Bill, this more or less is the result I achieved by adding a Winegard 18dB preamplifier. I found however using a lossyer balun actually helped because I was getting overloaded by the local UHF stations with my low-loss balun. I'm thinking you may be getting clobbered by locals on Grand Island too. I don't know about your set, but my LG measures signal strength only. So by adding the preamplifier I was increasing signal alright, but also increasing noise and distortion. I actually had a couple of channels with 100% signal that wouldn't raster. This was puzzling for about one day until I started tweaking. My Sony however shows both signal strength and bit error rate, but I didn't have it at the time to figure out what the problem was.

So I guess my point is do some experimentation before you declare the system optimized and don't be afraid to introduce some loss to your antenna system before the preamp.