WIRELESS NOTES!

Nelson Evening Mail, Volume LXXII, 28 January 1939, Page 5

WIRELESS NOTES!

NEWS AND NOTES .P C J Reading of Classics t The National Broadcasting Service s has arranged with Professor C. G. c Cooper, professor of classics at Auck- j land University College, to deliver a t series of six readings from the classics t from the studio of IYA. The first will i be given at 8 p.m. on Friday, 10th t February, and the remainder on successive Fridays at the same time. English Licensing < In England a portable set may be . used in a motor car without additional ! i fee, but, for a receiver which is part j j of the car’s equipment a special license j ; must be taken out. One license covers more than one receiver at the holder’s i address, whether these belong to members of his family or to servants; but , in the case of lodgers, boarders, or ? resident “guests” separate licenses are , [ required. On the death of a license i holder the unexpired term of the ’ license is transferred to any member , of his family. i 200-Feet Maximum The British Air Ministry will not alj low the 8.8. C. to use masts more than 200 ft high for its London stations. Con- . sequently their range has been limited compared to other 8.8. C. stations of equal power which use high aerials • with better anti-fading characteristics Accepting the embargo as permanent, the corporation is now trying to produce a scheme which will give greater , range and less fading. Few Changes An overseas radio engineer, who visited New Zealand recently, cannot see any indications of major developments = or inventions affecting radio circuits. ", Fundamentally there have been few innovations worthy of being called im-

portant since the wholesale adoption | of the superhet electric circuit several years ago. Components have been improved, better valves have been made, and dual-wave tuners have appeared on even cheap sets. In 1939 differences j in radio sets will be mainly those of fashion —different cabinets, automatic tuning gadgets, and externals —but there is no reason to expect much difference to take place inside. A Midget Set In the early days of radio midget receivers were quite a craze, and there were many about the size of the matchbox. But they were oddities and of little use. It has remained for an Englishman to develop a vestpocket two-valve radio receiver, which is at once entirely practicable, light in weight, and very efficient. The whole outfit, including the frame, aerial, battery, and earphone, is no larger than a small camera. The circuit is conventional, a/regenerative detector and one stage of transformer coupled audio, but the tubes are midgets and require little current. The power supply is unusual. One 44 volt torch battery supplies current for the filaments and also for the plate voltage. Using a microphone “hummer,” the volts is stepped up and rectified by a plate rectifier to give the necessary higher voltage. The total current drain is about 120 ma., so that the torch battery has quite a long life. 1 Definition of a Crooner j “An animated discussion was heard I the other day on the crooner question, | one listener verbally consigning all j crooners to perdition and two others declaring allegiance. Before the argument concluded, it transpired that there was a diversity of opinion concerning just what a crooner is. One of the protagonists included in his classification pli vocalists who sing with dance bands and all who feature songs of the lighter type, including sentimental ballads. These are not crooners. The dictionary definition of crooning is to sing in a low humming tone, to hum, to moan;

the radio crooner either moans or sings in a husky or whispering tone, and it is this which annoys so many millions.” —“Timaru Herald.” Car Aerials A receiver installed in a car has always the heavy handicap of a comparatively inefficient aerial. The best arrangement cannot pick up a signal comparable in strength with that from an ordinary domestic aerial. This is shown by Mr F. R. W. Strafford, of the research department of the English firm of Belling and Lee, Ltd., who in a recent issue of the “Wireless World” gives the results of investigations that he has carried out. The effect of the body of the car is shown by measurements taken with, a short vertical aerial inside a car and with the same aerial at exactly the same height above the ground without the car. The presence of the car reduced the signal picked up by the aerial to one-hundredth of its value with the aerial in the open. When the car doors were all opened and the “sunshine” roof thrown back, the value rose to one-

seventieth of the unscreened value, but the disparity is so great with cars having metal bodies that Mr Strafford concludes that it is essential to place as ! much of the aerial outside the car as i possible. Three types of external aerial j were considered—the wire or rod placed on insulators above the roof of the vehicle, a system of wires or plates slung under the chassis, and a vertical ' rod placed forward of the windscreen. In the case of the roof aerial, its height above the roof was important. For example, a copper strip half an inch wide and five feet long raised from half an inch above the roof to 24 inches gave i a four-fold increase of .signal pick-up. I A wire running round the edge of the j roof is more effective than a wire in ! the middle of the roof. By comparison | with the roof wire 2£ inches clear of j the top, a metal plate 4ft long and i Ift wide slung nine inches below the I main frame of the car gave a 25 per ! cent, increase of signal strength. The i best position of such plate depends up- ! on the type of receiver and is between i the chassis and a point half-way to the ground. A vertical rod mounted a foot in front of the windscreen and projecting about 4ft above the bonnet was better. It gave results about twice as good as the roof aerial or 60 per cent, better than the plate under the chassis, j Mr Strafford concludes that, although ! this increase is useful, the appearance of the vertical rod is against it, and ! that the underslung aerial, because it has a good performance and is completely.out of sight, is the most suitable in the majority of cases. The author says that the best car aerial is only about l-30th as effective as a standard type of outdoor aerial.