I used to have a similar problem. We lived right off of rt. 4 where 84 spills out into Farmington. Lots of distortion from John Dempsey, Avon Mtn etc. Sometimes I would pick up A&I better than I would H&W site. It was as if nothing was being said - ever. Now we're over in Bristol and I just use the H&W site and an SDS100 and I routinely hear more - it really is a night and day difference. One of these days I am going to bring the SDS100 back to where we used to live (by Mrs. Porters) and see how the unit performs. I suspect that I will actually be able to listen to the H&W site from that location and actually hear stuff.
*edit, before the SDS100 I was using a TRX-1, HP2, and 436hp ... out of the bunch the HP2 would tend to hear more and stay on conversations. They're all great scanners mind you, this type of stuff is so highly subjective based on location, weather, what you're scanning. That said, I really like how the SDS100 performs, I love the UI, and how it feels in my hand.