GB723979A - Improvements in and relating to directional aerials - Google Patents

Abstract

723,979. Directive radio systems. ANTIFERENCE, Ltd., and BEST, N. M. Nov. 5, 1952 [Nov. 7, 1951], No. 26113/51. Class 40(7). A directional aerial system comprises four or six similar elements radiating with equi-angular spacing from a common centre in a common plane. Where there are four elements switch means are provided for selecting any two adjacent elements to connect to a transducer as a dipole and for connecting a reactive impedance between the remaining two elements so that these form a director or reflector. Where six elements are used means for selecting any two co-linear elements to form the dipole are provided which at the same time connects an inductive impedance between one adjacent pair of the remaining elements and a capacitative impedance between the other pair to form an array of director, dipole and reflector. Movement of the selecting means changes the direction of maximum sensitivity of the aerial system, an operation which may be done from a position remote from the aerial. If the actual selecting means is distant from the aerial elements switched auxiliary reactances are necessary to prevent interaction between the various feeders and so the selector switch is preferably mounted in a junction-box supporting the inner ends of the elements as shown diagrammatically in Fig. 4. Here the end of the elements 40, 41, 42, 43, radiating in a common horizontal plane from the insulating junction box 44 are extended to contact studs inside the box which co-operate with rotary switch member 53 carrying contacts 49, 50 associated with feeder 54 and contacts 51, 52 associated with impedance 55. A stepping switch or Selsyn motor may be used to move the switch and this can be controlled from a position adjacent the transceiver. Fig. 8 shows diagrammatically the arrangement of a similar junction-box switch where six elements are used. The elements need not be simple rods but may be folded dipole units, one end of each unit being led to a common point and the other to the selector switch. V-shaped or conical assemblies can also be used as elements. Aerial systems according to the invention may be stacked coaxially so as to lie in parallel planes. Specification 666,285 is referred to.