliamperes was the optimum size for a
modern power supply, because a supply of
this capacity can power a wide variety of
equipment groups, each of which comprises
a functional unit. A few of the many possible equipment groups are shown in Table
I. The 1500 milliampere size makes possible significant cost savings relative to
older, smaller capacity designs, but retains
much of the reliability and flexibility inherent in the use of separate power supplies for each significant equipment unit
or group.
Groups and Power Supply Requirements
EQUIPMENT
PREVIOUS POWER SUPPLY
POWER SUPPLY AND
WP -15
USED
AND SPACE NEEDED
SPACE NOW NEEDED
SAVING
WP -15
171/2"
TK -21
.
,'
i
i
ilIl
S'`
?-
--
1
Black and White
Film Camera
2 WP -33B's
TK 11/31
Black and White
Live Camera
2 WP -33B's
TK -26
2 WP -33B's
Color
Film Camera
1
28"
1
580D
381/2'"
3
580D's
59'/z"
101/2"
1
WP -15
101/2"
2 WP -15's
28"
381/2"
21"
3 WP -33B's
TK -41
2
Color
Live Camera
580D's
63"
2 WP -15's
42"
21"
NOTE: Comparisons are based on the number of WP -33B
and 580D power supplies necessary to provide 1500 ma.
45
reached without risk of touching the hot
regulator tubes. This sanie construction
also provides a relatively cool location for
the voltage reference tube and the d -c
amplifier.
The 6336 regulator tubes are equipped
with simple but effective heat radiators
which help to minimize the air requirements for cooling. No forced ventilation
is required for up to three regulators
mounted immediately adjacent to each
other, or for up to five regulators if a
single -space blank panel (1ïß rack inches)
is mounted between each chassis. Larger
numbers of regulators may be mounted in
a single rack if adequate forced -air ventilation is provided to keep the tube bull)
temperatures within normal ratings.
Installation and Operational
Advantages
Like all RCA broadcast equipment, the
WP -15 is designed to serve as a "building
block" in a variety of operational systems.
ranging from very simple broadcast plants
to highly complex installations. The basic
mechanical design is compatible with other
equipment designs in the RCA line, so a
systems planner has maximum freedom in
determining where to locate the power
supplies. This is particularly advantageous
when planning expansions for existing systems; in such cases, rack space is often
at a premium, and is seldom arranged for
maximum convenience in installing new
equipment. The WP -15 also has a number
fiection output tubes. On the other hand,
it is sometimes desirable to operate the
processing amplifier, colorplexer, or master
monitor without actually having the camera in service. This type of operation is
readily obtained by the interlocked connection shown in Fig. 4 if the camera proper
is connected to Power Supply No. 1 and
the auxiliary equipment is connected to
Power Supply No. 2. In other applications,
it is possible, of course, to cross -connect
the supplies in such a way that neither can
be operated independently of the other.
For additional operating convenience,
the fuse-holders used on the WP -15 are
all of an indicating type : a neon lamp in
the cap of each fuse -holder glows when
the fuse blows out, making it easy to locate troubles rapidly. The 6336 regulator
tubes are all fused separately, so that failure of one tube will not automatically
overload the remaining tubes and cause
then to fail also. Preventive maintenance
to guard against sudden tube failures is
facilitated by provisions for metering the
current drawn by each triode section in
the regulator, using the RCA MI- 21200 -C1
plug -in meter.
The RCA WP -15 Regulated Power Supply thus represents a high current capacity
supply with up to 70 per cent reduction in
rack space priced at only 45 cents per
milliampere. This well -regulated source of
d -c voltage is excellent for television broadcasting; also for closed circuit, communications and laboratory applications.
of electrical design features which make it
easy to install and convenient to use.
One particularly convenient design feature is the provision for interlocking the
control of the regulator and rectifier chassis, or for interlocking two or more supplies
to each other. Figure 3 shows how the a -c
input wiring to the two chassis is interconnected such that OFF -ON control is
possible from either unit. The use of a
relay. as indicated. permits the desired
dual control without the necessity of handling the major current load through the
cable which interconnects the two chassis.
Figure 4 illustrates one possible method
of interlocking two WP -15 power supplies
in such a way that one of them can be
operated independently, while the other
can be used only in combination with the
first. A practical example of a situation
where this type of interlocked connection
desirable is provided by the TK -41 Color
Camera Chain. As indicated in Table I,
the +B requirements of the complete color
camera chain can be supplied by two
WP -15's.. These would normally be connected in such a way that the camera
proper is powered from one supply. while
the processing amplifier, colorplexer, and
master monitor are supplied by the other.
is
Since the processing amplifier provides
drive pulses to the deflection circuits in
the camera, it is necessary that the amplifier be "ON" whenever the camera is operated in order to prevent damage to the de-
RECT FIER
UNITS
REGULATOR
Ì
-
RECTIFIER
UNIT
REGULATOR
UNIT
Í_
I
iY
w
o-.. AUXILIARY
INTERLOCK
RELAY
l
CIRCUIT
MAIN
POWER
Ì
a-
USED
J
II
POWER SUPPLY NO .I
POWER
TRANSFORMER
UNITS
I
SUPPLY NO.2
FILAMENT
TRANSFORMER
AC
INPUT
FIG. 3. Schematic diagram in simplified form showing the a.c wiring
for the WP -15 power supply and interlock connections between the
rectifier and regulator units.
FIG. 4. Diagram showing the a -c wiring for two WP-15 power supplies
in an interlocked connection. In this connection, supply No. 2 can be
used alone. but supply No. 1 is operative only when supply No. 2
is also "On".
47
www.americanradiohistory.com
LATEST DEVELOPMENTS IN VHF
TELEVISION TRANSMITTERS
Unconventional Design Affords Savings in Space, New Convenience
of Operation and Utmost
Ease
Anew
series of low -band RCA VHF
Transmitters is now available with power
outputs ranging from 2 to 25 kw. After
considerable study three power levels (2, 6
and 25 kw) were chosen as most nearly
meeting the requirements of Broadcasters.
The 2 kw rating has been found to be
about the lowest practical power rating for
a VHF station eliminating. of course, satel-
.
by
F. E. TALMAGE,
Broadcast Transmitter Engineering
for Expansion
.
.,.,111
lites, boosters, and proposed drop -ins. A
power rating of 25 kw has been found to
be the most popular rating for obtaining
maximum erp on the low band when
used in conjunction with practical antenna
gains. An intermediate power rating of
6 kw was chosen because it is the most
economical driver unit for our 25 kw
amplifiers.
Features
Design objectives that were established
after a thorough study and which have
been accomplished in these designs, are
as follows:
(1) To make an appreciable reduction in
the amount of floor area required for
the transmitter -in particular, a reduction in the amount of equipment
which must be located in the operating area.
(2) To simplify conversion from a low
power level to a higher level with the
maximum use of the original equipment. This requirement made modulation at the lowest power level of
2 kw essential.
(3) To design the equipment for color,
linearity correctors were built in as
part of the transmitter modulator
thus allowing eventual elimination of
this circuit in the stabilizing amplifier. Inter -carrier frequency control
was also included which accurately
maintains the frequency separation of
the aural and visual carriers.
(4) To provide for remote control. Although this type of operation is not
yet authorized for domestic service it
is necessary, for economic reasons, to
FIG. 1. A front view of the 6 -kw transmitter shows that all of the status lights are grouped near
the top of the control unit. The meters are illuminated by lights instolled in the bottom of the
meter panel making it possible to easily read all of the meters even where room lights have
been dimmed for monitoring purposes.
expect a given transmitter design to
last for many years. It was decided,
therefore, to include as part of the
transmitter all the circuits which
would allow it to be completely controlled from a remote location when
operated in conjunction with commercial remote control equipment. Accordingly, meter shunts and external
terminals are included not only for
the meters required by the FCC but
also in the cathode circuit of all of
the power amplifier tubes above 50
watts rating. In addition, motors are
provided for controlling the power
output of both the visual and the
aural transmitters. In the visual transmitter this includes motor control of
video gain, pedestal level, and r -f excitation to the modulated amplifier.
