I don't have a PRO-97, but my solution for this on my other scanners is to set the frequency I want to listen to as "priority", then turn priority on. It will "check" the same frequency periodically, so just a very brief blip in audio when it switches while someone is talking, and it effectively turns off the power save, since with PRI active it wouldn't power down the receiver.
Again, don't know if that will work the same for a 97.