RADIO NOTES

Dominion, Volume 27, Issue 38, 8 November 1933, Page 6

RADIO NOTES

By

"ETHER"

CURRENT TOPICS No fewer than two hundred amateurs in New York, it is estimated, are now working on the 56 m.c. (5-metre) band. A large network of stations in the city has been organised to handle short-distance messages, telephony or modulated C.W. being used. In New 'Hampshire State a 5-metre transmitter, has been erected at the summit of one of the loftiest mountains in the neighbourhood, and distances up to nearly 150 miles have been covered. Regular traffic is handled by this station, particularly in connection with iforest fires. There are indications ■that amateurs in this country are also perceiving the exceptional possibilities of the ultra short waves, particularly as a solvent of problem. At long last it has been ordained that French. listeners must pay. The Chamber of Deputies and the Senate have both voted in favour of receiving licenses, 50 francs to be payable annually on valve sets and 15 francs on crystal. They have turned a deaf ear to appeals to postpone this enactment until after the passing of the longpromised Broadcasting Bill. As our Paris correspondent remarks, no one knows better than a parliamentarian how remote that happy day may be! The much-discussed tax on- valve imports is also an accomplished fact. In future, 3 francs will be payable on valves retailing at 50 francs, 4 francs on 50-70-franc valves,, and 5 francs on all exceeding this< price. Holland is now the only European country where listening is free. ' ♦ •• • • Some remarkable statistics concerning amateur transmitting activity in the United States have just been made public by the American Radio Relay League. Outstanding among the figures are those relating to messages 'handled by amateurs. During, 1932 no fewer than 1,194,995 messages were dealt with by 20,656 operators, wiileh contrasts strikingly . with 1926 (the first year ■ for Which statistics were compiled), when 294,972 messages were handled by 8140 amateurs. As is well known, American “hams” have an extensive network of stations for the transmission free of charge of private messages. Another noteworthy fact is that* there are now over 30,000 amateur transmitters in U.S.A., the popularity of this hobby,-it is . thought, being due to its inexpensiveness in these days of trade depression. . A learned professor has-been disparaging the .use, of lightning switches. The average lightning flash, he said, consists of:.:acurrent of . fifteen hundred million amperes propelled by iv voltage of ; two. thousand million, and it is no use expecting any - lightning switch to stand up to that. Are we to gather from .this that the learned man honestly thinks that a lightning switch ought to stand up to it without batting an eyelash?. It is high time that he learnt that, apart from -its normal function of dealing with small charges, the ordinary lightning switch, in the case of a direct hit, is expected to do its duty by perishing miserably. It should in fact, emulate the half-wit-ted youth who, we are told, was fool enough to stand on.the burning deck when, everybody else had done the sensible thing. • leakage problem Leakage taking place between the windings of a component such as a loudspeaker, transformer or choke, will always result in a decrease in the efficiency, the extent to which the efficiency is impaired depending upon the extent of the leak. You may think at first that it is rather out of the question to talk about leakage, but ,you would be surprised in what a large number of cases leakage to some extent actually takes place. There is also the question of an actual breakdown of the insulation, .but that is another matter and it generally makes itself quite evident. A leakage, on the other hand, may go unsuspected, and yet may be doing a great deal of harm to the efficiency of the component and of the set. This leakage is sometimes due to bad insulation or to damp. ■ 1

STUCK TERMINALS , Doubtless many readers have tried to disconnect their L.T. battery, only to find themselves baulked by a terminal that has become corroded. The common thing to do is to try to turn it with 4 pair of pliers. This, in most cases, results in the stem of the terminal snapping off, and the battery has to be taken to be repaired. A better way is to cut the wire as close to the terminal as possible and take the battery to the sink. Make sure that the stopper is in position, and then let the tap run gently on the terminal. After about half an hour it should be possible to unscrew the terminal with the fingers. A smear of “vaseline” will prevent further trouble. DRILLING PLATEGLASS No doubt some readers would like to know how to drill plate glass for pan°lSObtain an old worn-out three-cor-nered file, grind it to a sharp point on a wet grindstone, and fit in a carpenter’s brace. Drill halfway through, and turn glass over to finish. \Use American turps to drill. \

