RADIO AND ITS RECEIVERS

Sun (Auckland), Volume I, Issue 149, 14 September 1927, Page 14

RADIO AND ITS RECEIVERS

Conducted for THE SUN by

RADIO IN the: COUNTRY.

Since writing last week’s notes the writer has been on to Wellington keeping a weather eye on radio on the way. All the way through from Auckland—and it became more pronounced as one got farther south —it was plain that for the live, active type of dealer things were good: but to other men in the same town things had never been so bad. The conclusion of the writer was that the business was there for the active man who would go out after it. In fact, in Wellington a boom is starting. Every shop has a large crowd round it during the lunch hours, and one dealer stated that if he could get 1,500 good crystal sets he could sell them in a week. This is surely a result of the new attitude of the .Broadcasting Company in personally investigating matters of complaint, and so regaining the confi-

C. M. Taylor, B.Sc., A.M.I.R.E.

dence of listeners. In Wanganui t]

writer was on several occasions the guest of Percy Coleman, of motor-cycle lame. Percy is as genial as ever and seems as keen on breaking radio dis-tance-records as ever. One remarkable thing is the way in which Wanganui has taken to the big. expensive power type of speaker. Outfits costing over £7O are being sold with ease, and this branch of the radio trade is unique in New Zealand. In Wanganui the writer had the pleasure of meeting Mr. J. S. Bond, a radio engineer trained by the R.C.A. of America and sent out to New Zealand. Mr. Bond is returning to the States to spend a year or so in the laboratories, to bring his knowledge up to date with the new A.C. developments mentioned i, by THE SUN in a recent article, and has promised to keep the writer posted in new developments, which will be published as they arrive. A curious fact in Wanganui is that well-known five-valve sets cannot cut out 2YA and bring in 2FC. It must be the sets of course. Generally speaking, Wanganui is quite satisfied with radio in New Zealand since the advent of 2YA. In Palmerston North home construction is going on of Browning Drakes in all forms, closely followed by New Zealand all-wave receivers. In this respect the “Radio Record” constructional articles on the formet set are being widely read. Wellington, the home of 2YA, curious aerial systems and the Dominion Parliament, was reached in glorious sunshine. One noteworthy feature is the attractive window displays being made to attract the public. Preparations are being made to welcome the delegates to discuss the proposed Dominion conference, but, from opinions expressed, Wellington seems alone in its desire for such an organisation. IYA’S NEW ANNOUNCER Much favourable comment was heard from Auckland to Wellington on Auckland’s new announcer, and all hoped he would not be lost sight of in the future. ANOTHER SHORT-WAVE STATION The Associated Radio Co., of Melbourne, has in mind the erection of a short-wave station using a wavelength of 55 metres,' as an adjunct to its present broadcasting station 3AR. Whether or not the short-wave station will transmit the same programmes as 3AR, thus pumping on the air a simultaneous transmission, as WGY and other American stations sometimes do, is not stated. Probably for some time it will be used for general testing purposes. Recent afternoon tests made by 3LO, Melbourne, were so successful with PCJJ, of Holland, that the 3LO executive are in communication with PCJJ for the purpose of arranging a regular schedule. Next winter, with the proposed British station and all these arranged schedules and new stations, should make the prospects of oversea rebroadcasts very bright. THE HOWLING VALE NUISANCE WORST ENEMY OF BROADCASTERS As stated on numerous occasions in these columns the howling valve is the worst enemy of broadcasting. The average listener who has bought a receiver for the sole purpose of enjoying the concerts from the various stations has had quite enough of the shrieks and howls which nightly punctuate the programmes. One evening last week the writer heard a howler go up and down to wavelength band from 2GB to 7ZT for nearly three-quarters of an hour, not stopping for more than 30 seconds. At the time 2YA was on and the owner of this machine could obviously not even hear this station. The regenerative receiver which is featured by a contemporary is one of the worst offenders, and sets of this type which have a regenerator detector coupled sraight to the aerial should be prohibited. The regenerative receiver

is not, however, the only offender. Neutrodynes, which are not neutralised. home built radio-frequency receivers suffering from the same trouble, and prohibited circuits which listeners are using after sending in a crystal set diagram to the Telegraph Department, are equally, as bad. A number of officials have said in the past, “Educa.te the public.” but this will not stop the small boy with the onevalve set who nightly ruins programmes for other listeners. The only sure test of radiation is to touch the aerial terminal of set with a moistened finger, and if there is even the slightest click when the finger is removed the set is causing interference. If broadcasting is to remain popular in New Zealand the whole question of radiating receivers will have to be considered from every angle. The trouble is not going to solve itself, as stated some time back by Government officials, and instead it is getting worse every month. The result is going to be that many listeners are not going to renew their licences next year, which is bound to reflect on the programmes of the Broadcasting Company under reduced revenue. NEW APPARATUS Among the new apparatus mentioned by THE SUN recently after testing j were the three new Mullard P.M. IA, 2A, 5B resistance capacity valves. Further data is to hand from the Mullard Service Company giving additional data as; with an anode resistance

of 2 or 3 megohms these valves give ( an amplification equal to that of a c transformer, thus removing the main i objection to resistance - capacity < coupling, i.e.,' low amplification per ; stage, but maintaining equal amplifica- j tion of all audio frequencies and truth j of tone rendering:. P.M. P.M. P.M. ‘ IA. 3A. 533. ‘ Max. filament voltage 2.0 4.0 6.0 1 Filament current J (amps ) ... . . •. . 0.1 0.1 0.1 Max. anode voltage 125 150 150 Anode impedance.. 72,000 63,000 74,000 Amplification factor 36 35 37 Mutual conductance 0.5 0.55 0.5 Another Mullard arrival is the Pure Music H.T. Supply Unit for operation off A.C. mains, voltage 220-230 40-100 cycles. This unit on test gave excel- * lent results, a perfectly silent output * with plenty of pep. The outfit is contained in a neat metal cabinet with 4 H.T. tappings, negative and earth ter- r minals, the whole making an attract- i tive and serviceable substitute for the \ B battery. ( PROPOSED LISTENERS’ LEAGUE ; Delegates from all wireless listeners’ ’ societies throughout the Dominion will j meet at Wellington on September 29, 1 commencing with a special session at 11 a.m., when they will be welcomed } by the Mayor, Mr. G. A. Troup. Among ; those who have been invited to speak are the Prime Minister, the Right Hon. J. G. Coates, the Postmaster-General, ( Hon. W. Nosworthy, the Secretary of 4 the Post and Telegraph Department, and the general manager of the Radio Broadcasting Company of New Zealand, Ltd. The first session, which will ] be held in the Dominion Farmers’ In- ! stitute, will be open to the public. The establishment of a New Zealand Lis- ( teners’ League, to which all societies will affiliate, will be among the im- ■ portant matters to be considered. The Wellington society will be represented at the conference by its president, Mr. J. H. Owen, and Mr. I. M. , Levy, vice-president. Mr. R. Leslie Jones, hon. secretary of the society, : will act as secretary of the conference. :