Propagation over irregular terrain in the VHF band: a review of integral equation models

This paper deals with propagation over irregular terrain and its resolution using integral equations. We describe several kinds of integral equation models and we use three different softwares based on the following methods: Maclean and Wu (Wu et al. 1988), Ott (1970) and Hufford (1952). The results given by the three softwares are compared to analytical solutions on simple terrain irregularity in the VHF band. We use experimental results that are obtained at 61 MHz to draw a conclusion on the validity of each model. We show that the Hufford integral equation model seems to give the best results for this frequency band.