A multiple-beam high-frequency receiving aerial system

The paper describes a system, covering the band 1.5 MHz to 10 MHz, designed to give good beam-forming capability with all-round azimuthal coverage and occupying a much smaller area than a corresponding conventional rhombic aerial system. Although unsuitable for transmitting purposes, it provides, in general, externally noise-limited conditions to receiving equipment. Limited tests indicate, on the basis of error rate measurements, that the system described is as good as a rhombic array. The parts of the system are discussed in detail and references are made to ideas concerning the upwards extension of the frequency range and the size reduction of the beam-forming networks.