THE WIRELESS WORLD.

Otago Daily Times, Issue 19039, 8 December 1923, Page 2

THE WIRELESS WORLD.

• ,t», NEWS AND NOTES. (By Ma<3na Vox.) (Items of news, comment, suggestions, etc., will he, welcomed by “Mngna Vox.’’] At its meeting on Monday night the Otago Radio Association decided to defer action with respect to local broadcasting fill the result of the dominion conference of radio dealers, held in Wellington yesterday, is known. It was resolved that, if permission was granted, Mr J.. L. Passruore represent, (he association at the conference in Wellington but on Tuesday the secretary’ (Mr H. E. Barth) received the following telegram from the Wellington Broadcasters, LSI. : “Thursday's conference intended for radio dealers only,”- and therefore the Radio Association was not represented. It would bo interesting to know just what Mr Passmore, or anyone for that matter, would be able to do in the interests of the Radio Association if ho had attended this conference. The conference. which is ■ considering- the broadcasting problem for the whole of New Zealand from the viewpoint of the trade, can hardly be expected to solve the difficulties of the Otago -n-adio Association. That is purely a local matter. The Radio Association intends holding another meMing on Wednesday next, and it is to be hoped that a tangible scheme for the continuance of broadcasting will result. At the several meetings which have boon held there has been much talk and Little action. The problem if. certainly a difficult one to solve, but surely some moans can be devised whereby the present unsatisfactory position may be remedied. "Aerial,” of the Dominion, advises that a bagpipe solo broadcasted from Dunedin was received by him on a loud speaker and rc-transmi*;ed another half-mile by means of the ordinary telephone. An Invercargill resident advises that conceits from 4YA oamc in exceptionally loud, the modulation and speech being perfect. 4AJ. Mornington, is coming on very well, hut will have to give attention to timing as it is very broad. Quito a number cf the North Island amateurs are making rapid strides,: and can ho heard cutting out good work any evenLMr J. 'Obeli is leaving Christchurch to take up a position in the North Island. U is to be hoped that he will continue transmitting. Mr F. D. Bell, Shag Valley, is busy shearing, and has net, had so much time lately to devote to radio, Mr G. W. Forbes has a new one-valve set. and is getting some very good-results. The valve used is a low temperature 1 i volt, and works off one dry cell. Mr Ferens “bags” most of the New Zealand stations. Mr Green, of the Telegraph Department, also ba-s one of these sets, and obtains very good results Mr H. E. Barth handed in his .resignation as secretary of the Otago Radio Association at the meeting on Monday. Mr Barth regretted that this step was necessary owing to business pressure, but was willing to carry on bi« duties till a new secretary was unpointed, 4YO transmitted on, Saturday evening, but the modulation waa not nearly up. to the standard heard from this station'in the past. . ■;_ '- An amusing expedience occurred oft ’Sun- 1 day morning last, -when two of—Dunedin _s leading amateurs motored through to Waikouaiti. They took a one-valve set with a low temperature 1,-volt valve. On arrival there the two enthusiasts stopped outside the private hotel and rigged up a “rough-and-ready'' aerial and earth, a'l the items, which were broadcasted from 4YA being received. Quite a crowd gathered, and the boardinghouse peonle became so fascinated (.hat, they forgot about the midday meal, and returned to the kitchen to find the cab-b-ire boiled, dry and the dinner spoilt. However, they were somewhat pacified by the two -amateurs promising to return tonfornnv evening to put on a good enter* tamment. . „ , , 4YA has arranged whh Mr G. W. Johnstone and his punils to repeat the programme given in Burns Hall on November 23. As the part.v possesses considerable talent, a good transmission is assured. AN AMERICAN TEST. Cabled information states that Messrs l>. Bam burger and Company’s radio station WOK. at Newark, Now Jersey, U.S.A., commenced a radio test from Saturday last. Dominion amateurs will be interested ip those tests, ns they will embrace Japan, Australia, and New Zealand, a wave-length of 405 metres being used. The tests, which . are being carried - out from 