Accession Number : ADA115747

Title :   HF Ground Wave Propagation Over Smooth and Irregular Terrain.

Descriptive Note : Final rept. 1 Jan 80-30 Apr 81,


Personal Author(s) : Fulks,Gordon J

PDF Url : ADA115747

Report Date : 30 Apr 1981

Pagination or Media Count : 66

Abstract : This report addresses several aspects of ground wave propagation. Included are discussions of the general characteristics of ground waves as well as specific formulas for predicting ground wave field strengths at arbitrary locations from a standard transmitter. These formulas, from the work of Bremmer, apply to either vertical or horizontal polarization, to a smooth spherical earth, and to a wide variety of soil types. A computer program to evaluate the formulas is presented and sample results are given. Although this report concentrates on HF frequencies, many of the results are applicable to a much wider range of frequencies. Atmospheric refraction, which may enhance ground wave propagation, is discussed. Formulas for predicting refraction effects based on atmospheric temperature and humidity as well as temperature and humidity gradients are presented. Propagation over inhomogeneous and irregular terrain is considered. Only limited aspects of such propagation are discussed with an emphasis on irregular terrain. Obstacle gain is covered in some detail. Becuase of the lack of experimental data for ground wave propagation over irregular terrain at HF frequencies, an experiment is recommended. (Author)

Descriptors :   *Electromagnetic wave propagation, *Atmospheric refraction, *Ground waves(Electromagnetic), *Atmospheric temperature, *Terrain, Computer programs, Gradients, High frequency, Refraction, Strength(General), Wave propagation, Humidity, Transmitters, Propagation, Waves, Frequency

Subject Categories : Atmospheric Physics
      Radiofrequency Wave Propagation

Distribution Statement : APPROVED FOR PUBLIC RELEASE