RADIO NOTES

Dominion, Volume 27, Issue 32, 1 November 1933, Page 6

RADIO NOTES

By

“ETHER ”

CURRENT TOPICS So far as the Wellington station is concerned, the changes in wave-length from 416 metres to 526 metres should result in greatly improved results. It has been proved on numerous occasions that the longer the wave-length on broadcast band the better the results. Not only is fading reduced, but the areas in which fading occurs is moved further away from the station. Moreover, the change will probably result in a twofold' increase of signal strength in country lt must not be thought that this doubling of signal strength will have startling results. Signals may be four times louder owing to the square low effect of rectification, but as the human ear is unable to appreciate anything much below a. quadrupling of strength, listeners must not feel hurt if signals do not coine roaring in as If an extra valve had been added. ♦ » • We understand that one result arising out of the Lucerne Conference is that the famous Eiffel Tower broadcasting station will cease its transmission on January 1, 1935. In view of the forthcoming antiinterference law, the National Socialist Funkkammer has decided to clear the town of Baden-Baden of all man-made statics. Work has already begun under the direction of a post;, office engineer and the second burgomaster of the town, and it is hoped that by the middle

of October all such interference will have ceased. The authorities have inferred that the law against man-made interference will be based on the technical requirements of the Volksempfanger. (the new People’s Keceiver), so that every owner of this set will have clear reception without the necessity of providing shielded aerial down-leads * * * The change in the announcements of the different programmes transmitted on the Daventry shortwave sets is merely one of nomenclature. The various Empire programmes will in future be known as No. 1, No. 2, and so on. Thus instead of announcing a programme for “The Canadian Zone,” it will in future be known as “Programme "No. 5.” It has been found that there was so much overlapping of the formal rones that, in practice, the attempt to allot a certain programme to any certain zone was impossible. ATTRACTIVE FEATURES This Week’s “Radio Record” A full announcement by the Post and Telegraph Uepannient and the New Zealand Broadcasting Board is made in this week's issue of the "lladi'o liecord,” concerning the changes in the wavelengths of almost every radio station in the-Bo-minion. A table is published showing the old wavelengths and the new, so that listeners may make the necessary adjustments to their sets. Two pages are devoted to an interesting article by Mr. N. 11. Jacobsen, a world traveller, on his impressions of the Empire State building in New York, and the Taj Mahal in India —two world wonders. The Princess Irian’s libel suit against the film company which produced the film, ‘‘Hasputin and the Empress," is dealt with in full, and there are also articles on the history of Christ’s College, the building of the new 3YA on Banks Peninsula, the story of Richard Wagner and Minna Planer (written by Margaret Macpherson}, and the Lord Mayor’s Show, which is held in London on November 9 of each year. Full details are given as usual of the New Zealand programmes, and there are many attractive items set down in the Australian section. The technical pages present several features of interest to the amateur enthusiast, while the women'-s section this week is particularly bright, nnd includes a full page of fashions from the film studios of Hollywood. feed back Should instability, due to feed-back in L.F. stages, make itself evident in a battery-operated set (or H.T. eliminator and battery G. 8.), even when the detector-anode circuit has been decoupled on conventional lines, the trouble is probably in the grid circuits of the L.F., valves. Decoupling here will almost surely effect a cure. Insert a resistance of approximately 20,000 ohms in the G.B. minus lead, and connect a fixed condenser of 2 mfd. between G.B. end of transformer-, winding and L-T. mtnua.

GERMAN RADIO SHOW Modern Trend of Design The German Radio Show, which has just been held in Berlin, has received greater publicity and probably provoked more interest than any previous Berlin radio exhibition, says an English journal, partly for the reason that this year broadcasting has taken such an important position in political and Government affairs. The general appearance of the exhibition this year has undergone a definite outward change indicative of the importance which the German Government now attaches to broadcasting as a means of propaganda. We are, however, not. concerned here with the political aspects, and must confine our attention to a review of the technical progress which the exhibits at the show revealed. The set manufacturer has had the advantage of new valves of types similar to the new valves in this country to assist him in his designs, and the result is increased range and selectivity of receivers, a large number of superhets, Including those employing only a few valves, and automatic volume control in all the more important models. In view of the need for increased selectivity, practically all receivers have employed coils of high efficiency, and the solid dielectric type of condenser which was popular in Germany in previous years has been replaced by well-built air dielectric condensers.

The coils are almost invariably built in cylindrical form with stranded Litz wire. This improvement in tuning circuits has resulted in the appearance of even simple two-valve sets with tuning scales calibrated in station names. The German receivers this year are notable for the variety of types of tuning dials, nearly all with station names, and mostly indicating these clearly with illuminated scales.