Passive monitoring for improved HF frequency management

This paper proposes a number of techniques for the enhancement of frequency management within an HF radio network system. Specifically, passive monitoring techniques are considered, thus alleviating spectral congestion, and, within a non-radiating situation, enabling ionospheric assessment to take place without any active transmissions. Procedures are presented to allow accurate estimation of path MUF (maximum usable frequency) and SNR (signal to noise ratio) by means of passive monitoring