TIPS AND JOTTINGS

Radio Record, Volume I, Issue 26, 13 January 1928, Page 13

TIPS AND JOTTINGS

Any type of valve rectifying charger will give better service if the valve is" taken out occasionally and the legs cleaned with glass paper. Accumulator acid spilt on a carpet will cause a red patch that in a few days will burn into holes. ‘Trying to remove the acid with a damp cloth is useless. Jinely powdered washingsoda should at once be sprinkled over the patch, rubbed well in and_ left until all gassing has ceased. Ordinary chalk is another neutraliser. In case of getting strong acid on the hands,

Wasn tiem at Once iM a COPIOUS Ow of water under the tap, and then in a weak ammonia or weak washing-soda solution. Ordinary three-ply wood makes quite a good panel for a receiver, but it should be thoroughly dry. | Most of the receiving sets now described in the American radio journals operate with A.C. valves, dispensing with the usual A battery. At least ‘one dealer in Wellington is now expecting a shipment of A.C. valves, the (X226 amplifier and UX227 detector. Where the output of a receiver is fairly heavy, from a super-power yalve of the 171 or 256 type, a speciallymade choke coil will form a much better output filter than will an old audio transformer. ,

Care should be taken that a modern high impedence audio transformer is not used in conjunction with a valve taking such a heavy anode current that the transformer core is even partially saturated magnetically. In such a case the quality of reproduction would suffer. If the smoothing inductance in a B eliminator carries a current that saturates the iron core, the inductance value is reduced and the smoothing effect is lost.

Now that the tendency is to speak of "frequencies" rather than ‘‘wavelength," a suggestion has been submitted to the Radio Commission in America to do away with both terms so far as the ordinary listener is concerned. ‘The idea is to divide the ordinary broadcast band, which, of course, would also mean the receiver dials, into 96 spaces, to be known as "channels.’’ A station would then announce its transmission as being upon, say, "channel 16," instead of upon so many metres. The suggestion is good in that it gives a clear run of easily remembered two-figure ‘numbers, but to make the system complete, the teceiver should be calibrated correctly so that ‘channel 16" would be found at the number 16 on the dial, and not at 14 or 20.