48
www.americanradiohistory.com
(5) To design the transmitter shielding
so that the r -f radiation from the cabinet is at a minimum in keeping with
the recent FCC requirements on this
subject.
(6) To keep operating cost to a minimum.
The RCA 5762 air cooled triode was
therefore selected for the final amplifier of the 6 kw transmitter as well as
for the 25 kw unit. This tube has
given consistently long life in both
RCA FM transmitters and 25 kw
VHF amplifiers.
Perhaps the most radical departure from
previous convention is the cabinetry of the
2 and 6 kw equipments. To realize an appreciable reduction in floor area some
fundamental changes in construction were
thus indicated.
Space Reduction
Figure 2 shows a comparison between
the general floor plan of these transmitters
and a typical TV transmitter currently in
use. Although it does not necessarily represent the method by which the final design
was arrived at, it does show the fundamental reduction in the floor area that has
been achieved. Figure 2A is the outline of
a conventional transmitter consisting of a
group of racks arranged in a straight line.
Clearance is required in the front and rear
of these racks for access purposes.
FLOOR SPACE REQUIREMENTS FOR CONVENTIONAL TRANSMITTER
REAR
Co//VEA/r/ on/AL
F204 T
A
I
CLEARAA/cE
I
I
I
7-RA
iS M/ T TE,P
_J
CLEA,eA/cE
L_.
FLOOR AREA SAVINGS WITH NEW TRANSMITTER
It can be shown that at least 50 per cent
of a TV transmitter consists of switchgear.
blowers, rectifiers, transformers and filters.
It is not necessary that these items be
visible or even readily accessible from the
operating position. They then can be moved
to the rear as shown in Fig. 2B. It has also
been found that these larger components
normally require access from only one direction. The rear of these racks can then
be mounted directly against the wall with
a saving in floor area as shown by the
shadowed area.
The clearance area in the rear of the
control and r -f units can now be combined
with the clearance required for the front
of the rectifiers and blower, into a combined aisle as shown in Fig. 2C, resulting
in a further saving of floor space. Figure
3 shows the last steps in the evolution
of the TT -6AL transmitter. The doors
were removed from the rear of the r -f unit
and from the front of the rectifier units
and a single enclosure formed with a door
at one end. The design was further simplified and accessibility improved by eliminating the rectifier racks and mounting
the rectifier tubes on the rear wall of the
enclosure and the large transformer and
filter components directly on the floor.
A typical floor plan for the TT -6AL
transmitter is shown in Fig. 3. Although
the complete transmitter is housed in what
is equivalent to a single cabinet, the equipment can be broken down for shipping
into racks and panels of convenient size
for easy handling. The rear wall of the
transmitter contains no access doors or
components so that this side can be
mounted directly against the wall of the
room. Where space is limited, the right
side of the enclosure can also be mounted
against the building wall, provided an
opening for the air intake is made in the
wall opposite the air filter.
CLEA.2A/E
L--- _-J
---I
caA/r,eoL ¢
eF
L------J
I
RF
rca.yT,eaL
L------J
CLEA,eAA/CE
I
CLEA,eAicE
C
Floor plan comparisons between new series of low
band transmitters and a typical TV transmitter in current use.
FIG. 2.
15
V//////r//////////////////////////////////////.[7%////////////////////////////////.%
-rAIR
INTAKE
AIR DUCT
25N. LOW
N
a3
I
SUGGESTED UNDERFLOOR
DUCT LAYOUT
P T
M
I
7C4.í.
OPTIONAL)
TRANSMITTER
N
LE
OVTiONA L
36'. 69'
)
Unusual Flexibility
It has been conventional in the past to
arrange the circuits of a TV transmitter
so that the visual transmitter is on one
cOMB /,ED A/5LEI
CLEA.eA/eE
20
-
24MIN
4
FIG. 3. One possible arrangement of the TT -6AL trans-
mitter showing equivalent of single cabinet housing.
49
www.americanradiohistory.com
end and the aural transmitter is on the
other. In the TT -6AL note the departure
from this convention. The combined control unit for both the visual and the aural
transmitter is located on the left -hand end
of the front row of racks. To the right of
the control unit the driver unit or 2 kw
unit is located. This rack contains both
the aural and visual drivers as well as the
exciter and modulator units and is essentially the r -f and video circuitry of the
complete 2 -kw transmitter. The right -hand
rack contains both the aural and the visual
amplifier units.
Figure 4 illustrates the flexibility of the
TT-6AL transmitter. This arrangement
of particular importance where space
is
in
the operating room is very limited. Doors
have been added to the rear of the control
and r -f racks and a front wall added to
the rectifier enclosure. Since this rectifier
enclosure contains no meters, operating
controls or circuits requiring adjustments,
it can be conveniently located in an adjacent room or in the basement. A further
advantage of this arrangement is that the
remote location of the blower will result
in a reduction in the amount of noise in
the operating room.
Another arrangement, designed primarily for remote operation is possible where
a console is not used. Here, a suggested
location for the remote control racks would
be adjacent to the control unit. The input and monitoring racks would then be
mounted at the opposite end of the transmitter and in line, thus reducing the size
of the room required to house the trans-
IS'
d
N
\
4 -/////////////////////////////////i[//////////////////////////////////
I
E%NAUST
FAN--1
SOO CFN
BLOWER
AIR
INTAKE
OPENING IN
SIDE WALL
RECTIFIER
ENCLOSURE
/
/
-UAIREWCR
//
S\
CEILING EXHAUST
FAN
-4000 CPU
2
1
I
/
s
`\:\\\\\.::\\y\\\
EtR-\
I
NN.
CONTRO
UNIT
PA
UNIT
DRIVER
UNIT
I
SUGGESTED UNDERFLOOR
DUCT
LAYOUT
MOÑIPTORING
\\\
TRANSMITTER
CONSOLE
-
The TT -2BL transmitter is similar to
the 6 -kw transmitter except for a reduction in the front line length. In fact, the
control unit, the r -f unit, rectifier assembly
on the rear wall, and the end panels are
identical to those items used on the
TT -6AL. Only some of the larger components such as the high voltage transformers. filter assemblies and the blower
are different. The large number of identical
items makes it convenient and economical
for a broadcaster to start out with a 2 -kw
transmitter and at a later date increase his
power to 6 kw with a minimum outlay.
Figure 5 shows the TT -25CL transmitter which consists essentially of the
TT -6AL serving as a driver for our present
25 kw amplifiers. A comparison between
the floor area required for the TT -25CL
and the previous design shows a saving in
floor area of approximately 15 per cent.
All of the savings in floor area is brought
about by a reduction in the size of the
driver unit.
Fewer Power Supplies
Thermostatically controlled heaters under the covers keep the base of the
rectifier tubes. which are located on the
rear wall of the enclosure shown in Fig.
10, warm at ambient temperatures as low
as 0 deg. C. A thermostatically controlled
blower cools these tubes when the ambient
temperature exceeds a predetermined value.
Wherever possible the same d -c power
supplies are used for both the visual and
aural amplifiers. This greatly reduces the
number of components in the transmitter
and allows operation of the complete equipment with only 5 power supplies including
the exciter supply. The plate transformer
for the 3,600-volt high voltage supply actually consists of three single -phase units
connected in a three -phase full-wave circuit. The relatively small size of this
single -phase unit greatly simplifies the
handling problem.
Common Visual and Aural Exciter
A block diagram of the common visual
and aural exciter unit and its power supply is shown in Fig. 11. The visual chain
is shown at the bottom. Note that two
separate crystal oscillators are used. Either
oscillator can be selected from a remote
location by a relay which switches the
plate voltage to the proper tube.
