tabman,
Using a well made and long buried coin garden gives a hint of detector performance, just like an airtest, but better because the coin or ring is in a soil matrix. I've had a coin garden going on 14 years, I made sure all the coins were silver and laying flat and parallel to the ground surface and at a measured distance. My 8" coin garden dime rings out with a slightly modulated response, but in the real world coins are rarely parallel to the coil, I have found plenty of deep coins and they don't give a perfect signal, sometimes with just a one direction two way coil sweep response as you circle the target. That is because of a masking target nearby and one reason why you grid in different directions on a 'productive' hunting site.
I have had several forum members over to my house to try out different detectors on my coin garden, they have & run all of the top of the line detectors like E-Tracs, Explorers, XT 70, Sovereign GT, XLT, V 3i, XL Pro, IDX Pro. There is one target none of them could find, a Buffalo nickel with medium sized iron off to the side, it was invisble to those detectors, even the IDX Pro which is no slouch in the iron. Yet, all of my Tesoro detectors 'nail' this Buffalo nickel from any direction. Does this prove anything? Nope, because it is not a "real world" test.
