GB647198A - Improvements in and relating to antennae - Google Patents

Abstract

647,198. Aerials. BRITISH THOMSONHOUSTON CO., Ltd. April 17, 1947, No. 10238. Convention date, April 19, 1946. [Class 40 (vii)] The invention is a development of the antenna described in Specification 561,251 and may be fed from an unbalanced line, for example a coaxial feeder. One embodiment (Fig. 2) supported by an earthed metallic mast 11 comprises two arcuate conductors 1, 2 extending in the same plane round the mast and two further parallel and similarly orientated conductors 12 and 13. ' The conductors 1 and 12 and 2 and 13 are respectively coupled by conductive plates 19 and 20 at their adjacent ends and the opposite ends of conductors 12 and 13 terminate in plates 14 and 15 which are bolted together and also to bracket 17 supporting the assembly from the mast. The other end of conductor 1 which may be supported by insulator 18 from conductor 12 is energized from the central conductor 3 of the coaxial feeder and the other end of conductor 2 is connected to the corresponding end of conductor 13. Discs 24 and 25, the spacing between which is adjustable, are arranged between plates 19 and 20 and are used to tune the antenna. The size of the respective conductors is chosen so that the impedance of the antenna matches that of the feeder. In a second embodiment (Fig. 3 and 4, not shown), the conductors 2 and 13, which are joined at each end, are replaced by a single conductor which is in a plane between those containing conductors 1 and 12.