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Coin And Relic Detecting With The GPX 6000


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 Veery eeenterestig. The same method worked good on the old GPX (4000 on) so this will add some possibilities to the 6000.

 The 6000 has gone from the latest/greatest to fantastic to miracle but I'm still not buying until it's been proven as magic. 

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I don't have the GPX 6000 but if I did I would definitely be experimenting. One question Steve. On the forth set I find it interesting that the quarters, dimes, etc move to a high tone on difficult, the same as the foil and small gold. Seems like it would remain a low tone. It's almost like it wrapping back around. Can you explain why it's doing that? Or maybe there is no explanation. On the 4000-5000 I always just used Salt, Normal or sensitive extra for beach or relic hunting. Most coins would always stay a low tone. I never used sensitive smooth or fine gold as the ground has never been bad enough to use those settings. But maybe the older GPX's do a similar thing on the difficult ground settings.

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1 hour ago, Steve Herschbach said:

It should be getting obvious the GPX 6000 is a great nugget detector. I think it also has great possibilities for beach detecting for jewelry.

If somebody was to ask me about relic detecting, I’d tell them the same thing I say about the GPZ 7000 - way too sensitive to tiny ferrous. There is such a thing as too sensitive, and the fact that the GPX 5000 can be set up to miss the tiniest ferrous is actually an advantage. The 6000 will bang have on the tiniest slivers of ferrous stuff.

However, it might be something those who already have the machine might want to play with, and I have already been learning a few discrimination tricks while beach detecting. Anyone familiar with the Minelab PI detectors knows you get two main tone responses, either a high tone, or a low tone. The simple way to think of what these tones mean is high tone = small or weaker / low conductive targets, and low tone = large or stronger / high conductive targets. The dividing line between the two is not fixed, but varies with the ground balance setting. This means people in lower mineral ground will not get the same results as those in high mineral ground. It’s a complex subject, one I go into great detail at here.

The GPX 6000 has one bit of magic for this task. The Normal/Difficult ground setting button. It allows a change in the tone response by simply pressing a button. I do not know the details of Normal vs Difficult, but it changes the timings enough to flip the tone response on many targets. I found I could use it to get four different target classes.

  1. Hi tone normal, high tone difficult = Aluminum foil, misc aluminum, wire, most bottle caps, misc small ferrous - low VDI targets. Small gold.
  2. Hi tone normal, low tone difficult = Nickel range targets, larger aluminum. Larger gold.
  3. Low tone normal, low tone difficult = Zinc penny range targets. Even larger gold.
  4. Low tone normal, high tone difficult = Quarters, dimes, copper penny, high VDI targets, nails (larger ferrous). Silver rings.

The results closely mimic my coin detecting results with other ground balancing PI detectors, but with a big difference. With all the other machines I had two classes of targets. High tone small stuff, low conductors, and low tone large stuff, high conductors. This new method delivers four target classes, potentially a big step up in discrimination capability with a PI. Ferrous can show up in any of the ranges, just depends on size and type.

By digging the fourth category, it’s basically just high conductive coins, and nails. Not good if you have lots of nails, but I will be doing this in a park soon, as many parks are not loaded with nails. Others might be, so it’s site specific.

The other big caveat I already mentioned. This assumes bad ground, with a ground balance setting to match. The GPX 6000 is automatic and sets it’s own ground balance. You have no way to set and lock it, unlike a TDI. So I have no idea where the tone shifts will occur in other ground. The good news is that you really don’t need a PI as much in low mineral ground. This might allow people to get more depth on silver coins in really bad ground. The DD coil also skews results, depending on which mode it is in, salt or cancel.

In other words folks, I’m looking for people who are willing to experiment, and document. I will be doing more of this and adding new information here as I go. Any adventurous souls, please do the same. There is a definite crude discrimination system included with the GPX 6000, by way of an easy button push. Let’s figure it out, and it may open up some new detecting possibilities. :smile:

I blew it on my first go at this, as I dropped finds into different pockets of my pouch, to separate them by category for a photo, along with the trash. Then I got home and by habit just dumped it all in my sieve to sort the sand and trash out - oops. So will do better at that next time. Bottom line is I got real good at calling out the coins before digging. There are some real possibilities here for the adventurous types - PI naysayers need not apply! :laugh:

I used to have an app on my phone that would allow me to take a picture (maybe a video) of a nugget and then a short description--- Of course this would definitely be a pain unless you were really interested in delving in to the inner workings of the machine. I think it would be fun. 

Im not sure if that program arbitrarily logged the gps coords or not--- remember to set your location button the right way so it wont send it to the internet.

When in WA, the Taskmaster always had me set a waypoint on my mapping program (offline) when i found a nugget .

After we were thru with our push in 2018, it was fairly easy to see how the new nuggets that popped up right between two or more other patches already worked. But the push helped because there were many old piles we had to get moved.

Point being, recording finds could be managed fairly easily-- if it were nothing less than a pencil and a small notebook.

