Thanks Robert and Martin.
Yes, it make sense to explain the whole (future) plans:
1st i just will try SSB and small-band ATV ( SGLABS 20 watt amplifier already ordered). Maybe a preamp is not necessary.
I will use the LIMESDR USB (ext.clock available on it) but maybe the Adalm-Pluto is an option but that is the B version so no ext clock.
Also i have the minitiouner express for receive. So enough options to play with.
I think the LIMESDR USB will be it.
Next step would be wide-band ATV. I have a full spectrian SSPA from pyrjoseph but need some work to complete.
Therefore i need a Poty with N connector for that high power when i choose a Poty.
I'm not sure what would be the best for these 2 situations. Poty or helical for TX.
Also at some far future moment i will use these dish for other birds and eventually EME but that's a complete different story.
Regarding which TCXO LNB:
Buying a bias T from a other source is not big deal but the TCXO with only 1 ppm (i overlook that) is more important than the frequency offset because sdr console will deal with that. So would also go for the qro.cz (wiht helical or Poty?)
I also could change the LNB head if desirable for a specific mode.
So that's my whole story.
I will be happy for any advise on this.
Thanks again, Ben 73