ON THE AIR

Hawera Star, Volume XLVII, 11 August 1928, Page 18

ON THE AIR

(By "Wave Length.”)

“Wave Length" Invites readers to forward short accounts of their experiences In reception, and items oft interest on any subject likely to Interest their fellow radio enthusiasts.

NEWS AND NOTES. .Doubtless every radio listener-in will •be .in .sympathy ’with the appeal being imade for a big one-day 'drive to raise £IOOO t.o provide the .hospital with an up-to-date wireless installation. Othei hospitals have been equipped with radio and the benefits resulting have been all that were expected.

‘ ‘ Wavelength ’ ’ hopes that ajj. axidio Ihstenens will respond whole-heartedly to this appeal and so impart to others some of the joys we are already having of listening-in.

An- American writer says: “That night when you invited your friends in t.o” hear your receiver perform is a. .typical example. Your set was probable in apple-,pie order, and atmospheric, condition's execJl'cmt. But it 'failed lodo what it had done the, night before, simply because you were suffering front a ease of ‘buck fever, ’ or stage fright. You would not have admitted it; perhaps wore not even aware of it. -But just the same, knowing that your friends were waiting to see whait your set would do, you were a bit excited, nervous; and, as a- result, lost that delicate touch, that little margin of skill with the dials indispensable, for five best DX (long-distance) work. _ In other words, you found yourself in ■ranch the same situation as young pianist who can perform superbly alone, but who becomes merely mechanical when playing before an audience; though, if your friends had not been I there, you could probably have done jusir as* well as the night before.”

The. ability of an aerial to collect energy depends directly on its height. Thus, for a crystal receiver, which should have as much energy from, the aerial as possible, no pains should be spared to make it as high as possible,, amid as far above and away from trees and buildings as the resources of the listener will permit. If a valve set is used, an excessively long aerial is sometimes an embarrassment rather t'hau a. help, There a.re two main reasons for this. In the first place a. very long aerial will collect a great deal of static, and .reception will! be marred. This effect is not so pronounced on a crystal receiver. The second objection to* a long aerial for valve reception is thait iit- temfe to broaden tuning, and a weak station is difficult to pick up without interference while a powerful one is working. A crystal receiver is inherently broad in tuning, amt this effect of a long aerial .therefore is of little importance.

Russia, has 45 broadcasting stations ranging in power from- 20 watts to 40,000, and in wavelength from 150 to .1117 metres.

Much radio .trouble can be .traced to particles of dust getting between, the coud'cmiser plates. The moral is—keep your condensers clear. A pipe cleaner is a very handy article for cleaning between thi' .plates, as it is unnecessary to take the condenser apart,

Joseph Henry, the American scientist, was the first man to point out flint the charge of a condenser is oscillatory. This was in IS4O.