Link Power Budgetting

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/N_o(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/N_o]_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]