Tom; I had the same problem you described, it went on for quite a while. I contacted Moore, sent the probe back etc.,ect.,etc. What I finally found was that the coaxial cable that runs from the antena to the dial had bad connections. The center conductor was never soldered even though it looked like it was (cold solder joint) both ends of the cable had the same problem. To solve the problem you can pick up a new coax cable at an electronics store. You may have a problem finding one long enough, but you can put a couple of them together, (will need to buy a small connector to join them). I think the longest ones I could find were 15 foot. This solved my problem, the unit has been working great for the last two years..