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GPZ Concern


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 Hi all,

I have this nagging concern that maybe not every machine is as optimum as say the most "optimum" one. 

I have spent around 120 hours with the GPZ, and I am very pleased with the small gold it finds, and several 1 gram pieces, to the tune of 38 pieces for a total of 1/2 oz.

But I'm not getting the deep targets that some folks are reporting. For example, 2 of the deepest targets have been- a nail at 12" and a 22 casing at 10".  I've dug up over a hundred birdshot pellets of all the various sizes and many other pieces of various sized lead trash. I'm very comfortable with the settings I'm using which are consistent with what others on this forum are using, and I've been very diligent about removing inches of soil when unsure if I have a true target or not. The main settings I use are Normal ground, High Yield and Audio Smoothing off, but I mix up the Sensitivity settings and re-hunt productive locations after making changes to see if I might do better. I do follow the ground balance procedures and Re-set  Noise cancel recommendations that have been much talked about here and from other GPZ owners.

With this machine I have hit 3 locations that produced 5 or so nuggets in relatively close proximity, sort of "mini" patches. It's really hard for me to believe there aren't some deeper targets in these spots that I'm just not hearing. I have definitely found deeper targets (but not gold) with my beloved and long gone GPX 5000, but I don't think it would have heard most of the gold I have found with the 7000. 

What I'd like to learn from other GPZ owners is, how many "deep" targets you've been digging? A few, quite a few, lots? 

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I've dug one 0.58 ounce nugget at 18 inches, but that was an amazing depth for a specimen of wire gold - its still the deepest piece of gold I have dug with the GPZ, and a target that simply could not have been found with any other detector. I dug a one inch iron piece of trash at 24 inches. That is the deepest hole I've dug with the GPZ - I was sure I was digging in undisturbed ground until it came out of the hole. I've swung over small pieces of lead in a test target garden that the owner said was at 36 inches. 

Many folks who bought a GPZ 7000 have been totally convinced more deep nuggets remain in their patches. The results we are seeing both in the US and in Australia are that there are a few deeper pieces but most of what guys are recovering from old pounded patches are small bits, specimens and prickly, wiry gold. Just because someone believes that deep gold is present, does not prove that it actually is.

The GPZ is a great detector, but like all other prospecting equipment, it cant find gold if it isn't actually there to be found.

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What Chris says is the most likely cause for most of the cases, But I've given this same thing some though too, why it seems some see more depth increase then others, and I think it's interesting to talk about because in metal detecting everything is so relative to the operator and conditions that terms like depth are hard to quantify.

 

What were your settings on the 5000 when you cleaned those patches out initially AUddicted? And which coils did you run? Here's why I ask:

 

While I'm impressed with the 7000 as a whole, I'm not completely floored by the depth increases as some others are either and I believe it may in part relate to how I or any person was running their GPX. With the 5000 it's pretty common for people to not stray far from Fine Gold/Sens ~12/Stab ~10/17x11 EM even in mellow quiet areas and if a guy ran like that he'd be a lot more impressed with the GPZ depth on average than a guy who was running it a lot hotter and using a wider array of coils. If a guy detected in areas requiring Enhanced a lot then HY or Gen/Diff is definitely deeper. So it's relative.

 

Also the weight of the coil on the 7000 almost forces a person to maintain good detecting habits, that is to say low and slow. Even seasoned veterans are guilty of violations, I see it all the time. A person swinging with the coil much lower to the ground with a slow swing is going to hear more and deeper targets than a person who doesn't keep good habits no matter what PI they are running.

 

And, in some videos, especially the ones with smaller targets 0.1 gram to .5 gram, in many it's plainly obvious that the nuggets are in the sides of the hole and not in the bottom and so I think the depth estimations are exaggerated in some cases. It's also real easy to dig past a nugget and assume that once you got it out it was at the bottom of the hole but it might have been 2-4 inches up, I do it myself too.

