The thread on sweep speed and a mention of air testing in it made me think of this. I know I'm not the only one who experiences this because I've heard others talk of it. 100% of my hunting is at ocean (salt) beach, so I don't know if this occurs elsewhere. Very often I will be digging (w/ sand scoop) a target. I'll scoop, scan the hole, and if the signal is still there, I then dump my sand to the side and repeat the process. Once I scan the hole and get no signal (suggesting the target is in the scoop), I dump and spread my scoop full. Usually the target is in the spread and all I do is scoop up the signalling section, sift to retrieve the target, fill the hole and move along my way. Many times though, I will dump, spread, and scan but get no signal. One more scoop out of the hole and the target is usually there. It happens like this so often I can almost expect it to be in this next scoop, with little to no doubt. The only thing I can guess is that everytime this happens it is because the target is on edge. I've never air tested targets on edge, but I find it hard to believe that the coil wouldn't pick up, for example, a zinc penny on edge 1-2" deep? Does anyone have any insight into this mystery?