GB1410959A - All channel television antenna system - Google Patents

Abstract

1410959 Aerials RCA CORPORATION 14 Dec 1972 [27 Dec 1971] 57653/72 Heading H4A An aerial system providing wide-band operation over two frequency ranges comprises a VHF loop element 10 within which is a UHF dipole element 30 (or its orthogonal projection if not co-planar), having feed terminals 35, 36. There are two diametrically opposite gaps in the loop, one of which provides feed terminals 15, 17, and at the other of which a resistive element 27 is serially connected, at points 23, 25. By making the transverse dimension d of the loop less than #/2 (#= wavelength at the lowest VHF operating frequency) it is stated that the directivity outwardly from the feed terminal gap is made greater than that in the opposite direction (Fig. 2, not shown). As described, the loop 10 includes two semicircular bands 11, 13, which are tapered down at their ends. The feed terminals 15, 17 are connected to input terminals 19, 21 of a low pass filter, which is comprised in a combiner 20 (Fig. 5, not shown). The dipole 30 is of "bow-tie" type and it has two triangular arms 31, 33, which may have bent-down extensions 75, 76 at their outer ends 37, 39. The feed terminals 35, 36 are connected to input terminals 41, 43 of a high pass filter which is comprised in the combiner 20. Parasitic elements for the dipole 30, which are also inside the loop 10, comprise a reflector strip 45 and three directors 47, 49, 51 each formed by a respective pair of strips 47a, 47b; 49a, 49b; 51a, 51b. Additional directivity for the UHF aerial may be obtained by providing L-shaped slots 53, 55 in the band 11, and L-shaped slots 57, 59 in the band 13, as shown. Said slots are stated to reduce side-lobes (Figs. 3, 4, not shown). The system may be embedded in suitable dielectric material, such as foamed plastic, and then be mounted on a mast 81.