HF Ground Wave Propagation Over Smooth and Irregular Terrain.
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)
Document Details
- Document Type
- Technical Report
- Publication Date
- Apr 30, 1981
- Accession Number
- ADA115747
Entities
People
- Gordon J. Fulks