RAIN FADES ON LOW ELEVATION ANGLE EARTH-SATELLITE PATHS - COMPARATIVE-ASSESSMENT OF THE AUSTIN, TEXAS, 11.2-GHZ EXPERIMENT

Several hundred station years of rain attenuation measurements on eart h-space paths have been accumulated in the literature and were used to derive and test the CCIR fade prediction model. Only a few years of d ata are available for low elevation angle paths, however, and these sh ow a consistent tendency of the model to under-predict rain fades. We contribute four years of 11.2-GHz measurements to the data base, taken on a 5.8-degrees elevation path in Austin, Texas, and assess higher t han predicted fade results with respect to earlier measurements and th e CCIR model. At the fiducial 0.01 percent of time, the rainfall rate was 73 mm/h and the attenuation exceeded the 25 dB measurement fade ma rgin. The monthly variability of rainfall rates and dB fades follows a normal distribution. Durations of rainfall and fades are classified i nto events, episodes, inter-event gaps (longer than 4.2 h) and interep isode gaps (shorter than 4.2 h). Rainfall inter-event gaps and event d urations, as well as fade event, episode, and gap durations are lognor mally distributed.