GB688040A - Improvements relating to high frequency aerial arrangements - Google Patents

Abstract

688,040. Aerials. ELECTRIC & MUSICAL INDUSTRIES, Ltd. Feb. 19, 1951 [Feb. 18, 1950], No. 4209/50. Class 40 (vii). A unipole aerial and additional elements such as one or more directors or reflectors and possibly another unipole tuned to a different frequency, are supported by a rigid member which serves as an earthing device, effectively earthing the feeder employed for driving energy from the aerial. In a first embodiment, Fig. 1 (not shown), the member comprises a rod or tube on which the rigid tube or rod unipole is mounted by means of an insulating bracket, the ends of the member may be bent through a right-angle to lie parallel to the unipole and comprise respectively a director and reflector. A coaxial feeder may be used having its inner conductor connected to the lower end of the unipole and its outer to the member. If desired, the reflector and director may be separate elements insulated from the earth member and spaced from the unipole distances of O.1# and 0.25#, respectively, where all the elements are #/4 long. As shown in Fig. 2, a folded unipole 7, 8 may be substituted for the simple unipole in the embodiment described above. Additional reflectors may be added on a cross-piece attached to the earthing member 3 and at right angles to it, Fig. 3 (not shown). The earthing member may extend beyond the elements it supports.