I've been testing the replacement unit for several days now. I did manage to bork the f/w with the 5-23 release - it may have been related to the attached computer going to sleep because I forgot to plug it in to shore power, lol. Anyway, the radio would drop the connection then re-establish it every 30 seconds or so. Reycling power on both the laptop and P25RX-II did not help. Also, the talk groups that were discovered and I labeled were lost, replaced by garbage characters that continued to repopulate even after erasing the bad data. Reflashing with a later firmware fixed the issue.
I took the radio on the road yesterday to monitor several "foreign" P25 systems (Montgomery County MD and Howard County MD) to see how it would do. I did notice that when stationary, the radio produced very good audio with few artifacts, but when moving the radio did produce some warbles and garbles. RSSI was very good, generally in the -80's. I noticed that when moving, the Total Gains line was flat but not well defined, but when stationary, the line was flat and sharp. Screenshots are attached.