Short video I did about iron unmasking ---8/28/18 added another VIDEO

Nothing special but maybe shows something about how hard it is to unmask.
Part 1
[youtu.be]

Part 2
[www.youtube.com]

Keith

“I don't care that they stole my idea . . I care that they don't have any of their own”
-Nikola Tesla



Edited 1 time(s). Last edit at 08/28/2018 08:09PM by Keith Southern.

Great video. Like how it points out recovery is not separation. Did I say that right?



Edited 1 time(s). Last edit at 08/21/2018 01:21AM by Mike C.

Old skool

Good vid Keith

Food for thought. I got to watch my bad habits in the thinner iron as I tend to speed up. The site I found the silver buckle on is spread out just like your talking about in the video.

Very informative video,Keith--thanks for your efforts.

Some interesting stuff in that video; thanks Keith!

Steve

Hate to disagree with you, Keith...


but I think your video was very special! <g>

It just defies logic how the penny right on the end of the nail can be heard, yet become silent when moved FARTHER from the nail. Mine blowing!

Never hunted out. You don't know what you don't know. So many spatial possibilities for co-locates and we're trying to figure out what's behind (under) the curtain!

One of the more sobering aspects of what your video shows is how detector A with coil B and setup C can be just the ticket for one set of co-locates at point in time D, at location E, but conceivably be absolutely wrong for the next set of co-locates a moment and a few feet - even inches - later.

this (your) video = instant classic!

Wayne

ncwayne Wrote:
-------------------------------------------------------
>... detector A with coil B and setup C
> can be just the ticket for one set of co-locates a
> t point in time D, at location E, but conceivably
> be absolutely wrong for the next set of co-locates
> a moment and a few feet - even inches - later.


Perfect truth.

I found my F19 similar, once you get to beyond half the width of the coil it misses targets, the Rutus was probably one of the best i've tried in that scenario using general hunting settings, it seemed to hit from any angle.

F19 +hunter coil, [youtu.be]

Enjoy all your videos Keith. The Monte nail board test is just one of many tests....not the tell-all, end-all for showing a detectors strong (or weak) points. We can learn a lot from even your "thinking-out-loud-moments". Most of the nails I have dug have been rusty and bent....never dug a perfectly straight, shiny nail. What about a nice big rusty fence staple....man what a pain. What is your opinion on concentric vs DD coil, when it comes to masking?? It amazes me what the Vista brand detectors can do in iron...all with the DD coil. I tried a rare 8" concentric coil on the Minelab Sovereign and found a carved bullet out of a thick iron patch....what a shocker. I had to sweep super slow tho.

Appreciate the tips, Keith. I'm about to head to a site and use some of this today!

HH

truly makes ya wonder if JUST "fast processors" really do cut it.
apparently not,because even a 'super quick" reset when the distance
widened between the nails and the coin failed to get a clean high tone!
fascinating.

(h.h.!)
j.t.

Great video Keith. That's another reason why a site needs to be worked from several different directions and slowly.

Yes so much more to the un-masking puzzle than meets the eye.

You can get drawn into a false sense of sureness that your working a site to its full potential ...But hardly the case and in the real environs things are much more complex.

Always try to dig at least bent nails L-shaped in a nail ridden site if you've removed all the bigger iron and gotten it to just nails...the next step is drop disc lower on that site and dig some bent nails and yes the U-Shaped ones like fence staples is mandatory...The better nuanced audio your machine has the better this can be accomplished and the better resolution in iron range your machine has helps immensely as touch having variable tone break.

Ive stated this probably more than I should in last few months BUT again adding a Concentric coil to a machine that EXCELLENT at unmasking abilities like the Kruzer Impact Etc is quite welcome..Not really for depth gains in open areas but for ability to use the bleedy blendy audio exact tone break setups more audibly intelligent..A concentric offers some great things in trash and iron That DD's do not..one is less falsing..were we have become accustom to using a DD in iron on a say higher freq unit to give it advantages say on a machine like a T2/F75 type unit where they dont have alot of bleed or blend or exact tone breaks the DDs helps to Give it some of that bleed feel in the audio...But when we have a unit that can do it in the machine then you add a DD it can on some sites be to noisy and become less intelligent in the audio...The concentric seems to be a great match up to a more advanced filtering machine..Ive really latched onto something with the Makro/Nokta 7 Concentric...its as good Separating as the smaller 5 DD but deeper!! and just really offers CLEANER hits in iron on overall..I would welcome a 5' and 9" Concentric and have requested such..


we are just scratching the surface on TRYING to hunt in trash and iron intelligently ..That's why I dont focus much past a machine passing down the barrel on a nail,,, that's just a gauge for me to show some sort of workable promise but as far as really unmasking its at this point SKILL levels and understanding of target interactions and digging a lot of iron out of the way..Detectors can do alot of things but they cant also and you have to adapt your skill levels for the things it cant do..


