General purpose satellite link budget

Tooway link budget - out link

Information about the Tooway network

Tooway in the UK

Explanation of satellite links

Tooway and KaSat technical

VSAT remote site transmitting

Uplink freq GHz
Uplink TX antenna diameter m
Uplink antenna transmit gain dBi
Uplink antenna, power at the feed W
Uplink EIRP dBW
Range (35778 - 41679) km
Uplink path loss dB
Uplink pfd at satellite dBW/m^2
Bandwidth customer beam Hz
Satellite uplink G/T dB/K
Uplink C/N dB

Downlink frequency GHz
Downlink receive antenna diameter m
Downlink system noise temperature (antenna + LNA) K
Downlink receive antenna gain dBi
Downlink bandwidth (from five customer beams)
Downlink receive antenna G/T dB/K
Downlink satellite EIRP dBW
Downlink path loss dB
Downlink C/N dB
Uplink C/interference dB
Uplink C/N dB
Satellite C/intermod dB
Downlink C/N dB
Downlink C/interference dB
Total link C/N dB

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.

Last Revision: 23 June 2021