Get in on Television (Jul, 1931)

Get in on Television

HERE is your chance to become an expert in the miracle field of sending pictures through the air. At present, George Waltz, author of this article, is not a television expert, but he will be before he gets through. Go with him and learn all that he means to learn about this absorbing subject.

By GEORGE H. WALTZ, JR.

I SAW something a few days ago that gave me a real kick. I saw, from behind the scenes, the opening night’s program broadcast from station W2XGR, the new $65,000 television broadcasting studio in New York City. Besides getting a real thrill out of it, I was inoculated with the television bug.

What if television still is a long way from perfection? What if the picture you see is small and fuzzy and none too bright? With all its present faults, and it has plenty, it still seems almost like a miracle to me.

Chasing distant stations all over the dial of a broadcast receiver used to be a lot of fun. Now with the modern set, distance is so easy it’s not exciting and from now on my spare change is going into building me a television receiver. When I finally get one of those flickering pink “visions” on my own apparatus, I expect a bigger thrill than Admiral Byrd got out of discovering Little America!

My interest in television began a few weeks ago when I heard over the air a sound like a buzz saw with a couple of teeth missing. I was visiting a friend who experiments in short wave reception. He accidentally tuned in the funny buzz saw noise. He told me the ear splitting wail was pictures coming over the air and he pointed to the television program in the daily paper.

I’d read about television experiments, but actually hearing the signals over the air was what brought the thing to life for me. I determined to investigate and as the first step, I succeeded in getting an invitation to visit W2XCR, where I found out how television programs are put on the air.

At first, as I walked into the television studio, I thought I was in the wrong place. I had expected to find a room filled with weird and complicated looking machinery. Instead it was tastefully draped and for the exception of two small standards supporting the photo-electric cells, it looked quite like any radio studio, several of which I had previously visited. All of the mechanical equipment for picking up pictures was in an adjoining, smaller room that resembled a motion picture booth.

MOST of the space not occupied by studio equipment was filled with people who, like myself, had been invited to the opening night. In the reception room several of them were grouped around a piece of apparatus upon the front of which I noticed a pinkly glowing spot. As I moved closer, it became a picture of a man’s head.

I could see him smile and turn his head from side to side. Then I looked through the glass windows that separated the reception room from the studio proper and there in front of some apparatus was the man himself. I had seen my first television picture, for the small outfit we were looking at was the studio’s monitor set. It was tuned to reproduce whatever was being televised in front of the big machine.

After all the celebrities present had appeared before the machine and their smiles had been sent out on the air, there followed a brief talk on the equipment used. It did not, however, go into the details I wanted so after the crowd had left I buttonholed Harold Higginbottom, the engineer in charge of the station. He was kind enough to answer the questions that were buzzing around in my head.

“Mr. Higginbottom,” I began, “you said the subject’s face was scanned by means of a disk. Could you show me the disk and tell me just how it works?”

“Do you know how ordinary broadcasting is done with a microphone?” he asked as he snapped on a light over the scanning mechanism and swung open a door that covered a large thin metal disk painted dull black on both sides.

“I do after a fashion,” I replied. “The microphone takes the voice or music vibrations and turns them into electrical vibrations and these are pumped up to pretty high intensity and then applied somehow to the carrier wave of the station. I’m afraid I couldn’t explain just how that is done.”

“YOU don’t have to,” he said. “You’ve got the main facts. Television, after all, is only piecemeal broadcasting. We really don’t send pictures at all; only tiny little pieces of pictures one after the other. All the scanning disk does is to break up the picture into these tiny pieces so we can broadcast them. Do you see this row of holes in the disk?”

“You mean those small holes arranged in a spiral?” I asked.

“That’s it,” he replied. “Now what would those holes look like if you turned the disk very rapidly?”

“They wouldn’t look like anything to me,” I decided. “How could I see those tiny spots if the disk were spinning? They’d fly by so fast I couldn’t follow them.”

“Correct,” he said. “Now watch closely.” He turned a switch and the disk started to whirl. The spots representing the holes disappeared in the ordinary light of the studio. Then he held a drop light behind the disk.

“Now I see what you mean,” I exclaimed. “The disk looks as if it were made with a band of gray glass where that spiral of holes is and I can see the electric bulb right through the disk.”

“You only think you can,” he laughed. “You could see only a tiny part of that bulb through any one hole in the disk or even through all the holes if they were in line instead of being spaced out around the disk in spiral form. Your eye fools you. Seeing through that disk is an optical illusion just as motion pictures are an optical illusion, and a television vision is an optical illusion.

“When light flashes into your eye,” he explained, “the eye goes on thinking it sees light for over a thirtieth part of a second even if the flash only lasts for a thousandth of a second. The scientific sharps call that persistence of vision.

“Now, I’m going to turn on this big arc light back of the disk and put out all the lights in the room. Watch the wall there.”

THE arc sizzled and then glowed brilliantly. Then the lights in the room went out and as he again started the disk, a row of tiny, brilliant light spots chased each other faster and faster across the blank wall. As the disk picked up speed, the light spots traveled so fast they became streaks. Because of their spiral arrangement, each one a bit closer to the center than the preceding one, these streaks overlapped and as far as my eyes could perceive, the rectangular section of the wall was uniformly lighted all over.

