GPZ 7000 Tip From JP On Ground Noise Problems

[Steve Herschbach]

1. The GPX can scrub the ground usually with no problem. The settings used on a GPX to deal with salt ground depend on the amount of salt in the ground and how wet it is.

2. The GPZ can normally scrub the ground with no problem. JPs suggestion was a solution to a potential problem as described at my post at http://www.detectorprospector.com/forum/topic/970-minelab-gpz-7000-a-super-vlf-saturable-soil-tips/

3. The potential ways for alleviating saturable ground and salt issues are outlined at my post, but there appears to be no "solution" for running the GPZ on salt ground. It is problematic, and if the salt ground is bad enough it may be unworkable with the GPZ. Milder salt ground can be dealt with, but the machine will probably be noisy. It all depends on how much salt is in the ground and how wet it is, plus how much iron mineralization exists. This is a range of issues, not a single problem with a single solution.

[DDancer]

I've not had the chance to deal with salt yet~ my experiments on the beach here in NC had to be put on hold for work related reasons as I gear up for WA next month.  However as I read I'm reminded of how I use my own coil.  I don't scrub it much.  In fact I feel I've always had better balance and sensitivity with the coil a half inch to an inch above the ground and rig my bungee to maintain that.

Reading this I wonder if I'm just off in my thoughts.  Granted this is what I came up with on my old SD2100 and later with my GP. *addendum*  I read the link and saw what JP had to say about scrubbing~ interesting.  Still I am curious for other thoughts. *addendum 2* then I thought lets read Steve's post and now... well I'm just going to keep quite on the thought of how I rig.  Seems I'm ok.  Hahh.

 

Salts on the GP where dealt with similar to whats being described for the GPZ.

 

A silent thresh hold is what comes to mind as I think about the problem described.  How much does anyone think this will impact performance in noisy ground types?

[Reno Chris]

A silent thresh hold is what comes to mind as I think about the problem described.  How much does anyone think this will impact performance in noisy ground types?

The groan of the GPZ in salty soils is a target response. Salty soils are electrically conductive, so they generate a target response - the response sounds a lot different from a nugget, but its a target response none the less. If you dumb down the GPZ by lowering the threshold to the point where you cant hear the soil target response, then I think you are losing a lot of performance and sensitivity.

Slowing the sweep speed down - and I mean way down - helps a lot with the salty soil problem, raising the coil an inch does not seem to make much of a noticeable  difference, I am sure JP is correct in his suggestion and that raising the coil will have other beneficial effects especially in magnetically saturable soils, but in the salty soils the improvement is small.

[Steve Herschbach]

It is all a matter of degree. A little bit of salt will produce a little bit of an issue. Simply raising the coil could solve that or reducing the gain or the threshold, etc. More salt will have more effect to overcome.

Moisture is the big thing with salt soil. If wet you can really have big problems. The same ground when bone dry may have minimal issues.

Chris is spot on though but again it is a spectrum of issues and solutions. If the salt response can be dealt with while not having to reduce the threshold that would be preferable. But what if the operator simply cannot tolerate or differentiate a nugget signal from the salt signal? Then compensating with methods that in theory reduce sensitivity is the answer.

We can go in circles like this:

A. "I am driving my car too fast on a winding road and am afraid I am going to crash. Should I reduce my throttle setting?"

B. "Well of course, you do not want to crash and burn!"

A. "Yes, but if I reduce my throttle setting, won't I lose speed? I do not want to give up performance."

You have multiple settings on your detector that must be used like salt, pepper, and other seasonings in the stew. The goal is to minimise the ground signal while enhancing the nugget signal. You are looking for the combination that most makes the nugget stand out TO YOUR EAR. Some people like myself can listen to constant noise as a sort of threshold of its own and pick out a target signal. Others would argue that getting the quietest, smoothest threshold possible is paramount.

I rebel at the concept of a certain setting for everyone because I do not think we are all the same in how we hear and how our brains process sounds. The smartest thing to do is spend time experimenting in the field in real conditions with found targets or test targets to find what works best for you.

[Norvic]

Your on the money there Steve, there is no one way for everyone. As I stated in other post on this issue, I don`t wear many coil covers out because I don`t scrub the coil. I like as rock steady threshold as I can get, thus I`ll cut sensitivity somewhat.

We develop individual techniques over time, good and bad habits, thus I rebel a wee too that a certain setting is for all, at the same time consider others methods. An open and questioning mind is always the key.

[nvchris]

Im always trying different stances, swings and grips, once you learn how and where to put spin on the ball your game opens wide and you can master any course.

[Swifty]

hehe Chris is that a gpz 6 iron  or gpz wedge your using

[Norvic]

Donno, but reckon could check out at the 19th hole.