"BROAD TRANSMISSION"

Evening Post, Volume CXII, Issue 55, 2 September 1926, Page 14

"BROAD TRANSMISSION"

THE EXPECTED HAPPENS. It might have been anticipated—in fact, it was—that no sooner had the new broadcasting stations started than complaints would begin about their 'I broad tuning." An Auckland paper publishes a complaint by a local listener, who says:—"lf people are to be ■ interested in radio, then the local sta- , tion will have to be sharpened up a bit, so that it can be cut oat at will, instead of coming in all over the dials, as is now the case. It is done in other countries, so why cannot New Zealand do it with the radio expert who supervised the installing of the apparatus, which is supposed to be the last work in transmitting gear? Had we not had Australia to fall back on during our very long wait for the big New Zealand stations to start, there would not be so many sets in operation here to-day; and now that we have one of these stations in operation, why allow it to cut out thoso* Australian stations which have helped us so in the past? In the first piace, it is hardly a compliment to Australia; and in the second place, if Australia can be tuned in while our local station is operating, it will be a further inducement for people to buy sets, and "vrill thus be to the benefit of New Zealand broadcasting." Then, even' before the new Christchurch station delivered its first programme a similar but more weighty criticism came out. The Christchureh "Star" printed an editorial declaring: "The trial programme disclosed a somewhat serious difficulty. The new station tunes in so broadly that neither Dunedin nor Auckland can be picked up while it is operating, and, moreover, the fact that the Christchureh station has a wave-length separated by only 20 metres from the Auckland station, suggests to wireless experts that no lis-tener-in between Christchurch. and Auckland, except in proximity to either station, will be able to obtain good reception. Experts say the programmes will be jumbled together because neither station can be tuned in sharply enough to eliminate the other. It is urged that the Government should separate tliese stations by 50 metres at the very least, for, failing that, they will appeal to listeners-in in their own cities." These complaints about broad waves from transmitting stations are about the most tiresome and futile that come from the radio community. One gets rather weary of repeating that there is no such thing, and that inability to separate transmissions which are several metres apart is entirely a matter.of the quality of the receiver. 'It is true.that in practice it may be difficult to find a receiver sufficiently selective to ,hear the new Christchureh station in Auckland while the Auckland station is operating, and vice versa, but the fact remains that such receivers can bo had; it is all a matter of careful design and good construction. Broadness of tuning is' inherent in the receiver, not in the transmitter, and if one's receiver brings in the local station "all over the dial" and the owner is anxious to hear something else, he must get to work and modify it or get another. The Christchureh "Star's" supposition that neither station will be audible anywhere between Auckland and Christcliureh without mutual interference is simply ludicrous. At the samo time, while "Grid-Bias" disputes the ground of criticism advanced, he holds, with many others that the wave-lengths of the new stations are not suitable to the present commercial conditions, because they are too close to 450 metres, on which a good deal of Morse traffic is conducted by snips using spark sets. Unlike broadcasting stations and others using valve transmitters, spark transmitters do emit "broad" waves, which may create interference over a considerable range of tuning, whatever the selectivity of the receiver. The writer was unfortunately unable to listen to the Christchureh station last night, but has been informed that its tone and volume were excellent. One listener states that it is apparently not on its correct wave-length, being between Brisbane and Adelaide, and that Brisbane was practically drowned by Christchureh. But that the Christchurch and Auckland stations need not interfere with each other was shown by the fact that the Auckland station reported at the conclusion of its programme that several Auckland listeners had received the Christchureh transmission with better tone and volume than any of the Australian stations.