3-YEAR MEASUREMENT BY VSAT SYSTEM AND CCIR ESTIMATION FOR RAIN ATTENUATION IN KU-BAND SATELLITE CHANNEL

The reception level of a round-trip signal from a VSAT (Very Small Ape rture Terminal) was monitored continuously for three years starting Oc tober 1991. For these experimental measurements, a commercial satellit e channel (up-link 14GHz/downlink 12GHz, bandwidth 100kHz) was used an d rainfall was measured simultaneously. Data gathering time interval o f 2 seconds was adopted to elucidate very rapid variation and lower pe rcentage statistics. In this paper, attenuation due to rainfall is sho wn using the data obtained in this three-year period. It is shown that so far, the measured rain attenuation agrees very well with the value s estimated using the CCIR model, and limits the rang where the cumula tive time exceeds 0.01%, even for our VSAT system in Tagajo, Miyagi Pr efecture, Japan.