RADIO RECEPTION

Sun (Auckland), Volume 1, Issue 52, 24 May 1927, Page 14

RADIO RECEPTION

YOUNG AUCKLANDER’S ACHIEVEMENT SHORT-WAVE BROADCASTS The remarkable achievement of having exchanged signals with over 85 foreign radio stations within one month falls to the credit of a young Aucklander, Mr. H. Arthur, of Herne Bay. On his station wall he has the verification cards of dozens of American broadcasting and amateur transmitting stations, including many from Japan, Canada, Honolulu, Hawaii, China and Holland. With radio stations in all these countries, Mr. Arthur has exchanged signals. He has obtained these results with a 50-watt transmititng set and a twovalve receiver. The call-sign of his little station is OZ-lAN. Mr. Arthur, who is 24 years of age, and an enthusist in the fullest sense of the term, has quite optimistic views about the future of short-wave broadcasting. SHORT-WAVE ADVANTAGES ‘There is very little interference on the short-wave length,” he stated, “and it opens up a big field for the crystal-set owner. The local broad-casting-stations can relay the shortwave transmissions from foreign countries and the small set owner can enjoy them as well as those who possess valve sets.” KDKA, Pittsburg, New York; P.C.J.J.. Holland; 2XAF, Schenectady, New York; and 2XG, Christown, New York, arc some of the short-wave stations he has received. Among other amateurs who have picked up short-wave broadcasts in Auckland are Mr. L. K. Ewen, Wellesley Street; Mr. B. Fisher, Herne Bay; Mr. R. Kay, Mount Albert; Mr. J. Walding, Devonport; and Mr. R. White, Mount Albert. A FORECAST Mr. Ewen, in a brief interview, indicated what he considered the probable nature of future radio set construction. “I think,” he said, “that the short-wave broadcast will do away with the many-valve set. The set of the future will be of one or two valves, self-contained, portable, and put on the market at about £20.” THE SHORT-WAVE SET The marked success met with by amateurs in all parts of New Zealand during the last few weeks in the reception of programmes from overseas short-wave broadcasting stations, has renewed interest in the subject. When the American station KDKA, at Pittsburg, was transmitting programmes for New Zealand and Australia many amateurs made up short-wave sets. KDKA used a wave-length of about 63 metres, and as the American station WGY, and the Dutch station P.C.J.J., both of which have been received well by Auckland amateurs recently, use waves of about 30 metres, these receivers will require slight modification. The exact wave-length of WGY is 32.79 metres, and that of P.C.J.J. 30.2 metres. Short waves carry very much more effectively than the ordinary broadcast wave-lengths over great distances, and hence, while ?.n elaborate multi-valve receiver would be needed to receive the ordinary broadcast stations, even under the most favourable conditions, the short-wave stations can be received under most conditions on a simply-made two-valve set. CONSTRUCTING THE SET Although the construction of a short-wave set is not difficult, it is necessary that material of fairly high quality should be used in it and that some care should be given to the layout of components. Unless this is cone the receiver will be very difficult to tune, as a shortwave set is more liable to trouble from “body capacity” tuning defects than an ordinary broadcast receiver. In fact, the whole art of short-wave reception by the amateur lies in learning to handle the receiver and to have its oscillating tendency perfectly under control. Unless the receiver is mechanically well made, disturbing noises and a tendency for a station to “wobble” in and out of tune may mar reception. SIZE OF AERIAL A very small aerial is all that is needed for reception from very great distances. A wire 20ft -ong will give good signals if it is erected in a reasonably open position. An ordinary broadcast aerial will be found perfectly satisfactory. Clotneslines in contact, or intermittent contact bodies connected with the earth, or any long wires or large metallic bodies scraping together in the neighbourhood of the aerial, may cause strange noises in the short-wave receiver. Care must therefore be taken to clear the neighbourhood of the aerial from metallic objects with loose contact, which may cause interference.