Would a satellite positioned at Earth Moon L2 be stable enough? It would also need a relay to communicate with earth…

RFSoCs seem like extreme overkill for this frequency range, though since Xiphos makes a space-grade one, it's not so unreasonable I guess.

Alas, I'm working on a competing project that I won't go into detail about :).

s/dark side/far side/

You're generally correct, but in this particular instance it does actually make sense to call it the dark side. Dark, as in "quiet" from RF interference. Just like some areas on Earth, near radio observatories, are declared "dark" (i.e. everyone tries to avoid using high RF emitting stuff in these regions, even comms satellites avoid it).

> even comms satellites avoid it.

If only ... Starlink is nominally "off' over the RQZ in W.Australia, but still leaking interference from not fully shielded electronics.

Starlink Coverage holes (3 years ago) - https://old.reddit.com/r/Starlink/comments/ymm6rv/starlink_c...

(July 2025) Starlink satellites disrupting astronomy research in WA's Murchison, study finds - https://www.abc.net.au/news/2025-07-25/starlink-satellites-d...

Dark side of the moon = the side opposite the sun, doesn't change here

It's only facing away from earth, it can face the sun just fine. Rotation is every 4 weeks.