Abstract :
A review is given of the effects of irregularities in the terrain and of non-standard refraction in the troposphere on radio field strength characteristics in the v.h.f. band. The results of an analysis of existing data on long-range transmission in this band in the United Kingdom are then applied to the problem of determining the spacing required between two transmitters working on a common frequency when the degree of interference in each local service area caused by signals from the more distant transmitter must not exceed various specified limits. The effects of non-standard tropospheric refraction, in particular, are such as to make this spacing much greater than it would be if such departures from standard did not exist.
