Ground Balance Theory

[Ferric Toes]

WBGB is quite a few light years away.,,,,,Still waiting though...like many hobbiest's.

Serious though...theory is only theory as has been discussed for years here and there,,,,,,and.......wait........many years to come to in practical terms.

Question: when is the ultimate Ground Balance to be achieved in theory, let alone in practical terms......well I say never...................But very interesting though.

This game is all about resources and being drip fed. Only the ones with the finances and R&D can supply the public with what they are looking for.

Aziz....Aussies do it better

Cheers Sid

Agreed. Theory is just that until something practical proves it, or not. I am working in the latter stage and what I have going on the bench looks very promising. Bench is still a long way from the field but it is a step in the right direction to a practical detector. I have the benefit of the WBMVM, Soil Susceptibility Meter, and Conductivity meter, plus a wide range of soil and rock samples, to check out theory before I apply it to a PI detector.

Eric.

[clancy]

Eric, is there a net group delay equal to the value that Aziz gets for p that needs to be subtracted to compensate for the total net Tx back emf effective width + coil circuit "TC delay" + Rx electronics group delay, or have you already performed this operation on your data?

[Aziz]

WBMVM
(Greedlab is no longer dominating the "World's Best ..." - claim *LOL*)
Aziz

[Davor]

@ Ferric Toes, in your viscosity measurements, your samples are placed within a solenoid, so they are exposed to mostly homogeneous field. I wonder, how would application of the inhomogeneous field work with these samples, e.g curved field on the solenoid edge. Some odd idea popped to my mind...

[Aziz]

The Show Must Go On!

Hi all,

just a reminder. This interesting thread hasn't been finished yet.
Please keep the off-topic stuff where it belongs: to the garbage bin along with the other GB patents.

Aziz

[Tepco]

Hey Aziz, you wrote more off topic things here than all others combined, no need to hurry. I'm currently on Russian side with one promising VLF build but just that gave me idea for PI ground balancing, ultimate one. Newer chips, at least 12bit ADC, fast enough, and with enough processing power, what about 32 sample ground balance for example, not 2, patented or not. More samples, narrower the “hole notch” will be, now finally doable with single inexpensive and available chip. Only I really HATE code writing, and there is one more thing with higher priority:



I don't want to miss opportunity to make GoldScan 6 right under the nose of Eric Foster, in it's own thread. Using gradual improvement process, optimized timing, bipolar pulsing, differential input, 2sample GB made bit different, separate high gain motion filter, ability to operate non-motion etc. At a complexity of 2x surfPI, completely analog and easy to DIY. I think forum needs such a project, to prove that DIY machines still can be competitive, actually I directly challenge newest Garrett with this.


Until then, since i'm now in Russian business, some nice music, part of it can be used for ring tone melody:


http://www.youtube.com/watch?feature...&v=zrfkm-JuBXs

[nick_f]

Hi All,

Can somebody provide a refresher for the simpler minds, of how magnetic soil reacts to the pulses sent by a PI detector, compared to metals?
I haven't read in a while about the subject, but from what I remember, there were some particularities of soil vs metals. Soil has a decay time which is usually short (about how long is short?). And soil decay time is proportional with the width of the Tx Pulse, while a particular metal sample has a constant decay time.
Is there an algorithm (quite easy to understand) which can be applied to perform ground balance and is in the public domain (or patents expired) that can be used into a PI detector?
How can somebody simulate in lab "bad" soil conditions to test if a ground balance method actually works?
I've been recently in a trip in NSW, Australia (Ophir) to search for gold using a Hammehead PI detector and although the soil was quite mild in general, there were some areas where I could not "ground balance" the soil by increasing the first sample delay and/or decreasing the pulse width. I think my detector is capable of setting a maximum delay for the first sample of about 50 or 60 us (I modified the circuitry to allow faster sampling, but I can't remember what was the maximum delay achievable). By the way, Hammerhead was excellent at detecting rusty iron and aluminium cans at large depths, while it presented a magnificent gold rejection

Regards,
Nicolae

[mickstv]

Hi All,


How can somebody simulate in lab "bad" soil conditions to test if a ground balance method actually works?

Regards,
Nicolae

Next time you go out detecting, bring back a few buckets of the ground that doesn't balance, and use that in your lab. Or for a basic test you could use red (fired) house bricks as they also exhibit a mild response.

The HH would need major mods to make it work on mineralised ground.

[nick_f]

Next time you go out detecting, bring back a few buckets of the ground that doesn't balance, and use that in your lab. Or for a basic test you could use red (fired) house bricks as they also exhibit a mild response.
The HH would need major mods to make it work on mineralised ground.

Thanks Mickstv for feedback. There is a good chance I have bad soil in my garden as well. I am not sure if the whole place is full of junk or the soil causes my detector to beep. Now I incline more towards a bad soil.

So far, the best and most clearly explained article about metal detecting, ground balance and discrimination I found is on the Minelab web site http://www.minelab.com/__files/f/11043
If I read the article a few times more, I should understand better what's going on.

Nicolae

[mickstv]

Hi Nicolae, if the ground in your backyard is producing a fairly constant tone as you sweep the coil it's likely to be some form of mineralization. If it's constantly beeping then yes the ground is full of junk.

[Aziz]

Thanks Mickstv for feedback. There is a good chance I have bad soil in my garden as well. I am not sure if the whole place is full of junk or the soil causes my detector to beep. Now I incline more towards a bad soil.

So far, the best and most clearly explained article about metal detecting, ground balance and discrimination I found is on the Minelab web site http://www.minelab.com/__files/f/11043
If I read the article a few times more, I should understand better what's going on.

Nicolae

Hi Nicolae,

sorry to say but you won't get any significant and valuable tip from the Minelab paper to make a good GB.
For an example: Page 20
The ground/soil response in a PI:
k*V*{ T/t - ln[(t+T)/t] }
The formula above isn't even accurate (only an approximation).
Look at the nice looking girl and the formula I have posted some time ago. This is by far the best soil modelling formula.

Cheers,
Aziz

[Qiaozhi]

Hi Nicolae,

sorry to say but you won't get any significant and valuable tip from the Minelab paper to make a good GB.
For an example: Page 20
The ground/soil response in a PI:
k*V*{ T/t - ln[(t+T)/t] }
The formula above isn't even accurate (only an approximation).
Look at the nice looking girl and the formula I have posted some time ago. This is by far the best soil modelling formula.

Cheers,
Aziz

And ... if you fancy ploughing through the mathematical paper mentioned on page 21, here it is ->
http://eprints.nottingham.ac.uk/501/1/final.pdf

[Aziz]

And ... if you fancy ploughing through the mathematical paper mentioned on page 21, here it is ->
http://eprints.nottingham.ac.uk/501/1/final.pdf

No thanks!
Aziz

[Aziz]

Oh well,

I have given up using "Candy math". Totally crap. Crap². Crap³. Ulti-ultimate crap.
His VRM formula doesn't fit well in to the real measurement data.

But my own VRM formula fits perfectly well like chalk and cheese.

Cheers,
Aziz

[Aziz]

Ooops,

that wasn't meant advertising for AEGPF. BTW, I'm also advertising Geotech site at AEGPF. And there is no problem with it.
Aziz