If you start to feel like the machine is not registering good targets just GB again. Its so easy on the NOX to noise cancel and ground balance. I will manually ground balance a few times just to check during a hunt. The dirt in New Orleans is a little wonky with the sticky gray clay. One other thing that I noticed when ground balancing is that when the number jumps up to 80 or higher there is usually a mistake or something off. I reground balance a few feet away over a clean spot and it always adjusts down to a better level.