THE WIRELESS WORLD

Otago Daily Times, Issue 22823, 6 March 1936, Page 2

THE WIRELESS WORLD

NEWS AND NOTES By Magna Vox. Items of local interest are invited by "Magna Vox" for publication in this column. It is necessary that such matter should reach this office by Tuesday of each week for insertion on the following Friday. 2BI>, Sydney.—74o IC.C, 405 metres. 2KC, Sydney.—6lo K.C., 492 metres. 3AU, Melbourne.—63o K.C., 476 metres. 31.0, Melbourne. —770 K.C., 390 metres SCL, Adelaide.—-730 K.C., 411 metres. 4QG, Brisbane.—Boo K.C., 311 metres. IYA, Auckland.—6so K.C, 461.3 metres. 2YA, Wellington.—s7o K.C, 526 metres. 3YA, Chrlstchurch.—72o K.C, 416.4 metres. 4YA, Dunedln. —790 K.C, 379.5 metres. 4YO, Dunedin.—ll4o K.C, 261 metres

ANSWERS TO CORRESPONDENTS. " Crystal," Dunedin. — You have expressed a desire which is, I suppose, common to every enthusiast who has been dabbling in wireless since the pood od days. A selective crystal set, sufficiently sensitive to bring in all the local stations separately, has been the dream of most amateur radio men, but it is not so easy to- construct. Additional tuning circuits generally cause such loss of efficiency that no stations can be heard at satisfactory volume. The use of a wavetrap would be quite in order in a rare case such as yours where you have five fairy powerful local stations. You should have no difficulty in procuring constructional details of a suitable trap.

" Super," Middlemarch. —Background noise in supers is generally due to faulty alignment, but it varies a good deal with different coil kits, etc. An efficient kit with perfect alignment will usually receive any station worth hearing long before rushing background noise is heard, but if the aerial is inefficient or disconnected, or if the intermediates are out of alignment, then the noise may be troublesome. Try a bigger aerial and more careful general adjustment; change the pentagrid, grid condenser, and grid leak. If the trouble then persists, I am afraid your course is to have the coils checked by an expert. R. T. M., Mornington.—(l) Your friends comment is a distinctly unfair criticism of a first-class set, and would indicate that he is speaking from hearsay, or does not know what he is talking about. (2) I have never seen one, but I have no doubt that there is such a device on the market. An inquiry from some of the radio dealers would probably give you the information you require. (3) I am afraid not. What you are asking really amounts to a' request for about £2 worth of free service. Get in touch with a good serviceman.

RADIO VAGARIES. The vagaries of radio were strikingly illustrated in the recent stranding of the small launch Donald Sutherland on Farewell Spit, Nelson. The launch was equipped with a small transmitter of 20 watts input rating, or rather less than half the wattage of an ordinary receiver. The aerial output was little more than live watts, but, in spite of a short and very low aerial, the craft was aible to maintain communication with Auckland over distances of approximately 500 miles, although quite unable to communicate with Wellington, about 50 or 60 miles away. This was due, it is .-.ssumed. to the screening effect of tie high hills around Wellington. lne position is the more remarkable owing to the fact that the transmissions were on 600 metres, not the best wavelength for long distance low power communication. SHORT-WAVES AS A CURE. Ultra-short wireless waves are being used by Dr William Dieffenbach to cure the common cold. "It was discovered, runs the report, "that although wireless operators work in close, confined quarters they rarely get a cold. At the same time nearly all wireless operators experience a feeling of congestion in the head when oft duty Investigations showed that this feeling was due to abnormal condition of the blood, caused by the ultra-short waves. Consequently it was proved that waves i.ctually act as a warning to the white corpuscles to be ready to attack and keep cold germs at bay." POLITICAL BROADCASTS. Entertainment broadcasting in the U S.A. this year will be punctuated by political programmes leading up to the rational election in November. President Roosevelt started the ball rolling on January 8 with his speech at the Jackson Day dinner; on January 25 Governor Alfred E. Smith's speech at the dinner of the American Liberty League in Washington was broadcast over the networks and also via the short-wave relay stations. Thereafter the lid will be oft. The American radio will be open to practically all comers, the networks demanding only that the speakers be bona ride spokesmen for their parties. The Republicans and Democrats ' buy time o>\ the air" just like any commercial interest. In the 1932 campaign the Democratic National Committee bought 500,000 dollar's worth of carrier waves, mid this jcar will probably buy considerably more. BROADCASTS FROM STEAMSHIP. The British Broadcasting Corporation advises that it is proceeding with arrangements for periodical broadcasts from the giant liner Queen Mary on her maiden voyiMre from Southampton to New York in May. Microphones are being installed at various points throughout the vessel, so that listeners may learn, first hand, the progress the ship is making on what is hoped will be a record-breaking run. Listeners will also be able to gain microphone impressions of life aboard the Queen Mary as the instruments will be placed all over the huge craft from the masthead to the boiler room The 8.8. C. will utilise n short-wave link to connect the ship with the London headquarters, and it intends to broadcast over the short-wave as well as the ordinary broadcast channels.

