A General Computer Model of Radio Communication Link Performance.

A general-purpose computerized model of radio communication performance is described. This link status model determines to what degree any given communication link is operable as a function of terminal equipment and what propagation path conditions exist between units at each end of the link. Propagation via ground wave or via near-vertical sky-wave paths is considered. The ground wave portions of the model include methods for determining the nature and structure of vegetation and of altitude variations along the propagation path and in addition the model calculates path loss using the most appropriate of nine methods, eight of which are based upon the characterization of vegetation as a lossy dielectric slab. The model explicitly treats ground wave propagation for frequencies from 10 kHz to well into the UHF region over smooth or rough terrain, all with an arbitrary mix of vegetation and clear areas. All antenna heights including satellites and ranges may be accommodated, with due consideration for earth curvature and atmospheric refraction.