I have what I believe to be similar problems with my PSR-500 as well. I also use a PAR filter because of my hostile RF environment (in my case, a farm of powerhouse TV and FM transmitters a few miles to the northeast of me), I never considered the possibility of my ethernet setup causing me trouble though - I'll have to do some experimentation one of these days when I have the time.
I have decided, like all purpose-built tools, that it is good for certain things and not so good for others. 800MHz and UHF trunking seem to be what this unit excels at, VHF can be a little rough unless I'm well outside of the metro area. Air band is virtually useless and I usually find myself grabbing my Pro-97 if I want to listen to that as it seems to perform marginally better (My clunky old Pro-2006 is the real winner for this at home).
I have good days and bad days with the local P25 system, so much that I was considering the Uniden 396XT for a minute. However, after reading the Uniden forum it seems like users are having some similar frustrations with that particular unit. I'll probably just keep on keepin' on for now, I just wish it could be better.
I can only wish that someone would make a scanner this awesome, but with the selectivity of the venerable old Pro-2006.
