QST Looks at Television - 1944
January 1945 QST Article
you know that you are likely a TLV? That's right, a Television Looker.
The modern equivalent is CP - Couch Potato. In the early years of television,
TLVs were as fascinated with the device itself and the technology as
they were with the information being displayed. As this story tells,
Hams were involved in TV transmission (ATV) early on. I did not know
that amateur television was banned during World War II. During WWII,
all amateur radio operations were suspended with the exception of those
authorized to continue under the Radio Amateur Civil Emergency Service
January 1945 QST
of Contents]These articles are scanned and OCRed from old editions of the
ARRL's QST magazine. Here is a list of the
QST articles I have already posted. All copyrights (if any) are hereby acknowledged.
See all available
vintage QST articles.
QST Looks at Television - 1944
The "State of the Art" from an Amateur Viewpoint
T. Read, W9AA
For many years leading experimenters
in the amateur ranks have interested themselves in television and some
notable work has been accomplished. Since Pearl Harbor all amateur television
has of course been discontinued, but the commercial broadcasters have
continued to experiment and plan for the future. QST presents herewith
an account of present-day television as it looks from the amateur viewpoint.
Of all the electronic miracles which have been promised to the
postwar world the most widely anticipated probably is television. Ever
since the early days of radio broadcasting the possibility of being
able to see as well as hear by radio has intrigued the public's imagination
and every faltering step forward in this new art has been eagerly hailed
with the statement that "television is just around the corner." This
great public interest, accompanied as it has been by many irresponsible
predictions of immediate availability, has not been an unmixed blessing.
There is no television equivalent for the crystal detector or simple
one-tube receiver - even the crudest early attempts at video transmission
by means of rotary scanning discs required comparatively complicated
equipment - and most of the serious workers in the field have done their
best to head off premature promotion.
The eventual place of television in amateur radio is not yet clear.
As early as 1925 QST carried articles about the scanning disc systems
of that day and since then has consistently presented the facts about
new developments in the art when they seemed to offer possibilities
for amateur use. At the same time the limitations and problems still
to be overcome have been clearly set forth, a notable instance of "debunking"
being the article, "Television - What About It?" which Ross Hull wrote
in 1931.1 Late in 1937 QST started on a systematic development
program for amateur television. An introduction by James J. Lamb2
was followed by a series of articles on modern cathoderay television
adapted for amateur use, which were discontinued only when war put a
stop to most amateur experimentation. This report on today's television
is not intended as a continuation of that series but, rather, is an
appraisal of the present situation as a whole, an attempt to shed a
little light on what has recently become a most controversial subject.
The studio staff at WABD during the televising of "Parisian Memories."
It takes a full size crew to operate all of this paraphernalia.
The man in the left foreground is manipulating the microphone boom
to pick up the singer's voice without letting the mike show in the
WABD has presented many interesting shows. Here is a scene from
"The Boys From Boise," broadway musicomedy that was transmitted
complete with orchestra, chorus girls, and all the trimmings
The main control room at WABD. The large monitoring scopes have
14 inch screens and reproduce the picture in black and white.
The control room of Studio A. The small monitors on top use the
familiar 5·inch oscilloscope tube. The picture is green hut these
tubes serve the purpose until new equipment is available,
Which is which? One of the above pictures is from an original 8
X 10 photograph and the other shows bow it appears after having
been transmitted by television. You pick 'em out.
Turntables and main sound control panels at WABD.
A camera dolly carrying iconoscope camera, electronic viewfinder
(using another green 5 inch tube) and power supplies "for iconoscope,
Fig. 1 - Television channel No.4, showing how the six megacycles
between 78 and 84 are used by WABD. The video carrier is amplitude
modulated and has it. lower side band partially suppressed.
Television camera opened to show arrangement of parts. The iconoscope
tube is at the upper left with base including electron gun slanting
down to the right. Lens equipment for focusing picture on the screen
of iconoscope is at the upper right. The bottom cabinet contains
the preamplifier with the input tube placed as close to the Ike
screen as possible.
Antennas of WABD, station of the Dumont Television Corporation atop
the 515 Madison Ave. Bldg., New York City. The folded dipole is
the video antenna, the doughnut is for the accompanying sound.
The transmitters at WABD. Panel at extreme left contains exciter
and modulator for f.m. sound channel. Unit at the right contains
final amplifier for sound. The rest of the equipment is all video.
