I am trying to use Pat on a Raspi with Pactor. Everything appears to work fine. Pat sets the right frequency, and the modem (PTC-IIex) indicates that it uses Pactor. However, it does this only for the first connection attempt. For any further connection attempts the modem does not show any mode, although it does modulate the transceiver. I don't know what it transmits, though.
I use a Raspi 3B with Bullseye and Pat v0.13.0