A Compact Active Monitor Antenna for HF Spectral Occupancy Measurements

This paper presents a short dipole active HF monitor antenna which has been designed and developed during a Spectral Occupancy research project where limited space imposed a limitation. This short dipole is very lightweight and compact, as a result, it can be easily installed either vertically or horizontally on any mast. The active dipole's efficiency has been optimized based on a two-stage low noise amplifier. The first stage of this LNA cancels the high capacitive reactance of the antenna's impedance. The second stage operates as a common emitter amplifier in order to provide the required Gain to the receiver.