Did 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 (RACES).
January 1945 QST
Wax nostalgic about and learn from the history of early electronics. See articles
QST, published December 1915 - present (visit ARRL
for info). All copyrights hereby acknowledged.
QST Looks at Television - 1944
The "State of the Art" from an Amateur Viewpoint
By Cyrus 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.
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 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 picture.
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, preamplifier.
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.
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 cathode-ray 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.
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
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 amateur background.
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.
WABD's transmitters, 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
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
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 receiver."
To get 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
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
At WABD 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 televised.
The transmitters 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 a moving
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
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
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 it says.
1 Hull, "Television, What About It?" QST, November, 1931, p. 20.
Lamb, "Radio Amateurs in the Television Picture," QST, December, 1937, p. 8.
3 Southwell .."The Iconoscope," QST, July, 1944. p, 26.