Broadcasting (Oct 1931-Dec 1932)

'What About Television?" One Answer From a Highly Authoritative and Unprejudiced Source We Are Told What to Expect in Visual Radio EDITOR'S Note— Because of the intense interest »f broadcasters and advertisers in the prospect of elevision and because of the high standing of the luthor and his publication in the radio engineerng field, Broadcasting here reprints without furher comment excerpts from an article in the November issue of "QST," published by the Amercan Radio Relay League, the national amateur >rganization. pi By ROSS HULL Associate Editor, "QST" VHY, we wonder, must so many eople say so often that television 3 just around the corner? It may e, for all we know, but the stateient annoys us. Corners in any leld of scientific development are 0 rare anyway. And when we do ind them they are always blunt orners with a bold wide sweep nd a stiff head wind on the far ide. Unhappily, many television nterests have endeavored to avoid .he corner altogether. But in ;rossing the vacant lot they have Sound themselves tangled in the ■ eavy underbrush of unsound priniples and faulty methods. If we mist talk corners when we talk n television let us chant in unison /ith the rest of them, "Television, ebulous objective of mighty rrinds, is indeed around the corter." But let us continue, double ortissimo, "But, boy, oh boy, what . corner it be!" Television as practiced at the •resent time is well-removed from he field of amateur radio. As an experimental field, it possesses atractions for only a few isolated l.mateurs sufficiently well-equipped inancially to undergo the relatively ■normous financial outlays required |or _ really suitable transmitting equipment. Of course, there are nany thousands of independent experimental lookers-in, but the art ind science of amateur radio alvays inherently includes the transnitter as well as the receiver, makng possible two-way communicaions. The amateur viewpoint, hen, can be safely regarded as ufficiently critical to eliminate the nenace of rose-colored unreality. Visual Workers Divided THE PRESENT television intersts, it now seems, are divided into ;wo camps: those anxious to talk, ind those anxious to avoid talking, ^or this reason, it is not really Possible to gain an accurate idea of he status of the art. The most voluble, urtfortunately, have the 'east information to impart. Read 1 prospectus of almost any one of ;he television companies now engaged in stock promotion and you will know what we mean. At least some of the concerns low attempting to commercialize relevision appear to believe that :he public, so long dieted on plain iroadcasting, will eagerly swallow present-day television as a new and absorbing entertainment. Quite possibly they are right. There are other interests, however, desperately eager to delay the arrival announcement of the new entertainment— determined at least to glimpse a solution of these basic problems beforehand. These concerns are the non-talkers. Anxious to prevent a continuance of the premature and pitifully misleading publicity which has characterized television development, they have crawled into their shells. They have work to do. They have inventions to protect. They have nothing to say. Nevertheless, with rabid dogmatism on one hand and profound secrecy on the other, the formation of opinions is extremely difficult and the disclosing of facts impossible, We have somehow managed to make a very thorough investigation of the "big smoke" and get an adequate glimpse of just what sort of a stew was on the fire. There is no need to go into the technical details that were uncovered, or even do more than recall to mind the fact that, so far as is possible to determine, all existing television "services" employ for both transmission and reception some form of the scanning disk invented in 1884 by Nipkow, a Russian. This disk, so important a feature of all television equipment of the past, is retained chiefly because its advantages and weaknesses are so closely interlocked. It is much less expensive than any equipment yet produced to displace it; but it is, in essence, a mechanical expedient — a crudity. It is pimple in operation but it is limited in performance. It will probably provide the most accessible road to television, but it is a rutted detour strewn with many progresslimiting boulders. For the amateur experimenter the scanning disk unlocks all the fun it ever did. But to the engineer intent on developing commercial television the disk is widely considered to have most of its future behind it. Time alone will tell. Progress Since 1927 BECAUSE of the ever-present limitation of available channels on the frequency bands now exploited by these same "services," and because the width of the transmitted frequency band so definitely limits the picture detail, commercial television images are still almost as unsatisfactory as they were in the first public demonstrations of 1927. Sixty-line pictures continue to provide a momentary thrill for the uninitiated, they still reward the amateur experimenter for his efforts, they still point a finger at real television around the corner; but, as at first, they still fail to keep the family at home engrossed in a television program. This does not mean, however, that progress has not been made in the instances just mentioned. Many