Some factors influencing the design of broad-band H.F. monopole aerials

Some of the factors influencing the design of broad-band monopole aerials for use on shore-station terminals of h.f. band circuits (3¿30 Mc/s) are discussed. Two applications are considered in particular; firstly, that of a system suitable for omnidirectional radiation, and, secondly, a system suitable for wide-angle sector radiation. Attention is given to the effects of the aerial configuration on the terminal-impedance characteristic and the radiation patterns. The results of measurements made on various configurations are presented in a graphical form to enable the aerial designer to determine the basic design of a structure for a given requirement. Two typical examples, one for each application of the aerial, are discussed. The design of the associated feeder systems, particularly for transmission circuits, is also discussed.