WOMEN ANNOUNCERS 8.8.C.’s Latest Innovation SOME MEN BETTER A few nights ago I had the pleasure of listening to the 8.8.C.’s woman announcer, and I • recalled with some amusement the time when I pleaded for this innovation—-and was denied! writes the Viscountess Snowden, in ■‘Popular Wireless.” Two reasons were given for this re_fusal. It was thought unsuitable that a woman should. be employed late at night in the lonely . studios. and dreary corridors of Savoy Hill. There is an element of humour in this excuse. But with the other reason I was obliged to feel a certain sympathy. It was the difficulty of finding at that time a woman with the necessary qualifications who was free to take up the work. I had to admit that most of the voices of the women employed as speakers by the 8.8. C. were, dull at the best, and at the worst so unpleasant as to excite derisive comment: I ’ . Harsh and strident, over-modulated, terribly affected, patronising and didactic in tone when not dull and commonplace, I agreed with most critics-in those early days that it was difficult to give ear to a woman speaker. Indeed, I can remember only one woman’s microphone voice with pleasure—l mean of those regularly engaged—and from it I learned very much about a garden ! I will not express too definite opinion about the new woman announcer until I have heard her often. One must live with a “voice” for some time before one can appreciate all its worth; but I must say this: that unless practice makes a difference the much-ad-vertised woman announcer is not likely to be anything like as good as at least three of the anonymous male voices to which we have now become happily accustomed. o AUTOMATIC VOLUME Levelling Amplification ‘ It is well known that the sensitivity of the average receiver tends to fall off as / wavelength is increased; most receivers seem to work at their best at about 300 metres. As a result of fitting automatic volume control, there is generally an apparent levelling up of amplification, especially when the set has a fair reserve of sensitivity. This effect is, of course, a spurious one, as A.V.C. can do nothing to increase the sensitivity of the top end of the wave-band, nor should it reduce, sensitivity at lower wavelengths The aural impression. that it docs so seems to be due mainly to the fact that the overloading, which is normally produced by so many stations working in the neighbourhood of 300 metres, is no longer taking place. When it is suspected that the receiver is behaving abnormally it is always wise, before making a test, to disconnect the A.V.C. valve, or to render the control inoperative In some other way. SCHOOL BROADCASTS Latest “Radio Record” One' of the principal articles in. the “Radio Record” this week deals with broadcasting in schools. This service, which has been built up over a number of-years, was in danger of lapsing in some centres, but Professor James Shelley, of Canterbury Colege, came to the rescue in Christchurch and saved the service for 3YA. A brightly-written story on the forthcoming National Confidence Carnival, which starts in Wellington at the end of next week, is featured on another page, while an article by Margaret Macpherson on an Armistice Day in London will bring back memories to those people who know the hush that falls on the metropolis for two minutes on November 11 each year. . There is an illustrated article contributed by the Sunlight League, a story on Wellington’s new picture theatre, a*n amusing anecdote about the Mayor of Christchurch (Mr. D. G. Sullivan, M.P.), and the usual pages of New Zealand and Australian programmes, gramophone notes, technical notes, and matter for women. ' JOINING WIRES To make a neat joint in fiexible’wire, especially if adequate insulation is re-, quirnd, is not quite so simple a* job as it appears at first sight. Here is a neat and effective method which has the advantage of simplicity. After baring the wires which are to be joined together, a piece of systoflex about 1* inches long is slipped over one piece. The wires are then joined, either by twisting together or soldering, and the sytoflex “sleeve" is pulled over the joint. Choose a piece of systoflex that fits fairly tightly over the flex, so as to prevent any possibility of its moving after it has been drawn into position. If a choice of colours is available, :i I coloured systoflex that matches the flex wire will be found to make the joint remarkably inconspicuous.