GB517772A - Improvements in or relating to aerials or aerial systems - Google Patents

Abstract

517,772. Aerials. CORK, E. C., and PAWSEY, J. L. June 28, 1938, No. 19094. [Class 40 (v)] Relates to aerial systems, particularly for short-wave working, in which tubular radiating elements are arranged coaxially with, say, the iron mast of a ship. The object of the invention is to minimize the effect of the iron mast in dissipating power, or in distorting the radiation field. In one embodiment, Fig. 1, a metal mast 1 is surrounded by a tubular half-wave radiator 2 fed at its lower end by the coaxial line 3 the sheath of which is earthed at the points e, adjacent the radiator and d at a quarter wavelength therefrom. The mast 1 is earthed at the points b, a adjacent the ends of the radiator and the point c a quarter wave-length from a. The centre point of the radiator 2 is directly connected to the mast 1 by the member f so as to ensure a high impedance between the radiator and the mast; but this may be omitted, Fig. 2 (not shown). In a further embodiment, Fig. 3 (not shown), the upper end of the radiator is connected to a feeder branched off from the main feeder 3 at a point a quarter wavelength from the lower end of the radiator. In another form, Fig. 4, two half-wave tubular radiators 2a, 2b spaced half a wave-length apart are fed in anti-phase at adjacent ends from the single feeder 3 and are connected to the mast 1 at their mid points. Specifications 5387/00, [Class 40], 489,775 and 509,500 are referred to.