I should of been a little clearer in my previous statement in that the deeper the coin the lower the reading you'll get. I have never dug a coin in the iron range but I have coins in my test bed that are 8 or so inches down and they read as iffy iron targets.
Coins for the most part will give a good repeatable signal in an X sweep.
A copper penny will read 71 -72 if it’s 2-3 inches down where as that same coin will read lower in the zinc range if it’s 5-6 inches deep. Same is true for quarters, dimes and nickels.
Nickels are my favorite because they will bounce between 29 and 32 close to the surface and will bounce as low as 27 -32 if their deeper. That’s how you know if it’s a nickel and not a pull tab because pull tabs don’t bounce around they will lock onto 1 or 2 numbers. Beaver tail pull tabs being the exception I mistake them every time for nickels, but if your finding those than silver is not far behind.
As you become familiar with the F2 you’ll find it offers a lot of information by listening to the quality of the signals and comparing that against the numbers it’s producing and looking at that little depth meter on the right. I have found that depth meter to be more accurate than the depth read out during pin pointing. Think of the first block as the 0-2” and the second block as 2-4” and the third block to be below 4”.
Another little trick is say you have iron, foil and tabs notched out and you hit a target that sounds good and it reads in the dime - quarter range and the meter has all 3 blocks blacked out, but on one sweep the signal drops out and you get a queer reading on the numbers. I will turn the power off and back on so you’ll have nothing notched out (that’s faster than un-notching everything) and sweep the target again and you’ll find it’s hitting iron quite a lot. Guess what it’s a good size piece of very rusted iron.
Sometimes it will sound really good and the numbers will be crazy, that’s when I have found some really good stuff like tokens, brooches, knifes, etc.
The only drawback to the F2 is its lack of ground balance. I feel that’s what limits it depth, but you can rest easy knowing 90% of the coins are going to be within its reach.