GB1335276A - Broadcast receiving aerial - Google Patents

Abstract

1335276 Aerials; radio receiving apparatus CLARION CO Ltd and ASAHI GLASS CO Ltd 19 April 1971 [12 Feb 1970 4 March 1970 14 March 1970 18 Sept 1970 (2) 2 Oct 1970] 21063/71 Headings H4A and H3Q A broadcast receiving aerial comprises a pair of aerial elements located on and/or within a window glass, means providing reactance between the elements, and a feeder lead connected to one of the elements. When receiving A.M. signals both elements are effective, but when receiving F.M. signals the presence of the reactance means results in only one of the elements being effective. As described, a windscreen 1, Fig. 2, of a motor car carries an aerial 2 which is made up of a vertical portion 3 and a horizontal portion 4, the latter being provided with two reactance elements 5. A cable 6 connects the lower end of the portion 3 to a radio receiver 7. The aerial conductors may be wires or strips and may be provided upon the surface of the windscreen or between constituent lamina thereof. In a second embodiment, the aerial consists of a single horizontal conductor and a single vertical conductor. These are arranged in T formation, a reactance element being interposed in the vertical conductor near its junction with the horizontal conductor (Fig. 5, not shown). In a third embodiment, an aerial similar to that shown in Fig. 2 is provided with a pre-amplifier of chip form, located in or on the windscreen (Fig. 6, not shown). Suitable integrated circuit amplifiers are described, using either a transistor (Fig. 7, not shown) or a diode, such as a tunnel diode (Fig. 8, not shown). In other embodiments, two separate aerials are provided in or on a window glass, for different frequency bands, a reactance element being interposed in one prior to connection to a common feed point. Thus, as shown in Fig. 17, a central vertical aerial conductor 30 is directly connected to the input of a pre-amplifier 33, whilst an aerial conductor 31 of approximately ]-shape, which runs along the lower edge of the window from its centre towards one side edge, continues along that side edge towards the upper edge, and then runs along that upper edge towards the centre, to complete the ]-shape, is connected to said input through a reactance element 32. The preamplifier 33 may comprise a field effect transistor (Fig. 18, not shown). In other embodiments also using two aerials, the pre-amplifier may be omitted, and the shape of one or both aerials be modified. For example, as shown in Fig. 13, the aerial for the lower frequency bands may consist of two ]-shaped portions (similar to that shown in Fig. 17) each provided with additional vertical members extending between their upper and lower horizontal members. Alternatively, such additional members may be horizontal and extend from the side members towards the centre (Fig. 12, not shown).