and this is what I have found:
Current nickel at 6" deep = The 3d will not hit on it in enhance mode. It will ever so often intermitantly beep, but not constant and the 3d meter will jump from pulltab, foil. This is with sensitivity at 4 and with descriminate at 1. If I move descriminate up to 2 or three, it will not hit it at all. This is with a low - mid tone bounce and every now and then a high tone, but rarely.
1937 Buff nickel at 6" = The 3d will not hit on it in ehnace mode unless I drop descriminate down to 1 or zero, Then the 3d will give a low to mid tone & bounce from beavertail to foil or square pulltab.
Now, in salt mode, the 3d will hit both nickels with a high tone and register as nickel on the meter.
But in enhanced mode, in order for a nickel to even register, I would have to run zero descrimination and even then, nickels would be low to mid tone, and I probably wouldn't dig them anyway especially if the meter shows pulltab & I'm in an area where there are a lot of pulltabs.
I sent Fisher a email to see what they have to say about. But right now, I don't see how this detector would be good in an older site if nickels are hitting in low-mid tone.
Thanks,
Mike