I got some great footage of some coins in iron and here is one of them. Less than 3 minutes long.
Here I dug a smaller coin in fairly heavy iron at 8. You can really see the Fe numbers CONSISTENTLY stay down, at least from one angle. Don't pass up those Fe numbers in the 20's - investigate them from different angles. Also, I try out TTF and it really improved the signal - it gave a more consistent high tone and yet showed the iron right next to the target. Clearly the iron (and not iron mineralization) was pulling the numbers down, as you can see from the wide pinpoint imo.)
Considering that this coin was in heavier iron than most that I have dug and that TTF gave a better signal, I am now looking at TTF with new appreciation. I was afraid of missing deeper coins in TTF due to the lower Fe numbers but that wasn't true here. Also, the pinpoint was totally thrown off by the iron (and perhaps trash) so be careful with pinpoint or even quick mask dropping Fe numbers (due to iron).
I edited this to be educational, so there is a fair amount of subtitles to point out some observations. I truly got a lot out this myself from watching and listening again.
Enjoy,
EMS
ps - watch it in fullscreen at 480 resolution.
E-Trac - Coins in Iron I