Hi Tony, I dig very very few nails(at least ones that I dont think are), and the sites I hunt are loaded with them.. After a while you can tell in either mode what a nail sounds like and a good target sounds like, they really are not the same. Its pretty hard to explain the difference, but the easiest way I can is, does the target seem to be trying to be more positive or more negative. in other words does it sound like its trying to null more than its trying to come through positive.. Some bent nails still fool me,but even on those I dont have high hopes. sometimes in my pounded sites where I get less picky I dig the iffy ones I think are nails or iron, and so far I havent got many pleasant suprises so it can be done even in conductive audio, but like others said ferrous makes it much easier. Just keep digging anything that your not sure on as thats the way you learn,, pretty soon you wont feel that your missing anything by passing up the ones you get your ear tuned to be definately bad.. Iron definately has a different tonal quality to it, but there are some times its too close to call so ya gotta do it.. I know one thing if you dont ever dig iron your definately passing some good stuff, but you can get it down where you dig very little unless you want to.. Never hurts to dig some anyway just to clear it out of a site, at least one that you hunt often and can dig as many holes as you want to.. Iron hides stuff pretty good.. I have quite a few sites so iron filled I know theres lots of good stuff hiding under it, its just a matter of how much you want to clear out.. One site I have if you take a trowel of dirt you will have anywhere from 6 to 10 nails in the dirt.. that place you can set a dime on top of the ground and not pick it up with any machine I have tried, but its impractable to dig it all out of the way.. Prime site too 1700's cellar hole and these nails and rusted away tin surround the hole for about 15 feet out from it.. one of these days I will take a sifter to it. As to your question about the probe, you should be able to judge how deep the target sounds, either by ear or using the meter. if your digging an iffy iron hit, take a deep plug and stick the probe in. iron will null and if you get falsing type tones, throw it in pinpoint and see where its pinpoints.. the probe hardly every false rght over the target, but off to a sides and null solid over the target.. if its doing that then its iron, fill in the hole and move on, or dig it out and get rid of it...