4 to- 6 a.m. Eastern standard time, daily, will conclude. „n December' 15.' Tt is expected that-witu the receiving seta in operation in New Zealand at tlw present lime the concerts will Le beard quit© all rig’bf. Mv W. K. .Lane, •A Motueka, has, for example, been receiving the American broadcasting stations on bis loud sneaker; and Mr H. Atmore. M.P. for Nelson, and the local postmaster have both listened in to tiro concerts and heard whore they came from..'The concerts; transmitted from the Ambassador’s Hotel. Los Angeles, a good 60C0 miles away, have been heard so plainly on Mr Lane’s receiver that he could even hear when the people stopped dancing to applaud the musicians. VALVE ADJUSTMENT. Il is perhaps not generally realised what an important,lpart the grid leak plays m the ordinary tvp-e of valve receiver. , The. fact that the actual component itself is simple to construct— -nothing, surely, is easier than making a. few lines with a piece ’of soft load pencil—mar have a lot to do_ with the summary manner in which it is disposed of by the ordinary amateur; and yet it is not too much to say that a detector valve without a grid leak and condenser is inoperative. , . Certain readers may remember that in “pre-grid leak” days the potentiometer and battery combination answered the same purpose. ’ One has, however, only to look at a dozen modern valve receiving sets to see that uP-to-datc valve aoparatus has nothing in common with the last-mentioned means of obtaining prolonged rectification, and it would to-day be difficult to find a receiver on the market employing a potentiometer, and dry colls. . The correct ohmage value of a «nd leak is undoubtedly best appreciated by those amateurs Whose apparatus depends npon_ a single variable condenser or adjustable inductances for tuning. Simplicity of control is the aim of all designers of valve receivers, ancT the advantages to be derived from apparatus which can be adjusted by the movement of one control, such as the simplified form of “fciwev’ circuit, are obvious. Such circuits, however, will, according to the condition of the atmosphere, be found to vary a good deal in sensitivity of reception. and the elimination of jamming often becomes n formidable problem. Those readers who have experienced the annoyance of achieving exceptionally good results —and talking about them—and then failing dismally, perhaps the very next dav, to iustif.y such remarks to others, will do well to use a variable grid leak. ■ It is not. of course, an infallible cure for dll the troubles experienced by the “listen-ers-in,” and it is not claimed that, its inclusion in the circuit is a sovereign remedy, for atmospherics; but when next your favourite circuit fails to function to your satisfaction, and you have tried without success a hundred-and-ope testy to find out why, give a thought to the too-often-forgotlen grid leak, and try varying its value—-you may be surprised at the result. DOTS AND DASHES. It is interesting to note that the Radio Society of Christchurch is holding a weekly Morse Code practice class on precisely similar lines to those followed by the Invercargill Radio Club. Mr G Shrimpton, of the experimental radio station, 2XA, Lyall Bay, Wellington, was conversing by radiophone with Gisborne on a recent Saturday afternoon. This was quite a feat for daylight communication. The shortest wave-lengths known produce X-rays, which have the property of passing through many bodies that are impervious to light rays, and of causing chemical action on photographic plates. X-rays have a wave-length of about 2.5 millionth of an inch (the one-thousandth part of the thickness ol a cigarette paper is about onemillionth of an inch). The wireless electric waves measure from about 200 feet to 50,000 feet. The speed of a wireless wave is about 186.000 miles per second, which ia (he same velocity as that of light. Franco lias just come to the fore with a nenny in the slot radio telephone. This marvellous little instrument in appearance is very much like the “common or garden” variety of public telephones, though the only number one would be likely to get froin it would be the latest comedy, song. For the modest fee quoted above one can got anything that happens to be “iff the air” at the time, through. the receivers. Over 3000 of these machines were sold at a novelty fair held in Paris' recently.