New to linear satellite operations and getting mixed advice about power levels. I understand the basic concept that transponder has limited output power and high power signals reduce downlink power available to other users, but looking for practical guidance.

What's considered appropriate EIRP for different satellites? Seeing recommendations from 5W to 25W EIRP depending on the bird. Also confused about SSB and CW operation through the 20-50 KHz transponder bandwidth - do I need to worry about adjacent channel interference like on HF?

Running FT-847 with home-brew 10el on 435 and commercial yagi on 145.

Great question! 5 watts to 7 dBi antenna (25W EIRP) is typically max recommended, but lower power works well too. Start low and only increase if you can't hear yourself clearly on the downlink.

The power sharing aspect is critical - I've seen guys running 100W completely stomp on everyone else in the passband. Your setup should be plenty with 10-25W EIRP. Listen first, use minimum power needed.

Adjacent channel isn't really a concern within the transponder passband since it accepts FM, CW, SSB, SSTV, PSK, and packet simultaneously. The bigger issue is AGC - strong signals suppress weak ones across the entire transponder.