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Reversible Television
January 1948 Radio-Craft

January 1948 Radio-Craft

January 1948 Radio Craft Cover - RF Cafe[Table of Contents]

Wax nostalgic about and learn from the history of early electronics. See articles from Radio-Craft, published 1929 - 1953. All copyrights are hereby acknowledged.

That Hugo Gernsback was a prolific writer, inventor, visionary, designer, and builder is unquestionable given the huge number examples of each that can be easily found on the Internet and in libraries. Gernsback was never bashful about giving himself credit for technology predictions when thy come to fruition and for the coining of new terms. In this "Reversible Television" editorial column that appeared in a 1948 issue of his Radio-Craft magazine, Gernsback claims to have been the first to use the word "television" in a technical article - but not necessarily having invented the term. He did have an idea for a "Telephot," a portmanteau of "telephone" and "photograph." The device would take the form of phone with a built-in video display to allow parties to view each other whilst conversing. While the concept never proved marketable as envisioned - despite all the promises of such appliances in technical and home improvement magazines in the 1970s, '80s, and '90s - we do now have Skype or equivalents thereof that provide the type of service Gernsback described. Gernsback knew a video phone was beyond his present day capabilities, mostly because of the expense and complexity of the cathode ray tube (CRT) which would be needed. Not to be discouraged, he went on to suggest remote cameras that could be stationed in outdoor and indoor public areas, on manufacturing floors, in manufacturing process areas, in patients' hospital rooms, and similar venues.

Reversible Television - Coming New Television Developments

Reversible Television, January 1948, Radio-Craft - RF CafeBy Hugo Gernsback

In the December, 1909, issue of my first magazine, Modern Electrics, I wrote an article: "Television and the Telephot." This was possibly the first time that the word television was used in any technical article.

The article began as follows:

The principle of television may be briefly stated thus: A simple instrument should be invented which would reproduce objects placed in front of a similar instrument (called Telephot) at the other end of the line. In simple language, it should be possible to connect two mirrors electrically, so that one would show whatever object is placed before the other and vice versa. As in a mirror, the objects must be reproduced in motion (at the far-off station). The theory further requires that both Instruments (one at each end) must be receive as well as transmit. A good parallel of this requirement is found in the ordinary Bell telephone receiver. As is known, the Bell receiver (without the use of a microphone transmitter) will receive as well as transmit, that is, one can talk in a receiver and also hear the other party, using one and the same instrument.

In the Telephot it should be possible to see the party at the other end while that party should see you - both through the medium of your Telephot.

Unlike the mirror, however, you should not be able to see your own picture in your own Telephot. In this the Telephot differs from the mirror analogy.

The above was written 38 years ago. Since then television has made a great deal of progress, thanks to photoelectric cells and the cathode-ray tube, neither of which were known in 1909.

While television is with us today, much remains to be accomplished technically before it can become as universal an instrument as the present-day radio receiver. That this will be achieved in the foreseeable future, I do not doubt in the least.

As I see it, the obstacles in the way of television today are the following:

One of the major ones is the comparatively high present cost of television receivers. The ideal of a television receiver in every home in the U. S. requires a price range around $75 to $100 for the popular models. With mass production of telesets, this goal will probably be reached in less than 5 years.

Today, television manufacturers will throw up their hands in horror at such a price prediction - yet they know that if the American system of free broadcasting - advertising sponsored - is to prevail in television, as it does in broadcasting, then there must be a television audience in the tens of millions, against less than 150,000 - our present audience.

Yet, the future looks exceedingly bright for television. Prices are coming down. New inventions, new processes, new ideas are appearing at an astonishing rate. American ingenuity is once again out in full force - soon the results will be apparent.

