MARVELS OF TELEVISION

Dominion, Volume 22, Issue 79, 27 December 1928, Page 10

MARVELS OF TELEVISION

THE LATEST HOBBY To televise or not to televise, that is the question. Here is a new word in the rich and fertile vocabulary of the American radio fan. Those who love tinkering with discs and scanners are already purchasing their television apparatus, but are being warned at the same time not to expect very satisfactory results as yet. Just as the kinema, the gramophone, and radio took years of experiment to bring to their present state, so perfect television will only arrive by degrees. How near or how far off this perfection of television may be is a matter of considerable debate, according to the “Literary Digest,” of New York, which quotes a number of representative opinions on the subject, published in “Popular Mechanics.” The inventor of the radio tube, Dr. Lee de Forest, who was asked when radio television and radio moving pictures would be available to the average radio fan for home reception, says “ten years or, more.” Another radio inventor, Dr. C. F. Jenkins, remarked: “Radiovision receivers will be available for Christmas presents this year.” Mr. D. Sarnoff, vice-president and general manager of the Radio Corporation of America, considers that four or five years more are needed for perfection; and another competent authority, Mr. H. P. Davis, of Westinghouse Electric, declares that “anything so far demonstrated would be premature if offered to the public as a service.” According to the manufacturers of television kits, television lias already arrived. “Popular Mechanics” comments as follows: “Here are five different views, ranging from right now up to ten years—ami probably every one of them is absolutely correct—a paradox that arises not through disagreement, but through different interpretations. Messrs. Sarnoff, de Forest, and Davies, see television as something that should not be offered to the public until it is as complete, as simple, as perfect, and as fool-proof as radio broadcasting is to-day—after years cf experimental development. Dr. Jenkins and the various manufacturers of television kits and parts believe there is a host of radio fans who got a lot of joy out of tinkering with crystal sets, coherers, fancy home-wound coils and all the accessories on which radio was raised from a pup, and, who will get equal or greater pleasure through a vicarious television. Anybody with an average acquaintance with the insides of a radio set, with fair mechanical ability, and 45 dollars to invest, can buy one manufacturer’s kit, including an elec rie moUr, scanning disc, neon lamp and other parts, fit a television receiver together, hook on some batteries and his existing radio receiver, insert a few tubes and start receiving pictures. The- may be, in the words of Dr. de Forest, “small, poorly illuminated, coarse-grained, unclear silhouette and half-tone effects.” But they will be pictures, either niirrored images direct from life or radio movies. They will come through the air to you, and if you got a thrill a few years ago out of a jumble of squeals, there is a bigger thrill in seeing. an image in the frame of a homemade television receiver. The first photographs by wire and radio were not perfect, either.”

. Here are the views of several men who have been intimately associated with television and broadcasting:—

"Both television and radio movies,” says Mr. Davis, vice-president of Westinghouse, “are accomplished facts in electrical engineering laboratories, and there are no fundamental principles which to-day have not been solved. However, before these developments leave our laboratories a considerable period will ensue, during which various elements must be perfected and coordinated.

“Leading ’scientists and engineers all over the world are now working out the problem. The day is coming when television and radio movies will be at the service of the radio public. “I cannot believe that we should offer anything in an experimental condition. The development period in television should be passed in the laboratories, and when offered w to the public it should be a finished product. Anything so far demonstrated in television, in my opinion, would be premature if offered to the public as a service.” . Francis Jenkins, an inventor himself, and one who believes in letting all the amateur inventors in, says:— “Radio movies on 46 metres are broadcast Monday, Wednesday and Friday evenings,from our station, and regularly received in many homes already. Our transmitters will soon be attached to stations now broadcasting music, and radiovisor receivers will be available for Christmas presents this year.’ Lee de Forest has frequently voiced warnings against benig over-optimistic about television, repeatedly pointing out that when it comes it will always be better over telephone wires, because free from static Interferences. Ho repeats them now Satisfactory television in the home is a very long way off. For the next few years radio fans will, however, derive much interest and amusement from receiving small, poorly illuminated, coarse-grained, unclear silhouette and half-tone effects. Real television will some time arrive, but will always be much more satisfactory ov»r the wire than by radio. I consider this development may be a matter of ten years or even more.” The possibility of theatre owners and kineina companies being afraid/of television as a rival to their business is discountenanced emphatically. Sir. Carl Laemmle says he has never seen the time when science and' invention ever damaged the motfon picture in’ dustry. Whether or no radio movies or television were just round the corner, their advent would prove a blessing, and not a curse. Jenkins is broadcasting radio movies from his station at Washington on a wave length of 46 metres. He uses a system of 48 lines to a picture. .Other stations are broadcasting television with 36 to 24 lines to a picture. Each broadcaster so far is producing pictures one and a half inches square. Obviously, the amount of action and detail to be crowded into such a small picture is limited. Jenkins has improved on other systems by installing a large magnifying glass in front of the frame, giving the illusion of a picture four inches square. Enlargement beyond the size is according to present means impossible. The reason lies in the scanner disc, and the number of “lines” employed by it in transmitting the scene. The great difference between ordinary radio broadcast of music or voice and the broadcast of television is that the first is a one-dimensional straight-line affair, and the second is two-dimen-sional, having both width and length. No one has ever found a means of transmitting an entire picture as an entity. Instead, an optical illusion is utilised, the same optical illusion which makes the movies possible. In telexision, the radio, .engineer, .cuts each

picture up into sections, transmits each through the air as a straight-line radio signal, and then pieces the sections together before the eye so rapidly that the images of all linger as one picture. The cutting process is done with a scanner, a large metal disc, revolving at a high speed, and containing a series of holes, arranged in a spiral. In all discs so far used, the distance between the outer hole of the spiral and the inner hole is 14 inch, and the result is a picture 14 inch square. The number of holes that can be used and the number of pictures which can be transmitted each second depend entirely on the sensitivity of the photo-electric cell. Cells are improving rapidly. Hardly a year figO the best cells would not respond rapidlv enough for a disc of more than 24 ‘ lines. Lately the Westinghouse Company has demonstrated radiomovies, using 60 lines to the picture. What does such a picture look like? The average newspaper half-tone illustration has 65 lines to the inch; in other words, 65 dots each way in its screen. That rating is to the inch, and all television images to date have been 11 inch square, so the best transmission yet, with 60 tines, has been spread over an area of 50 per cent, greater pach' way than the newspaper illustration.