GB502972A - Improvements in directional aerial systems - Google Patents

Abstract

502,972. Directive wireless systems. MARCONI'S WIRELESS TELEGRAPH CO., Ltd., FURNIVAL, J. M., WITT, B. J., and COCKERELL, C. S. Sept. 28, 1937, No. 26282. [Class 40 (v)] In an equi-signal radio beacon comprising a plurality of aerials, the radiation of any horizontally-polarized component along the equisignal line is prevented by arranging the aerials parallel to this line. This eliminates the production of false equi-signal indications at the receiver due to the horizontally-polarized components of the transmitted radiation being -picked up by horizontal components of the receiving aerial. In Fig. 1, the equi-signal line E is produced by the two aerials A, A<1> and a horizontal component is radiated from the horizontal portions ab, a<1>b<1>, cd ... e<1>f<1>. This component is eliminated in Fig. 2 by arranging the aerials A1, A2, A1<1>, A2<1> parallel to the equi-signal line E, and the overlapping characteristics are obtained by setting back the aerials A1, A1<1> relative to the aerials A2, A2<1>. In a modification comprising three aerials parallel to the equi-signal line, the centre aerial is continuously energized and the two outer aerials, which are set back relative to the centre aerial, are energized alternately in dot-dash sequence. Alternatively, two directly - fed parallel aerials may be used, "slewing" of the beams being effected by suitable phase adjustment.