Properties and Performance of a New Compact HF Aerial Design for Multi-Band Operation

摘要

This work is an extension to that of Telfer and Austin [1] in that here a balanced feed embodiment of an inwardly-inclined folded dual monopole aerial is presented and discussed in terms of its improved performance over the original configuration. This includes greater control of the stability of the far-field (FF) lobe pattern with operating frequency, and a considerably extended frequency range (3:1 ratio) over which Near Vertical Incidence Skywave (NVIS) propagation in the high frequency (HF) bands can be exploited. Furthermore, the FF lobe patterns at frequencies > 2 X the fundamental design frequency are such that advantage can be taken of conventional non-NVIS horizontal propagation at those frequencies using the same aerial. At the fundamental frequency, compactness of design and robustness of its NVIS FF pattern to orientation make the novel balanced aerial design a convenient replacement for a full-length low dipole in cluttered environments. The paper also presents a vehicle-mounted version for medium range operation within HF skip distances. Applications highlighted include stations for remote monitoring of environmental measurements in difficult or hostile terrain.