Improvements in or relating to direction finding radio receivers

Abstract

Abstract 480,572. Directive wireless signalling. TELEFUNKEN GES. FUR DRAHTLOSE TELEGRAPHIE. June 17, 1937, No. 16895. Convention date, June 20, 1936. [Class 40 (v)] To secure visual or audible indications, free from " night-effect," in a switch-controlled direction-finding aerial used in conjunction with " impulse " signals, the direct groundray is used to vary the gain of a high-frequency amplifier to such an extent that it becomes insensitive to the impulse " echo " reflected down from the Heaviside layer. As shown in Fig. 2, a vertical aerial A is constantly switched at U, to aid or oppose the voltage pick-up from a frame aerial R, the resultant being fed to a cathode-ray or other indicator J. The first or direct impact of each signal pulse produces a gain-control voltage at E which is fed back over a lead V to disable the amptiHer HF so far as the reflected " echo " impulse is concerned. A resistance W and condenser C imposes the necessary time constant. The frequency of the transmitted impulses is preferably double that at which the switch U is operated. The arrangement is applicable to automatic " homing "and direction-finding.

Inventors

No inventors recorded.

Bibliographic Details