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. All copyrights hereby acknowledged.
QST Looks at Television
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 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,
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
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 amateur background,
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.
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 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.
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.
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 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
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
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
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.
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."
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
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
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.
2 Lamb, "Radio
Amateurs in the Television Picture," QST, December, 1937, p. 8.
3 Southwell .."The Iconoscope," QST, July, 1944. p, 26.