Mixed path ground wave propagation: 1. Short distances

Abstract

An expression is deri ved for t he mutual impedance between two sho rt \'ertical antennas o n a flat eart h with a straig h t bou nd ary separat in g t wo media of differing electri cal constants. After m akin g som e ap prox im at ions t h at a rc ntlid at lmy and medium fr eque ncies and wh ere t he ant e nnas a re not near t h e boundary, t he integral formula fo r t he fi eld is evaluated for a wide ran ge of t he pa ra m eters. The numeri cal r es ul ts computed in t hi s p ape~' a re show n to b in r easo nab ly good ag reem en t wi t h experim ent. F ina lly, t he efl' ect of t h e ob liqueness of th e bou nd ar y is cons id ered by a "cfin em c nt of t he stationary phase evalu ation of the integ ral s.