First Successful Television Broadcast

Radio Record, Volume I, Issue 34, 9 March 1928, Unnumbered Page

First Successful Television Broadcast

Two Hours of Magic Herald am Epoch Making Advance

PATNI MM MOTT DIMINUTIVE moving picture of a smiling, gesticulating gentleman wavered slowly within a small cabinet in a darkened room of the General Electric Company’s radio laboratories this afternoon and heralded another human conquest of space (states a special telegram from Schenectady, N.Y. State, to the New York Times, dated January 13. Sal ike ST Sent through the air like the voice which accompanied = the picture, it marked, the demonstrators declared, the first Rb) demonstration of television broadcasting, and gave the first absolute proof of the possibility of connecting homes throughout the world by sight as they have already been connected by voice. While a score or more of company officials, engineers and IUUTULAHUHT Mi -)., ™ mewspapermen in the darkened room heard and saw the radio = announcer in another section of the laboratory, other groups = in three Schenectady homes gathered about their receiving = sets, the old loud speakers and the new television receivers, Bi and joined in the reception of the dual broadcasting 4 programme. TOT TTT TTT Te AL TTT HUI TMT TT TP eg

PHU UTM OOOO 'THE® moving picture of the announcer, seen within the aperture three by three inches in each television cabinet, would float back and forth slowly as if on a screen, but it came clearly and distinctly, every motion being visible in all its details. FACET eT In their seats before the cabinets the groups in the homes had the drama of the laboratories brought before them. Although the apparently simple instruments gave no hint of the years of expérimenting and the tedious process of trial and error, they produced the combination of sound and appearance which meant success, a man smoking a cigarette and commenting on its taste and an ukelele player humming a song. = = The device failed to reproduce colours; one performer held a brightly-coloured cravat in front of the transmitter’s eye, but to the receiver it appeared only plain cloth, without distinguishing colours. MUU UU es OTTO TT TT TTT Bs) TTT TTT TTT

(TELEVISION has been demonstrated before. Last spring the American Telephone and Telegraph Company showed what might be done, but to-day’s performance, according to the inventors of the machinery, was the first broadcasting and reception by means of instruments which within five years, some engineers predict, may be in most of the houses that now possess loudspeakers. Home television was developed by Dr. KH F. W. Alexanderson, consulting engineer of the Radio Corporation of America and the General Electric Company, and his assistants. For seven or eight years he had worked on the principle of television, but the home sets are the deyelopment of comparatively recent months. SEE AND HEAR BROADCASTER. To those who were awaiting the demonstration to-day he introduced his work with an explanation of his experiments and conclusions, adding the prediction that they would be "the starting point of practical and popular television." David Sarnoff, general manager of the Radio Corporation of America, told the visitors that they were to witness the demonstration of ‘‘an epoch-making development.’’ It was au event, he suggested, like the demonstration of wireless telegraphy by Marconi when he sent the first message through the air for a mile or two. The visitors were ushered into a darkened room and crowded about two receiving cabinets, each a little more than four feet high and much resembling phonograph cabinets, The voice of Leslie Wilkins, of the General Electric testing department, came from the loudspeaker next to one of the cabinc‘s. "T understand there is an audience in the receiving room now,’’ he said from the alcove where he was broadcasting, so now we will start." In the small openings of each of the cabinets appeared the image of his face. WATCH AND LISTEN TO MUSICIAN, "Now I will take off my spectacles and put them on again," he said. ‘The picture suited his words. "Here is a cigarette. You can see the smoke," he continued. The audience saw him breathe out a smoke ring and watched it drift upwards across his face. Louis Dean, the regular announcer of WGY, succeeded Leslie. He was the first to broadcast music with his own picture as he played. Ain’t She Sweet??? he trummed on his ukulele, and his smile flashed through the air to the onlookers, _ he picture ,of each. performer was not steadily maintained but shifted in the cabinet opening to left and right. Tf the image went too far to one side, another similar image appeared alongside the first, like two pictures on a strip of moying picture film, although in this case the images were identical. . (SAH 4 , b LS! HM 4 d AIS Te UE SeQSAT TTT ST Rel | SS THTITILTH cuntacuntitom — | PITS 4 f AUTH Comparative . steadiness, it was explained, could usually be maintained, however, The steadiness dee pends on the "steering’’ of a control knob on the face of the cabinet which regulates the speed of the revolving disc used in the receiving set and synchrouises its rate with that of another disc used in the broadcasting set. ENGINEERS EXPLAIN PROCESS. {NGINEERS interpreted what had been demonstrated while the programme continued for two hours or more, AAA ZS ¥ y NA:

