June 1955 | Technical Report NBS Report 3554
Preliminary Report on the Extreme Range of Regular Propagation of VHF Radio Waves by Ionospheric Scattering
Cite This Publication
Richard C. Kirby, “Preliminary Report on the Extreme Range of Regular Propagation of VHF Radio Waves by Ionospheric Scattering,” Technical Report NBS Report 3554, U.S. Department of Commerce, National Bureau of Standards, Central Radio Propagation Laboratory, June 1955.
Richard C. Kirby
Abstract: Initial results through December 1954 are reported from a continuing investigation of the extreme distance range of regular VHF propagation by scattering in the lower ionosphere. Signal strength observed at 36/Mc/s over an experimental path from Newfoundland to the Azores, 1411 statute miles distant, has been recorded without interruption except for equipmental reasons since 4 October 1954. October and November results indicate a medium value of 85 decibels loss relative to the Cedar Rapids- Sterling path, 743 miles, after normalization of frequencies and antenna systems; during weakest signal periods, the loss diminished to about 3 decibels relative to the Cedar Rapids- Sterling path. Smaller diurnal and seasonal variations are observed over the long path, but much greater indicence of Es-type propagation. Signal fading and correlation coefficients of about .3 to .4 are observed for a spacing of 4a, and about 0.2 to 0.3 for a spacing of 10A. Some of the geometrical aspects of extreme-range propagation are discussed and results of calculations given for vertical angles of arrival and departure, and required antenna heights vs. path lengths.
Keywords: fading; VHF; ionospheric propagation; propagation measurement
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