Height‐gain experimental data for groundwave propagation: 1, Homogeneous paths

Abstract

Experimental height‐gain data for the magnitude of electromagnetic groundwaves propagating over flat homogeneous paths were obtained by microwave (4.765 GHz) modeling. The experimental results were compared with height‐gain theory, and the limitations of the theory were established in terms of surface impedance, height of the receiving point, and antenna separation distance. Earlier experimental studies of this problem have not been entirely conclusive due to an inadequate knowledge of the surface impedance and the influence of the surface upon the antenna impedance. Here, extensive corrective measures were taken to eliminate or account for these effects.It is concluded that the theory for the total field is remarkably accurate as the height above or distance along the surface is varied, even at distances as close as 2λ0 from the source. Furthermore, the question as to the choice between the various forms of numerical distance seems academic. The restriction on height above the surface is eliminated, and the restriction upon the magnitude of the surface impedance is relaxed depending upon the presence of a significant trapped surface wave.Part 2 is a companion paper which relates the homogeneous path height‐gain to mixed‐path experimental measurements versus height and distance.