I appreciate that insight. Thank you!
One more question? On many single frequency detectors we hear about really deep coins almost out of detecting range (and possibly because of surrounding mineralization) being ID'd as iron or the numbers skewing close to that. Based on what you know from the Etrac & CTX, could this massive skewing also happen to them and the EQ on super deep coins even though the multifrequencies handle the mineralization better and they are known to give better ID's at depth (even deep), or is there just a point at where multifrequency detectors begin to skew toward iron also on coins because they are almost out of detecting range?
Curious if this phenomena does happen with multifrequency detectors because we seem to hear about it a lot with single frequency units...
CTX, Etrac I know for a fact, will start IDing nonferrous objects in higher mineral soil as ferrous (both ID and tone).
Deus will too.
Other Vlf detectors do too like Fisher F75, etc.
The fbs/fvs2 units are a bit strange though in milder soil.
They have what Incall good effective depth, meaning they give tone and ID and for the most part this extends to a longer range then shuts off moreso.
Where some single freq detectors seems can (at times) go a bit deeper providing tone, ID unreliable (meter).
Now conductivity of targets, size, shape play into this " when a target transitions" to ferrous.
Fbs style units like higher conductors better on average.
Remember a highe conductor starts out higher in the food chain with conductivy.
As a target deepens the felt conductivity by the detector this starting point of target conductivity key.
A small cuff button will become compromised much faster than a silver dime.
Now, this needs to be said.
There is soil masking.
And there is what I think is combo soil/ decomposed ferrous masking.
Fbs units handle soil masking better I think than decomposed ferrous masking.
A story to share with you and others here.
You will notice my post on use of round HF coil for Deus posted yesterday and today.
Today I get a compromised signal, I felt was nonferrous lurking.
Upon digging and turning over plug.
The Deus went bonkers with mix of ferrous tones and a little nonferrous tone indication.
I gently moved the dirt around and then my nonferrous target was a lot better signal wise.
After removing the small nonferrous target.
Imswept the dirt.
Notta, no iron tone whatsoever.
What happened?
I can't prove but highly suspect,, decomposed ferrous was bound up, enough so Deus would see the ferrous.
But my disturbing the what looked like soil, I weakened this bound up mess, hence Deus would no longer detect the ferrous.
Btw this happened about 5 times today.
No visual nails, Ferrous noted either.
This is what happens in 250 year old approx sites.
So a detector has to deal with both of these types of masking.
Now remember mild soil but old site, still could mean problems for detector exposing nonferrous.
How in the world these engineers develop algorithms to unlock these situations is beyond me.
You can't really man make these situations I don't think.
I would give my eye teeth to visit and talk to XP and Minelab engineers/testing facilities , etc.