Fire charred ground and the gs5 ??

[wyndham]

While browsing in another forum, someone mentioned that his ML 4000 got real goosey when he tried to ground balance over recent ground burned by forest fires.
The charcoal was the problem because of the signal it gave off. I am wondering about the GS5 in a similar area. Does the GS5 do better or the same, having problems with charred material.
The other thought, because my mind works more like a hamster on a wheel, running real fast and getting nowhere, is about the ground conditions in the Aussie Outback.
Is there a possibility that there is a higher background amt of a carbon material in the soil that along with the iron in the soil produces a nastier mix that Eric, you have been working on in the Magnetic susceptibility of the soil prob.
Like I said I'm just a squirrel on a wheel thinking I'm getting somewhere. Wyndham

 

[Reg]

Hi Wyndham,

Do you have a PI such as the 4000 or the GS 5 or know anyone who does? In fact, this is a good test for anyone who has a PI. If you do have a PI, regardless of brand you might try this little experiment and see what really happens when you try to detect burnt wood. Clear an area free of targets and then place a handful of charcoal briquettes on the ground and try to detect them with a PI. Let us know what you find out.

This will answer your question better than trying to explain it. Once we get a few results, we can try to explain what is really happening. Eric has mentioned it before and is the most knowledgeable one on the subject. Hopefully, after we get a few answers, Eric will chime in.

Reg

 

[Sabra Jim]

G'day Wyndham,

I've spent quite a bit of time the last couple of years nugget hunting in very old burn areas and the GS5 is most excellent in identifing the spots of charred ground, even when covered by substantial wind blown topsoil thru the years..Even very small spots will give a loud signal...

In the same type of ground, using my Minelab 2200 with a 12x24" Coiltek mono coil, the old charred spots will be ignored..

I keep my GS5 adjusted to it's most extreme sensitivity and do not attempt to "tune out" the charred ground because I want to know where the heavy brush really was before the fire, since those places were not detected properly because of the aforementioned brush and I concentrate very hard on those small areas...

So here is another type of use for my GS5 that serves me well... When nuggets are found with the GS5, I always go over the area with my Minelab and large coil and am sometimes pleasantly surprised..

As you already know, to catch fish constantly, a person has to have at least two types of fishing reels..

Regards, --Jim F.--

 

[Reg]

Hi Jim,

If you get a chance, you might try the experiment with the charcoal briquettes I mentioned in my previous response. Since charcoal briquettes are simply burnt wood, it should simulate burnt wood in the field. If you do try testing the briquettes, please try both the GS 5 and the ML. I hope someone tries this and posts their results. I think people will be surprised.

Reg

 

[wyndham]

Hi Reg & Jim, the post on the problems with burned over area was either nuggetshooter or nuggethunter forums, can't remember right now. The fellow was surprised by the charcoal response.
Somewhere in all these signals from different material has to be a correlation between material and a response that a micro-controller should be able to have a lookup table and filter out at least some of these false target.
I guess that PI machine would cost a million $$$$ and take a team of engineers to run it. No I don't have a PI yet but some day maybe. I've got an old GB1 that finds all the trash I can dig(North Carolina has very small gold).
The carbon response reminds me of a question no one seem to want to get into. It was about using carbon fibers in making a coil instead of any metal. I never could find any info on the inductance or other electrical properties of carbon fiber. Just an old thought since we are in the general area. Later Wyndham

 

[Wirechief]

Howdy Reg, I took my Beachscan across the street from my house where a small house was burned. The burned wood from this house didn't seem to give a response but a small chunk of well cooked cement that is probably 60 years old or older does give a response. It is probably some of the material in it giving the response. But it is black so doubt it is well done! Ok God Bless everyone and maybe this is somewhat helpful.

John Tomlinson,CET
John's Detectors

 

[Reg]

Hi John,

Thanks for responding. I think you will find if you test a large piece of charred wood or even a bunch of charred wood that none of it will cause a response on a PI like it does on a VLF. Neither will a handful of charcoal briquettes which are nothing more than charred wood.

People have this idea that since charred wood can cause a weak response on a VLF that it should cause a response on a PI. So, they assume that to be the case in the field when they come across a burnt area. For those who have never operated a VLF around burnt wood, these people see the burnt remains and hear a signal so they assume the burnt wood is the culprit. They mention it, like what happened on one of the other forums and other people simply believe it rather than test the idea themselves. Unfortunately, it is errors like this that confuse people. Some errors are just minor, but others can mean the difference between being successful or not.

This is why I recommend people test and experiment with their detector just to see what is really causing the signals. Sometimes it may take a while to find the right reason, but once you do, it does help better understand how a PI really works and what to expect in other areas.

BTW, I believe Eric addressed this burnt wood problem a long time ago and explained what was really happening.



Reg

 

[Wirechief]

Hi Reg, ok mighty fine and glad I could give this subject some feedback. Yes I took some fairly large chunks across the coil and nothing. By the way Reg I always read your posts with great interest. Well I will chat with you later. God Bless.

John Tomlinson,CET
John's Detectors