The Study of Rain Specific Attenuation for the Prediction of Satellite Propagation in Malaysia
Specific attenuation is the fundamental quantity in the calculation of rain attenuation for terrestrial path and slant paths representing as rain attenuation per unit distance (dB/km). Specific attenuation is an important element in developing the predicted rain attenuation model. This paper deals with the empirical determination of the power law coefficients which allow calculating the specific attenuation in dB/km from the knowledge of the rain rate in mm/h. The main purpose of the paper is to obtain the coefficients of k and α of power law relationship between specific attenuation. Three years (from 1st January 2006 until 31st December 2008) rain gauge and beacon data taken from USM, Nibong Tebal have been used to do the empirical procedure analysis of rain specific attenuation. The data presented are semi-empirical in nature. A year-to-year variation of the coefficients has been indicated and the empirical measured data was compared with ITU-R provided regression coefficient. The result indicated that the USM empirical measured data was significantly vary from ITU-R predicted value. Hence, ITU-R recommendation for regression coefficients of rain specific attenuation is not suitable for predicting rain attenuation at Malaysia.
KeywordsRain specific attenuation Rain rate Effective path length
The authors are grateful to Electrical and Electronic School of USM Engineering Campus for technical support. I would like to acknowledge Institute of Graduate Studies (IPS Fellowship) -USM and Research University Postgraduate Research Grant Scheme (USM-RU-PGRS). The work reported here would have not been possible without the grants from Universiti Sains Malaysia. The authors would like to express sincere thanks to the reviewers whose comments helped to improve the original version of this article.
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