Frank,
I agree with Randy. The digital mode identifies nickels quite well.
I hunt almost exclusively using the smart screen. What I have done is to cover the screen with the "Palm Zire 71" screen protector (to prevent scratches on the screen). Then, I run a nickel past the coil and place a dot on the screen where the nickel hits. When hunting and the cursor lands on the dot, then it is most likely a nickel. But, keep in mind, that the target response becomes less reliable as the ground mineralization increases, the target gets deeper, or there are multiple targets under the coil.
HH,
Glenn
