Horizontal Rhombic Antennas

A N introductory discussion has been given in a previous paper 1 of a type of antenna which maintains a desirable degree of directivity throughout a broad continuous range of frequencies. This structure was descriptively termed the "diamond-shaped" antenna in that paper, but has since become known as the "rhombic antenna" and will be so designated here. This paper discusses, in some detail, the theoretical methods employed by the authors in dimensioning horizontal rhombic receiving antennas from data obtained by preliminary surveys of the incidentplane angles of wave-arrival at the proposed receiving site. Experimental proof is given of the engineering accuracy of the directivity calculations on which this work is based. Checking measurements were made on small-scale rhombic antennas operating at correspondingly short wave-lengths. Confirming data were also obtained on large, adjustable rhombic antennas during the reception of European signals. The paper also includes a brief discussion of the antenna-to-transmission line coupling circuits employed and, in addition, the resistance terminations, located at the end of the antenna remote from the receiver, used for suppressing standing waves and promoting unidirectivity. Some of the performance curves obtained on these devices are reproduced. ANTENNA DIMENSIONS