Scintillation fading on a low elevation angle satellite path: assessing the Austin experiment at 11.2 GHz

Since June 1988, the University of Texas at Austin has been observing an 11.2 GHz INTELSAT satellite beacon with an elevation angle of only 5.8°. Based on 48 continuous months of observations it was found that: (1) scintillations on a low elevation angle path are pervasive; excluding the 2.41% of the time with rain fading, 10 dB peak-to-peak variations were observed at the 0.01 time percentage; (2) separation of scintillation and rain fading by filtering can be accomplished, however the fastest changes in precipitation fading overlap with slowest (low-amplitude) scintillations; (3) scintillations exhibit both diurnal and seasonal periodicity; (4) the method of CCIR Report 564 predicts monthly scintillations based on monthly wet refractivity with adequate accuracy; (5) the power spectrum of the logarithmic amplitude variations has three distinct regions with different slopes, of which only the high frequency part above 0.1 Hz is in agreement with turbulence theory; and (6) the variability of the average hourly standard deviation can be expressed with a gamma or lognormal density function