(OPTIONAL)
(OPTIONAL
36 69"
mitter and at the same time simplifying
the inter -unit wiring.
I
IN
FIG. 4. Alternative floor plan of TT -6AL for use where operating room space is limited.
50
www.americanradiohistory.com
Another feature is the use of a buffer
amplifier immediately following the crystal
oscillators. This allows operation of the
oscillators with a very low r -f voltage on
S6
6
FOR
TT2SAL
31'
26'
FOR TT2SRL
0
VESTIGIAL SIDEBAND FILTER
AURAL PA
TRAY SF
42
24
_L
VISUAL PA
TRANSF
24i 42.
TT6AL
DRIVER
AURAL
VISUAL
PA
CONT
UNIT
PA
CONT
UNIT
TRANSMITTER
CONSOLE
(on IONAVI
36'+ 69'
k
INPUT
MONITORING
RACKS
(oT16NAL)
FIG. 5. This arrangement illustrates the space requirements of the TT25CL
the crystal. Since one of the major causes
of frequency drift in a crystal controlled
oscillator is heating of the crystal due to
excessive r -f voltage these oscillators are
inherently very stable.
Accurate Frequency Control
The aural chain starts off with a 6V6
master oscillator frequency modulated by
two reactance tubes and followed by a
series of multipliers and amplifiers, which
are identical to those used in the visual
chain. The circuitry making up the frequency control for the aural master oscillator is designed to accurately maintain
the frequency difference between the aural
and visual carriers.
A small amount of the energy from the
aural and visual oscillators is fed to a
mixer tube. When the aural oscillator is on
frequency the output of this mixer will be
1/12 of the frequency difference between
the aural and visual carriers on 375 kc.
This 375 -kc signal combines with the output of a crystal oscillator in a second
mixer. The sum of these two frequencies
is then fed to a chain of three dividers
with a total division of 100. This amount
of division is necessary to reduce the
swing at the frequency detector to a point
where the carrier will not drop out under
any normal conditions of modulation of
the aural transmitter.
t
ansmitter.
A crystal control reference frequency is
also fed to the frequency detector. By
making the same crystal oscillator serve
both as the heterodyne oscillator and as
the frequency reference source, very accurate control of the inter -carrier frequency
can be obtained. Three dividers with a
total division of 80 are employed in the
reference frequency circuit. The frequency
detector is essentially a balanced modulator with a d -c component in the output
which will change polarity depending upon
whether the signal frequency is above or
below the reference frequency circuit. This
d -c voltage is fed back to the reactance
tubes in such a way as to correct the frequency of the master oscillator.
When the frequency of the master oscillator has been corrected so that the signal frequency and the reference frequency
at the detector are the same, the frequency
detector then functions as a phase detector.
The operation of this circuit differs from
a conventional discriminator in that no
error in frequency is necessary in order for
Control unit is shown with door open.
Auxiliary switches are located on the panel in
the center. Above this panel are all the overload relays as well as the auxiliary relays associated with the overload recycling circuit.
FIG. 6.
51
www.americanradiohistory.com
a correction voltage to exist at the reactance tubes. The error of the difference
frequency is therefore a function of and
directly proportional to the accuracy of
the reference crystal oscillator. This means
that the difference frequency between the
aural and visual carriers can easily be
held to several hundred cycles, even without a temperature controlled crystal in
the reference -oscillator circuit.
FIG. 7. Lower half of the
2 -kw driver rack with the
lower access doors open,
showing the combined
visual and aural exciter
unit which can be seen on
the left and the modulator
on the right.
A frequency- interlock circuit is included
and can be connected either to an alarm
or to the transmitter -interlock circuit and
thus prevent application of plate power to
the amplifiers until the frequency control
circuits are locked in. This type of frequency circuit has several inherent advantages in addition to the accuracy of
frequency control. The tuning of the frequency control circuit is the same for all
channels and therefore can be preset at the
factory before the equipment is shipped.
In the event of a failure in the frequency
control circuit the master oscillator can
be switched to manual frequency control.
This oscillator is inherently quite stable
and will maintain its frequency within
tolerance for long periods of time after it
has once warmed up. While the master
oscillator is being manually controlled the
frequency control circuit can be serviced
and program continuity maintained.
FIG. 8. The modulator unit
is hinged at the bottom
allowing it to be tilted
forward for servicing.
Minimum Tube Cost
The 2 -kw transmitter is shown in the
block diagram of Fig. 12. Note that in an
effort to keep tube cost to a minimum the
tubes in the visual and aural chain are
different. The visual chain consists of three
stages ending with a grid -modulated 6076
tube while the aural chain consists of only
two stages ending with a 4 -1000A tube.
transmitter the r -f circuit
that used in the 2-kw transmitter except that two 5762 tubes operatIn the
6 -kw
is the same as
ing in a grounded grid linear amplifier circuit have been added to the visual chain
and a single 5762 tube added to the
aural chain.
FIG. 9.
Exciter unit tilted
forward for servicing. No
exposed circuits of the ex.
citer chassis contain volt.
ages above 350 volts.
Thus, no interlocking is
required.
Built-in Linearity Correction
A block diagram of the modulator unit
is shown in Fig. 13. Note that two stages
of approximately unity gain have been included to provide for linearity correction.
The output stage is a high efficiency
shunt -regulated cathode follower. Back
porch clamping is employed. Sync for the
clamp circuit is separated at a low level
and amplified in a separate chain of tubes
thus providing reliable clamping even with
a very degraded input signal.
The signal is clamped in two stages;
therefore, any hum which may be present
on the input signal will be greatly reduced
in the modulator. This together with the
fact that the linearity correction circuits
are built into the modulator may, in many
cases, eliminate the necessity for a stabilizing amplifier at the transmitter location.
It will be noted from the block diagram
that the monitor amplifier can be switched
to many parts of the circuit, greatly aiding
in making adjustments and in servicing.
Unattended Operation
A simplified schematic of the carrier -off
monitor unit is shown in Fig. 15. This is
a protective device and is being offered as
optional equipment and is of particular
value for unattended operation. It is also
being recommended for use with RCA 25
kw and 50 kw amplifiers. It is essentially
a comparison device and functions from
information supplied by the two reflectom-
eter units.
When used with the 25-kw or 50 -kw
transmitters it will compare the voltages
from the output reflectometer and the
driver reflectometer. As long as the input
and output of the amplifiers are propor-
10. View of the rear
wall of the transmitter enclosure showing the rectifier
tubes and thermostatically
controlled heaters under the
FIG.
covers.
6v6
REACTOR
TUBE
6v6
AUDIO
F
NP UT
O5C
5763
TRIPLER
5763
DOUBLER
5763
DOUBLER
_ol5763
AMPLIFIER
AURAL
R F
OUTPUT
REAC6v6TOR
TUBE
DIVIDERS
6A 56
SECOND
MIXER
6AQ5
AMPLIFIER
6AC7
-
6AC7
-5
5
2021
OFF -FRED,
INTERLOCK
6AC7
-4
6AC7
-S
12 AT7
FREQUENCY
DETECTOR
300v
6AK5
X
TAL
OSC
NOI
5763
TRIPLER
5763
DOUBLER
5763
DOUBLER
150v
t
DIVIDERS
5763
AMPLIFIER
VISUAL
R F
OUTPUT
6AK5
003
t
VOLTAGE
REGULATOR
POWER
SUPPL
STACKED
.E RMANIUM
RECTIFIER
ATAL
OSC NO 2
FIG. I1. Block diagram of the combined aural and visual exciter unit.
53
www.americanradiohistory.com
I
350
III
vIDEO
INPUT
1
FIG. 12. This is a block diagram
of the 2 -kw transmitter.
