GB400279A - Improvements in or relating to directional wireless signalling - Google Patents

Abstract

400,279. Directive wireless signalling. BOWEN, J. P., Trinity House, Tower Hill, and MARCONI'S WIRELESS TELEGRAPH CO., Ltd., Marconi House, Strand, both in London. April 23, 1932, No. 11740. [Class 40 (v).] A beacon transmits a rotating directional beam modulated with television signals which when reconstituted at the receiver produce a picture giving the name and a portion of a moving compass card giving the. instantaneous direction of the transmitting station, means being provided to maintain synchronism between transmitter and receiver during the periods when no directional signals are received. Alternatively a plurality of differently directed fixed beams may be utilized to give the same information or a fixed single beam for example to give a lead into port may be modulated to give the name and direction of the transmitter on a television receiver. As shown, a rotating aerial 2 is energized by television signals produced by known apparatus 6 .. 10 the image comprising a station identifying panel 5 and the part of a compass card 4 rotating with the aerial 2, which corresponds with the instantaneous direction of the aerial. Synchronizing signals may be transmitted omni-directionally from a further aerial (not shown) working on a different wavelength, or on the same wavelength, the synchronizing signals lying outside the frequency range of the television signals. Alternatively transmitter and receiver may be controlled by independent master frequency devices. The compass card scale markings may be corrected for errors introduced by local surroundings.