A buddy found a notch filter made by Stridsberg that is about -20 dB at 150 MHz. It's the FLT225 (
Receive Filters, FM Notch and High Pass models). I'll lose a lot at 225 MHz and below, but most of those frequencies are rural agencies that I rarely need (although I'm sure after I install the filter, something big will happen and I'll need those frequencies again). I haven't been able to find a better filter than that one, unless I order a custom-made filter. It wouldn't hurt to use a 2-meter filter on my scanner since I also use an ID-800H about 10 inches away from the scanner as well, though I rarely run that at it's full power, 50w.
I don't think I will be running APRS at 75w anymore, I am thinking about replacing the IC-V8000 with a Kenwood D710A. Either way, I am considering using an Antenex ETRAB1440 phantom "shark fin" antenna. I will probably install this on the roof, either directly in the center or as forward as possible near the windshield. However the max power rating on that antenna looks like 60w, but if I am using a TM-D710A that won't be a problem.
Any thoughts?