RADIO NOTES

Rotorua Morning Post, Volume 2, Issue 320, 6 September 1932, Page 6

RADIO NOTES

HINTS TO LiSTENERS CARE NEEDED IN SELECTION OF RECEIVING SETSVOLUME CONTROL

(Notes by "Kathode.") The past week has been fair for long distance reception and several American stations have.arrived with good volume. KFI, Los Angeles, has been heard with almost the volume of 2YA, and KGO, the General Electric j station in San Franeiseo, has been a good second. KPO, KRLD, FFWB, KGU, KFOX ,KHQ and KMTR were also logged, though fading detracted from the pleasure of listening to several of them. The Australian stations have been up to standard and satisfaetory receptiori of 2FC, 2BL, 2GB and 4QG have been possible from 8 ! p.m. each evening. Noise level is still I very high in Rotorua, otherwise dozens | of long distance stations could be logged on four or five valve receivers. The pentode valve took the radio world by storm a short while ago, and is still used by a majority of manufacturers, though the trend is to go back to the always popular 245 type. Two 245 valves in push-pull will be used in future Silver-Marshall models an'd no doubt other well-known makers will follow suit. The pentode will always find a p'lace in portable and compact receivers and in short wave sets especially, but where compactness is not important, future design will revert to the three-electrode valve. The word pentode is derived from the Greek, and means containing five elements or electrodes. The electrodes are: filament, plat/e, and three separate grids. Experiments with dilfcrent earths are always worth while, especially in Rotorua, where a low resistance contact is difficult to secure. Short lengths of pipe driven into the ground are practically useless for radio work, as any form of resistance in the ground-lead broadens tuning and wealcens signals. If a buried copper or motor-car radiator is out of tbe question, drive a galvanised iron pipe twelva to fifteen feet into the soil and dig a trench around it, about 12 inches deep. The diameter of the trench need only be sufficient to clear the pipe. Procure three or four pounds of bluestone and sprinkle it evenly round the trench, afterwards pouring several gallons of water over it. Fill the trench with soil and the job is done. At least once a year, the bluestone treatment should be repeated. Common salt, rock salt or caustic soda could be used in place of the copper sulphate (bluestone), though the writer recommends the latter. The small Australian stations heard to advantage during the week were: — 2CO, HI), 3IIA, 3UZ, 4TO, 3YB, 2GB, 2GH, TWL, 2UE, 2SM, 2KKY and 2KO. Many others could have been logged had they not been seriously hetrodyned. In 1898, twenty-three years before the first broadcasting began, Sir Oliver Lodge wrote: — "Broadcasting might be desirable for the purpose of following the day's happenings, such as army manoeuvres, for reporting raees and other sporting events, and generally for all important matters occurring beyond permanent lines of communication." How strangely true ihe prophecy proved to be. Broadcasting, of course, is a modern development, but not a modern idea. It required the brilliant efforts of such wizards as Senatore Mareoni, Sir Oliver Lodge, Hertz and others to cl >ar away the wa 11s of ignorance and lay the foundations for the science. Volume and more volume. Listeners wanted volume, and radio designers and engineers saw that they got it. They produced dynamic speakers, a.c. valves, and push-pull circuits — they increased the power and production percentage of radio transmitters, and they improved receiving circuits until to-day volunre is easily gained (except on long distance reception). Listeners have now too much volume at their command and it is not uncommon to hear sets in action several doors up the street. Too much volume is a mistake. It requires careful eoncrol and appreciation of musical values. One wou'd not think of having a full brass band play in a sitting room, yet a modern receiver, when opened out, can deliver similar volume. In America no license is charged for radio listening. In Denmark, the charge is 11s, and in Germany £1 4s is paid for the privilege of listeningin. Unwary buyers are apt to be misled about the capabilities of the sets they are considering. Now that the YA stations have decided to broadcast at least 12 hours a day, it is essential that receivers in Rotorua have a good daylight range. Under good conditions, ewn an average set should be able to pick up 3YA Christchurch after 3 p.m., though this station should begin to waaken now that summer is approaching. Where temporary aerials or mediocre earths are used, of course, even the most sensitive receiver might find it difficult or impossible to pick up any other station than 2YA before 5 or 6 p.m. A demonstration of telephony between a plane and train in motion v/as recently held in England. The test took place between the Flying Scotsman and the "Heracles," a 42-passen-ger plane. A 200-foot trailing aerial was used on the plane and power v/as obtained from a wind-driven generator. Th aerial on the train was suspended below the roof and power was derived from batteries. Arrangements have been concluded between the Colombia Broadcasting Co. of America and tbe Budapest studio for regular intferchange of wireless progranimes. Listeners in Rotorua who are fortunate enough to pick up one of the Colombia chain of stations will probably hear relays ! from Budapest. The Colombia chain broadcast on the ordinary channels and may be picked up on any average receiver.