The effects of atmospheric discontinuity layers up to and including the tropopause on beyond-the-horizon propagation phenomena

Field-strength measurements at distances extending far beyond the horizon from a transmitter on a frequency of 91.3Mc/s have been carried out in an aircraft flying at heights of about 10000ft. It is shown that the results obtained and other experimental data can be explained more readily on the assumption that the mechanism of tropospheric propagation over such distances is due to reflections from discrete discontinuity layers in the atmosphere up to the height of the tropopause than by the theory of forward scatter due to turbulence.