For the past many months the writer's principal duties have
been to attend meetings and read voluminous reports, anything and everything
that might conceivably have an impact on amateur frequencies. In the
process he has been privileged to attend various panel and committee
meetings of the Radio Technical Planning Board, meetings of the State
Department's committee on radio allocations, and the recent hearings
of the Federal Communications Commission. At many of these, television
was the principal subject and the heated discussions between adherents
of the present standards and frequencies and those who want to use more
scanning lines and move to the u.h.f. region were strongly reminiscent
of the 'phone-vs.-c.w. or high-vs.-low power arguments in amateur circles.
QST, of course, is neutral regarding the television controversy as this
is not an amateur matter. However, no dyed-in-the-wool ham can remain
completely unmoved in the presence of a real good scrap over technical
matters, so we determined to find out "what the shootin' was all about."
Through the courtesy of Dr. Allen B. DuMont, ex-W2AYR/W2AHD, and Dr.
T. T. Goldsmith, director of research for the DuMont Corp., we had the
opportunity to visit WABD and inspect a modern television station.
WABD in Operation
WABD is on the air three
nights a week from 8 until usually about 11 P.M. Practically the entire
staff of engineers and technicians is made up of regular DuMont employees
who are operating this television station on an overtime basis in addition
to their full-time job of war production in the plant at Passaic, N.
J. As might be expected, most of them are amateurs or have an
While WABD operates under a commercial
license and many sponsored shows are regularly transmitted, the entire
setup is still of a more or less experimental nature. DuMont provides
all of the technical facilities and personnel but programs are largely
furnished by New York advertising agencies who have gladly accepted
this opportunity to gain practical experience in the newest of advertising
mediums. This cooperation has resulted in many interesting shows for
the TVLs (television lookers), a notable example being the recent transmission
of an entire Broadway musical comedy complete with orchestra, chorus
girls, and all the trimmings.
Promptly at 7:30 P.M. we
arrived at 515 Madison Avenue, New York City, and were greeted by Morris
C. Barton, jr., ex-W4CRV, chief of operations.
main control room, and studio A are located on the 42nd floor, while
offices and studio B are on the 2nd floor. The studios are somewhat
similar in arrangement to those used for standard broadcasting but they
contain much more equipment. One wall is covered with scenery - back
drops, stage furnishings, etc. Overhead are banks of incandescent flood
lights, the type in which the reflector is a part of the bulb itself.
Two camera dollies, small rubber tired trucks which carry iconoscope
camera, preamplifier, power supplies, and camera man, trail a tangle
of coaxial cables and power wires behind them across the floor while
other cables run to an enormous spotlight and 'to the microphone which
is suspended from an overhead boom, a la Hollywood. It takes a full
size crew to operate all of this paraphernalia. In addition to the people
normally used in any broadcast studio, such as sound effects men and
announcer (in television a charming young lady), there are camera men,
men to push the camera men around on their rubber tired mounts, spotlight
operators, microphone boom swingers, property men to move scenery, announcement
cards, etc., and a couple of assistant directors. Camera men and directors
are "wired for sound" - they wear headphones through which they can
receive orders from the principal director in the control room.
Television employs many techniques of the theater but there are some
rather startling differences. Because the monochrome camera does not
respond well to red, the lovely girl singer who was about to go on appeared
for work wearing dark brown lipstick. The scenery was painted in various
shades of gray which have been found by experiment to give the most
natural appearance on the screen. The nonchalance with which scenery
was moved during the performance also was rather surprising until we
realized that no stage curtain ever invented could conceal such activities
as well as switching off the camera.
We did not get to
see the whole show as we were far too busy asking questions of the engineers
and trying to find out "what made the wheels go 'round." The part that
we did see was highly interesting and well worth watching. There has
been much argument of late about the quality of present day television
pictures. We viewed. the WABD show on the control room monitor which
operates directly from the coaxial line running to the transmitter and
on the main station monitor which picks up the program from the air.
Both of these use 14-inch tubes and the picture appears
to be about 8 X 10 inches or slightly larger. This is not nearly as
large as will be available on good home television receivers in the
future - it is expected that a projection type set capable of producing
a picture 18 X 24 inches in size will have been announced before this
article appears in print. It is possible, .of course, to get close enough
to the screen so that the line structure becomes visible but the same
is true of almost any kind of pictorial material. Moving pictures are
very crude when seen from the front row and world famous oil paintings
cannot be appreciated until viewed from far enough away so that the
brush strokes are not predominant. From a normal viewing distance the
525 lines of present day television are not noticeable. This is in no
sense an argument against a greater number of lines. If better television
can be produced we are all for it, but the present version is good enough
to make us put some of those war bonds into an envelope marked "television
back to WABD. The studio control room also is much like the conventional
b.c. type but with extra equipment and personnel. The sound control
desk, which in ordinary broadcasting is the center of attraction, here
is relegated to one side of the room. In its place before the plate
glass window is a large console containing video controls, camera monitoring
scopes, main studio monitoring scope, small scopes which show the detailed
characteristics of the various video signals, scopes which show the
"shading voltage" by means of which minor defects in lighting the picture
may be corrected or special effects produced, and in fact more scopes
than we had ever before seen in one place. In spite of the fact that
Dumont manufactures these tubes W ABD has to get along for the most
part with prewar equipment, all new production being needed for war
use at present.
