The aim of the Alphasat TDP#5 experiment is to study the usability of the Ka, Q, V frequency bands in the satellite communication for the exploitation of the larger bandwidth. In frame of contract with ESA, the Budapest University of Technology and Economics, Department of Broadband Infocommunications and Electromagnetic Theory is also participating in this project. My main goal was to check up how to relate the measured signal level of the Ka-(19.7 GHz), Q (39.4 GHz) unmodulated beacon signals to the detected rainfall rate, and how much this rapport can be accorded to the recommendation of the ITU-R.
Based on ITU-R recommendation I calculated the parameters of the signal propagation at specific frequencies and polarizations for the first step. Furthermore, with the equations of the publications I determined how the aberration of the signal level from the nominal depends on the rainfall rate according to ITU-R.
After that, I processed the attenuation and rainfall rate data in daily resolution using MathWorks® Matlab program. I drew the conclusion about why the two values don’t correlate in some cases and chose the convenient days for my calculations. I also compared the rainfall rates observed by the department’s receiver station to those observed by the OMSZ’s receiver stations.
Later I examined the distribution of the attenuation at different rainfall rate. Subsequently I analyze the measured rainfall rate and the estimate rainfall rate based on attenuation and ITU-R recommendation. Thereafter I plot the attenuation data by ITU-R with the estimated ones together. Finally, based on the received attenuation and rainfall rate values, I made our own function and graph just as in the ITU-R recommendation. The results/coefficients obtained with this method was compared with the ones according to ITU-R.
I would like to express my thanks to OMSZ (Országos Meteorológiai Szolgálat) for the support by sharing the rainfall rate data obtained by their receiver station at the “Petőfi híd budai hídfő” for the period examined.