DEVELOPMENTS IN RADIO

Press, Volume LXXI, Issue 21510, 27 June 1935, Page 11

DEVELOPMENTS IN RADIO

BIG ADVANCE CLAIMED BY GERMANS ultra-short waves (TOITED rP.ES3 ASSOCIATION —BT ELICTBIO TELEQEAPH—COPXaiGHT.) (Received June 26, 9.20 p.m.) BERLIN, June 25. The German Telefunken Company announces that experiments begun in 1933 with "decimgtre waves, that is, from 10 centimetres to one metre, are now far advanced. It claims that the waves can be transmitted in a straight line to a given destination without the possibility of detection by anyone outside the line of transmission. They are also immune from atmospherics and other interference. They would be of immense value in wartime. Even if decimetre waves of the j same wave-length are used by dif-j ferent stations, interference can be eliminated by turning the apparatus in the required direction. A magnetron gridless valve no bigger than a thumb solved certain reception problems. A demonstration to-day showed that the waves can be used to assist in guiding ships and aeroplanes by the craft keeping to the path of the ray. The German invention appeal's to be, similar to the first commercial microray radio service in the world, which has been operating between the civil airports of Lympne, in Kent, and St. Inelevert. in France, since January, 1934. The actual wave-lengths are 17 centimetres in one direction and 17.5 centimetres in the other. This separation enables duplex working to take place simultaneously by teleprinter and telephone. The object of the service is to speed up the transmission of essential traffic messages and meteorological reports on cross-Channel air roules. , jThe waves used are highly directional, and are reflected on precisely the right path by a concave mirror a yard or so across. The power used is very small.