The uninstructed obseryers saw in the receiving set only the cabinet with its regulating knols and the opening with its magnifying lens at the front and a whirling perforated disc at the re@r. Just behind the disc was a lamp of pinkish colour. At the broadcasting end was only an are light directed through another and larger revolving perforated disc on the face of the subject. A printed explanation, distributed by the engineers, thus explained these features :- "The elements of the television hom: receiver are a light source, the scanning device and the synchronising system. The signal, or electro-magnetic wave from the television transmitter, is received in equipment designed to receive modulations as high as 40,000 cycles. The amplifier is substantially the same as the amplifier of the home loudspeaker. The receiving system differs from a modern loudspeaker system in that a neon gas-filled lamp is substituted for the loudspeaker, ‘Ihe amplified current is delivered to this iamp, known as the Moore lamp, which responds to the intensities of the current and gives fluctuations of the light intensity just as a diaphragm of the loudspeaker reproduces pulsations of the air waves. LENSES ENLARGE PICTURE. "THE scanning disc is 24 iné¢hes in diameter, with 48 smiall holes, each hole 35 mills in diameter and arranged in a spiral so that each of the 48 holes will pass each other and trace successive lines of the picture, completing or literally painting a picture in one revolution. In other words, if the disc were revolved very slowly a rav of light through successive holes would trace over the entire object. "The disc is revolved by a standard motor, similar to those used in household devices such as the washing machine or yacuum cleaner, The teyolutions occur at a speed of eighteen per second, slightly faster than a film passes through a motion picture camera, An observer, looking at this revolving disc as the light from the Moore lamp shines through these small holes, would see the image being sent by radio, but this picture would be but one and one-half inches square. "Magnifying lenses enlarge the picture twice, so that it is three inches square in the aperture in the front of the receiver calinet. ‘‘Synchronisation of the scanning disc of the receiver with the scanning dise of the transmitter is obtained by manually operated control, a push button held in the hand, By means of this button, of the bell-ringing type, the picture may be held in the field of vision with a little practice as naturally after a time as driving an automobile or steering a bicycle, THE TRANSMISSION SYSTEM. "MAH reproduced picture or object has a pink colour, which is characteristic of the neon gas used in the lamp. D. Mcl‘arlan Moore, inventor of the lamp and an engineer of the Edison lamp works of tlie General Tlectric Company, found in early work that this gas was most efficient and miost sensitive for reproducing a light which will go on and off in a millionth part of a second. ‘ "The transmission system is of the type using a disc with spiral holes, a duplicate of the disc in the receiving machine. A spot of light is projected on the object through the moving disc, and the reflection of this light is intercepted by photo-electric cells which convert the light to electric waves, ready for the short-wave transmitter, ‘The transmission was made on 87.8 metres wavelength." MMA EAA ECE

TO EXPLORE SECRETS OF SPACE. \ ITH these devices not only the obvious commercial possibilities will be exploited, but the secrets of space itself will be explored, according to Dr. Alexanderson. By the systematic study of television across the continent what may be learned about wave propagation can only vaguely be imagined, he declared. A part of the equipment is a new type of projector autenna which is now being tested with music and voice modulation, and favourable results have already been observed in San Francisco and Europe. It is built in a checkerboard pattern, the sides of each square being a wire half a wavelength long, All these halfway antennas are connected in such a way that they oscillate in phase and require no tuning or adjustment, D®*: ALEXANDERSON disclosed that a duplicate transmitter is being erected in the San I‘rancisco broadcast station of the General Electric Company to provide means for systematically studying the physical phenomena. of wave propagation over long distance, the eye" being infinitely superior to the ears for analysing and ascertaining facts. ‘This has already been proved," he said, "by our television tests in Schenectady. Occasionally, when we .look in on television at our homes uptown, we observe a visual echo of the wave from the electronic layer on the upper atmosphere. ‘The evidence of the echo is that two images appear side by side instead of one. "The echo image is usually displaced a distance corresponding to one fifteenth-hundredth of a ‘second, showing thereby that the echo wave had travelled abont 200 kilometres, and yet the echo image is occasionally as strong as the direct image, which travelled only a few kilometres. Such phenomena cannot obviously be observed by the ear." PREDICTS FUTURE OF TELEVISION. N R. SARNOFF in his speech warned that television sets were not at once ready for the market, and he made no promisé as to the time when developments still being made would permit the start of manufacturing in quantity. He did predict that in five years television would be "an art and.an industry in this country." Px ZALES a AAT WATT no a il ! PY zTITIHIINE "With all that has been accomplished there are still many experimental stages to be travelled before a commercial television service can be established,’’ he said. ‘Tlie first step contemplated is the placing of laboratory models of the present television receiver at central and strategically located points, so that with the aid of technically trained observers future experiments may be continued not only in the re« ception but in the simultaneous transmission, bot! sight and sound. , "The television receiver, as at present developed, will supplement and not replace the modern radio receiving set in the home. Broadcasting of television, it seems clear, will develop along parallel lines with broadcasting of sound, so that eventually not only sound but also sight through radio broadcasting will be availale to every home." TTT? AM The receiving sets in private homes were at the residences of K. W. Allen, vice-president of the General Electric Company in charge of the engineering; Edwin W. Rice jun., honorary president of the board of the company; an Dr, Alexanderson. ES TES SEN TTEN OS =¢6 AANA PAVE