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4.Calculation of  uplink to noise ratio
 1.Up link rain attenuation (dB)    Rain fall results in attenuation of radio waves by scattering , and by absorption , of energy from the wave. Rain attenuation increases with increasing frequency and in worse at Ku band compared to C band. Studies have shown that the rain attenuation for horizontal polarization is considerably greater than for vertical polarization.

2.Satellite G/T (dB/k)    G/T ratio indicates figure of merit.  G/T ratio is the ratio of gain of the satellite to the thermal noise temperature of the satellite. G/T ratio depends on the satellite components. 

3.Uplink C/No(dB Hz)      The up link of a satellite circuit is the link in which the earth station is transmitting the signal and  the satellite is receiving it .
Carrier to noise ratio of up link is given as
                            [C/No]U = [EIRP]U + [G/T]U - [losses] U + 228.6
                                           =Transmitter EIRP- (Up link path losses + Up link rain attenuation) + Satellite G/T  + 228.6…………(dB)………………………..[6] 

Example : calculate power rating of ground transmitter operating at following conditions Transmitter EIRP37.97 dB W, Up link rain attenuation-0.0 dB, Up link path loss 199.62 dB, satellite G/T(dB/K)-5.00
Solution:
                            [C/No]U = 37.97 –5.00-199.92+228.6
                                          =  61.65 dB

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