Abstract

At present, portable receivers generally use ferrite rod antennas for LF and MF (below 2 MHz), and whip antennas for HF (up to 30 MHz). Each type has proved effective in its particular application. However, a whip antenna is much less convenient for the user of the receiver, and the obvious question is whether a ferrite rod could be used instead at HF. Yet another possibility is the loop or frame antenna, which was popular before the introduction of ferrite rods. With the BBC wishing to expand transmissions of DRM, the subject is becoming increasingly important. This report discusses the use of loop and ferrite rod antennas at HF, and presents both theoretical and practical results. It also introduces a spreadsheet calculator for allowing the user to assess the effects of altering the various parameters. The conclusion is that ferrite rods are suitable for use at HF, but that frame antennas could be even better. The report was prepared for the information of staff involved with radio reception in general and the DRM project in particular.