Anita G. Longley

Abstract: This report summarizes the results of a number of studies of path-to-path, or location, variability of transmission loss at 20 MHz to 10 GHz. The studies show that such variability appears to be normally distributed and can, therefore, be represented by a standard deviation. Location variability increases with increased frequency and terrain irregularity, the standard deviation increasing from about 5 to 25 dB. For non-urban areas an expression is given which defines location variability in terms of radio frequency and terrain irregularity. The effects of tall buildings in highly built-up urban areas, and of trees are discussed.

Keywords: irregular terrain; vegetation; broadcast systems; location variability; urban communications; mobile systems; radio transmission loss

Disclaimer: Certain commercial equipment, components, and software may be identified in this report to specify adequately the technical aspects of the reported results. In no case does such identification imply recommendation or endorsement by the National Telecommunications and Information Administration, nor does it imply that the equipment or software identified is necessarily the best available for the particular application or uses.

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