Link Power Budgetting
7.Calculation of Downlink path loss
1. Down Link frequency Down link frequency is frequency at which satellite is communicating with ground station. For C band up link frequency is in the order of 4 G Hz , 12 G Hz for Ku band.
2. Downlink path loss Down link path loss depend on up link frequency & distance between satellite and ground station.
'd' is the distance between satellite & ground station
'f' is the frequency of the down link wave
'C' is the velocity of the light = 3 x108 m/Sec
Here f is in Giga hertz
Example : calculate downlink path loss for the satellite located 37000 km far from the earth station and operating 3,950 GHz frequency
Down link loss = 20 log (4pd/(3/10*f)
= 195.73 dB