Double knife edge diffraction propagation studies over irregular terrain

Mounta in c li ffs constitutin g knife edges inOue nce radio wave propagating fro m VHF to mi crowave freque nc ies. T he diffr acti o n phenomena caused by th ese sing le o r multi ple knife edges are a do mina nt propagati o n mecha ni sm th a t has to be take n int o account in planning TV, FM ne twork s, cellul ar radi o, mi c ro wave netwo rk, e tc., in mounta in o us regio ns. In orde r to in vesti gate th e a bove mecha ni sm fi e ld stre ngth measure me nt s we re conducted over fi ve do ubl e knife edge path s a nd the measured sig na l levels a re compa red with severa l predic ti on techniques. T he deviati ons of th e predi c ti o n techni q ues and th eir suitabil ity are present ed in thi s paper. It is seen th at o ut of a ll th e predic ti o n me th ods G iovane ll i's method g ives best agreeme nt with th e o bserv ed result s.