GB436355A - A new or improved method of and apparatus for clustering short and ultra-short electro-magnetic waves - Google Patents

Abstract

436,355. Directive wireless signalling. NAAMLOOZE VENNOOTSCHAP MACHINERIEEN - EN APPARATEN FABRIEKEN MEAF, 30, Croeselaan, Utrecht, Holland. April 13, 1935, No. 11527. Convention date, April 13, 1934. [Class 40 (v)] A directive array of shortwave aerials, spaced a halfwave apart as shown by the line of crosses in Fig. 1, is combined with a curved sheet or wire-gauze reflector 3, which concentrates the radiation (without altering its phase) in the two " shaded " beams, in a direction at right-angles to the original figure - of - eight field. The aerial-array is energized inphase, and may extend beyond the "open" apex 4 of the reflector. In Fig. 2 alternate aerials are energized in phase-opposition, as shown at + and -, and one curved reflector 6 is displaced by a quarter wave length from the other reflector 5 so as to maintain the phase-relation. In both cases the reflected beams pass substantially clear of the aerial-array and accordingly do not interfere with it. The dipole aerials may be replaced by small frame aerials, and the reflecting surfaces may be formed of a series of rods. The arrangement is applicable to reception as well as transmission. Some of the aerials may be energized indirectly from the others. The reflectors may be derived from the sphere, ellipse, hyperbola, or parabola.