An improved method for directive wireless telegraphy with several separated antennae

摘要

147,442. Ges. f³r Drahtlose Telegraphie. June 11, 1918, [Convention date]. Directive wireless signalling. - In systems for the directive propagation of waves by the phaserelated excitation of widely-separated aerials, currents of relatively low frequency and of small intensity are supplied from a central station and are amplified and raised in frequency at the transmitting stations. The currents from a two-phase generator 2 at the central station are led through circuits 3 (loaded with Pupin coils 4 to prevent distortion) to the input circuits of amplifying-valves 6, the out-put circuits of which are connected to frequency-doubling rectifiers 9, which deliver double-frequency currents through tuned circuits 18 to the aerials 1. Signals are transmitted by a key 5 at the central station. Amplification and frequency-transformation may take place in several stages, and magnetic frequency transformers may be used. A large number of separated antennµ may be excited in the above manner, different groups being used for simultaneously transmitting signals in different directions by waves of the same or different lengths.