GB191505783A - Improvements in or connected with Aerial Conductors for Wireless Telegraphy. - Google Patents

Abstract

5783. Marconi's Wireless Telegraph Co., and Franklin, C. S. April 17. Duplex and diplex signalling; directive signalling; aerials.-A station arranged for duplex working is provided with two similar directive aerials connected to a receiver or transmitter through radiogoniometers and a separate transmitting- aerial arranged to have equal and opposite effects on the receiver of the directive aerials ; while, by suitably spacing the aerials and connecting them to two receivers through specially tune circuits, signals of the same wave-length may be received in opposite directions from two stations without interference. In the arrangement shown in Fig. 1, two aerials A, a, each consisting of two frames at right-angles to each other, are placed at onehalf or preferably one-quarter of the received wave-length from each other, aud at equal distances from a transmitting-station B. The frames of the aerial A are connected to the fixed coils of a radiogoniometer C, Fig. 2 ; while the frames of the aerial a are connected to the fixed coils of a radiogoniometer c. The movable coils D, d of the radiogoniometers are connected to a receiver H through coils F, G and a tuning-condenser E, and coils f, G and a tuning-condenser e respectively. The couplings F, G and f, G and the radiogoniometers C, c are arranged so that the oscillations emitted from the station B have equal and opposite effects on the receiver H, while radiations coming in directions at right-angles to the coils D, d produce no effect on the receiver H. If the aerials A, a are placed one-quarter of a wavelength apart, the oscillations set up in the radiogoniometers are 90 degrees out of phase, and if the circuits connecting the radiogoniometers are arranged so that the phase of the oscillations in one circuit are advanced by 45 degrees and those in the other circuit retarded by 45 degrees, then the oscillations produced by waves coming in one direction oppose each other, while those produced by waves coming in the opposite direction are in phase. By coupling the radiogoniometers to two receivers so that waves coming in one direction produce opposing effects on one receiver and assisting effects on the other, waves coming in one direction actuate one receiver, and waves from the opposite direction actuate the other receiver. By replacing the receiver by a generator, the apparatus operates as a directive transmitter.