The most classical approach of determining rain attenuation for radio-wave frequency has been to theoretically determine the specific attenuation. At frequency over 10？GHz, rain and precipitation can influence the attenuation a lot; the effect of atmospheric attenuation between the source and destination over wireless communication is of major concern and a proper site visit and proper method are required to control the attenuation level so that the performance can be increased. In this paper exponential model has been used to determine the attenuation level for k-region (India) which can be used for region having similar condition. The analyzed predicted attenuation data have been compared with ITU-R measured rain attenuation, and the results will provide useful estimation of rainfall attenuation on microwave links in tropical regions that have similar conditions as (Almora) Uttarakhand region. 1. Introduction Rain causes attenuation in electromagnetic waves through the process absorption and scattering [1]; rainfall attenuation is a phenomenon relative to the rainfall rate and frequency which results in increasing path loss, limiting the coverage area, and consequently degrading the system performance. Rain attenuation model in this paper is modeled from data collected over location from different sources. The effect of absorption is presented at certain frequencies, which can be significant at frequencies near 22？GHz and 60？GHz due to water vapor and oxygen, respectively [2–4]. ITU-R is an organization which standardized the rule for telecommunication and provided a step by step approach for prediction of rain attenuation on any terrestrial radio link; however, this model does not perform well in tropical region [5] and at high rainfall rate since average radius of raindrop in tropical region is greater than that in nontropical and data for ITU model is based on data collected from temperate region of the world [6]. Almora is situated in Uttarakhand region with coordinates at 29.62°N and 79.67°E. It has an average elevation of 1,651 meters (5,417 feet). It is located on a ridge at the southern edge of the Kumaon Hills of the Himalaya range which is surrounded by thick forest of pine and fir trees with average annual temperature of ？3 to 28°C, average summer temperature of 12 to 28°C, humidity of 27%, and 1010？hPa pressure. The aim of this paper, therefore, is to emphasize on difference between measured rain attenuation in tropical Almora, Uttarakhand, India, and ITU-R predictions and results may also be extrapolated for use in tropical regions that
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