Title: Estimation of rain induced Specific attenuation
Abstract:This paper describes research on Specific attenuation on a terrestrial microwave communications link set up at Nawandgi-Wadi (Karnataka State), India, which has reported signal failure for a number of...This paper describes research on Specific attenuation on a terrestrial microwave communications link set up at Nawandgi-Wadi (Karnataka State), India, which has reported signal failure for a number of times under rainy conditions, especially during July to September, each year. The clear air and rainy climatic data has been secured from India Meteorological Department, Hyderabad for a comparative analysis with the live data of rainfall recorded with the aid of two tipping bucket gauges, and a disdrometer. A simple model of interpretation of specific attenuation has been utilized with simple formulae to suit the purpose of estimating the rain-induced specific attenuation at the location of the link. The results of this experimentation are in agreement with the disdrometer observations and the data collected through experiment tallies with the Micro Rain Recorded (MRR) data secured from the ISRO-operated-MRR rainfall data secured. The model used in the experimentation, it is hoped, would enable further research in to the aspects of specific attenuation of terrestrial microwave links in different Terrestrial locations of interest. and research for higher frequencies which may be used under tropical conditions in India. The radio frequencies above 20 GHz or millimetre waves in general, due to inherent advantages have a number of applications. The reliability of such a system may be severely degraded due to fading. As such, knowledge of rainfall rate & rain-induced attenuation at the frequency of operation is necessary to design a reliable communication system at a particular location. Rainfall rate and attenuation data are also desired in many important applications including radio link systems, radar systems and remote sensing (3). The current prediction method of ITU-R uses physical as one of the parameters in the estimation of fade on earth to space path but overestimates the attenuation when applied to tropical zones. The method is based on the data collected in temperate climates and assumes the mean related to the of 0°c isotherm (4). Application of this method to tropical region gave unsatisfactory results and led to the concept of effective height. The non-uniform horizontal structure is accounted for, by using rate reduction factor to convert the physical path length to an effective path length. This simple vertical structure assumes that rainfall is uniform from the ground to the rain height Hr. The effective and attenuation can be obtained from the analysis of the data on sky noise temperature and point rainfall intensity. In view of this, it appears that the in tropical regions cannot be easily related to the freezing (0°c isotherm height). It has not yet been possible to find a meteorological parameter to determine the effective accurately.Read More
Publication Year: 2014
Publication Date: 2014-01-01
Language: en
Type: article
Access and Citation
AI Researcher Chatbot
Get quick answers to your questions about the article from our AI researcher chatbot