PSR600 and ST2
When I first got my psr600 I had a lot of intermod from distant radio and tv broadcasts - especially on vhf high
I thought a notch filter would be needed.
I identified the frequencies I wished to scan that were being interfered with and toggled the attenuator on for them.I also adjusted the squelch higher to reduce the occasional junk.
For the most part this has worked for me. There is only one vhf channel that gives me problems now and then -but I can live with it.
For all the other channels I scan the ST2 is doing a great job bringing them in.
Good luck.