WIRELESS BEACON.

New Zealand Herald, Volume LXVI, Issue 20387, 16 October 1929, Page 13

WIRELESS BEACON.

ASSISTANCE TO SHIPPING.

NEW SYSTEM IN ENGLAND.

(Kcceived October 15, 6.35 p.m.) British Wireless. RUGBY. Oct. 14. Experiments with a wireless lighthouse at Orford, Suffolk, havo proved so successful in assisting ships' masters out of sight of tho land to find their true bearings that it will bo worked continuously for two months from October 20. This wireless beacon is worked under tho Air Ministry and Board of Trade to assist both shipping and aircraft. It has been more particularly useful to mariners as the owners o£ commercial aeroplanes have their own particular system for obtaining wireless bearings over cross-Channel routes. It consists of a lower, containing an electrically-con-trolled revolving frame aerial. This sends out certain signals to specific points of tho compass in such a way that an air pilot picking up tho signals can, with a stop-watch, gauge his bearing.

Installations for the assistance of navigation known as wireless beacons were first put under construction by Trinity House at various points around the English coast in August, 1927. Tho purpose of these beacons is to send out distinctive wireless signals, at reguar intervals, enabling vessels fitted with wireless direction-finders to take bearings on tho beacon stations and accurately determine their position. These installations form a valuable addition to tho aid to navigation for ensuring the safety of life at sea and are of tho greatest assistance to marine navigation when ships are approaching land, particularly during darkness and in foggy weather. Tho first wireless beacon station to bo put into regular commission by Trinity House was tho ono situated at Round Island in tbo Scilly group. This sot, which was designed by tho Marconi Company, has a power of 500 watts and is operated on a wavo-length of 1000 metres, the specified wave-length for wireless beacon stations. Each beacon station has a special call sign, and that at Rounjl Island is tho letters GGG in Morso code. During fair weather this call sign is repeated continuously at the rate of 15 words per minute for 47secs., followed by a prolonged dash of lOsecs. duration and one repetition of tho call sign, tho whole operation taking exactly 60secs. This transmission is followed by a silent period of ■ three minutes, and is repeated threo times, covering a total period of nine minutes each half hour. In foggy weather the signal consists of tho one minute's transmission and three minutes' silence ropeated continuously. Tho jipparatus is automatic and is controlled by a master clock, which, using special contacts, starts up and switches off the power machinery and wireless apparatus at tho requirod times. It is designed so that a minimum of attention is requirod, and no skilled men are necessary for its operation. All moving and wearing parts aro' duplicated, and if a valve burns out, not only does tho transmitter automatically over to a duplicate pair, but a warning noto is sounded in a loud speaker to call t.nu lightkeeper's attention to tho fact that a valvo requires replacement, and this warning continues until tho necessary ieplaccment has been mado. The iango of the station for accuralo bearings to a ship using a normal Marconi diroe ionfinder is 70-100 miles, but under favourable conditions regarding _ atmospherics and jamming this range is increasec.