COMPARISON OF RAIN ATTENUATION PREDICTION METHODS FOR EARTH-SPACE PATHS OVER NORTHERN INDIA

To identify a suitable attenuation prediction method for the estimatio n of rain attenuation, a comparison of some current attenuation predic tion models is made against radiometrically deduced attenuations at 11 GHz with 10-degrees elevation angle over Delhi and at 13.4 GHz vertic al paths over Delhi, Ranchi and Gulmarg. The results show that Garcia- Lopez's method gives the least r.m.s deviation over the other methods. Also based on the observed values of attenuation, the scaling equatio n of CCIR (1991) method which converts attenuation from 0.01% of time to other percentage is modified and a new equation is presented for th is region.