Keith

“I don't care that they stole my idea . . I care that they don't have any of their own”
-Nikola Tesla

Would be something to see a Vista Gold, XP Goldmaxx, or Deus use a concentric coil. Im not sure if a mono coil is the same as a concentric, but i prefer it over a DD coil on the pulse TDI.

And...… In carpets of nails...……………. at best...…… with today's modern technological advancements...… we're still only unmasking no more than 5% of the non-ferrous targets. (More like 2% - 2.5%).

Keith - thanks for the video - very informative

Great video Keith. Now all we need is a detector that can see thru iron and tell gold from foil.

Rick

I've often wondered about a continuous tone report disc circuit..Have it be able to almost be non motion even have the soil create a tone by intensity of it in the low Hz range below iron tone..Just move along and as targets come under coil have a calliope type report of colour rises and falls blending together ...Have it so you can just inch by inch and paint a sonic picture of the area under the coil in your minds eye..


FBS on smooth setting can get close to my Vision.but not quite.

Keith

“I don't care that they stole my idea . . I care that they don't have any of their own”
-Nikola Tesla

The video shows 2 entirely different mechanisms that are often misunderstood. When a nail and a coin are co-located, "recovery speed" is meaningless. An induction-mode detector sees the 2 targets as a single target; the nail response cannot be separated from the coin response, no matter what the recovery speed is. The result is a composite signal that depends what the targets are, orientation & depths, plus how the detector is designed (mostly the frequency and DSP). Generally, the nail "pulls" the coin VDI to a lower value. If you place a quarter and a nail together, perhaps the overall result is a dime, or maybe a zinc cent. If the disc is set somewhat low, you get a "good" result and you think, "Hey, my detector can see a coin through a nail!" But maybe a nickel gets pulled into the the foil or iron region and gets disc'd out.

As you separate the coin and the nail, eventually the detector sees 2 distinct targets. The distance at which this occurs is a measure of recovery speed. When I test a detector for recovery speed, I place a coin with nails on either side so that left-right sweeps give the same response. The detector is in motion-disc mode with disc turned all the way down so all targets can be heard, and preferably with tone ID and iron grunt turned on. I start with the nails way out, maybe 8 inches from the coin. Few detectors are so slow that they cannot resolve 8" separation. I sweep the coil to the tick of a metronome, at a rate of 3ft/sec. I move the nails inward toward the coin until I no longer get a distinct bonk-beep-bonk response. This is a measure of recovery speed. I then place the nails as close to the coin as possible, but not touching, and measure the composite response (as a bonus).

The variables involved are immense, so this test has no absolute meaning, only relative. Coin type, nail type, orientations, depth differential, and ground conditions all play a role. I use a quarter and new 16d nails, coin & nails coplanar, nails perpendicular to the sweep, and 3ft/s sweep speed, in the air (actually I have a wood test fixture). While not a real-world test in the least, it is repeatable by anyone anywhere, and does give a meaningful result in terms of recovery speed.

The iron / coin test video shows that this type masking does happen.....to me that reality is important. What to do to resolve or minimize the problem is debatable. Some metal detectors dont even blend (average).....iron signals tend to dominate and low tone (or silence). Many variables is understood. To resolve a problem we must first admit that a problem exists....sometimes seeing is believing. There are various types of masking, but masking is still masking. Any input is appreciated....it is a group effort to fully comprehend it all. Thanks



Edited 1 time(s). Last edit at 08/26/2018 03:25AM by Arkansas.

