As on above picture, on VSAT system, the higher the frequency, the smaller will be the antenna size. Against on it, more impact of rain attenuation suffered by the higher frequency (e.g Ka and Ku band) To mitigate of rain fade attenuation, there are some techniques ; - On Forward Link : Use of DVB S-2 with Adaptive Coding and Modulation Automatic Uplink Power Control (AUPC) - On Return Link : Adaptive Coding Symbol Rate Change Automatic Uplink Power Control (AUPC)
My writing on satcom and vsat, slightly of networking, and small portion of my hobby