SUBSIDIES FOR B STATIONS. In opposing the suggestion that a limited number of "B stations should be given a subsidy by the Broadcasting Board out of the revenue derived from license fees, an Auckland association makes the fantastic estimate that it costs £BO,OOO per annum to maintain existing "B" stations in New Zealand. It goes on to state that the board has ar. outstanding liability in connection with the purchase of old plant of the Broadcasting Company. That is true, but when the deal was made the money was advanced by the P. and T. Department under an arrangement by which it was to be repaid in five annual instalments. Had it wished, the. board could have discharged that liability long ago. Then it is pointed out that the board is committed to very large expenditure in regard to stations and buildings. Again, that is correct (states an exchange), but supposing the four new stations when completed have cost as much as £200,000 —the figure should be much less—that is not one year's revenue, and when the new 2YA plant has been paid for, the board will have money to burn, and should be able to spend say £IOOO year each in subsidising ten selected "B" stations. INDIVIDUAL LISTENING. It has often been suggested that if wireless telegraphy and wireless telephony had been invented first and had teen succeeded by the invention of means to convey the same intelligence along wires for the telegraph and telephone services, communication by wire would probably have been regarded as the greater invention. The reason would, be that it enabled point-to-point communica-, tion to be carried out without broadcasting the information to anyone who cared to listen in, and also because the power required for the transmission would generally be less. The same arguments can be put forward in regard to the wireless loudspeaker in the home. The loudspeaker was heralded as a wonderful improvement upon ordinary telephones, because it enabled all the family to listen to broadcasting at the same time and without the discomfort and inconvenience of wearing headphones, which prevented one from moving about and doing other things to a background of broadcasting. Circumstances have changed since loudspeakers first came in, tiid it seems as though telephones have much to recommend them to the consideration of listeners to-day. The idea ot having a set turned on continuously is not so popular as it used to be. _ Listeners are more inclined to discriminate and listen only when they can settle down in comfort and give their undivided attention to some item they really want to hear. Tastes differ even in the same family, so that it is seldom possible to have a set tuned to a programme which is equally welcome to every member of the household. How much more logical it would seem to be if, by the more general use of telephones for reception 11-. place of, or as an alternative to, the loudspeaker, a programme could be listened to without disturbing other users of a room who may be engaged in different occupations. We feel that' it is a subject well worth consideration by listeners generally and by the set manufacturers who, at little additional cost and trouble, could provide plug sockets to enable phones to be used with any set, if desired, ■•ind make provision for disconnecting the loudspeaker meanwhile. There is no doubt that it is possible to concentrate much more easily on a programme when listening with headphones than it is with ? loudspeaker. Quality is very good, and although not, perhaps, up to the standard of the best of modern loudspeakers, there is no reason why telephones should not be improved. After all, they have not received anything like the same attention from designers for the reason that their popularity waned in favour of the loudspeaker comparatively soon after broadcasting started. With some improvement in reproduction quality and a little attention to the most comfortable arrangement for wearing them, telephones might easily return to favour even to an extent where their popularity rivalled that of the present übiquitous loudspeaker.