WIRELESS.

Star (Christchurch), Volume XLIV, Issue 708, 8 March 1933, Page 4

WIRELESS.

Notes and News from Far ; and Near. THE NEW STATIONS. (By " AERIAL.’’) Listeners who have heard the new local station, 3ZM, testing have expressed themselves as favourably impressed. So far, 3ZM has not put forth its full power of 250 watts, and therefore there is reason to believe it will become popular. Modulation has been good and there has been a pleasing - absence of generator hum. 3ZM may be heard on 1450 kilocycles—a wavelength of 207 metres. The tests being carried out on the Peninsula by the 100-watt 3YA Testing Station on 570 kilocycles (526.3 metres) have also been favourably commented on, it being realised that, with the low power used and the distance from the city, it is not reasonable to look for static-free reception. Station 2YA Auxiliary does not appear, from all “ Aerial “ hears, to be attracting much attention locally. The reason appears to be that, except for selective sets, 2YA Auxiliary, on 297 metres, is too close to 3YA and several 4,4 B ” class stations. Testing for “ Hum.” Luring the last few days several radio firms have had receivers sent in for overhaul, the complaint being that hum ” had developed. Inquiry has disclosed that the trouble has been evidenced when tuning in 3YA and listeners promptly jumped to the conclusion their sets had become faulty. On test, however, the sets have been found in good condition. For the benefit of these listeners, it may be mentioned that not only hum ” but, when volume is cut down considerably, fading also has been noted on reception of 3YA—probably seasonal faults that will disappear shortly. There is, of course, the possibility that “ hum ” may develop in any receiver. To test: Tune off the station being received. If the “hum” persists. the fault lies in the set; if not, the fault lies with the transmitting station. jj 5J Keception at Coleridge. j.A. writes:—“ln a recent issue of the ‘Star’ a correspondent at Lake Coleridge, close to the power station, wrote about the good performance of a five-valve T.R.F.. as against eight-valve sets in the same locality. The correspondent stated that, having increased the- length of his aerial to 100 yards from the original length of 80 feet, his daylight reception had considerably improved, but what about his tuning? The big Increase in aerial length must have caused a corresponding increase in the breadth of tuning, and thereby impaired the selectivity of his set. Because a listener with a five-valve set prefers to listen to the local station does not mean that another listener with an eight-valvep cannot do this, as is almost suggested by your correspondent. The writer of this letter knows a listener at Lake Coleridge who has an eight-valve superhet of a good make, and whose average results leave nothing to be desired, using an aerial of about 100 feet in length to get 4 Aussie,’ and generally none at all to get the YA stations. The superhet in question is used mostly in conjunction with a gramophone pickup, but as a receiver it s’ selectivity is very good. It is useless for anyone to expect outstanding reception near the power house, whether wijh T.R.F. or superhet, but 1t is only a matter of time when the authorities

concerned will take steps to minimise, and if possible eliminate, the large amount of interference experienced by listeners in this locality.”