UNRULY RADIO SIGNALS.

Press, Volume LXIX, Issue 20919, 28 July 1933, Page 12

UNRULY RADIO SIGNALS.

EMPIRE BROADCASTS. ENGINEERS* PROBLEMS. (rftoU OT7B OWM COBMSPOHDMT.) SYDNEY, July 20. The problems encountered by the British Broadcasting Corporation in its Empire transmission, mentioned in a cable message last week, are not fundamentally new, according to Australian physicists, although they are new in their application to Empire broadcasts. According to the cable message the transmission to Australia misses New Zealand, which easily picks up the signals designed for West Africa. Canada picks up the 25 metre signal intended for Australia when she ought to be receiving the 19 metre broadMr G. H. Munro, physicist attached to the Radio Research Board of Australia, said that although these Empire transmissions were not sent out on beam, they were broadcast from directive aerials. The problems of the 8.8.C. engineers were apparently due to the fact that the signals strayed from the paths into which they were directed. The effect of using a directional aerial was that signals were very much stronger in the path in which they were sent. Long distance transmissions, however, depended on the amount of day and ■ night in the path of the signals, and this varied at different times of the year. Because of those variations it was difficult to predict what wave lengths would be most suitable for i reception in a distant land. Stray Signals. "For some reason," said Mr Munro, : "Paris broadcast signals are stronger in Australia than those of London, but if you look at the globe ' you will see that the path of London 1 signals to Australia is much further ; north than that of Paris signals, and 1 the ray goes nearer to the North Pole. • The direct line from London to New ' Zealand is still more northerly. ; That probably explains why the : programmes sent to Australia by ; the British Broadcasting Commis- ' sion are not well received in New - Zealand. They meet different con- . ditions on the way. As I read the ; cable, both Canada and New Zea- : land are receiving stray signals E away from the directional path. ' Canada receives the Australian sig- ■ nal sent across Europe and not the other one which follows a path across Canada. New Zealand gets the West African signal which is i sent out in an almost southerly 2 direction and should miss the I Dominion. The answer to that j seems to be that the directional sysl tern is not 100 per cent, efficient, , and that conditions may happen to t favour the stray signals." It is pointed out that the 8.8.C. r engineers are now working on 49 , metres in the hope that this wave [ length will suit both Australia and " New Zealand. This channel has been very popular and effective in ' other parts of the world, notably the United States and Asiatic countries whose broadcasts have been well [ received in Australia.