Something about hearing those tones though that puts the info at a higher level of comprehension.

And yes i am rambling---lol--- it is raining this morning in Klawock AK and im just enjoying a coffee and the forum.

Good luck to y'all

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3 hours ago, abenson said:

I don't have the GPX 6000 but if I did I would definitely be experimenting. One question Steve. On the forth set I find it interesting that the quarters, dimes, etc move to a high tone on difficult, the same as the foil and small gold. Seems like it would remain a low tone. It's almost like it wrapping back around. Can you explain why it's doing that? Or maybe there is no explanation. On the 4000-5000 I always just used Salt, Normal or sensitive extra for beach or relic hunting. Most coins would always stay a low tone. I never used sensitive smooth or fine gold as the ground has never been bad enough to use those settings. But maybe the older GPX's do a similar thing on the difficult ground settings.

The key here is to check in both Normal and Difficult, to get the pair of tones. These tones are 100% related to the ground balance setting, and the timing mix (we have two, Normal, and Difficult). If you play with GPX 4000 - 5000 settings the tones will change the same way - just depends on the ground balance and the timing selected. So it's not "these tones = that" across the board, more like something a person can learn for themselves, for their own locations. If there ever was a "don't use canned settings and responses" type scenario, this is it.

The responses in Normal are what I would normally expect to see on a Infinium, ATX, TDI, SD, GP, or GPX. It's the addition of the difference that I am seeing in Difficult that makes the magic happen. Difficult by itself would be fairly useless as far as tones, a mix of large and small. But it is the fact that Difficult is different, that gives us four classes of targets instead of two, so it's a good thing. I could dig nickels and high conductors, and ignore zinc pennies. Never could do that before with a PI!

If enough people get involved, and more data collected, we might get more continuity as to what works where etc. My original post should be considered very preliminary, subject to change.

So just to repeat, the tones may respond entirely in a different way for somebody else on different ground. Or not. More reports will fill in the gaps and help answer the question.

At the end of the day I'm more a "it just is what it is" guy, observing what happens, and figuring out if I can use what happens to my benefit. The why part is interesting, if it can be determined, but not really needed. Heck, we still don't really know how gravity works, but we all know the practical applications. :smile:

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I got used to using my ATX in Hawaii to focus on rings while eliminating large junk, by just digging the high tones. It was very effective.  I went to Grand Cayman once, and was using the same methodology, and it took a while to notice something was wrong. Basically no mineralization, and so the ground balance was set more to salt than ground, completely skewing the results. I had to go back to digging everything.

The TDI is the most informative, because you can manually set the ground balance at specific locations, and doing so changes results. The pulse delay setting also changes things. There have been some relic hunters sort that all out to a very fine degree. It's all referenced eventually in my link above to the Fisher Impulse, which then links to notes of the GP 3500, Infinium and TDI. Lots there for anyone that wants to deep dive into it.

The Fisher Impulse AQ is leveraging this knowledge to create crude discrimination, but this will never come into its own until a fully digital PI is created, that can analyze this stuff on the fly.

I think this chart was lost due to websites going offline, etc. It is by Reg Sniff, and attempts to illustrate the White's TDI tone shift on some targets, at different ground balance settings.

whites-tdi-tone-response-chart-reg-sniff.jpg

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Wow great insight here.

Steve - does mono vs. dd coil make any difference wrt to the 4 target group breakouts?

I need to figure out how mini balls and different button types would behave in this construct to gage how this could be truly exploited for relic hunting.  I only use a PI in difficult ground.  If the above targets stay low in scenario 4 while the nails bang high, we might have something.  There are a lot more nails than silver and copper coins where I hunt that it might be worth it to just bypass those low/high targets altogether as long as the relics stay low/low, hi/low, or high/high .  If relics mostly go low/high then all bets are off because nails come back into play.

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33 minutes ago, Chase Goldman said:

Steve - does mono vs. dd coil make any difference wrt to the 4 target group breakouts?

Yup, says so in the post. You now have salt and cancel modes to contend with, and all I know is it seemed different, so that is another data collection area needed. I'm sticking with mono for now for simplicity sake. I'll sum up the DD question by saying I don't know for sure.

As far as nails go, size matters. Small nails are like wire, and read with the low conductors. But you can get rid of big nails with the high conductors. I'm certain I could use this to good effect while chasing bullets.

Long story short, the GPX 6000 may be too hot on tiny ferrous, but if that range can be eliminated entirely via this methodology, while still getting desired targets, then we may have a sleeper relic machine here. I'm not claiming there is anything here that might not be done with earlier GPX models, or even the GPZ, if you flip the right settings. In fact I'm almost certain the GPX 5000 could do this by toggling the right settings. It is just the ease of access with a well placed button push that helps a lot on the 6000, just too easy to flip back and forth. And the lack of settings options actually keeps people from getting lost in the weeds. This is easy and explainable - hit the ground type button, observe results, dig enough targets to put two and two together..

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