AUSTRALIAN WAVELENGTHS

Radio Record, Volume I, Issue 27, 20 January 1928, Page 14

AUSTRALIAN WAVELENGTHS

PROPOSED ALTERATIONS, A Melbourne writer says:"There have been some references in the Press to the effect that the wavelengths of the Australian broadcasting stations are to be altered. ~The basis and extent of the alteration have not been disclosed; but the PostmasterGeneral’s announcement is of considerable importance. The announcement is something in the nature of a warning that some changes will take place early this year. The need for prior notice of the change is very obvious when we read. that the lowest wavelength is likely to be alont 223 metres At present it is 255 metres, and it is doubtful if many receivers-except the latest types--are capable of being tuned to anything below 250 metr2s

ALTERATIONS TO RECEIVERS NECESSARY. "The alterations will not be costly, but it will be a mnisance to owners of sets to haye to gct their tuning brought down to 225 metres, There is no reference to changing the upper section of the broadcasting hand of wave-lengths-that is, above 650 metres-so we may assume that the authorities do not intend making any alteration in the long-wave station at Perth, ‘The existence of that long-wave stationthe only one in Australia-is rather surprising, and may have something to do with the failure of broadcasting in West Australia. "With crystal receivers of the slider coil inductance type it will probably be necessary "to rewind the coil or coils-and similarly with valve sets using fixed inductance an alteration may he necessary. With a modern efficient condenser designed to receive frequencies between 200 and 550 metres of wavelength the effect of the proposed change will be negligible. "The best way to make sure of this is to get your dealer tc test the set. Tf the dealer is up to date he will have a set tester or an oscillator which will enable him to gencrate in (the oscillator a radiation of, say, 200 metres. The oscillator will act as a transmitter, and the receiver under test will pick up the 200-metres transmission ‘if its tuning range is suitable If not, the test will be made in 210 or 220 metres; and thus the tuning range of the receiver will be ascertained.

WHY CHANGE WAVELENGTHS? "This question will occur to many readers, and forcefully so to those whose receivers are incapable of "going down’ to 200 metres. A little reflection will remind us that the wavelengths as used to-day are not satisfactory. There is a crowding of the stations between 850 and 400 metres. "Ihe Postmaster-General’s announcement refers to the Washington Confer-

ence and. its decision on wavelenytlis. That decision apparently is guiding the authorities here in the matter. The decision was that broadcasting should be carried out on wavelengths between 200 and 609 metres, with two additionnl bands between 1000 and 2000 metres, The latter. band was put in to meet the conditions in Europe, where there are. a number of long-wave stations like Daventry in Iingland on 1600 metres. ‘The 200-600 metre band gives the set manufacturer a better chance of making efficient sets, ‘The sets can be more compact, simpler in operation and the aerial can be smaller, as listeners know since the change to 371 metres of 31,0. "The subject of the most snitable wavelengths for broadcasting is_ still one for argument, but it wonld be a great pity if our present conditions were to be altered in any drastic manner."?