I-
MODULATOR'
-27476
L____1
54I
IST VISUAL
AMPLIFIER
VISUAL MOD
AMPLIFIER
6076
2 V652
4- 65A
2V65O
V S
I
+N01
AUDIO
AURAL
VISUAL
INPUT
EXCITER
MI
+700
+3800
-100
I
MI- l9051Á
+3800
+600
_J
ITRINGI
MONO
DIODE
250
TO
DIPLE%ER
EI F
REG
+0
J
-27475
TO
600
NO
+250
+0
NO2
-50
-50
+2100
l
TO 600
NO2
I +3800
t
t
20
AURAL
AMPLIFIER
AURAL
AMPLIFIER
IST
4
-65A
4-1000A
2
V600
2 V6O1
TO
DIPLEXEP
i
AURAL
REFLECTOME TER
I
+0
N0.2
+070600
+700
6AL5
6VI
TO 600
NOI
II
-900 -100 -50 -50 -50
-500 +350 +575
2100
+600 +250 +250
REG
t
t
t
SUPPLY
LOW
RECTIFIER
2 8665
MI
3
-27469
IV203
165L7
12 V II
12V10
VO LTAGE
RECTIFIER
6 673s
5R4GY
I2V9
IV205
2 56515 1V202
+3800
NIGH
2 8665
6A575 IV204
1V206
V8
12
MODULATOR RECTIFIER
AND FIXED BIAS
VOLTAGE
REGULATOR
LOW
VOLTAGE
12V7
NOI NO2
12V1 THROUGH
1V201
12V6
(OPTIONAL)
ali
575
]A6 VIDEO
A 4PL FIER
607
]no
SO
VIDEO
AMPLIFIER
250
REG
OA2
676
MODULATOR
MOM)
6136
ATOR
REG
O2
61416
REF
5651
607
REF
5651
250CLAMP
CLAMP
6AL5
6AL5
SYNC AMPL
SYNC
If
C
j6SN7GT
6SN7GT
R
SYNC
PU
SEP
j6SN7CT
SE
GEN
I6SN7GT
I
N0TE. 5303 CONNECTS
CLIPPER
PULSE AMP.
165N7GT
CLIPPER
j 65N7GT
PULSE AMPL
565
MODULATOR
MDOULA70R
61416
61,16
MODULATOR
61 ,16
REF
5651
j65N7GT
1RSN7GT
RE
0A2
REF
5651
BLACR
LEVEL
106
TO
POINTS MARRED
-as
IPPER
RE
3]0]
MONITOR
MONITOR
AMPLIF.ER
6ÁO7
AMPLIFIER
6ÁO7
REF
5651
MONITOR
O
75
ISO
.250
REG
REGULATO
062
OD3
475 REG
REG
t
EWLATOR
REGULATOR
6Á5l6
6A57G
DC
AMPLIFIER
65L7GT
DC
AMPLIFIER
651.741
REGULATOR
REGULA OR
6Á57G
6AS7G
FIG. 13. Modulator block diagram show-
ing inclusion of two stages of approximately unity gain for linearity correction.
54
350
s,5
MODULATOR
OUTPUT
FIG. 14. Rear view of the 2 -kw r -f unit showing the visual chain on the left and aural chain
on the right.
tional to a preset value the monitor will
not operate. In the event of an r -f arc
inside the amplifier circuit which, in a
broadband amplifier does not necessarily
detune the circuit enough to operate the
overload relays in the cathode circuits of
the tubes, this balance will be upset. The
monitor will then operate and the relay
in its cathode circuit will trip the transmitter interlock. If desired, this unit can
also be connected to compare the output
of the reflectometer to a d -c voltage or to
the output of the modulator. In the latter
case, it will of course be necessary to connect to a circuit in the modulator where
the d -c components are maintained.
Thus, these new space -saving RCA
VHF transmitters represent the answer to
medium power low band requirements. A
simple power increase resulting from a
minimum of changes converts the TT-6AL
transmitter for 25 -kw operation. The departure from standard design concept,
insofar as cabinetry is concerned, has
yielded an appreciable and valuable saving in space.
TO OUTPUT
RE FL ECTOM ETER
TO DRIVER
RE FLECTOM ET ER
OR MODULATOR OUTPUT
6+
OD3
FROM
TRANS M ITTER
TO
TRANSMITTER
INTERLOCK
FIG. 15. A simplified schematic of the
carrier-off monitor unit.
55
TV and the
Pioneer St. Louis ETV Station Tackles Teacher -Classroom
by PAUL A. GREENMEYER, Managing F.diI'r. BROADCAST
NEII.i
and
LOUIS
KETC,
St. Louis's educational TV
station, is one of the pioneers engaged in
a vast evaluation program to find the exact
place of television as an aid to education.
It is an exceptional example of cooperation,
involving two higher educational instituWashington University and St.
tions
Louis University
and some fifty different
school systems, both public and parochial.
As a non -profit community- supported
institution, KETC derives its financial
support from Mr. Average Citizen, various
school systems, private foundations and
industrial corporations. Local commercial
radio and TV stations are lending support
to the experiment. The two metropolitan
daily newspapers
the Globe-Democrat
and the Post-Dispatch-and the St. Louis
Public Library are also among its chief
supporters.
-
-
-
An impressive list of solid accomplishments in the station's first year and a half
of operation includes: substantial enrichment of the St. Louis primary grades'
curriculum through direct school program
service; production of a record number of
first -rate programs for national distribution
through the Educational Television and
Radio Center; development of a new TV
56
T.
IGLEHART, Director of Public Relations. KETC
programming concept for children at home;
and the presentation of an excellent array
of music, drama, art, and public affairs
programs for its adult viewing audience.
In addition, several college -level courses
have been offered for credit, including a
course in algebra and trigonometry for
"up- grading" engineers in local industrial
plants. In the advanced planning stage is
a proposed "College of the Air ", in which
a complete two -year Liberal Arts curriculum would be offered as a joint project
involving Washington University, St. Louis
University and KETC.
Station Management
Governing body of this non -profit enterprise is the St. Louis Educational Television
Commission
a group of St. Louisan
prominent in the fields of education, civic
affairs, business, and labor. The Commission has placed full administrative responsibility on the station management. It
makes programming decisions, usually in
consultations with specialists, and it sets
budgets for Commission approval.
-
At the outset, management of KETC
was put in the hands of men with experi-
ence in the production end of commercial
television. This experience has been of
great value to the station operation. But
the management of an educational station
involves a balancing of resources and purposes remote from commercial TV. Hence
the Commission decided that an Executive
Director should be appointed for the station with the administrative experience and
additional orientation required for the head
of an educational institution. A station
operations manager with professional experience in television production was appointed to be responsible to the director.
In September 1955, the Commission
announced the appointment of Arthur H.
Compton, former chancellor of Washington
University, as Executive Director; and
George L. Arms, formerly of KUHT,
Houston, Texas, as Operations Manager.
Arms' top operational management team
consists of Clair R. Tettemer (former TV
producer of "Ohio School of the Air" at
Ohio State University), Director of School
Programs ; Jack A. Chenoweth (formerly
with WLW -TV), Chief Engineer and Facilities Supervisor; and Vincent Park, promoted from KE'l'C Senior Producer to
Production Supervisor.
Crisis in Education
Shortage and Gives Engineer- Starved Industry Imaginative Boost
Photo Credits: Paul J. Adams, h'ETC Stop' Photographer
1. Dr. Arthur Holly Compton, first Chairman of the St. Louis Corn.
mission, Nobel Prize winning physicist and former Chancellor of Washington University. said on accepting appointment as Executive Director
of KEPC: "It is the challenge of the effectiveness of TV in shaping American thought that induces me to turn my prime efforts toward its use. "
FIG.
2.
George L. Arms (left). KETC Operations Manager, and Clair
Tettemer, Director of School Programs, meet on Channel 9 set to discuss
KETC's fall school programs. Teachers polled indicated that all 14 of
I(ETC's school program series made "a contribution to the learning
situation over and above what the teacher was doing in the classroom. "'
FIG.
