GB653405A - Directional antenna - Google Patents

Abstract

653,405. Aerials. BRIZA, J. Dec. 31, 1947, No. 35056. Convention date, June 8, 1945. [Class 40 (vii)] A rhombic aerial adapted to be adjustable with regard to its directivity and operating frequency comprises conductors 31, 32 supported by a rotatable cap to the mast 1 and insulating cables 4, 50 attached to cars 20, 21 running in a circular track. A fourth car attached by an insulated cable to the pole 1 and situated diametrically opposite the car 20 may be provided for supporting purposes. The direction of the radiation pattern of the aerial is controlled by the position of the car 20 and the sharpness of the pattern and the tuning of the aerial is controlled by the spacing of the cars 21 from the car 20. The mast 1 rises above the plane of the circular track so that the aerial hangs obliquely and the inclination of the aerial axis to the horizontal and the angle between the conductors 31 meeting at the pole 1 may be adjusted according to the wavelength and desired sharpness of the directive pattern by varying the spacing between the cars 21 and adjusting the length of the cable 50, which is attached to a weight 60, accordingly. The aerial is terminated in its characteristic impedance at 9, and is fed at its other end by a feeder 70 supported as shown by insulating cable 51. Alternative methods of supporting feeder 70 are illustrated in Fig. 2 (not shown). Apart from its use in directional communication systems, it is stated that the aerial may be used for direction-finding.