Cal_Cobra Posted May 13, 2020 Share Posted May 13, 2020 I thought this was interesting. I've noticed that a U.S. silver dime will TID spot on at 25 when either air testing or when at shallow depths. BUT as the coin gets deeper, the TID goes up. I've seen anywhere from 27-32, the deeper the higher. This phenomenon along with the additional modulated audio at depth, and frequently loss of pinpointing, will almost always result in a deep (9" or deeper) squeaker silver coin for me. Once I understood this pattern, I'm personally okay with that, I actually even prefer it that way because when I get a target with these conditions I have a fairly high confidence it's going to be a silver coin at good depth (I've observed similar results on deep silver quarters as well). Are others observing the same phenomenon? Disclaimer: Almost all of my hunt time (none lately due to C-19 SIP restrictions) is dedicated to relic hunting environs. 3 Link to comment Share on other sites More sharing options...
Dan(NM) Posted May 14, 2020 Share Posted May 14, 2020 43 minutes ago, Cal_Cobra said: I thought this was interesting. I've noticed that a U.S. silver dime will TID spot on at 25 when either air testing or when at shallow depths. BUT as the coin gets deeper, the TID goes up. I've seen anywhere from 27-32, the deeper the higher. This phenomenon along with the additional modulated audio at depth, and frequently loss of pinpointing, will almost always result in a deep (9" or deeper) squeaker silver coin for me. Once I understood this pattern, I'm personally okay with that, I actually even prefer it that way because when I get a target with these conditions I have a fairly high confidence it's going to be a silver coin at good depth (I've observed similar results on deep silver quarters as well). Are others observing the same phenomenon? Disclaimer: Almost all of my hunt time (none lately due to C-19 SIP restrictions) is dedicated to relic hunting environs. I've come across this on deep, at the fringe of detection targets, not just coins. I've dug 3 ringers over 9" that registered between 33-38 at an 1850 fort site. The first time it happened I was quite surprised to see a piece of lead read so high. The first time it happened was on a 9.5" silver dime using the 15" coil, my first thought was I was about to dig a rusty nail. 1 Link to comment Share on other sites More sharing options...
Mark Gillespie Posted May 14, 2020 Share Posted May 14, 2020 I've noticed the same thing with deep copper pennies and also dimes and quarters. To me that is a good thing. I remember a few times when I knew it was going to be a deep quarter but it turned out to be a deep dime. But, I'm good with up averaging with depth. I'm very happy with my Equinox. 1 Link to comment Share on other sites More sharing options...
Happa54 Posted May 14, 2020 Share Posted May 14, 2020 Last week 2 deep wheats were hitting 39. 1 Link to comment Share on other sites More sharing options...
Hardtimehermit Posted May 14, 2020 Share Posted May 14, 2020 Same for me, i have had quarters, dimes, and pennys fool me with their high tid at depth. 1 Link to comment Share on other sites More sharing options...
Tom Slick Posted May 15, 2020 Share Posted May 15, 2020 I've dug a number of deeper silver dimes that I thought were quarters for sure. I always recheck my holes and have been surprised that there wasn't another dime in there. I much prefer the detector up averages the deeper targets but on a few occasions I've had deep fringe targets read lower than they should. That's just the way it is. We all wanted "deep" detectors and when it seems they had reached their limit, we all wanted "fast" detectors for better separation and target unmasking. I think we'd all love to have a detector that is deep, and fast, with a rock solid, non-wavering, locked on, VDI. No up averaging, no down averaging. Just a good solid repeatable number. Now that would be nice. Link to comment Share on other sites More sharing options...
Seandub Posted May 15, 2020 Share Posted May 15, 2020 I had a merc last week at an inch or less bouncing from 21 - to 24. And I've seen deep wheats (in nice shape) read into the 30's, but usually there's iron close by. Link to comment Share on other sites More sharing options...
GB_Amateur Posted May 16, 2020 Share Posted May 16, 2020 My experience has been different, particularly in my test-stand. (That performs sort of between air test and true long-buried coins.) What I've seen in Park 1, Recovery Speed = 5, Iron Bias F2 = 5 is that the spread in TID's increases but the centroid (or median, or average, different quantities but correlated) stays pretty close to the typical shallow depth / air-test values. That is consistent with what I've seen in the field, although obviously there I have no control as to object depth or orientation let alone nearby conductors. Specifically I'm talking about silver dimes and to a lesser extent, copper alloy pennies. I've not done any testing with USA 'nickels' and in the field I tend to mentally discriminate to TID's which concentrate at 12-13. So if a deeper nickel were to TID at, say, 15 I would conclude it's a pulltab and likely move on. Definitely worth some study. My soil is of moderate mineralization, between 2 and 3 bars on both the Fisher F75 and Fisher Gold Bug Pro. I do agree with others that TID's bleeding upward is way more desirable than downward as items get deeper. The latter is what happens with my F75, unfortunately. 1 Link to comment Share on other sites More sharing options...
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