As in the studio itself, the control room
requires a large staff. One sound engineer is sufficient but there
are video engineers for each camera, a principal video engineer at the
main monitoring scope, and the program director who supervises the entire
production. By means of two simple gain controls the principal control
engineer is able to make "lap dissolves," that is, fade from one scene
to another, which would be the envy of any Hollywood technician.
At the rear of the control room a large panel contains amplifiers and
the synchronizing pulse generator which is the heart of the entire system.
This generator provides the timing, vertical and horizontal sawtooth
voltages, blanking voltages, and synchronizing pulses.
the camera man never lines up the picture by visual means, Instead his
viewfinder is entirely electronic, a five-inch scope in a viewing hood
mounted on the side of the camera and fed by a coaxial line from the
control room amplifier. For this reason he makes no allowance for parallax
and there is no danger that he will cut off the heroine's head in a
close-up. It is as though the operator of a movie camera could watch
the scene he was taking through the camera's lens system instead of
through a separate optical viewfinder, certainly a very real advantage.
At present the camera viewfinders and the individual camera monitors
in the control room use standard 5-inch tubes which show the picture
in varying shades of green, only the large tubes make use of the new
type of fluorescent material which responds in black and white. Incidentally,
the contrast and brilliance of the pictures on these black and white
tubes was much better than we had anticipated, although it is claimed
there is still room for improvement. As is also true of moving pictures,
black and white are purely relative terms, the unilluminated screen
of the scope itself being white. However, the variations of brilliance
between the illuminated and unilluminated portions of the screen do
produce a very satisfactory degree of contrast.
From the studio
control room the program goes to the master control room located next
to the transmitter room on the 42nd floor. All video signals are carried
by coaxial cables while the sound goes over an ordinary wire system.
In the master control room the program is monitored again before being
fed to the transmitter. In addition, master control switches between
studios connect the special equipment which permits movie film to be
themselves are mounted in typical broadcast fashion in a large steel
console extending the length of the room. Behind this imposing exterior,
however, the rig looks strangely familiar, particularly to anyone who
has done much work on the v.h.f. ham bands.
In the transmitter
console the f.m. audio rig occupies the sections at either end and the
video equipment fills the other five sections. WABD operates on channel
four - 78 to 84 Mc. The audio channel starts off with a crystal on 129.244
kc. and multiplies by means of quadruplers, etc., to reach 41.875 Mc.
in the f.m. exciter unit. Modulation is introduced through a compressor
and a pre-emphasis amplifier and is accomplished by means of a phase
shift method similar to the Armstrong system. After leaving the exciter
the audio signal goes through an 807 doubler, an 829 buffer, a pair
of 100THs, and into the final pair of 450THs. The output, approximately
one and a half kilowatts, goes to a ring antenna mounted on top of the
tower. The center frequency of the audio channel is 83.75 Mc. and the
deviation is 75 kc. plus or minus.
The video channel starts
with a 4953.125 kc. crystal in a Pierce oscillator using a 7C5. After
quadrupling twice the signal is amplified and applied to the modulated
stage, a pair of 100THs. Grid modulation is used and the modulator consists
of two HK257s. Three broad-band ClassB linear amplifier stages follow
the modulated stage. The first is a pair of 152Ts using a coil and capacitor
in the grid circuit while the plates go to a linear tank. The following
two stages - use linear tanks throughout with hairpin coupling loops,
all on a rather massive scale judged by amateur standards. The driver
consists of two water-cooled type 8002 tubes and the final of two 8898
which are water cooled arid in addition have a blast of air blowing
on the glass seals. The final stage operates as a grounded grid amplifier,
excitation being applied to the filaments while the grids are bypassed
to ground. This arrangement is much easier to drive at these frequencies
than the usual system and nearly eliminates the need for neutralization.
The antenna for the video signal consists of folded dipoles arranged
in a cross just below the doughnut which radiates the audio signal.
The unmodulated video carrier is at 79.25 Mc. with an output
power of approximately 6 kilowatts and has one side band partially suppressed.
All of the video amplifying equipment in the station is essentially
flat to 5 Mc. but the signal that finally goes out is cut off at 4.25
Mc. The disposition of the two carriers in the 6 Mc. channel is shown
in Fig. 1.
