The Great Lakes Propagation Measurement Program: Comparisons of the Canadian Data with the Predictions of FCC R-6602

摘要

It was found that there was insufficient propagation data to determine reliably either the interference levels that would be encountered, or the applicability of the existing FCC R-6602 propagation curves, in the region of the Great Lakes. Accordingly, it was decided to conduct a joint study to assess, and if possible resolve, the propagation issues. Attention is confined to comparisons of observed field strengths in the Great Lakes area with those predicted by R-6602, and to an interpretation of the differences in terms of various paths and systems parameters. It is shown that, while the R-6602 curves accurately predict the long term (annual average) values of F(50,50) and F(50,10), they do not take into account observed diurnal and seasonal variatons of signal strengths of up to about 30 dB. Qualitatively, signal strengths over all paths are found to be higher at night than during the day and higher in summer than in winter. Empirical expressions are presented which relate the signal strengths predicted by R-6602 to those actually observed, and which take into account time of day, day of year, path length, and percentage of propagation path covered by water.