Rain Attenuation at 10-30 GHz Along Earth-Space Paths: Elevation Angle, Frequency, Seasonal, and Diurnal Effects

Three experimental programs at Bell Laboratories, Crawford Hill, NJ, have collected rain attenuation data at three frequencies in the 10-30 GHz range for over 2 years. As expected from a simple geometrical model, rain attenuation statistics scale approximately as the cosecant of the path elevation angle. Thus, greater attenuation is encountered on lower elevation angle paths. The increased rain attenuation at higher frequencies is illustrated by comparing cumulative rain attenuation distributions at three widely separated frequencies. Typical year-to-year variations in these distributions are presented. Periods of severe rain attenuation are shown to occur more frequently during the summer months and during the afternoon hours. Cumulative attenuation distributions are compared for these and other time periods.