QST has published many articles dealing with
the theory and operation of television equipment so no attempt will
be made to cover the same ground here. The most recent of these, an
explanation of iconoscope operation, appeared in July, 1944.3
However, one feature of modern television transmission which has mystified
many hams is the method by which moving picture film of 24 frames per
second is transmitted over a system employing 30 frames and an explanation
of the method may prove interesting. Actually this is not as complicated
as it sounds. Because of the interlacing action of the television scanning
beam the picture is covered by 60 fields per second, that is, the beam
starts at the upper left-hand corner of the picture and scans alternate
lines and then returns to the top of the picture and scans the other
half, filling in the vacancies left the first time through. Thus two
of the 60 fields are required to completely fill in a single picture
or frame. As this scanning action is continuous there is nothing in
video transmission which exactly corresponds to the shutter action of
The conversion of 24 frame-per-second
movies to 60 field-per-second television is accomplished by scanning
one frame of film for 2 fields and the next for 3. In this way half
of the frames are scanned twice, 12 frames - 24 fields, and the other
half three times, 12 frames - 36 fields, making a total of 60 fields
or 30 television frames. With the high-speed continuous action of the
electron scanning beam this process gives results that are as smooth
as could be desired.
Disregarding for the moment the postwar use of television by amateurs
let us consider its probable commercial form. In the very nature of.
things television programming will have to be far different from the
practices which have grown up in the broadcasting industry. Ordinary
broadcasting has come to be, in many homes, a normal background accompaniment
to all household activities the day-long parade of soap operas, shopping
advice, and the like, constituting a gentle obligato to the song of
the vacuum cleaner. Such cannot be the case with television. Once admitted
to the home this new medium will prove far more exacting - demanding
as it does, our complete and undivided attention. Unless the housewife
can develop eyes in the back of her head and a dual personality she
will certainly be unable to peel the potatoes, mind the baby, and do
the week's washing while raptly listening to and watching the adventures
of "somebody's other wife."
The pioneers in this new industry
are well aware of these difficulties in program planning and are prepared
to take appropriate action. It is very doubtful if continuous programs
of the type now offered by standard broadcasting will be available,
certainly not until a real demand arises. For the immediate future it
appears that television broadcasting will take place during two well-defined
periods of the day, a few hours in the afternoon devoted mainly to educational
subjects, perhaps actually presented in cooperation with local school
or college classes, and an evening program of entertainment running
from 7 to 11 or 12 P.M. The costs of television programming are much
higher than comparable sound broadcasts and this factor, combined with
the inability of the TVL to sit still and look for more than a few hours
at a time, seems reason enough to expect that our postwar television
programs will be furnished only at those times when a comparatively
large audience may be reasonably expected. In the event that this prediction
turns out to be all wrong and we find that the "viewies" run night and
day without even time out to polish our glasses we will have to admit
that we grossly underestimated both the commercial possibilities of
this new art and the ability of the American public to "take it."
Now for the amateur possibilities.
During our visit to WABD we met Chief Engineer S. R. Patremio, W2ITL,
to whom we are indebted for taking time out in an extremely busy evening
to describe the various circuits and explain their operation. We also
met Howard Schubert, W2JUO, in master control; Melvin Stagg, W2CNO,
and Otis Freeman, W4HGN, video engineers, and Richard Adler, W2NPB,
sound engineer. In addition to the hams just mentioned, the following
are members of the Dumont staff: W1ISI, W2AHU, W2EBU, W2ENY, W2GZA,
W2HOD, W2HRZ, W2KCN, W2LNT, W2LT, W2LMA, W2LYS, W2MOH, W2NYY, W20MI,
vV8TNC, ex-1RJ, ex-1SS/1RI, ex-W2HEI, ex-2XC/2XD, ex-W6CRM, and exW9KHG.
A similar group probably can be found at other television stations.
Knowing the proclivities of amateurs who work in broadcast stations
to take a busman's holiday and sit up half the night pounding brass
or yelling into a mike after having done a full day's work at practically
the same thing, we think it highly probable that. the operators of television
stations will likewise go in for ham television .
It now appears
that postwar amateur bands will include not only our traditional long-distance
frequencies but will have in addition lots of room on the ultrahighs
- what better use can we make of these frequencies than to plunge wholeheartedly
into experimentation and research in this newest of communication mediums.
Who can tell - the day may soon come when CUL will mean exactly what
1 Hull, "Television,
What About It?" QST, November, 1931, p. 20.
2 Lamb, "Radio
Amateurs in the Television Picture," QST, December, 1937, p. 8.
3 Southwell .."The Iconoscope," QST, July, 1944. p, 26.