GB692472A - Improvements in or relating to radio receiving systems - Google Patents

Abstract

692,472. Directive radio systems; multiplex radio signalling. PHILIPS ELECTRICAL, Ltd., and ODELL, L. F. Sept. 7, 1950 [Sept. 30, 1948], No. 25495/48. Classes 40 (v) and 40 (vii). A radio receiving system comprises an Adcock aerial system, each element of which is coupled through its own master thermionic valve to feed its own plurality of slave valves in parallel, the slave valves being connected in sets consisting of one slave valve fed from each aerial element to feed a plurality of loads, one load being associated with each set of valves and the master and slave valves being so arranged that the matching for each aerial element is independent of the load, no interaction occurs between the different load circuits and the output of each slave tube is substantially matched to the associated load impedance. The invention is of particular value where it is desired to feed a number of independent direction-finding receivers from a single aerial system or for the directional reception of a number of broadcast programmes at the same time on a single aerial. The master and slave valves may conveniently be connected as cathode followers and each load circuit may comprise a goniometer feeding a receiver. In one embodiment, four Adcock aerial elements N. S. E. W. (of which only the element N. is shown), arranged in the conventional manner, feed through phasing units 1 and master cathode follower valves 2 their own series of slave valves 3. Considering one set of slave valve outputs N1, S1, El, W1 the N 1 and E1 1 signals are reversed in phase by units 4 and the N1, S1 and E1, W1 signals applied to opposite ends of potentiometers 5, the adjustable tapping-points on which feed receiver 61. Variation of the tapping-points on the potentiometers varies the direction of maximum sensitivity for the reception of signals and other receivers 62 and 63 may be connected by similar means, not shown, to other sets of slave valves.