57
www.americanradiohistory.com
Crisis in Education
KETC's Manager, George
L. Arms, an educational television veteran has expressed strong feelings about the role of television
as an aid to education. Typical of his direct and incisive comments are these excerpts from his speech delivered to several
large St. Louis civic and service organizations:
"Television is new. Its national impact has been within the last
five years. It is expensive. It is technically imperfect. It has certain
arbitrary limitations. But we know this much about television. Students
learn as much from televised instruction as they do in a conventional
classroom. Not always; not in every subject and not at every level;
but in enough subjects and at enough levels to invoke the feeling
that television can be used as a major educative tool.
"Now let us be accurate. We do not hold that formal education
by television is a replacement for, nor equivalent to the traditional
educational ideal of a teacher working closely with a small group of
students. But when the ideal is unattainable, we must do something
more than to lament the good old days.
"Does anyone seriously think that we can double the number of
college classrooms in fifteen years? Does anyone seriously think we
can double the number of trained faculty members in fifteen years?
Let's be realistic and plan to meet the challenge of the coming
years with the new resources of the coming years.
"Let us remember: if an educational television station obviates
the necessity for the construction of one major building on a college
campus it has paid for the cost of its installation and operation for
five years.
"This is basically an administrative problem. Students are not
going to storm the academic bastions demanding that college courses
be put on television; Academicians are not going to demand the
right of exposure to the thousands instead of the tens; and educational
television station operators themselves are in no position to bring
pressure to bear for this kind of evolution. But most of the key experiments have already been made. It has been competently demonstrated that this kind of educational television is academically sound,
and physically workable. We now need immediate recognition of the
implications by key administrators who have the willingness to orient
their school systems, college or state organization to a continued
series of controlled experiments in various areas. Then as the pressures mount from grade to grade television and education alike will
be ready to meet the expansion needed at each level.
"Who says educational television
expensive? Education is expenand television together
offer the only economically probable way to meet the floods of
youngsters that are storming the doors of our schools and colleges
with anything more than a raised palm and a pious look towards
the nearest state legislature. We have predicated an important
aspect of our American democracy on the right to an education.
We can continue to meet our obligations, if we get education on
television. Is it not about time we got started ?"
sive. Television is expensive.
is
But education
The Commission has been studying possible uses of TV in connection with the
serious educational crisis developing from
a rising birth rate and growing teacher
shortage. It has been estimated that
8,000,000 more students must be accommodated by 1960. In order to maintain
present student -teacher ratios it would be
necessary in a few years for one -half of
all college graduates to become teachers.
Research done recently. however, has
shown that students can learn some subjects as well over television as in the actual
presence of the teacher. In attacking this
problem, the Commission proposed to the
Fund for the Advancement of Education
that support be given to some imaginative
and systematic experimentation on a large
scale to determine how television might be
used effectively in schools.
The Commission made it clear that this
proposal to replace all live teachers
with elecronic instruments. In some subjects the role of the classroom teacher
might be revised to the leading of students
in discussion, based on lectures and demonstrations which have been transmitted by
TV. It gives the teacher more time for
counseling and for personal work. It multiplies the range of the teacher's service a
hundredfold.
is not a
To assist in solution of this problem the
Fund for Advancement of Education made
a grant to the Commission of $95,000 for
the teaching of three experimental courses
on the high school and elementary school
levels. The Fund said, "We feel this
demonstration in St. Louis is likely to have
far -reaching implications for American education." This project is being carried on
in addition to KETC's regular school
program service.
TV Teaching Project
School Program Director Tettemer says
of this project financed by the Ford Foundation, "The results of direct teaching to
large groups by television are being com-
prehensively evaluated. Teachers working
on this project have been released by the
school system for this specific purpose so
that the planning and presentation of these
television lessons is their major assignment
for the year. Three courses are being
tested in this experiment
second grade
spelling, ninth grade English composition,
and ninth grade general science."
-
The evaluation program
is
being carried
on to answer such questions as:
Can large groups be taught by television
as effectively as by standard classroom
methods?
58
www.americanradiohistory.com
What are the difficulties in the handling
of these large groups?
What are the limitations of teaching by
television?
Students participating in this program
are assigned to a television experimental
group or a standard classroom controlled
group. The experimental and controlled
groups have been matched according to
IQ, socio-economic background, reading
level, and educational.
The television classroom size ran up to
150 in one room. These groups watched the
television lessons on four 24 -inch direct
viewing sets. The sets were mounted on
special stands and auxiliary speakers were
installed. This gave every student a clear
view of at least two sets.
The Fund for the Advancement of Education grant for carrying out this project
was received in the summer of 1955. Planning and preparation took several months
and the experiment officially started February 8, 1956. The final results will be
available early in 1957.
School Program Service
Apart from this special evaluation project, KETC maintains a sustaining and
varied direct program service to schools in
the St. Louis area. Television sets have
been installed in several hundred elementary and secondary schools in the metropolitan area. These include public, parochial and independent schools in the City
and surrounding counties in Missouri, plus
several counties across the Mississippi
River in Illinois. During the school year,
KETC broadcasts programs primarily for
reception in the schools. These programs
can be received in homes since they are
broadcast on Channel 9. The responsibility
for these school programs rests solely with
the educators in the St. Louis area. Groups
of teachers from the schools plan, prepare
and present these programs. The station
furnishes the staff for the production of the
television programs.
FIG. 3. Starting September 24. KETC will telecast
programs exclusively for the schools from 9 a.m.
to 3 p.m. continuously five days a week.
Programming scope at KETC is great,
ranging from puppets for pre-school children to
college.level credit telecourses for adults.
FIG. 4.
Each series has a television teacher who
appears on all programs. Since the job
requires personality as well as knowledge,
these teachers are selected by competitive
auditions. The best TV teacher is the one
who combines a pleasing personality with
an expert visual presentation of a subject.
The school program service supplements
the regular classroom instruction and,
therefore, enriches the curriculum. Through
the power of TV, children in hundreds of
schools are simultaneously given experiences they could not have by any other
means. They take field trips, witness
FIG. 5. St. Louis Mayor Raymond R. Tucker explains city budget to a group of high school
students on KETC public affairs programs.
59
www.americanradiohistory.com
scientific demonstrations, hear fine music,
and listen to good literature. Television
gives every school and every student a
great new window to the world.
College of the Air Plan
Perhaps the most challenging of the
projects envisioned by KETC is the proposed "College of the Air". Under this
plan, a complete liberal arts curriculum
for the first two years of college would be
offered over television. Students successfully completing the courses would be eligible for the degree of "Associate in Arts ".
The stated purposes of such an undertaking are revealing: "To enlarge the
opportunities for higher education . . .
for those unable to enroll in college immediately after high school
for interested
and qualified adults, and for those who
might otherwise be excluded
because
of shortages in teaching personnel and
physical facilities
and to operate as a
`pilot experiment' that may be of service in
other parts of America."
...
...
...
FIG. 6. Brookings Hall of Washington University. The
university gave the use of its land on the northwest
corner of the campus for new KETC studio building.
KETC Manager George Arms emphasized the nature of the undertaking when
he stated, "This is not a move to replace
the teacher, to abandon the campus, or to
lower educational standards. It is an attempt to assess the possible role of television in meeting the impending crisis
caused by teacher and classroom shortage.
"We do not know how well, or even
whether, it will work, but we do feel that
it offers a splendid chance to evaluate television's effectiveness in helping to provide
adequate educational opportunity in a
democratic society."
A Joint Committee representing Washington University, St. Louis University,
and KETC has submitted a proposal to
the Fund for the Advancement of Education requesting funds to underwrite this
experiment for a six year period. Many
difficult problems inherent in such an ambitious undertaking were discussed and
ironed out by the representatives to this
Joint Committee. The range of problems,
academic and administrative, was vast:
Registration procedure, transfer of credits;
mutually acceptable curriculum; amount
of supplemental classroom, laboratory and
residence requirements; criteria for selection of faculty (involving teachers from
both universities in addition to visiting
lecturers of national prominence); relation
of "College of the Air" to traditional university administration and control ; etc.
