Tooway Return Link Budget
Return link from remote customer VSAT sites to a gateway hub.
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.
Any problems or comments please e-mail Eric Johnston
Copyright 23 Feb 2012 Satellite Signals Ltd All Rights Reserved