Minelab 8000

[Aziz]

Hi all,

I can tell you which technology will excel in identifiying deep good targets in highly mineralised soils and noise conditions. This hasn't been realised yet.
By simply post-processing the signal output and analysing it with the Hilbert–Huang transform.

The technology is already beeing used in seismic applications (earthquake and volcanic eruption prediction), weather forecast, ultra-sonic applications, medical applications, astro physics, etc.
This is a cheap solution to overcome ground noise, EMI noise, difficult ground conditions with the existing technology to get the very faint signals buried in a lot of noise.

A blutooth wireless module could make it possible with all the processing stuff and pass it to the real audio output.
There is a big potential in Hilbert–Huang transform.

Hilbert–Huang transform
Hilbert–Huang transform
Hilbert–Huang transform
Hilbert–Huang transform
Hilbert–Huang transform
Hilbert–Huang transform
Hilbert–Huang transform
Hilbert–Huang transform
Hilbert–Huang transform

[Aziz]

BTW, the Hilbert–Huang transformed output signal should deliver a signal like detecting extra terrestical planets by observing the brightness change in front of crossing over their central star.
This is owed to the fact of sweeping the coil over the buried target.

So let's find some planets - oops - deep targets. Let's do astro physics on metal detecting.

[Riss]

https://www.youtube.com/watch?v=JlKkECM6sWE - watching this video in the interval 4min 05 sec to 5min 55sec, one of the numerous Australian flies "entered my head" and I wondered what would happen if the GPZ 7000 was "zeroed" (set to have no reaction) to ferrite - hot rock and then we check if there is a reaction to well-fired ceramics in a kiln? (Roman floor brick or modern brick). Has such a test been done?

[Aziz]

Hi Riss,

https://www.youtube.com/watch?v=JlKkECM6sWE - watching this video in the interval 4min 05 sec to 5min 55sec, one of the numerous Australian flies "entered my head" and I wondered what would happen if the GPZ 7000 was "zeroed" (set to have no reaction) to ferrite - hot rock and then we check if there is a reaction to well-fired ceramics in a kiln? (Roman floor brick or modern brick). Has such a test been done?

look at this unbiased detector tests:
Part1: https://www.youtube.com/watch?v=qvTHG4bX0mw
Part2: https://www.youtube.com/watch?v=7V-qObzOKic

The GPX 5000 with a large mono coil is still overkill.
Old GPX machines with new coils will defeat the GPZ.

[Aziz]

Part3: https://www.youtube.com/watch?v=uvPDnSHxdms

Just available

[Aziz]

Been thinking of a simple and effective coil geometry description language for complex shaped coils, which should be easily defined by an external text file.
But on the level of wire elements. It's a successive trial & optimize process. I have started with the basic parser part.

[Riss]

Thanks for the links Aziz, but I didn't find a video where the probe passes over ferrite, then over ceramic or vice versa. In Australia there is no ceramic in the gold fields...

[Aziz]

Hi Riss,

Thanks for the links Aziz, but I didn't find a video where the probe passes over ferrite, then over ceramic or vice versa. In Australia there is no ceramic in the gold fields...

In Australia, the ground is full of so-called "ceramic" in the gold fields.
Let's look at the "ceramic" building process. Clay containing iron minerals is beeing burnt at high temperature to form the red "ceramic". Clay does also contain organic matter (carbon).
At the burning process, the iron minerals can be formed to high magnetic susceptible form of maghemite. Even hematite (low magnetic susceptible) can be formed to maghemite.

Iron oxides do exist in various chemical forms in the ground: iron-oxide-hydroxide (Goethite), magnetite, hematite, maghemite, etc...
Australia is full of such iron minerals in the gold field ground.

Bush fires in Australia form regularly a fresh layer of maghemite in the ground. This is what makes the detector go wild.

See here for more:
Maghemite formation in burnt plant litter at East Trinity, North Queensland, Australia
https://www.researchgate.net/publica...land_Australia

I have already tested this chemical process by my own. By simply "burning" rust or hematite with charcoal powder at 800 - 1000 °C. After burning, the result is very very ferro magnetic.

Aziz

[Aziz]

Hi all,

my own produced maghemite samples have lost some magnetic property and has been converted to the stable form of hematite.

I have asked the AI how to refresh it.

Two chemical processes:
Phase 1:
Hematite powder with charcoal powder burning at 600 - 800 °C under absent of oxygene (like in the ground layer). Charcoal (organic matter, carbon) reduces hematite to form magnetite and carbon monoxide (do it outside).

Phase 2:
Cooling down to 200 - 250 °C.
At this temperature range, the converted magnetite can be oxidized to maghemite. Get the hot mixture contanct to fresh air and mix it regulary at this temperature.

Maghemite and magnetite is strongly ferro magnetic.
There we have. Most freakin hot mineral ground condition like in the Australian gold fields.

[Riss]

To be more precise, I have in mind diagrams 3, 4, 5 and 7 from https://patents.google.com/patent/US4030026A/en . First, the ferrite (magnetite) vector is "zeroed", then (clockwise) the ceramic vector is "zeroed", which is about 5 degrees behind the ferrites according to the patent. This is the case with sinusoidal VLF detectors, and with PI detectors the ceramic creates a long "tail" - 250 - 300 microseconds after turning off the current through the transmitting coil. Probably the Australian soil after forest fires has a similar behavior to the ceramics produced by man in Europe, for example. Hysteresis losses during remagnetization ...

[Aziz]

Hi all,

I am progressing very slowly with the coil software due to lack of time. But I am still progressing.
The evolution of the coil geometry description language takes some time.
This is looking like (placed in an external text file):

// This is a comment until end of line
ref 0, 0, 0 // reference point for coordinate calculations

path // New path definition

pol 0 0.1 // polar coordinate <angle> <radius> [z]
rep 11 // repeat 11 times the next coordinate command
dpol 30, 0.1 // delta polar coordinate <delta angle> <radius> [z]
close // close the path to the beginning point
end // End of definition, stop parsing

There are more commands implemented to be able to be more flexible. But this is an evolution process at the moment. And the parser code needs to be changed sometimes. I am far from generating the wires yet.

Cheers,
Aziz

[Aziz]

Hi all,

the basic coil geometry description language is getting better. I have added a dmod command (delta modifier). So I can modulate angle, radius and z-position of wires.
Look at the chalice coil..

The simple code generates the coil.

ref 0, 0, 0 // <x>, <y>, <z> reference point, default 0, 0, 0 (for dxyz vectors), optional
path // New path definition (optional)
pol 0 0.1
dmod 0 -0.001 0.001 // delta modifier, <dAng, dR, dz>
rep 240
dpol 30, 0.1
end // End of definition, stop parsing

But I am still far from the ultimate solution. The description language has to pass a lot of use cases and needs an evolution.
Aziz

[Aziz]

Oh man!,

I am stucking too much. It takes me some time to find an elegant description and implementation solution. Then it requires a lot of changes. I am not complaining. This is a normal evolution process. So the coding goes on.

[Aziz]

Hi all,

I have found now an elegant and simple solution. There will be section commands (sec <..>) to define a section of a wire path. And there will be duplicate section commands (dups, dupm, dupr).
The symmetry of some coil designs can be described with minimum definitions therefore. By only applying scale, move and rotate commands to the section.
I am sure, this will give us the best flexibility of coil design.

Evolution goes on.