A Characterization and Prediction of Wideband HF Skywave Propagation

Existing HF propagation models such as the ITS-78/HFMUFES 4 prediction model (ref. 1) or CCIR method (ref. 2) are mainly concerned with the prediction of the optimum operating frequency, the maximum usable frequency (MUF) and the HF skywave signal strength (and noise) or circuit reliability dependence on frequency. The propagation predictions obtained from HFMUFES are suitable for narrowband analog voice HF systems. They are not sufficient to predict the performance, select the optimum operating frequency or determine the lowest usable frequency (LUF) of digital systems which employ diversity (explicit or implicit) because they do not provide sufficient details about the multipath characteristics of the HF channel. In this paper, we describe a propagation model suitable for prediction of all of the relevant HF propagation parameters that are needed to characterize the HF channel.