Take for instance the cathode-ray tube - the heart of the television receiver. A 20-inch tube costs $150.00 today - just the tube alone. No wonder a big set costs over $750. But the tube price will soon go down below $25!. The reason? Present-day tubes are made of costly Pyrex glass. The glass "bottle" alone costs $75, F.O.B. the glass factory. But why use fragile glass? Several laboratories are now hard at work on metal cathode-ray tubes, with a glass front for the viewing side. Not much is revealed about this development - it's still under thick wraps. But I do know that this single new improvement may well revolutionize television receivers in the near future. Believe it or not, a $5 seven-inch cathode-ray tube - now listing at $30 to $50 - is on the horizon during the next few years.

So far no television receivers have been mass-produced. Our manufacturers are even now trying to perfect ways and means to streamline production. Remember, telesets are infinitely more difficult to assemble than ordinary radio sets. For one thing, a television set is in reality 2 sets, one for the video (the television part), the other the audio (the sound part).

But the video end - due to the high voltages employed as well as the high-frequency components - is much more difficult to assemble than a radio. Perhaps doing away entirely with present-day wiring assembly methods* will bring mass production and lower price levels.

While television in the home is now assured, let us not overlook other and just as important uses of the new art which are now evolving.

Let us turn back to my 1909 article, part of which was quoted at the beginning of this page. I said, "The theory (television) further requires that both  instruments (one at each end) must be reversible, that is, each must receive as well as transmit."

In the 38 years of television progress, this condition has not been attained.

Yet to make industrial television possible so that every office, every factory can afford a 2-way television installation the above requirement must be fulfilled.

Just as we have present-day inter-office public address systems, we will soon have interoffice tele- or video-address systems - sight plus sound. To do so we must have flexible, reversible television. No executive will clutter his desk with a huge video transmitter and a console-size teleset! But he would not object to a box 1 foot high and 1 foot wide - or even smaller than this if possible.

This problem of reversible television, in which the same compact set is both a transmitter and a receiver, is possible of solution. Briefly, this is the way I image it:

Our present-day cathode-ray receiving tubes have a round screen face. But due to the raster, the image on the tube is rectangular. This leaves 2 spaces, one above and the other below the raster, in the shape of 2 flat segments. These 2 spaces are never used now. They are blocked off, to give us our rectangular, scanned television image.

Why not utilize one or both of the now useless spaces on cathode-ray tubes? I propose simply to incorporate our transmitting tube elements right into the receiving cathode-ray tube. In other words place the light sensitive elements - the mosaic - into one or both segments

In the tube itself we would at first use 2 electron "guns," one for the receiver and the other for the transmitter. In time, however, I confidently believe that a single gun will do both the transmitting and the receiving.

A simple lens system attached to the upper side of the cathode-ray tube would gather the light, just as does our present orthicon transmitter tube. Thus a person sitting in front of such a "tele-trans-ceiver-tube" would be televised and at the same instant he would look at the image received from the distant set.

I appreciate that a reversible television tube won't be built tomorrow, but I know now that it will be in the not too distant future, once the necessary technical difficulties have been overcome, as surely they will.

When this goal has been achieved, industrial and commercial television will boom in earnest.

Let me cite here only a few of the thousands of uses for the future tele-transceiver:

Interoffice use. Conferences can be held between different officials in different rooms. As each man speaks, his image appears on the screens of all the other conferees.

Factory supervision of workers, who will see the supervisor in person on their tele-transceiver. Bank teller to bookkeeper, for visual verification of check data, such as date, endorsement, signature, etc.

Restaurants - between captain (or headwaiter) and chef.

Department stores - between customer and stockroom, to pick out items not in stock at counter, etc. A customer in a special booth - provided for this purpose-can "shop" via television, ordering a long list of merchandise from stockrooms in a minimum of time.

Hospitals - doctor or intern, in a fraction of time now required, can make his round of the patients by seeing and talking to them. (Teleset at foot, or side, of bed.)

Newspaper offices - editors can read last rush proof via television. Compositor props "copy" 'in front of teleset, editor then reads it without leaving his office.

Industrial plants - inspection and verification of visitors at gate-reception office from office in plant. But why go on? You can make your own list of uses - it is unending.

* see Radio-Craft, September, 1947, page 20.

 

 

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