GB587543A - Improvements in antenna systems - Google Patents

Abstract

587,543. Aerials. PRESS WIRELESS, Inc. June 30, 1944, No. 12506. Convention date, June 15, 1943. [Glaas 40 (v)] The terminating impedance of a rhombictype aerial used primarily for transmission is constituted by a similar rhombic-type section mounted beneath the radiating section and connected to it by a transmission, line. As shown in the Figure, the aerial comprises a radiating rhombus 1 of copper wires energized from the transmitter 11 through the transmission line 12 and mounted on poles about 100 ft. above the ground over a dissipating rhombic section 2 to which it is connected by the transmission line 16, 22, corresponding wires of the two sections being in the same vertical plane. Due to its ctose proximity to the ground, the lower section has a high attenuation which may be increased by forming it of stainless steel wire and the near apex 26 may be earthed directly or through a resistance equal to the characteristic impedance Zo of the system. Alternatively, the two legs 18, 24 may be bridged near the apex 26 with a resistance equal to Zo having an adjustable earthing point, Fig. 6 (not shown), or the apex 26 may be connected to a two-wire transmission line of high attenuation which may be terminated, in a further network of spaced wires at a place where the ground-induced resistance is more favourable, Fig. 7 (not shown). The legs of the sections may be given an exponential instead of a linear separation to obtain impedance matching, Fig. 5 (not shown). The planes of the two rhombic sections may be inclined towards each other to modify the directivity of the aerial, Figs. 8 and 9 (not shown). Details of the supports are illustrated in Figs. 2-4 (not shown). The Specification as open to inspection under Sect. 91 describes a single rhombic aerial in which impedance matching is obtained by forming each radiating conductor of two diverging wires, the plane of each pair of wires being at an angle to the vertical. This subjectmatter does not appear in the Specification as accepted.