EMPIRE BROADCASTING

Poverty Bay Herald, Volume LIV, Issue 16705, 24 July 1928, Page 10

EMPIRE BROADCASTING

■ SHORT WAVE DEVELOPMENTS | Considerable improvements are antiei--1 pa ted in Empire broadcasting in the near future. Hitherto the clifiiuult-y lias been in ; applying high power to the uerial in 'short-wave transmissions. Wonderful resuits have been secured in the use of low power and short wave.;. Amateurs using j only a few watts have been able to ' transmit messages around the World. j With a power less than that used by the average "13" class station musical programmes have been transmitted from one lend of the world to another' to be there i intercepted and re-transmitted td the 1 country of their origin. these were merely experimental transi missions, and could, not be regarded* as i t-lio forerunner of continuous Empire broadcasting. They, however, pointed the way to further developments. Ertgii neors have been for the past 12 months ' assiduously endeavoring to apply power to short-wave transmission. Successful ■ experiments in this direction have been conducted by- Amalgamated Wireless' in Australia., by the Marconi Company in ' Britain, by the General Electric, Company in America, and the Philips labora--1 tones m Holland. HIGH FREQUENCY FREAKS. In the experiments being carried out in the application of high frequency to low waves by the engineers of the General Electric Company some peculiai ro- ' suits were observed, indicating the tremendous power there is latent in tiio radio vacuum tube. When testing highj power short-wave tubers in the laboratories at Schenectady it was found that jan incandescent lamp, such as is used I for lighting purposes, when pulled from jits carton for the first, time lighted to full i'l'illaucy without wires or socket : a copper bar lying on the floor blistered the hand that picked it up, though Die metal was cold to touch : a neon tube suddenly Hooded the room with its lurid red glow ; meters in adjacent rooms ran wild, and delicate measuring instruments Mere twister! or broken so that accurate scientific work in the vicinity was impossible. When investigators came close to the new apparatus they felt a comfortable glow permeating their system, such as results from the judicious use of stimulating liquors, but this was soon followed by pains in the limbs and joints. Rats in a.cage placed close to the radiating wire ibecamo excessively lively for a time, bat when exposed too long they died. The cause of these remarkable phenomena was an innocent-looking vacuum tube five niches in diameter and about- two feet long, placed in a wooden cag© and surrounded by a network of wires', condensers, and electric meters. Tins tube operates as a selfexcited oscillator on a wavo-longlh of six metres, and. is capable of radiating from .10 to 15 kilowatts of high, frequency power, which is about 50 tunes as much power as any short-wave tube previously produced. The tuned aerial circuit is a copper bar approximately three metres long, and 'bis is able to radiate into space the full 15 kilowatts generated by the oscillator.

Mr. H. J, Nolts, one of the engineers responsible for the development of this lube, said there was nothing new in the principle on which it operated. ''Very short radio waves," he said, "have always been easy to produce at low power, and high power has been available for a considerable time for the longer wave lengths. This is the first time, however, that we have been able to combine the two so as to get relatively large power outputs on short-wave lengths. This new tube is a step in the development of short-wave radio transmission that wo have been intensively engaged on for several years. At present wo have'generated the power, but we have not yet devised a method of controlling its' frequency within the close limits necessary for commercial operation. We have not studied the applications of the new tube at *all, except to make a, record of interesting sidelights that its operation have brought about. These demonstrations indicate that many of the high frequency phenomena may be worth investigating, and it is likely that in the future applications will suggest themselves, as they' always do when a new field is entered."

RADIO COOKING EXPERIMENTS. •Dr. W. R. Whitney, director of tho research laboratory, said it was clear that further experiments mast be carried out, as the indications were that , by means of this tube radio might he commercially applied to a. number: of new purposes only dreamt of at present. ''For instance/' he said, "the property of warming the blood might be of tl.se medicinally for the purpose of inducing eonvalcßcoiieo in patients suffering from certain diseases. Another purpose is 'radio cooking.' In studying ('He application of' this lube a wire was suspended over a Gable some distance from the radiating aerial,.and parallel to it. A sausage; placed in a glass tube was hung from the receiving aerial, and in a few minutes it began to steam. On being removed it was found to Have been beautifully cooked by the high frequency currents induced iu-it, although no flames or other visible means of hear, were applied. Eggs were 'fried' in a glass tube, and served hot to the amazed spectators. An apple was impaled upon the end of the' receiving aerial, and in a short time was thoroughly baked to the core. With a different, arrangement, pastry was baked and water boiled by the induced currents received through space." On a recent occasion, when discussing the future of electricity generation and distribution. Me. Forbes Mnrkay, the general 'manager of the City Council's electricity department, stated it was quite probable that in tho future it would be practicable to get electricity from the air without tho means of wires save by a "receiving aerial." such as that used for the reception of broadcast entertainment al present. These experiments indicate, that, this idea is by no means an idle dream. FIREBALLS PRODUCED. Probably the most spectacular of the experiments carried out. by the Goaral Electric Co. with this marvellous lube was the production of a standing electric are, which was a. close imitation of the "ball of tire'' which is sometimes seen travelling along electric wires in Sydney and other parts

oi' Australia when u, thunderstorm bursts. The operator touched tho end of the, radiating aerial with a. mutalfipped pole, and immediately a greenish white arc arose to a height of a foot or more. When the pole was removed the arc remained, like a. ball of lire, sputtering, and sending molten copper in all directions, until blown out. By skilful manipulation as many as three of these arcs were established simultaneously along the aerial, giving the appearance of a, row of flaming gas jets. No more extraordinary sights could be imagined than a powerful electric, thousands of volts, standing entirely by itself on the end of a. wire Without visible return circuit 1 . Smaller standing arcs of this nature were established on tho ends of a receiving aerial several feet from the radiating system, demonstrating the trausmisisou of power currents through space!