FIG. 7.
use of
Aerial view of St. Louis University. The university gave
its grounds for erection of KETC transmitter and antenna.
60
www.americanradiohistory.com
There was a remarkable display of cooperation and agreement between the two
universities on these critical issues. The
s
FIG. 8. A class of Emerson Electric Company employees views with attention a KETC college mathematics telecast in
company's offices. The five -credit freshman course for on- the -iob training was inaugurated in an effort to help fill the nation's
critical shortage of engineers. Over 100 employees viewed 45- minute lectures in college algebra and trigonometry four days
each week. Once a week an instructor met with groups of around 20 students for a problem -working laboratory session.
joint proposal
was prepared in final form
in a relatively short time as a result of this
harmony and the final action now rests
with the Fund for the Advancement of
Education. Once the experiment is under
way, the eyes of the academic world, indeed of every American interested in the
future of education, will be focused on St.
Louis and KETC.
Experiment
Earlier this year, KETC initiated another
educational project with far reaching implications. In cooperation with the Department of Mathematics of Washington
University, a five hour credit course in
algebra and trigonometry was telecast for
a small but important basic audience. The
"students" were 121 employees of Emerson Electric Company. They attended
"classes" during regular working hours in
special rooms provided for them at EmerKETC and the Emerson
son's St. Louis plants. Their tuition was
paid by the company.
Four days a week they viewed 45 minute
lectures presented on KETC by Washington University's Professor Ross R. Middle miss. On Tuesday of each week Professor
Middlemiss met with his pupils at the
plant for personal help, consultation,
quizzes, and examinations. The course was
the University's basic freshman course,
Math 115, undiluted in scope and content
and running for a full semester. Practically
all of the students who began the course
went through the entire semester.
How did
this remarkable experiment
come about? KETC's George Arms says,
"I had been casting about for a specific
project which could demonstrate educational television's usefulness to the St.
Louis industrial community. Due to the
critical shortage of trained engineers with
which all technical industries are faced, 1
thought this might be the field where we
could prove most helpful. The Washington
University Mathematics Department and
Emerson Electric Company responded immediately to the proposal. Within a week
after my initial contact, we were underway with our first TV credit course for
industry."
On- the -Job TV Training
This unique method of helping industry
its trained engineer shortage
attracted widespread attention, especially
among other firms faced with the same
problem. On the basis of the interest expressed it is expected that KETC will
cope with
re- schedule this course and perhaps others
in the fall with many more companies participating in what has become known as
the "Emerson Experiment".
61
Station Equipment
The station operates on Channel 9, with
a 5 -KW RCA TT -5A transmitter and an
effective radiated power of 30,000 watts.
Its signal covers a radius of approximately
50 miles, serving a population of some two
million people.
Two field cameras, type TK -11, are used
for both studio and remote pickup. The
control equipment includes two field monitors, one film control unit, one field type
master monitor and a field type switcher.
A 600 -foot Ideco triangular tower is located on some of the highest ground in
the area. It is topped by an RCA Type
TF-6AH 6 -bay superturnstile antenna.
(This is the bottom half of a 12 -bay antenna so that the other 6 -bay section can
easily be added for expansion to higher
power.)
a Navy Panther jet fighter
parking lot for live show telecast.
FIG. 9. Though not equipped to do remotes,
was transported
to the KETC studio
FIG. 10. RCA TT -5A transmitter showing input equipment.
Earl Nelson operator.
11. View at rear of transmitter showing
mounting of diplexer and phasing section. Ps.'
transmission line was used for construction of
phasing section. All other line is 31s Teflon.
FIG.
Transmitter Building
This is on the grounds of the St. Louis
University several miles from the studio
building. RCA microwave equipment is
used for the link from the studio to the
transmitter. The transmitter building features one large room in which is installed
the 5 -KW transmitter (Fig. 10). The side band filter and diplexer are mounted behind
the transmitter (Fig. 11) The control
console is directly in front of the transmitter. At the left of the control console
is rack -mounted equipment and microwave
terminating equipment. At the right of the
control console is space for an engineering work bench used for maintenance and
repair work. Here also are shelves for
.
storing tubes and spare parts.
FIG. 12.
View of base of transmitting lower showing microwave receiver
to pick up signal from passive reflector mounted on tower.
antenna mounted
63
www.americanradiohistory.com
FIG. 13. The Baer Memorial Studio, home of KETC.
The studio was constructed as the result of a gift
from Arthur Baer, president of Stix Baer & Fuller
Co., as a memorial to his parents. Julius and Freda
Baer. The studio went into operation March 1, 1955.
44.
.
_...._.
_.,.
t.
FIG. 14. Floor plans of the Baer
Memorial Studio, station KETC.
BASEMENT PLAN
FILM
KINESCOPE
PROuECIION
RECORDING
)NFERENCE
.;
DAR
ENGINEERING
000P
GE
FIRST FLOOR PLAN
www.americanradiohistory.com
I'S.
Main Building
A new building designed by Jack Chenoweth, Chief Engineer of KETC, was constructed recently on ground made available
by Washington University. Called the
Julius and Freda Baer Memorial. its construction was made possible by a grant
from Arthur B. Baer, prominent St. Louis
department store executive and strong
booster of all KETC activities. Construction is economical in cost and generous in
space due to the use of a unique product
called Cemsteel. This is a panel type construction using cemesto board and light
gauge steel. The facade of the building is
of masonry construction. There are 15,000
square feet of floor space and the entire
building is air conditioned.
The accompanying layout shows the
numerous offices as well as studios and
other facilities and room for expansion that
have been incorporated in the structure.
Studio
FIG. 15. Video operator controlling
In the studio the acoustics problem is
solved by lining the ceiling and walls with
fiber glass panels held in place with
`chicken wire.' Overhead tracks carrying
drapes of various colors allow the studio
to be divided into three separate areas.
There are several fixed sets, for example,
the fireplace corner and a puppet stage.
These fixed backgrounds can be covered
by the drapes in order to change settings
rapidly.
studio lights. Operator is Frank
Muriel, staff engineer. on duty.
Lighting control panel located at video control operator's
position. Lights are relay controlled
and may be preset.
FIG. 16.
Studio Lighting
The studio lighting system was designed
by Chief Engineer Chenoweth so that the
master control can handle several shows at
one time. Conventional lighting grids each
accommodate a total of forty outlets which
are operated by individual three -position
toggle switches controlling relays. The outlets are divided into four groups of ten
each and each group is controlled by two
master switches. For example, a change
can be made from high- to low -key lighting of any group by throwing one master
off and the other on.
Complete lighting for a program can be
preset by the individual switches and then
the complete bank turned on by merely
throwing a master switch. While one program is running, lights can be preset for
another so that by turning one master off
and the other on, it will completely light
the second set.
Critical lights can be arranged and
switches set in advance from the control
position. The video operator can manipulate light switches by merely turning
around. Eight different combinations are
possible.
FIG. 17. Part of light grid in studio to show unique conduit
construction that supports lights and also carries wiring.
65
FIG. 18. View of control room showing video equipment-two field
camera controls, auxiliary switcher, film cornera control, master monitor and field switcher. Operators Carl Johnson (left) and Frank Muriel.
FIG. 19. Front of camera showing mounting of
3-inch Fresnel light used for filling eye shadows.
Illuminating studio cards, etc.
Projection room is equipped with RCA iconoscope film
camera, grey telop and 16mm projector. Operator Walter bake.
FIG. 21. KETC film editing room with Dan Loving
FIG. 20.
'fhe lighting grid was designed for low
cost construction. It is built of 11/4 -inch
conduit that serves two purposes. It acts
as support for the lights and it also carries
the wiring. Receptacle boxes for outlets
are built directly into the grid.
