Propagation prediction for hilly terrain using GTD wedge diffraction

A terrain sensitive propagation model based on the geometrical theory of diffraction (GTD) modified for finite conductivity and local surface roughness is applied to hilly terrain including multiple diffraction, with the results compared with measurements and the Longley-Rice model. Even though the approach used to calculate multiple-wedge diffraction is known to be invalid in certain situations, the comparison is favorable to the GTD model results.