Actually, I'm in Aurora. I have found targets at deeper depths, but hardly any coins deeper than 6". Yeah, that would be great! I usually hunt the parks and older schools in metro Denver, but can come up northwest and cross check our two machines.
I have an area set up to do a coin depth test.
You're welcome to participate in it. I hope we get over this artic blast hitting Colorado right now soon, so I can go back and do the test
I found a pull tab and an aluminum thin lid part of the pull tab that was probably out of an oil additive for engines that was 8.5" inches in the ground and my AT Pro detected it with no problem, my Garrett trowel tool was 3/4 of the way deep into the hole.
It was giving me double tones so I knew there were at least two items underground.
As it turned out the pull tab eas at arounf 6" deel and the lid was at 8.5".
The lid measured 3" in diameter. I know it's way bigger than a coin, but knowing it goes deep on large objects it's refreshing. I have no doubt it would've detected it a little deeper
I'm going to use the same hole to bury a coin 10" deep and test both of my coils over it
I'm just as eager as anybody else to run a depth coin test with my AT Pro both with the stock 8.5x11" stock coil and my new NEL Hunter Coil measuring 8.5x12.5"
My set up for these findings, including a 1990 US Quarter in the same area was:
Pro Mode zero
Iron discrimination at 30
Ground Balance at 80. Ran smooth, quiet and it only gave tones on actual metal, ferrous or non-ferrous. No false tones...
Sensitivity all the way up.
Hope this helps...