Depth of targets

[I Detect Metal]

I read so much about how deep peoples finds turn out to be. My question is:...is that from below the actual surface of the top of the ground, or the depth in relation to the bottom of the swinging coil. I know that I have been in parks where the grass is 2" high and add at least an inch for the bottom of the coil to swing over the top of the grass.....Taking all that into consideration, my avg deepest finds are around 4" from the top of the ground, which would mean that I am finding them at around 7" down??

[Captain Silver]

I wore out the bottom of my coil keeping it to the soil. 7" deep means 7" below the actual surface...Keeping the coil 3" above the ground means you'll be digging mostly clad at 4" or less...