GB1487424A - Omni-directional antennae - Google Patents

Abstract

1487424 Omnidirectional antenna MARCONI CO Ltd 27 Nov 1974 [19 Feb 1974] 7589/74 Heading H4A A broadband H.F. vertically polarized antenna comprises a skirt portion formed as a tapering surface of revolution, the board base of which being on the ground, and a flat plane arranged at the narrower end of the skirt, electrically insulated therefrom. The signal is fed to the plane by the inner conductor of a coaxial cable, the outer earthed conductor thereof being connected to the skirt. In Fig. 2, the radiating planes are skeletonized. Wire radiating elements 10 which constitute the skirt are supported by a central pole 22 arranged at the centre of an earth system of buried conductors 12. Wires 10 are secured at their upper ends by rigid loop 26 anchored to centre pole 22 and electrically connected to the coaxial cable outer conductor (16, Fig. 1, not shown), and are constrained in diameter by two belts 28 so that their shape is approximately exponential, to minimize reflections and improve the launching mode of low angle waves. The inner conductor of the coaxial cable is connected to horizontal radial wires 18 constituting the base of cone 20, which further comprises wires extending from the top of the pole 22 to a point a distance R2 along the ground wires 12, the lower portions below wires 18 being electrically insulated from the cone 20,