The winter weather broke in my area so I was able to get out and do some testing with my Smart. I buried a nickel at 11" in my ground. When I ground balance, it balances at 1:00, which is a little in the red zone. Not exactly sure how mineralized this would be. Useing the 11"x 7 1/2" coil, useing boost, disc. at 11:00. I get a fairly repeatable signal in 2 tone, although I get a combination ferrous-high tone some times. If I switch to all metal I am able to get a solid signal, even raiseing the coil above the ground about 1". Put the 10 1/2" round coil on with all the same settings. In 2 tone, I could get a more solid signal, with less ferrous tone bleeding thru. When switching to all metal, I could get a solid signal at least 4" above the ground. What does this all tell me? That I wish they would build a 13" to 15" round coil, so I could get that much needed extra depth when I am relic hunting. If the amount of iron in the ground becomes too much, I could always pull out one of the smaller coils designed for the Smart. Also if you happen to be hunting a location with taller grass. It would be worth hunting in all metal to locate your targets. Then switch to one of the discriminate modes after stomping the grass down to check if the target is good. Because of the increased air-gap depth in all metal you will hear signals that you wouldn't in disc. Just my winter ramblings. Mark