Thirty scoops and 15 spotlights are employed, also 12 banks of reflector floods
designed by the station engineers. Each
bank employs six reflector floods. In addition three -inch baby spots with 150 -watt
bulbs are mounted on the front of each TV
camera above the turret. These arc used
for filling in on facials, closeups on cards,
etc. The control switch is mounted on
the back of the camera convenient to the
operator's hand.
Studio Control
Station engineers built their own "bypass
switcher ". This enables them to feed film
and announce booth directly to transmitter.
It frees the studio camera, switcher and
audio for rehearsal purposes while film
programs are on the air. This bypass
switcher operates rack -mounted relays to
switch audio and video.
When the second studio is finished and
completely equipped, the present field controls will be used for it. Rack studio type
control equipment will be employed when
proposed plans are consummated.
Projection Room
The projection room has two RCA
TK -20 film chains together with 16mm,
Telop and slide projection equipment.
Complete editing facilities are available in
the film department. A Moviola, ganged
66
www.americanradiohistory.com
at editing table.
synchronizer and other equipment is available for handling double system motion
picture footage on the three editing tables.
An animation stand constructed by the
KETC staff is also available in the film
department.
Kinescope Recording Room
Facilities for making either single or
double system Kinescope recordings are
available. During the past year over 500,000 feet of Kinescope were made at KETC.
The equipment consists of a G.P.L. recorder with a Maurer optical sound recorder for single system recordings. A
Stancil- Hoffman 16mm magnetic film recorder is used for recording double system
sound tracks,
Part in a National Network
Educational television stations such as
KETC are affiliated with the Educational
Television and Radio Center with headquarters in Ann Arbor, Michigan. The
Center, supported principally by Ford
Foundation funds, makes grants for the
production of programs for distribution to
all the member stations. In this way, the
best programs produced in each city are
distributed on Kinescope film to the others.
During KETC's first year it assisted with
the work of the Center by producing 11
series totaling 135 programs for national
distribution. The Center now provides 20
educational TV stations with one hour of
programming each evening. It is fulfilling
the dream envisioned at the 1952 St. Louis
conference for an educational television network bringing "the nation's greatest teachers and the finer elements of our culture
into the living rooms of all our homes ".
KETC and Film Center
Station Manager Arms says, "Station
KETC has a $90,000 contract with the
Center this year. The Center pays for
programs and production costs plus kine
recording costs. By this means KETC has
been able to double its number of kinescope
programs. Ordinarily, we would do about
forty during 1956. With the assistance of
the Center, we will do eighty."
A Budget
for Education
by Television
The operation of a TV station is a complex business. Even apparently simple
forms of production such as the professional
presentation of a series of lectures require
the art of an able producer and a team of
skilled technicians if the power of TV is
to be used effectively in communicating
FIG. 22. Jack A. Chenoweih (left), KEIC Chief Engineer, receives
equipment presented by John Roberts (center), president of 800
North 12th. Inc. This gift was "a gratifying example of generous
business support of a community -owned television station."
with the general public. The basic operating
budget of KETC is $250,000 annually
with additional expenses authorized on the
basis of grants received for special program
production. Thus the total rate of expenditure during the first year has been about
$300,000. The budget has been maintained
at the same level for the present year.
The school systems base their contributions on a rate of approximately $1 per
year per student. Such appropriations for
the first year amounted to $137,000. Approximately $144,000 has been appropriated by the schools for the second year.
Large sustaining gifts for the operating
fund, mostly from St. Louis businesses,
account for approximately $50,000 annually. Small gifts from individual citizens- "Sponsors of Channel 9 obtained
primarily from a year -round mail campaign, total about $10,000 annually.
"-
FIG. 23. Bill Martin, Jr., spinner of tales for the younger set, is
featured in a weekly half -hour show, The Storyteller." This
series is kinescoped and will be distributed nationally.
67
www.americanradiohistory.com
All KETC work. including telops and
studio cards, is designed and created by staff
artists David Kuskowitz (left) and Burton Dobinsky.
FIG. 25. Puppets used on children's programs are
designed by Valerie Haynes. Val operates pup.
pets and provides voices on "The Finder" show.
Operating under this budget, KETC
continues to have the largest full -time paid
staff of any educational TV station now
on the air. Though salaries are necessarily
modest, persons launching television careers
have been attracted to educational TV because of the freedom it offers for experimentation in new forms of production. But
the primary mission of KETC is, in Manager Arms' view, "To televise education.
Within its budget the station can perform
the service expected of it by the schools.
It can broadcast college courses and programs that deal wisely and courageously
with public issues and problems. In addition it can offer simply produced programs
revealing what is best in music, books and
the arts, and it can produce worthwhile
children's programs."
being kinescope recorded in the KE'I'C
studios this summer by the senior members
of Washington University's Mathematics
Department-Professor Holbrook M. Mac Neille, Professor H. Margaret Elliot, and
Professor Middlemiss. They will be shown
twice daily so that the student may conveniently fit them into the rest of his
schedule. In announcing this forward looking educational concept, Washington
University said in the bulletin announcing
the course that it "increases the opportunity for individual instruction and assistance and makes available to every student
the department's most experienced and
able teachers."
FIG. 24.
Math 115 via TV
A significant by- product of the Emerson
experiment has just recently emerged. Encouraged by the success of Professor Mid dlemiss' televised course, the Washington
University Department of Mathematics
made a bold decision. Beginning with the
Fall Semester of 1956, all students who
enroll in freshman mathematics will take
their courses over television. The pattern
will be roughly the same as followed in the
Emerson experiment. Students may view
their lectures either at home or in special
TV classrooms on the campus. Special time
will be provided for personal assistance,
quizzes, tutorial sessions, and examinations. However, all freshman mathematics
students will receive all their lectures by
television from KETC. The entire course is
68
FIG. 26. Fred Conway, nationally prominent St.
Louis artist, created a special mural depicting
educational television as a community influence.
tVASHINGTON
u NI VE
W
ltSITY
U
Department of
Mathematic..
nnoua,y
A
NEW METHOD
OF PRESENTING
For the Future
Forward planning for programming and
financing are inseparable and it is desirable
that fund raising programs should stay at
least a year ahead of broadcast operations.
Also the building of a reserve for contingencies and additional equipment is
essential. The eventual purchase of equipment for remote and color telecasting would
enhance KETC's usefulness to the community in many ways in future years.
While current program commitments must
be balanced wih funds currently available,
financial goals are being projected for the
future which balance with the vast potentialities of this new medium.
KETC looks to the future with confidence, striving to improve its services to
the community and anxious to widen its
growing repuation as one of ETV's most
active pioneers.
MATHEMATICS
115.
COLLEGE ALGEBRA
AND TRIGONOMETRY
For the 1956 Fall
Trna
FIG. 27. Freshman mathematics via TV is offered
by Washington University beginning fall 1956
with regular college credit.
.
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120
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210'
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DIRECTIONAL
OF
!
E%1, PERSONA L
MICROPHONE
RCA's BK -6B
Miniature Mike
1
t
I
o
300°
Half the size (by
volume) of the
BK-6A!
CHARACTERISTICS
BK -6B MICROPHONE
1
1
Excellent speech
balance when
talking "Off Mike!"
Wide range Frequency Response!
Smallest dynamic microphone ever developed for radio and television broadcasting! You'll be amazed by its frequency response and
directional characteristics that provide superior speech balance
when used "off mike" or worn on the person.
Picture shows hou much
smaller the BK -6B is than
the BK-64
yet efficiency
is improved!
...
Tiny ... less than three ounces in weight, this new miniature mike is
easily concealed in hand, under necktie, or corsage. Versatile ... it
provides increased efficiency to difficult walk -around operations,
allows performers greater flexibility and freedom of movement
adds informality to every such production. Tough
the BK -6B
takes the roughest treatment in stride, is furnished with flexible
30 -foot cable especially designed for ease of manipulation and
long life.
...
.
.
.
