GB251946A - Improvements in radiating antenna systems - Google Patents

Abstract

251,946. British Thomson-Houston Co., Ltd., (Assignees of Alexanderson, E. F. W.). May 9, 1925, [Convention date]. Aerials; directive signalling.-An aerial system in which the rotated energy is projected as a space wave inclined to the horizontal, and is characterized by a predominant horizontal polarization, comprises two or more horizontal radiators 11, 12, Fig. 1, mounted above the earth a distance equal to at least one-eighth the effective wave-length. The distributed inductance of the aerial may be neutralized by series condensers in known manner. High-frequency current is supplied from a suitable source 3 to each radiator through non-radiating vertical leads 15, 16 and 17, 18 comprising phase-adjusting means 19, 20. When the currents in the two radiators flow simultaneously in the same direction, the wave-emission is a maximum vertically upwards and at right-angles to the length of the aerial; when the currents are in phase-opposition, maximum radiation takes plate at 45‹ inclination and in the length direction of the aerials. Fig. 6 shows a linear radiator 36 with series condensers 38 in combination with a similar reflector 37 to increase the directional effect. Two or more horizontal radiators may be fed in parallel, the spacing of the radiators, and the phase relation of the current supplied to them being adjusted so as to control the angle of direction and the concentration of the radiated beam. The radiators may also take the form of one or more closed loops suspended vertically, and the currents in the vertical limbs may be adjusted so that the effective radiation is confined to the horizontal sides. Fig. 9 shows a vertical closed loop 51 with series condensers 54 fed centrally from a source 3, and adapted to be swung into various inclined positions as indicated by the dotted lines 52, 53. Series condensers may also be distributed along the supply lines from the high-frequency supply to prevent the radiation of vertically polarized waves. Specification 243,706 is referred to.