Directional spread characteristics of HF signals received over paths within the auroral zone

The ionosphere within and close to the auroral zones is a dynamic propagation medium that is not perfectly horizontally stratified, and consequently the signals associated with each propagation mode may arrive at the receiver over a range of angles in both azimuth and elevation. In order to better understand this type of propagation, measurements have recently been made over two paths: (a) from Svalbard to Kiruna, Sweden, and (b) from Kirkenes, Norway to Kiruna. An analysis of these data is presented in this paper. The directional characteristics are summarised, and consideration given to modelling the propagation effects in the form of a channel simulator suitable for the testing of new equipment and processing algorithms.