Scintillation effects at 4 and 6 GHz on a line-of-sight microwave link

Midday measurements of 4- and 6-GHz radio signals which have propagated over a common 26.4-mi path indicate that the scintillation amplitude is normally distributed in dB with a standard deviation in the range of 0.2 to 0.5 dB. Attempts to determine the frequency dependence of these amplitude statistics were confounded by nonstationarity of the propagating media and signal level, the appearance of additional loss mechanisms, and by a nonuniform data recording rate. The tentative indication is that the amplitude fluctuations do increase slightly with increasing frequency in these microwave bands.