GB550009A - Broadcasting antenna systems - Google Patents

Abstract

550,009. Wireless directive signalling ; aerials. STANDARD TELEPHONES & CABLES, Ltd. Sept. 19, 1941, No. 12065. Convention date, Sept. 25, 1940. [Class 40 (v)] An antenna unit comprises three or more radiating members 30 ... 33, Fig. 3, arranged in the form of a square or other closed pattern. Energy from the transmitter 34 is fed over lines 36, 37 to energize members 30, 31 adjacent their mid-points and in phase opposition. The ends of members 32, 33 are turned inwards at 38 to provide a capacity coupling with the members 30, 31 by which they are energized. Each of the members 30 ... 33 has a voltage node at its mid-point, so that they may be supported at these points without insulation from each other or from ground. Fig. 4 shows a practical form in which the members 30 ... 33 are of aluminium channel or tubing supported from a metal post 44 by metal tubes 40 ... 43, the leads to members 30, 31 passing through tubes 40, 41. Several such units may be mounted one above the other, Fig. 7 (not shown), the feed line being connected by branched transmission lines to the units in such a way that they are energized in phase. Fig. 1 shows a broadcast antenna array comprising two or more units 11, 12, 13, each producing a toroidal field pattern having a uniform value in a horizontal plane, and spaced apart vertically by a distance of the order of 200-400 electrical degrees at the operating frequencies. Heating elements for removing sleet may be mounted inside the radiating members, Fig. 8 (not shown). The radiating members of each unit may be arranged to form a circle, a hexagon, or a triangle, Figs. 9, 11, 12 (not shown). In Fig. 10, each radiating member 30 ... 33 is bent at right angles as shown, the ends of members 32, 33 being bent to overlap the ends of 30, 31 to provide the necessary coupling capacity. Specification 538,036 is referred to.