RADIO TOPICS.

New Zealand Herald, Volume LXIII, Issue 19217, 5 January 1926, Page 7

RADIO TOPICS.

BY THERMION. ARTIFICIAL INTERFERENCE. Since the inception of 'broadcasting the New Zealand listener has mado considerable progress in the reception of distantstations while the transmitting amateur, aided by sensitive and selective apparatus, has been able to excludei interference to such an extent that he could communicate on low powers with country after country throughout the world. The manufacturer of receiving sets for broadcasting has also tackled tho problem anct is producing equipment suitable for long-distance reception. Unfortunately, satisfactory long-distance reception is unobtainable* where artificial interference, of the types now spoiling the efforts of local listeners, is present. Such interference is to be regretted in that it is avoidable. Firstly, there is the interference duo to the spark transmissions of commercial shtp and shore stations., the ships in some cases working on wave lengths within the broadcasting band. It is understood that some effort has been made toward limiting marine traffic within this band. Ships, however, transmitting on their 600-metre wave length in close proximity to receiving stations, considerably interfere with broadcast reception on wave lengths 400 metres above, owing to the broadness of the tuning of spark stations. Then, too, the listener has to contend with the interference caused by the local commercial station, VLD. Repeated statements have been made that this station is to be modernised, but the interference still continues. When it is remembered that the Post and Telegraph Department retains & sum equal to one-sixth of the license fee of each listener, tho public is surely entitled to expect that tho department's stations will be equipped with satisfactory apparatus so thf.t they will have some prospect of receiving broadcasts.

Iri long-distanco reception the interference caused from oscillating receivers is very marked, but, just as every New Zealander respects the common interests of his neighbours in other directions, so it may bo assumed that the wireless listener will exercise caution in the uso of his apparatus .is he gradually acquires the knowledgo of how this interference is j caused and how it may be avoided. Defective electric installations may bo another source of artificial interference. If the point of disturbance were located and a report made to the owners of the defective electrical apparatus such a fault would probably be remedied immediately. Wellington listeners have, of late, been experiencing such interference. As regards the greatest enemy of longdistance reception—static—which is a natural interference, it: can only be said that thero is, as yot, no prospect of an immediate solution of this problem which has exercised the minds of the most eminent radio engineers and scientific investigators ever sinco the discovery of radio.

AFTERNOON BROADCASTS. A South Island writer mentions, that the matters discussed at the first meeting of the Broadcast Advisory Board included that of " an agitation from the Auckland radio dealers for afternoon broadcasting, to enable them to sell radio sets, the Broadcasting Company being expected to foot the cost of operation." The writer quoted has been misinformed on the discussion dealing with afternoon transmissions. There was no suggestion of an agitation although it may have been mentioned that the radio trado would have liked such transmissions for the purpose of demonstrating their receiving sets. The writer, as listeners' representative, could not see-the necessity for requesting afternoon broadcasts at present, but_ indicated that they would bo necessary with an increased number of listeners. To this, Mr. W. Goodfellow, representing the broadcasters* unhesitatingly agreed. If, however, the radio trado considers there should be afternoon transmissions, it has a just grievance. The radio dealers pay a license fee up to £lO per annum, ninety per cent, of this going to the funds of the Broadcasting Company. The amount the company receives from the radio trade must therefore be appreciable and the trade is entitled to receive some return for it. From the company's viewpoint, too, such broadcasts might be desirable in that each set sold by a radio dealer means a new listener, ana therefore increased revenue for the company. This far-sighted policy was adopted in Groat Britain and in Australia, so why not in New Zealand 1

f RADIO FABLES. Wireless is essentially a technical subject and there .are many cases on record where the public's lack of knowledge of the intricacies of the science has been used for the dissemination of false ideas. The latest example cornes from Dunedin, where the broadcasts from the exhibition have been most unfavourably compared with the Australian broadcasts as received in New Zealand. A statement was made that the poor reception of the Dunedin broadcasts was due to a proximity effect which always obtains, and it was further said that the Sydney broadcasts were impossible to listen to in Sydney, but that they lost their undesirable characteristics by the time they reached New Zealand. The writer hardly thinks that listeners would be prepared to accept this nonsensical, if ingenious, attempt to explain the poor modulation of the Dunedin broadcasts. Another fable, of a different nature, has been originated by a Christchurch writer in an endeavour to explain what was, until recently, a reduction of the strength of tho Australian broadcasts as received in New Zealand. This writer states; in all seriousness that the power*of the Australian stations was deliberately reduced so that New Zealand listeners could not hear them, this being done as a retaliation for the refusal of permission to Amalga mated Wireless to broadcast the Dunedin Exhibition entertainments. Comments on these statements aro need less.

NOTES AM) HINTS. The Wellington station, 2YK, liias recommenced broadcasting. The regular transmissions will be on Monday, Wednesday, Friday and. Sunday nights, from 8 till 10. The power input is 120 watts and the wave length is about 300 metres. Selected gramophone and piano-player records will be given at present. When the testing has been completed, concert items will be broadcast. The studio is located in a building about half a mile away from the transmitting station. Mr. C. A. Drummond is the announcer and Mr. Huggins, late oi: Auckland, is the operator. A survey based on sales of manufactured sets by la: ;a retail stores in New York and Chicago, conducted by retailers, indicates that interest in regenerative receivers is practically gone in America. The which was next in popularity with the regenerative set in 1922, began to lose its status early in 1924. The neuiirodyne achieved an important place in 1924 and held it until 1925, when it began to recede from favour on the appearnnco of the superheterodyne. If the present survey were based upon production instead of sales, the neutrr>dyne would be second in popularity to-day, but simple radio frequency is first now among constructors, and the superheterodyne second. "Supers" are losing their popularity among the home-made sets, following a rapid rise to first place 'a pteference during 1924; neutrodynes are holding considerable interest, even though they fell off sharply in 1924.