GB735860A - Wireless antennas - Google Patents

Abstract

735,860. Aerials. POWELL, A. E. Jan. 8, 1953 [Oct. 8, 1951; Aug. 1, 1952], Nos. 23379/51 and 19537/52. Class 40 (7). An aerial primarily intended for the reception of vertically polarized television signals comprises a dipole formed of two in-line quarterwave sections 1, 2 which are connected together by an insulator 3 and supported from one end in an insulating bracket 4 so as to be inclined at 45 degrees to the vertical, and which are arranged with one of the sections supporting two additional parasitic quarter-wave sections 6 and 7. A coaxial cable extends through the lower section 2 and connects with the dipole at the centre. The sections 6 and 7 are prefer- ' ably carried by the lower section and may be supported by and electrically connected to the section by means of an adjustable tubular boss 8 having socket members 9, 10. If the parasitic sections are mounted on the upper section they are insulated therefrom. To permit the attainment of desirable directivity characteristics and discrimination against interference, the parasitic sections are adjusted around and along the dipole, and the whole assembly is rotated in mounting 4. According to alternative features of construction of the parasitic sections: (1) they may be formed as a continuous half-wave element adjustable in a socket offset with respect to the dipole; (2) their angle of inclination to the dipole, normally 90 degrees, may be made adjustable; (3) they may be supported so as to be individually rotatable about the dipole; (4) they may be welded or brazed to the lower section of the dipole or carried in hole therethrough. Fig 2 (not shown) illustrates details of a socket assembly for'joining sections 1 and 2 of the dipole to a clamp and socket assembly for securing the parasitic sections to the lower section of the dipole.