Okay. Brand new LNB, same problem. I tried switching the input cables on the LNB, but the problem persisted and didn't move to the other receiver. I did trace the line to the receiver with the problem and sure enough there is an inline amp about 60% of the way down the line from the dish. I'll take back the new LNB and try a barrell connector in place of the amp and see how it goes. Of course I have as million of those barrel connectors in my way when I don't need one and can't find one when I do. Have to go back to radio shack to return the LNB anyway so no biggie there.

I'll check back in once I try removing the amp. BTW: I think I understated the length of the run in my first post. After tracing it, it could be closer to 200'