This is not a VDI chart. It just shows where the gold jewelry finds I have at the moment show up on the low to mid conductor part of the Nox 900 target ID scale along with some very common trash and ammo finds from the parks I hunt. I made this chart for me but if it does you any good.....great. These are air test numbers with the target about 3" from the coil. In the ground at the same depth, they have very similar numbers. Why people are always asking for charts like this boggles my mind.