Influence of directional fluctuations on the gain of horizontal rhombic aerials for high frequencies

The response of a horizontal rhombic aerial to waves which fluctuate in direction of arrival is considered, and numerical values of the gain degradation from this cause are given for a wide range of practical aerial and wave parameters. Experimental data on the directional variations associated with single modes of propagation at long ranges are briefly reviewed, and it is concluded that such variations do not constitute any limitation in practice on the size of rhombic aerials for high-frequency communication.