How much power does a commercial station run to its satellites?

[Carl WA1KPD]

Somewhat off topic. Does anyone know about how much power a commercial base station, for  data etc transmits to its satellites? Not the ERP, but the actual transmitter.

Thanks

Carl

/KPD

[W5CEM]

It really is a matter of ERP!  As with all RF systems, it's all about antenna gain.  The large earth stations antennas are in excess of 30-40db of gain and if data is the only thing being uplinked the transmitters can run as little as 1-2 watts.  Many of the sats won't accept an extremely strong signal and the transponder can be shut down.  That can change with cloudy, rainy, skies where the power output is raised to compensate for rain fade. 

Accessing the same satellite for broadcast uplinks, on one vehicle we have a six foot dish, so we usually start with about 30 watts to the antenna...on the same sat, we start with 8 watts if using the 12ft. dish. 

hope this helps...

cleve/W5CEM