GB592343A - Antenna arrangements - Google Patents

Abstract

592,343. Antenna arrangements. STANDARD TELEPHONES & CABLES, Ltd. Oct. 22, 1943, No. 17458. Convention date, March 23, 1942. [Class 40 (v)] An antenna for use in aeroplanes comprises a pair of arms 10 and 11, each an odd number of quarter-wavelengths long and mounted at one end on a hollow metal strut 12 extending vertically. from the fuselage, the arms being conductively joined to the strut and arranged to extend in a direction such that in flight they lie in the plane of polarization of the energy to be picked up or radiated, e.g. the plane of the arms may be parallel or substantially so to that of the wings of the aircraft. The examples shown are intended to be mounted above the fuselage in a low wing monoplane having a conducting skin and in order to render the antenna substantially non-directional the arms 10 and 11 are disposed at an angle to each other of about 80 degrees. This gives an elliptical response curve having a ratio of major to minor axis about 2.5 : 1 for the antenna alone, but the curve is modified due to the aircraft fuselage so as tb be approximately circular in a horizontal plane when the aircraft is flying on a straight course. Connection to the arms 10, 11 is effected through conductors 14; '15 emerging from strut 12 and attached to the arms a short distance (about 6 inches' with the antenna operating at 100 megacycles) from the vortex of the V-shaped structure formed by the arms. The forms shown in Figs. 4 and 5 are said to give improved non-directional characteristics. If desired, curved arms having shapes approximating to those shown could be employed. It is stated that the angles between the arms or the inclined portions thereof may vary between 40 and 120 degrees, that the arms may be mountedfrom 0.07 to 0.15 wavelength above the fuselage, and the point of connection of conductors 14 and 15 to the arms may be from 0.02 to 0.06 wavelength from the junction of the arms. The members 10, 11, 12 may be formed of beryllium-copper alloy sheet and are preferably streamlined, the structure maintaining its performance in rain and ice conditions. In the case of a high wing monoplane, the antenna would be arranged below the fuselage. The antenna described is said to respond satisfactorily over a range from 96 to 104 Mc. without modification of the antenna or its connections.