Interdependence Between Hourly Median Transmission Loss and Surface Refractivity Index Observed at 900 Mc on a 232-Mile Far-Beyond-the-Horizon Path

A detailed analysis is made of propagation data obtained from the North Atlantic Scatter System installed in Iceland. In particular, the correlation of the transmission loss and meteorological observations on a long path is analyzed in detail. By separating the data into various time periods, it is shown that for periods of time during which the received field is lowest, the correlation between transmission loss and surface refractivity is very high. The ability to establish a strong correlation between transmission loss and surface refractivity for this period allows the system designer to make more accurate predictions of the lower expected received fields and thus is able to calculate the minimum required transmitter with greater accuracy.