Hey Michael,
I am not a pro, but I'm gonna tell you something anyway.
When I have my sensitivity turned up high (like 27 manual), I notice I get high-pitched falsing when my coil goes towards or is pulled away from the ground. This also happens when I am detecting uneven ground like you are. When I go over a hole, I get a false. When I go over a high area, I get a false. So it seems like if the ground is moving vertically relative to the coil, I get a false signal. When I turn my sensitivity down, this minimizes falsing.
Even though I get high-pitched falsing, I know that none of the coins I have ever found sound like that. I use Mike Moutray settings, iron mask -15, and conductive sounds. In these settings, my machine makes a pitch that is way too high to be silver whenever the falsing effect occurrs. So I just ignore the super high pitches. I am not bothered by these signals because they don't sound like coins in these settings. But in Ferrous tones, falsing confuses me because I am not familiar with the sounds.
So if you are using Conductive sounds, you can eliminate falsing confusion by carrying a silver quarter with you. Compare the silver quarter sound to the possible false tone. After a while, you will be able to identify tones that are too high to be silver due to elevation changes between the coil and the ground. If you are using Ferrous sounds, I don't know what to tell you.
Mike
