Transmission loss of space waves propagated over irregular terrain

It is explained why two particular equations be used for a study of space-wave propagation over irregular terrain. It is believed that these two equations provide a method of separating the systematic from the random effects of terrain irregularities. Our development of a transmission loss formula is based upon the determination of a smooth curved surface (either concave or convex) which approximates that part of the actual terrain which is effective in the ground-reflection process and the subsequent use of well-known methods of attenuation calculation applicable to such smooth, curved surfaces.