Alan Applegate
Junior Member
I've been reluctant in publishing this, until I could prove to myself it wasn't a soil conductivity issue or some other esoteric anomaly. In any case, I present it here for what it is worth, but I'd be delighted to hear what others have discovered.
Most of my detecting is with a Garrett GTI-2500. I find it works better than the Ace 250 I gave to my grandson, the AT Pro I borrowed for 6 weeks, or my Fisher 75 which I recently sold.
Most of my local detecting is done in kiddy lots. We're fortunate here, in that Roswell, NM has some 28 city-owned properties where detecting is legal, and even encouraged (even the court house isn't off-limits!). Like most parks which allow picnicking, controlled BBQs, and similar activities, there are a lot of pull tabs encountered, especially the newer two hole ones. They are the ones which most people bend off their soda cans, and heave hither and yon.
Anyone who hunts regularly has discovered the detection signature these two hole tabs generate. As a result, most of us don't dig for what we assume is a pull tab. Based on what I have found, I suspect that's not such a good idea.
If you reset a Garrett GTI series (any of them), the sensitivity is reset to 7 on the indicated scale. When one of the two hole pull tabs is encountered, the scale jumps about. The amount they jump around is somewhat based on which direction they're scanned, as most of us know. But I've discovered something that defies common logic about the sensitivity setting with respect to the signature these two hole pull tabs generate. To wit….
If you increase the sensitivity to 10 on the built in scale, the range of the jumping around decreases! Logic would tell you it should increase! I also discovered that dimes tend to signature like the two hole pull tabs, until the sensitivity gets beyond 9.5 or so! But that's not all!
For some time, I've been able to tell the difference between a copper penny, and a clad one. That's no revelation. However, once the sensitivity is reset higher, the difference on the scale between a copper one, and a clad one diminish! This blurs the distinction to the point, I dig them all!
Since the issue defies logic, I borrowed a Garrett GTI-1350 from a detecting partner. I have discovered that it too exhibits the same anomaly, in that higher sensitivity settings tend to narrow the signature of both pull tabs, and coins. What's more, it doesn't seem to be reliant on soil conditions.
I've sent an email to Garrett about this issue, but to be honest they haven't had time to respond. If any one else has noticed this, I would like to know.
Most of my detecting is with a Garrett GTI-2500. I find it works better than the Ace 250 I gave to my grandson, the AT Pro I borrowed for 6 weeks, or my Fisher 75 which I recently sold.
Most of my local detecting is done in kiddy lots. We're fortunate here, in that Roswell, NM has some 28 city-owned properties where detecting is legal, and even encouraged (even the court house isn't off-limits!). Like most parks which allow picnicking, controlled BBQs, and similar activities, there are a lot of pull tabs encountered, especially the newer two hole ones. They are the ones which most people bend off their soda cans, and heave hither and yon.
Anyone who hunts regularly has discovered the detection signature these two hole tabs generate. As a result, most of us don't dig for what we assume is a pull tab. Based on what I have found, I suspect that's not such a good idea.
If you reset a Garrett GTI series (any of them), the sensitivity is reset to 7 on the indicated scale. When one of the two hole pull tabs is encountered, the scale jumps about. The amount they jump around is somewhat based on which direction they're scanned, as most of us know. But I've discovered something that defies common logic about the sensitivity setting with respect to the signature these two hole pull tabs generate. To wit….
If you increase the sensitivity to 10 on the built in scale, the range of the jumping around decreases! Logic would tell you it should increase! I also discovered that dimes tend to signature like the two hole pull tabs, until the sensitivity gets beyond 9.5 or so! But that's not all!
For some time, I've been able to tell the difference between a copper penny, and a clad one. That's no revelation. However, once the sensitivity is reset higher, the difference on the scale between a copper one, and a clad one diminish! This blurs the distinction to the point, I dig them all!
Since the issue defies logic, I borrowed a Garrett GTI-1350 from a detecting partner. I have discovered that it too exhibits the same anomaly, in that higher sensitivity settings tend to narrow the signature of both pull tabs, and coins. What's more, it doesn't seem to be reliant on soil conditions.
I've sent an email to Garrett about this issue, but to be honest they haven't had time to respond. If any one else has noticed this, I would like to know.