“I suppose you noticed,” Mr. Higginbottom said, “that when the disk started up the rectangle was just wide enough to allow one spot of light to disappear at the edge of the rectangle at the instant the succeeding spot appeared at the opposite side. That means that there is actually only one spot of light in that entire rectangle at any one time.

“Now the amount of light reflected to your eye from the blank wall is steady because the draperies on the wall are all one color, but if you were sitting in front of it, the spot would reflect a lot of light when it struck your white collar and a lot less light as it passed over the neckband of your suit.

Those photo-electric cells, which you see placed on either side of the piano in the studio, are affected by the amount of light reflected and are hooked into the broadcast transmitter in place of the microphone used in ordinary sound broadcasting. The result is that the radio wave carries a string of electrical pulsations equivalent to the variations in the one-after-the-other streaks of light.”

“It’s beginning to filter through my thick cranium,” I interrupted. “By means of the traveling spots of light you get a piecemeal electrical picture that you can put on the air. Then all I have to do to receive that picture is make up some apparatus to reverse the process so I can turn the electrical impulses back into light that can be seen. Is that it?”

“YOU’VE got the right idea, Mr Higginbottom replied. “In theory all you need is another disk like this one, a radio receiver, good audio amplifier, and a light that will flicker according to the electrical impulses. The neon light is the only one available to the amateur that will do the job.”

“I’ll buy one tomorrow and start making the disk,” I said enthusiastically. “Then I’ll hook it to my radio set and watch your next program.”

“Go to it,” he grinned. “Only remember that your radio set will do fine to bring in the sound accompaniment which goes out on a broadcast wave but it isn’t a bit of use on the television signals. To begin with, it won’t tune down to where the television signals are and besides, the audio amplifier in it isn’t good enough.

“Television signals cover a much wider band of frequencies than broadcasting and you have to have a special, distortionless, wide-band audio amplifier. The television image isn’t so good that you can afford to make it worse by using an unsuitable amplifier.”

“Besides the special amplifier and short wave receiver, what other equipment will I need?” I asked.

“Of course,” Mr. Higginbottom replied, “you will need a motor to drive the scanning disk and a neon lamp.”

“How much do you think all of the equipment should cost me. That is,” I added, “if I make and assemble some of the parts mvself?”

“Let’s see,” he said. “If you buy all of the parts, it probably will amount to about $120, but if you hunt for bargains, assemble your own amplifier and short wave receiver, and make your own scanning disk you ought to be able to cut a third off that or maybe more.”

“THAT’S a lot of money. What I am wondering,” I asked hopefully, “is what kind of programs I am going to receive after I get the set built?”

“I think you’ll like them. Our programs consist of musical numbers, vaudeville skits, speeches, and then, of course, interesting moving pictures with sound accompaniment.”

“Moving pictures?” I asked. “I suppose you broadcast those by allowing the film to run through an ordinary moving picture projector and pick it up with a disk and photo-cell?”

“Partly right,” he said, “but we don’t stop the film a certain number of times a second as in the regular moving picture machine. It runs through continuously and the scanning disk has radial slots instead of holes. You see,” he added, “the film runs by vertically and the slots in the scanning disk run by horizontally so that the combination of the two gives us the same effect we would get if we stopped the film twenty times a second and used a disk with holes accurately arranged in a spiral.”

“What sort of pictures are you going to broadcast?” I asked.

“Just the same kind you see in a theater. Of course, they won’t be brand-new feature pictures but I think you’ll like them.”

“How many television stations are now broadcasting in this country?”

“Well,” he said, “on the last listing I saw there were twenty in all. Eight of these are located in New York, four in New Jersey, four in Illinois, and one each in Maryland, Indiana, Pennsylvania, and Massachusetts. Of these stations, eleven are operating on regular broadcast schedules.”

“HOW about outdoor broadcasts?” I asked. “Have you been able to put outdoor scenes on the air yet?”

“In an experimental way, yes. Here,” he said, pointing to a cameralike piece of apparatus, “is a television camera. Unlike the scanning mechanism used here in the studio this depends on the brilliant illumination of the subject for its operation.”

“It has a disk just like the other, hasn’t it?” I asked.

“Yes, it has a disk. The reflected light coming from the brightly illuminated object passes through the holes in the disk and scans a photo-electric cell housed at the rear of the camera,” he explained.

“Oh, I see. The fact that the only light which reaches the cell is the spot of light reflected by the object allows you to use it out of doors,” I said as the explanation struck home.

“That’s right. Now, on the side of the housing is a control board,” he continued. “The operator plugs in a pair of ear phones and by manipulating the various switches, controls the out-going signals as well as the sight.”

“I guess next fall I’ll be able to sit in my living room and enjoy a football game,” I said enthusiastically.

“I doubt that,” said the engineer. “This camera at the present time is just an experiment, and there are lots of difficulties that must be ironed out before we can use it with a fair degree of success.”

“Football or no football,” I said, “I am going down to the bank tomorrow and draw out some money and then shop around and see what I can pick up in the way of bargains in television equipment.”

2 comments
  1. Stephen Edwards says: April 18, 20086:32 am

    Amazing: they rasterized the image by shining a moving spot of light on the subject, then collected the reflected light with a single, unfocused photodetector. This is definitely a technology that didn’t last long.

  2. David Moisan says: April 18, 200812:34 pm

    Google John Logie Baird. He developed mechanical TV and pushed it hard. He made a mechanical *color* scanner.

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