GB485583A - Improvements in or relating to radio direction finders - Google Patents

Abstract

485,583. Directive wireless signalling. MARCONI'S WIRELESS TELEGRAPH CO., Ltd. (Telefunken Ges. f³r Drahtlose Telegraphie) Nov. 20, 1936, No. 31847. [Class 40 (v)] In a direction-finder, corrections both for quadrantal error and for " mast effect " are automatically added to the normal readings by composite threedimensional cams, the appropriate contour of these being selected by means geared to the wave-length switch and the tuning knob of an all-wave receiver. As shown in Figs. 2, the hand wheel Hr is geared to the directional frame (not shown), and to a rough or uncorrected scale 51. The corrected scale S is mounted concentrically with the compass card K, and an indicator ring Z, which is given a movement compounded of the rotation of the hand wheel Hr and of a correction picked up by a slider O1 riding over the composite cam MFB so as to correct for quadrantal error. The two movements are compounded in a differential gear G1. The control of the energy fed from an auxiliary aerial (not shown), in order to compensate for " mast effect," is derived from a slider O2 riding over the composite cam MHAB, through a lever 15 and gearing 17, 18 which control the mast-correction shaft HAB. The position of the sliders O1, O2 on the contour of the cams MFB, MHAB is controlled from the wavechange switch St and tuning knob D of the receiver E through the medium of a cam U, a differential gear G2, and nuts 13, 14 sliding on a screw shaft 12. The composite cams are built up of individual discs each cut for a particular wave-length, the sliders O1, O2 being shaped to give a mean value of correction between two adjacent discs.