Detector comparisons: ground mineralization readings

I often see various comparisons between different detectors relating to air tests, in-ground depth, separation, visual ID, ad infinitum.
But I don't recall seeing any comparisons between different detectors' ground mineralization readings.

Case in point. Hunted a property with a Racer and stock coil. Mineralization pie chart varied between 15% to 20% filled and approximately 40% to 45% filled over the course of the hunt.
Next day, same areas detected, same conditions. Same temps, no rain since the previous day. F75SE update w/stock coil displayed almost no mineralization with readout varying between none and occasionally .01 to .03 Fe2O4.

What's to be made of this difference between these two detectors and their mineralization readings?

Has anyone noticed the same thing with these or other detectors?

Pleasant Garden, NC
AT Max, Nokta Impact, MX Sport, Nokta FORS Relic, GPX 4800, Infinium, Racer, Deus, F75SE, Nautilus DMC II (order of acquisition, last to first)

Does an archeologist argue with a plow? A bureaucrat with a bulldozer?

Here are my observations between Deus, F75, and Racer. With stock coil on racer I notice about one more segment blackened vs the small coil over the same ground.

Racer (stock coil) with half to one less segment blackened equates to 3 bars on my F75ltd2 meter (stock coil)--Deus (11" coil) just less than half a meter blackened.

Racer with one segment over half filled equals to 4 bars on F75ltd2 (all stock coils)

Racer with 3/4 to one additional blackened equates to 5 bars on F75ltd2, Deus full meter except for 2-3 dots. Again all stocks coils, Deus 11" coil.

Software superiority

Software superiority, Des?

The ground readout for mineralization is just a reference point. Like a VDI number. They are specific to that detector. Sure you can compare them, but just because machine x displays differently than machine y doesn't make one superior over another. What I would consider more important is the usefulness of the information. Since this feature is measuring ground mineralization strength, I would expect that anything that decreases or increases the amount of ground signal the detector sees, like coil size and frequency, to show a corresponding change on the display. The resolution of the display should be such that these actions can be visually displayed to user so that they can make intelligent decisions about how to set up for the site and targets desired.

HH
Mike

All flagship detectors should have mineralization meters. Here's something I would like to see maybe answered. In hotter ground Deus and F75 seem to perform better with faster recovery settings/processes. Do the minelabs also perform better in the hotter ground with recovery fast set to ON vs off??????

Mike Hillis Wrote:
-------------------------------------------------------
> Software superiority, Des?
>
> The ground readout for mineralization is just a
> reference point. Like a VDI number. They are
> specific to that detector. Sure you can compare
> them, but just because machine x displays
> differently than machine y doesn't make one
> superior over another. What I would consider
> more important is the usefulness of the
> information.

Specific to that detector...

OK, so if it is accepted that higher mineralization limits the depth and affects the accuracy of visual ID readings, then is a detector that reads the same ground as more highly mineralized more likely to be adversely affected by the mineralization than a detector that reads the same ground as less mineralized?

When one detector reads the mineralization at, say, 40%, and another reads the mineralization of the same ground as .03 (units not defined) Fe4O2, which is more useful?

Wayne

Pleasant Garden, NC
AT Max, Nokta Impact, MX Sport, Nokta FORS Relic, GPX 4800, Infinium, Racer, Deus, F75SE, Nautilus DMC II (order of acquisition, last to first)

Does an archeologist argue with a plow? A bureaucrat with a bulldozer?

Quote:"Is a detector that reads the same ground as more highly mineralized more likely to be adversely affected by the mineralization than a detector that reads the same ground as less mineralized?"
A machine's ability to measure ground strength, and it's ability to deal with it, are unrelated.

And how a machine chooses to display " Ground Fe" level to the user is entirely arbitrary. Pie charts, bargraphs, numeric values, %ages.
The meter on the T2 / F75 is the most 'scientific' one, if you look in the manual you can find a conversion chart from the 0.1 / 0.3 etc into true scientific measurements.

On machines like the T2, with interchangeable coils, the meter (Fe3O4) will be 'calibrated' for the stock coil. As the T2 unfortunately doesn't know what coil is fitted to it, it will read less on the meter if you stick the 5" coil on it, and more if you fit a larger coil.



Edited 1 time(s). Last edit at 06/13/2015 02:30PM by Pimento.

ncwayne Wrote:
-------------------------------------------------------
> Mike Hillis Wrote:
> --------------------------------------------------
> -----
> > Software superiority, Des?
> >
> > The ground readout for mineralization is just a
> > reference point. Like a VDI number. They are
> > specific to that detector. Sure you can
> compare
> > them, but just because machine x displays
> > differently than machine y doesn't make one
> > superior over another. What I would consider
> > more important is the usefulness of the
> > information.
>
> Specific to that detector...
>
> OK, so if it is accepted that higher
> mineralization limits the depth and affects the
> accuracy of visual ID readings, then is a detector
> that reads the same ground as more highly
> mineralized more likely to be adversely affected
> by the mineralization than a detector that reads
> the same ground as less mineralized?
>
> When one detector reads the mineralization at,
> say, 40%, and another reads the mineralization of
> the same ground as .03 (units not defined) Fe4O2,
> which is more useful?
>
> Wayne

"Should I have said, [ more refined software ] in Fisher's case as they have been around a lot longer.
They have by now completed some very effective ground signal / ground cancelling algorithims showing in the way the FE034 set up is less effected by minealisation compared to the relative 'newbie' Makro/"

Pimento Wrote:
-------------------------------------------------------
> Quote:"Is a detector that reads the same ground as
> more highly mineralized more likely to be
> adversely affected by the mineralization than a
> detector that reads the same ground as less
> mineralized?"
> A machine's ability to measure ground strength,
> and it's ability to deal with it, are unrelated.

