High Frequency (HF) Radiowave Propagation

Abstract : This report serves to introduce the basics of high frequency radiowave propagation in the earth's ionosphere. It is intended for people who are not fully acquainted with the physics of the problem but have had some experience working with or will have to work with over-the-horizon radar systems. This material, after an introduction to propagation theory and terminology, concentrates on the features of the OTH radar. First, backscatter ionogram is introduced as the primary diagnostic tool for the management of the radar in terms of the ionospheric environment. The synthesis of these ionograms is presented in detail as a way of leading to a better understanding of HF radiowave propagation. Special emphasis is placed on a description of the effects of ionospheric clutter and sporadic-E on the performance of the radar.