Satellite is at 6/4GHz and bandwidth 72MHz. Bellow is the earth station. I have Pt = 200 Watt , Gt=30dB (gain satellite) ,Gr=42dB, Lm=6.7dB( loss other than free space loss) and distance is d=35870km . Earth station temperature is 20 Celsius.
Pt is transmit power Gt is gain transmit (satelitte antenna) Gr is earth antenna gain L loss
S/N of threshold is 15dB after amplifier and i need to calculate the gain of the LNA.
I can calculate Pr receive power but then i am not sure what to do. I cant calculate Teff(effective system temperature) as i dont have noise temperature of transmition line or filter. Also i dont know what has earth station temperature has to do with the system. S/N or C/N should be the same as i know but this really confuses me. All formulas calculate system temperature but i havent found how to calculate when it is between.