Are they? Then the machine is providing information (ground mineralization value) that is useless to the operator?
If not useless, then the operator might be expected to use that information, right? How? To throw up his hands and leave?
If not that, then perhaps to make adjustments to the machine to obtain the best machine performance based on the ground mineralization level.
I see that as a relationship between a machine's ability to measure ground "strength" and its ability to deal with it.

What I don't see is one machine calling a site non-mineralized or only slightly mineralized; and another machine calling the same site significantly mineralized, i.e., 40%.

And again, if the ground mineralization is to be useful to the operator, then a machine that sees the ground as significantly mineralized, logically, would be giving notice to the operator that signal depth and accuracy of audio/visual feedback is probably significantly affected by the ground mineralization. And the machine that measures the same site as not significantly mineralized, logically, is telling the operator that the machine is functioning properly and no operator intervention regarding effects of mineralization on the machine's performance is necessary.

Pleasant Garden, NC
AT Max, Nokta Impact, MX Sport, Nokta FORS Relic, GPX 4800, Infinium, Racer, Deus, F75SE, Nautilus DMC II (order of acquisition, last to first)

Does an archeologist argue with a plow? A bureaucrat with a bulldozer?

Oh boy. Major misunderstanding time. Let me try and explain it a bit more.

Ground is full of microscopic iron and "rust". These are magnetic, and so are seen by machines such as metal detectors.
When you lower your search-coil from 1 metre (40 inches) above the ground, to 1cm (1/2 inch) above, your coil picks up the ground, and this gives a very real signal inside the detectors circuitry. If a designer chooses to, he can add electronics/software to the detector to measure this signal, and present it to the user on a display. It could be a log or a linear scale, or anything else, it could be a row of LED's, it could be arbitrarily scaled like "%" or "0 - 10", or detailed numbers. All of this is independant of a machines ability to find deep coins etc. You could add this ground strength feature to an ACE250 if you wanted.

Finding metal objects buried in this ground is a different problem. This ground signal 'wobbles' up and down as you sweep, making it hard to distinguish the one-off 'up-down' signal of a real target from the continuous 'up-down-up-down....' of the ground. Good detectors are ones that best extract target signals from the troublesome ground signal.

So: You can make an awesome detector without a ground Fe meter. You can make a basic kids detector with a terrific ground Fe meter.

Regarding specifics of your post:
Then the machine is providing information (ground mineralization value) that is useless to the operator?"
It's not useless, I never said it was or wasn't.
"How might the operator be expected to use that information? Perhaps to make adjustments to the machine to obtain the best machine performance?"
Unfortunately, most of the time there's not much you can adjust on the machine. A few possibles might be:
On an F75, choose PF mode, this forces the ground filter into one particular mode, rather that the machine auto-choosing.
On multi-frequency machines like the Whites V3i, there would be dual/triple frequency modes that would help overcome difficult ground, and countering this, if you knew you had mild ground, you could perhaps benefit from single-freq operation.

The most useful thing about a ground Fe meter is what the operator chooses to do, as you correctly described here:
"Significantly mineralized ground, logically, would be giving notice to the operator that signal depth and accuracy of audio/visual feedback is probably significantly affected"
So for example, if ground Fe was strong, you would be aware that targets would start reading as 'iron' at a shallower depth, and you could investigate the borderline signals more, in order to see if they were iron or non-iron.

And re. this :"What I don't see is one machine calling a site only slightly mineralized; and another machine calling the same site significantly mineralized, i.e., 40%" and "The machine that measures the same site as not significantly mineralized, is telling the operator that ..no intervention regarding effects of mineralization .. is necessary."

What level of mineralization a site has is determined by the site alone. If two different machines say there's a difference, then it's because the machines are different, and the calibration of their "ground strength instrument" is different. But as figures like "40%" mean absolutely nothing, then it's arguably a waste of time attempting to interpret it. Unless the user manual gives some kind of "calibration chart". But even that would be tricky, you can bet that a US machine will use Imperial units, and a Turkish one will be SI metric, or some such.

Good stuff Pimento. And this is why I compared my other detectors readings over the same ground as F75. The F75 like you said is really the only one that is described more in detail vs Deus, Racer, etc. So now I have a pretty good idea what more mineralized ground looks like on my other detector's meters, hence I can deal with it as I see fit.

Makro and XP should have explained their graph much like Fisher did. And there are others too that should.