Take a look at cat5/BNC video spec baluns, they may do what you want for a fraction of the price. One at each end of a cat5 link and cheap enough to experiment with.

Maybe something like these but I'm sure you can source locally plus a phono/BNC adaptor. Comms can run over BNC as is.

Meridian owner since 1992
Prime & PSU, Focal Elear headphones, Roon (ROCK 8Gi5 NUC), Explorer 1 & 2, F80. 200/203, various Sonos (via Roon).