creditable contributions have served to improve the effectiveness of transmitter pick-up devices; to enlarge images at the receiving end; to increase their brilliancy. Then, minor improvements in the mechanical and electrical apparatus have simplified the problems of synchronizing and "framing," improved the operation of receiving amplifiers, and increased the reliability of the apparatus in general. It is just a pity that all these d-' velopments have been so restricted in their usefulness by the fundamental limitations imposed on any image transmitted electrically with a strictly limited band of frequencies. Fundamental Problems LONG before television had started out on its premature and eventful jaunt from the laboratory it had been realized in some technical circles that any conceivable improvements and refinements in the then known systems could not possibly lead the way to truly successful television until two fundamental problems had been solved. It was seen at once that, barring miracles, the detail available in a television image must have a very close relationship to the band of frequencies occupied in its transmission. Since even three or four 10-kilocycle channels (let alone one) proved insufficient for the transmission of well-detailed pictures, it became evident that successful television called either for the opening of some territory where many stations could all have a big slice of frequencies for their own, or for the curtain to be rung up on a scientific near-miracle. Behind all that is Problem I — not insolvable but not solved. Problem II is concerned with scanning — the process of resolving images into thousands of units and their reassembly at the receiving end in the right sequence and original light values. It is concerned particularly with the displacement of mechanical methods by another more suited to the work. It is no secret that vigorous laboratory work has resulted in what are probable solutions to both basic problems. The cathode-ray tube has been shown to promise an effective means for scanning. It has every indication of being one logical successor to the scanning disk, free from the inaccuracies, the inconvenience and the speed December 1, 1931 • BROADCASTING limitations of any mechanical device. Then, as a way out of the frequency-band limitation problem, it is proposed to operate in the relatively extensive and almost unoccupied territory above about 40,000 kc, near the 5-meter region. Several powerful transmitters already have been built for the express purpose of transmitting television images in this portion of the frequency spectrum and there seems to be no particular reason why they should not be successful. But even with these developments it is obvious that television — the entertainment — is not yet here. The cathode-ray tube has been put to work with striking success. It is, though, quite expensive; it is relatively untamed; it has yet to emerge from the tube production plant with a clean card of conduct. From the transmitting angle, it is not certain that the ultra-high frequencies are capable of good service. We know that they afford some elbow room; that they will allow simultaneous operation of transmitters in different cities on the same channels; that they will be free from most of the troubles of selective fading and atmospherics. It is far from certain, however, that even powerful transmitters will provide good signals throughout a city such as New York; that automobile ignition racket will not play havoc with much reception; that the effects of elevator motors and steel-frame buildings will not ruin the rest. What We May Expect BUT THIS does not mean that all is lost. In two or three months it is probable that important conclusions will be reached concerning these particular problems. At that time it should be much less difficult to make a prediction of television's future. Should everything go smoothly it seems likely that within two years many cities will have their ultra-high frequency television transmitters raining programs from high and centrally located buildings. Spectators able to afford the receiving equipment and willing to give their full attention to a small green and black image will be able to follow programs originating in studios attached to the transmitting stations. Wire linkage of many stations throughout the country (even the transmission of events outside the station) probably will still be impractical because of the limitations of wire lines in carrying high frequency currents. Images, however, will be beautifully detailed. With perhaps 240 lines to the picture there will be little danger of mistaking the soprano for her poodle. Of course, something may come along to upset all this. Television may be quite thoroughly commercialized in 12 months and it may be nothing like the thing we have visualized. Our guess is only based on a glance into the stewpot. Though there was a big fire in the stove the cooks were still without a recipe book. To get back to earth we might say that television of the moment is an intriguing and utterly absorbing field for the experimenter. It is a profound and pregnant problem for the laboratory. It is a field with obviously limitless commercial possibilities. But as entertainment for the masses it is, we believe, around the corner. It still Page 13