I agree with bgsco. I made a test garden this spring along the side of my house, and at first I couldn't hit any of the coins measured out 8 inches or deeper. The shallower stuff, no problem.
A couple weeks ago, after a thunderstorm, I tried again with the new pro coil. I have a silver dime between 8-9 inches, that would barely hit and bounced all around the smartfind. And I have a buffalo nickle at 8-9 inches that rides up/down the the right side of the smartfind? Both targets didn't sound that good either.
And the sickest one....I have a corroded indian head slug at around 10inches, that hits almost solid iron. I couldn't get it to pull to the right. (But it didn't hit totally tight top left corner, and bounced around)
I was running 23 manual sensitivity with the screen wide open, bumping it up didn't seem to make the signals improve, just made the machine more jumpy. I was at park later that day and was hitting wheats at 8-9 inches w/solid coin ID, no problem at all.
I tried the test garden a few days later with my tesoro tigershark, which also couldn't hit the deep stuff. Then tried the SE, and I guess since the moisture was gone, all was quiet again.
Dream