Tooway Return Link Budget

Return link from remote customer VSAT sites to a gateway hub.

Assumptions:

Uplink from customer to satellite (bw=236MHz):

The return link, per customer beam, assumed to comprise, or equivalent, 78 carriers each occupying 3 MHz, total 236 MHz (half of 29.5-30 GHz). Note up to  max 78 customers operating simultaneously.

Return link customer HPA is rated 3 watts and operated at 2 watts. 78 x 2 = 156 watts.

Uplink satellite G/T assumed to be (-3 dB contour) +50.6dBi - 3 - 10 log (400) = 21.5 dBK

Downlink to gateway hub (bw=1180MHz):

Total bandwidth out of (18.38-19.7 GHz) as 5 transponders x 236 MHz merged together into 130W TWTA.

Assuming satellite output amplifier operated at 130W per 1180 MHz

Operating EIRP towards the gateway hub site (-2 dB contour)  = (130W + 50.6 -2 dBi) =69.7 dBW

The input figures are all guesses and estimates.  You need to overwrite the figures with your own assumptions.

Amend any white boxes and then click the calculate button to obtain results in the green boxes.

Suggest trying 50W TWTs for satellite to hub.