You'll find it a "giant" in performance for a wide variety of broadcast applications. Ask your RCA Broadcast Representative for complete information. In Canada, write RCA VICTOR Company
Ltd., Montreal.
RADIO CORPORATION of AMERICA
BROADCAST AND TELEVISION EQUIPMENT
CAMDEN, N. J.
iiaaa
111M11111®1711111111
New RCA25
KW VHF
Assures flexible arrangement for economical floor plan
Combining all the newest design features of the recently announced RCA 6 KW TV transmitter and the enviable performance record of RCA's famous 25 KW power amplifiers,
the new TT -25CL is today's best value! No other transmitter
in this power class embraces so many advantages ... advantages
that engineers and station managers have asked to have incorporated in a single transmitter.
FLEXIBLE FLOOR PLAN -The "block build" design of
the TT-2 5CL permits several combination arrangements. The
layout may be as illustrated in the accompanying floor plan, or
a modification of this general plan. The 6 KW Driver and
P.A. Rectifier and Control Cabinets can be arranged in "U"
fashion with the P.A. tanks moved forward and the driver
power supply enclosure placed at a remote location to further
conserve space.
-
PRECISE COLOR PERFORMANCE Built -in linearity
correction circuits and intercarrier frequency control, which
accurately maintains frequency separation between aural and
visual carriers, assure excellent color signal transmission.
EXCELLENT ACCESSIBILITY -Broadband tuning controls in the 6 KW Driver are accessible without opening
any doors. All important driver circuits are adjusted from
the front of the unit. Exciter and modulator units have
"tilt -out" construction for quick, complete accessibility.
-
THERMOSTATICALLY CONTROLLED HEATERS
for rectifier tubes are suited to ambient temperatures as low
as 0° C. Designed for attended or remote -control operation.
ECONOMICAL OPERATION -A well- chosen tube
complement affords lower power costs. Complete overload
protection with "grouped" indicator lights makes troubleshooting quick and certain.
TIME -PROVED TUBES -Long life RCA 5762 tubes in
both P.A.'s and Driver. Many broadcasters using other RCA
transmitters which employ the 5762 tubes report "extra
dividends" due to their long-life, economical operation. Over
100 RCA 25 KW amplifiers have been in
continuous service to date -each employs
the famous 5762.
PLUS
...
OTHER ADVANCED FEATURES
-
too numerous to mention here! Get the
complete story from your RCA Broadcast
Sales Representative or write for descriptive literature (Catalog Bulletin B- 4011).
In Canada, write RCA VICTOR Company
Limited, Montreal.
TELEVISION TRANSMITTER
"ON-AIR'
kaum
ti GP-TV
CHATTANOOGA, TENN.
(Type
F
L
TT -25CL,
O O
R
P
Low Band)
L
WRGP is receiving excellent reports on transmission since putting the TT -25CL "on- air." Par-
ticularly gratifying comments came from color
program viewers who are impressed
with the fidelity of WRGP color
A N
transmission.
VESTIGIAL SIDEEAND FILTH
VISUAL PA.
AURAL PA.
PLATE TRANSFORMER
PLATE TRANSFORMER
AURAL POWER AMPLIFIER
VISUAL POWER AMPLIFIER
DRIVER
PA.
AURAL
RKTIFIH
PA.
LUSAS
CONTROL
VISUAL
RECTIFNR
PA.
VISUAL
PORTION OF THE ABOVE
25 KW TRANSMITTER (LESS
CONTROL
TTJ AL DRIVE
AMPLIFIERS) IS AVAILABLE AS A
COMPLETE 6 KW TRANSMITTER
Where floor area is at a premium...
"down- town" buildings, or where space must be yielded to other equipment, the
-25CL is highly adaptable. When new transmitter buildings are contemplated, the space saving TT -25CL helps to save building costs. The rectifier sections of both the 6 KW Driver and
also the Aural and Visual Amplifier Rectifiers can be separated and placed in an adjacent
room or basement. This is an added feature that saves valuable operating area.
such as in
TT
RADIO CORPORATION of AMERICA
BROADCAST AND TELEVISION EQUIPMENT
CAMDEN, NEW JERSEY
Flow RCA Television is helping to solve
the teacher -class room shortage
to plant workers in industry, and laid plans for a
The teacher above is not giving private spelling lessons. She has hundreds of unseen students scattered
throughout many St. Louis schools. She is teaching
them by television.
university of the air.
RCA Television Equipment plays an increasingly
important role in teaching by TV, whether it originates from stations like KETC or is transmitted by
closed circuit from within individual schools, colleges, and universities. Applicable to business, industry and medicine as well, RCA Closed -Circuit TV
Equipment is built to strict professional standards
with the accent on quality and reliability.
This is KETC, St. Louis' pioneer educational TV
station where new, imaginative concepts of televised
education are being developed by world renowned
educators, TV producers and engineers. Their goal,
like the many other educational TV stations, is to
help alleviate the teacher -classroom shortage. In
little more than a year, KETC has transmitted a
successful grade school program, several college accredited courses, begun teaching technical subjects
R
A D
Radio /pro-
RCA Precision Instruments mea-
vides instant 2 -way communication
between office and vehicles in
the field. lt speeds service, reduces
mileage and telephone expense.
sure and lest to laboratory-occurote standards. Used in designing,
developing and producing complex
electronic equipment and systems.
RCA Mobile
RCA Beverage Inspection Machine automatically checks bottled beverages for minute foreign
particles, assures bottlers of
dependable electronic inspection.
I
For free booklet on the profitable uses of RCA Television, or
for information on other RCA electronic products, write
Dept. GD-168, Radio Corporation of America, Commercial Electronic Products, Bldg. 15-1, Camden, N. J.
O
C
2 -Way
O
R P
O
R
A T
I
O N
O
F
A M
E
RCA 16mm Projectors are light
weight, compact, simplest to operate. Used for selling, demonstrating,
teaching ... by businesses, schools,
churches, hotels, institutions.
R
I
C
A
NOW-Another
.I
RCA first
in
Camera Tubes
..
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For Black -and -White
RCA -5820
(With new MICRO -MESH)
For Color
RCA -6474
(With new MICRO -MESH)
announces a major development- MICRO-MESH SCREENin Image Orthicon design that substantially improves the picture
quality of TV cameras -even beyond present -day high- quality
standards of performance!
RCA
In RCA MICRO -MESH, the fineness of the mesh has been increased
from 500 lines per inch to a new high of 750 lines per inch -with
a mechanical exactness heretofore unattainable. Here are a few ways
this improvement works for you. (1) It eliminates mesh pattern
and moiré effect without need for defocusing -both in blackand-white and color. (2) It permits improved picture -detail contrast.
(3) It is particularly effective in color cameras where detail
contrast cannot be improved by operating the tube above the knee.
Under continuous development for more than 5 years at RCA,
MICRO-MESH in RCA Image Orthicons is evidence of RCA's intensive
engineering effort to bring telecasters camera tubes of the
highest possible quality.
Image Orthicons -with new MICRO-MESH -are available immediately from your RCA Tube Distributor. For technical details on RCA
Image Orthicons, write RCA, Commercial Engineering, Harrison, N. J.
RCA
ADVANTAGES OF MICRO -MESH
For black- and-white or color
Eliminates mesh pattern and moiré effect without defocusing.
More than meets all technical requirements of
525 -line TV system.
For color only
750 -mesh tube with aperture- correction circuit
provides 100% response for 350 -line information. 500 -mesh tube without aperture- correction
circuit permits only about 60% response for
350 -line information. Although correction circuit can be used with 500 -mesh tube, such use
emphasizes moiré and beat -pattern problems.
Minimizes beat pattern between color sub carrier and frequency generated by beam scanning mesh -screen pattern.
Improves detail of color pictures.
TELECASTING
CAMERA TUBES FOR
AMERICA HARRISON,
RADIO CORPORATION OF
N. J.
Printed in U.S.A
3.12955
www.americanradiohistory.com
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