 

The last thing is, from both my experience and the Bruce Candy White Paper I think just in general the 7000 depth increase is more pronounced on the smaller bits so that's the bulk of what is being pulled up out of patches. And a lot of people are only specifically recovering old patches at this early stage.

 

These are the conclusions I've come up with after many hours of wandering thoughts while swinging away as to why the depth increase is completely amazing to some and to others is less so. Interested what others think.

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I have nothing of size also but the ground I`m in hasn`t the depth to have hidden any from the GPX, but does have the depth to hide the subgrammers to grammers from the GPX which the GPZ is picking up no drama. I did think there was larger pieces out of range of the GPZ, and felt a little like you, but because it is getting those smaller ones that the GPX would have no trouble with shallower. I now believe those larger pieces have been got. A clue to this and I cannot remember exactly JP`s early words is he felt sometimes disappointed then it changed and it was like the GPZ was making gold. I think it may be just that, no larger gold there.

But gotta keep an open mind and will as I get the hours up, think of this.

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JP has commented a couple times that in his opinion the GPZ with 13"x14" coil gets about the same depth on large nuggets as a GPX 5000 with about an 18" or even 20" mono coil. That tells me if the ground has been hunted hard previously by an operator using a GPX with large coils than there is little chance of the GPZ going any deeper. The solution there will be the larger GPZ coil. However, this assumes the gold is reasonably solid stuff that both machines would do well on. The GPZ has a real and distinct advantage on specimen type gold regardless of the coil used on a GPX.

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 I haven't seen a depth performance improvement over the 5000 yet after nearly 100hrs with the Z. On small gold, spongy gold. wiry gold and quartz with specs of gold the Z is unquestionably the best but it's going to take me a long time to pay for it. Maybe Minelab would be willing to give me an "up to %40" refund.

 I'll be doing some deep bore holes and digging with the excavator this weekend so this will be a good test for the Z.

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I have read many forum thread concerns that one GPZ isn't equal to another GPZ! I personally have not seen this in the goldfields with our group of Detectorist. We comonly, call each other over to swing over a likely target for comparison and self training of each other on the GPZ. We hardly use the exact settings as each detectorist likes differ in some degree. The target sounds of the GPZ is the major learning curve for the deep targets. You've seen the GPZ chart with all the dots for size nuggets found at different depths. I understand, why they didn't list the found target that are off the chart...this detector will make you shake your head at the depth you'll dig a nugget. Again, not all patches will produce deep nuggets. But learn the new target sounds of this machine, it will surprise you! Until the next hunt

LuckyLundy

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Chris has found a .58 oz piece at 18", Rob Allison (You Tube vid.) found a 1/3 oz piece at 18", Doc (You Tube vid.) found a 1.2 dwt piece @ 18". And there are more You Tube vids. with deep finds.

 

I just want to find a piece of trash at 18" to know my machine is working as well as the others. I hunt a lot of different areas with different soil depths and percentages of trash so I feel I should have dug up a deep target by now. If it can't hear deep trash then it can't hear deep gold either.

 

It would also be helpful to hear about other's deep trash examples (like Chris's 24" deep iron piece, even though iron will be louder and more obvious) to get more info. on the potential depth of the 7000. 

 

 

On a side note: I can't help but wonder if Minelab were to set up an SDC2300 with a 14" coil would it equal or better the performance of the GPZ?

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Don't know if the SDC with a larger coil would be better however I caught wind that there maybe another SDC coming about.

JP just posted a video about audio smoothing and dug a nice piece at depth.  Not trash but it kind of took me back to this thread and concerns~  Check it out if you've not already.  Trash or gold I don't think the Z will miss much of it.  Its done well with all the practice pieces I've planted in the yard.  I'll know more when I'm in the thick of it coming June.

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On my first time out using the Gpz I dug a 2/10 of a gram at around 14 inches, have not come close to that depth again.. Main difference has been the ground was damp from rain 2 days before that first dig. We have not seen any rain since and I have been getting great results digging many 1/2 gram nuggets in pounded patches but most have been @ 6-8 inches deep.

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