35-50 Silvers on the E-Trac

What is a 35-50 Silver?

    A 35-50 silver, quite simply, is a silver which shows up, primarily, with a target ID (TID) of 35-45 to 35-50 on the E-Trac. More abstractly, it is my term for a silver (or any conductive target, really), that is so difficult to detect that the E-Trac TID system fails, and gives you mostly a 35-50, cause it doesn't know what else to do.

    I use this term alot on the forums, so I figured I'd write up an article about what I mean when I say that, and hopefully help you find some.

    Really, what it comes down to is this. The E-Trac's TID at depth is awesome; no machine I have ever used is even in the same ballpark. But no machine is perfect; even the E-Trac will fail to identify really deep, small targets (like deep silver dimes, especially on their side, for example), accurately, all of the time. If you were writing the software (and I've written millions of lines of code in my life), what would you do with something like this? Throw up a random TID, or drop an unknown on the boundary? I don't know what the Minelab engineers did, but I'd print "unknown", or something like VDI +95 as the DFX does (a boundary); perhaps the E-Trac software prints 35-50 (a boundary).

    I don't know. What I do know is that silvers can print at 35-50, cause I've dug 'em, and here is how I try to sniff 'em out.

The QuickMask Mistake

    (First, note the language above. I hedge by saying "mostly 35-50", or words to that effect. That means an occasional bounce out of that zone. I'll clarify more on that later. The distinction matters only for my technique, which is somewhat lazy, and a more "all metal mode" (AMM) technique, which requires more work).

    If you are like most E-Trac'ers running multi tone conductive (this article makes less sense for TTF; its more for hunted out parks), you run a screen where the top 2/3s is white, and the bottom third is black, with a cutoff at FE 27 or so (and if you don't, you should consider it). With this, you run an entirely white QuickMask.

    When you get a chirp or beep, which may or may not be a desirable, non-ferrous target, could be a ferrous target, you hit QuickMask for a second opinion. QuickMask shows you an FE of 35 most of the time, you say ferrous, and move on.

    Mistake. These can be 35-50 silvers. They are usually ferrous, but they can be silvers. Remember, it is simply a function of TID failing.

How Do You Tell?

    You can't, for sure. But you can increase the odds, without having to dig everything. (Contrary to popular opinion, "dig everything" is a really bad idea, IMHO). Here's what I do.

    First, I run with "sizing pinpointing". This is not the default, but I think it helps.

    Then, if all the following are true, I consider that it may be a 35-50 silver, and dig it.

    • It is very deep.
    • It pinpoints without a hassle.
    • It pinpoints with coin size and shape.
    • It bounces to a low FE number about 5% of the time, lives at 35-45 to 35-50 the rest of the time.

    This will still be ferrous most of the time. There is no free lunch here. But, you'd be surprised how often it will be silver (often a deep dime on its side). My estimates, if all the rules are true, are that these are conductive targets (sometimes wheaties or even clad, unfortunately), about 35% of the time.

Breaking it Down

    First, it has to be deep. If you are getting an FE of 35 on a shallow target, it is generally iron. The premise here is failure of TID, and the E-Trac just doesn't fail that often on shallow targets.

    Second, the pinpointing is where the rubber meets the road here. Nails pinpoint with a hassle cause the motion (discrimination mode) sees the high chirp you hear projecting off the end of the nail, while the pinpoint mode (AMM) is seeing the whole nail. So, it pinpoints in a different place than where you think it should based on the chirp, and it feels like a hassle. Moreover, sizing pinpointing will often give away the shape of a nail. If it doesn't pinpoint easily with the size and shape of a coin (just a small boop right where you think), it likely isn't a coin. These can still read 35-50. (Exception: (and this stuff can be hard and take a bit of experience), coins on their side will project out a bit from the coin, and can pinpoint a bit awkwardly; sometimes an article simply can't substitute for experience).

    Bottom line, if its deep, but pinpoints bigger than a coin, and reads FE of 35, its iron, unless its a really deep silver dollar or something. I guess you never can really know.

    Finally, its the bounce. I like to see that bounce 5% of the time out of 35-50 into a lower FE (20 or so will do it, but the lower and more often, the better). Deep silver coins like to bounce on the FE number. And the tone of the bounce will sometimes give it away. Every one of these I've dug has had this little bounce, but it can be as low as 5% of the time. Of course, as I alluded to earlier, if it didn't have this bounce, you would never see it in the first place if running as screen with the bottom 3rd black.

    Put another way, if they only bounce 5% of the time, you will miss many of them unless running AMM (all white screen). You can run an all white screen and probably catch more of these if you have more patience than me; in fact, there are probably some that don't bounce at all.

Some More Random Words

    Again, there is no free lunch here. You will still dig iron, mostly small nails. You should not be digging large iron, or even long nails, but unless you are digging small nails, you are not doing it this right.

    This is different from dig it all. Dig it all is a really bad idea. This is an attempt to dig the minimum of bad targets and give a shot at the most good targets. Maybe there is a better way; this is just my approach, and it works out for me. My rule is that I want there to be a 20% or better chance that a target is a silver before digging.

    This is for hunted out parks where pinpointing is possible. At a trashy site with thousands of nails everywhere, I'll bet it would be really hard to sniff out a 35-50 silver. Use TTF and the wiggle method instead. And all bets are off if the target is affected (two different types of targets in the same hole).

    I run deep on, fast off, most of the time, in variable, but usually pretty highly mineralized ground. I know that this affects TID. You may not get these in clean, low mineralized ground or with different settings. As always, YMMV.

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