it a cool idea in concept but is no better than an air test, aged coins in the ground ( aged test garden) give a much truer reading because of the dirt actually being around the coin
Did you watch the whole vid, DP? That is what he's doing. He hasn't filled it yet. BTW, I am joining the ATP crew next week partly because of posts like yours about it
I would think this is somewhat worth doing though because the dirt will make a difference. Much like how a small nugget will show up on the Ace 250, but put it on the dirt and it disappears.