The Possibity of Extending Air-Ground UHF Voice Communications to Distances Far Beyond the Radio Horizon

Certain of the results of a detailed research investigation of 220 Mcps tropospheric "scatter" field strengths at long distances and high altitudes carried out here at the Air Force Cambridge Research Center are reviewed in some detail. On the basis of the airborne data obtained to date, supplemented by fading statistics obtained here and elsewhere, reasonable initial estimates can be made of the UHF radio wave path loss expected to obtain for various percentages of the time out to distances of several hundreds of miles and up to altitudes of several tens of thousands of feet. It is concluded, upon the basis of these path loss estimates, and initial airborne voice reception tests, that the scatter mode of propagation will permit the extension of reliable good quality air-ground UHF voice communication to distances far beyond the radio horizon.