System

Radio Telephone

New Guinea Now Has Most Modern System

rpHE installation of a radio-telephone 1 system linking four New Guinea towns, and giving a service based upon principles at least as advanced as those of any similar service in the world, was announced in July by Sir Ernest Fisk, chairman of Amalgamated Wireless (Australasia), Ltd.

Sir Ernest Fisk said that the towns are Lae, Salamaua, Bulolo and Wau. The§e places are from 25 to 60 miles apart, and the intervening country is so rough that to erect telephone lines there would be difficult. Lae and Salamaua are on the coast; but Bulolo and Wau, up in the mountains, would have been cut off from most of the amenities of civilisation, had it not been for aeroplane transport and communication by wireless.

Now, the radio-telephone system gives connection between any two of the four townships by the mere lifting of an or dinary handset telephone, and the press ing of a button to give the pre-arranged signal for the desired station. As soon as a conversation is completed, the re placing of the handset leaves the equip ment in readiness for calls from or to other stations.

Technical Difficulties

The technical difficulties of the instal lation were overcome in the research laboratories of Amalgamated Wireless, which organisation designed and con structed the equipment by arrangement with the Bulolo Gold Dredging Company and Guinea Airways, by which companies it is used for communication in carrying on aeroplane transport services.

Although incorporating the most mod em principles of radio communication, said Sir Ernest Fisk, the system had to be simple, calling for no expert skill nor attention and capable of operation by any layman. Actually, six complete alter nating-current-operated transmitting and

receiving equipments have been provided, fitted for duplex privacy operation, and employing four different transmission frequencies.

Two equipments have been installed at Lae, and one each at Bulolo, Wau and Salamaua, the sixth being a standby.

No Eavesdropping

Eavesdropping has been rendered im possible by the mechanical inversion, or “scrambling”, of speech. If anyone should succeed in overhearing a conversation, the words would be unintelligible, as the inverted speech is only rectified at the receiving instrument.