Basic ground-wave propagation characteristics in the frequency band 50????????800 Mc/s

摘要

The relation between existing experimental data on transmission at very high frequencies, at distances such that variations in atmospheric refractive index are of little significance, and fundamental propagation theory is discussed. An empirical correction for the difference between the field strengths observed over irregular terrain and theoretical values is given, and basic ground-wave characteristics for the frequency band 50????????800 Mc/s are suggested which should be applicable except in very mountainous country or in densely built-up areas. Over this frequency band, and for distances inside the normal horizon, it appears that there is very little variation of median field strength with frequency for a given effective radiated power.