Geotech Wrote:
-------------------------------------------------------
> The video shows 2 entirely different mechanisms th
> at are often misunderstood. When a nail and a coin
> are co-located, "recovery speed" is meaningless. A
> n induction-mode detector sees the 2 targets as a
> single target; the nail response cannot be separat
> ed from the coin response, no matter what the reco
> very speed is. The result is a composite signal th
> at depends what the targets are, orientation & dep
> ths, plus how the detector is designed (mostly the
> frequency and DSP). Generally, the nail "pulls" th
> e coin VDI to a lower value. If you place a quarte
> r and a nail together, perhaps the overall result
> is a dime, or maybe a zinc cent. If the disc is se
> t somewhat low, you get a "good" result and you th
> ink, "Hey, my detector can see a coin through a na
> il!" But maybe a nickel gets pulled into the the f
> oil or iron region and gets disc'd out.
>
> As you separate the coin and the nail, eventually
> the detector sees 2 distinct targets. The distance
> at which this occurs is a measure of recovery spee
> d. When I test a detector for recovery speed, I pl
> ace a coin with nails on either side so that left-
> right sweeps give the same response. The detector
> is in motion-disc mode with disc turned all the wa
> y down so all targets can be heard, and preferably
> with tone ID and iron grunt turned on. I start wit
> h the nails way out, maybe 8 inches from the coin.
> Few detectors are so slow that they cannot resolve
> 8" separation. I sweep the coil to the tick of a m
> etronome, at a rate of 3ft/sec. I move the nails i
> nward toward the coin until I no longer get a dist
> inct bonk-beep-bonk response. This is a measure of
> recovery speed. I then place the nails as close to
> the coin as possible, but not touching, and measur
> e the composite response (as a bonus).
>
> The variables involved are immense, so this test h
> as no absolute meaning, only relative. Coin type,
> nail type, orientations, depth differential, and g
> round conditions all play a role. I use a quarter
> and new 16d nails, coin & nails coplanar, nails pe
> rpendicular to the sweep, and 3ft/s sweep speed, i
> n the air (actually I have a wood test fixture). W
> hile not a real-world test in the least, it is rep
> eatable by anyone anywhere, and does give a meanin
> gful result in terms of recovery speed.

Why don't you give us a demo Mr. instead of criticizing Keith.

Mickie Wrote:
-------------------------------------------------------
> Geotech Wrote:
> --------------------------------------------------
> -----
> > The video shows 2 entirely different mechanisms
> th
> > at are often misunderstood. When a nail and a co
> in
> > are co-located, "recovery speed" is meaningless.
> A
> > n induction-mode detector sees the 2 targets as
> a
> > single target; the nail response cannot be separ
> at
> > ed from the coin response, no matter what the re
> co
> > very speed is. The result is a composite signal
> th
> > at depends what the targets are, orientation & d
> ep
> > ths, plus how the detector is designed (mostly t
> he
> > frequency and DSP). Generally, the nail "pulls"
> th
> > e coin VDI to a lower value. If you place a quar
> te
> > r and a nail together, perhaps the overall resul
> t
> > is a dime, or maybe a zinc cent. If the disc is
> se
> > t somewhat low, you get a "good" result and you
> th
> > ink, "Hey, my detector can see a coin through a
> na
> > il!" But maybe a nickel gets pulled into the the
> f
> > oil or iron region and gets disc'd out.
> >
> > As you separate the coin and the nail, eventuall
> y
> > the detector sees 2 distinct targets. The distan
> ce
> > at which this occurs is a measure of recovery sp
> ee
> > d. When I test a detector for recovery speed, I
> pl
> > ace a coin with nails on either side so that lef
> t-
> > right sweeps give the same response. The detecto
> r
> > is in motion-disc mode with disc turned all the
> wa
> > y down so all targets can be heard, and preferab
> ly
> > with tone ID and iron grunt turned on. I start w
> it
> > h the nails way out, maybe 8 inches from the coi
> n.
> > Few detectors are so slow that they cannot resol
> ve
> > 8" separation. I sweep the coil to the tick of a
> m
> > etronome, at a rate of 3ft/sec. I move the nails
> i
> > nward toward the coin until I no longer get a di
> st
> > inct bonk-beep-bonk response. This is a measure
> of
> > recovery speed. I then place the nails as close
> to
> > the coin as possible, but not touching, and meas
> ur
> > e the composite response (as a bonus).
> >
> > The variables involved are immense, so this test
> h
> > as no absolute meaning, only relative. Coin type
> ,
> > nail type, orientations, depth differential, and
> g
> > round conditions all play a role. I use a quarte
> r
> > and new 16d nails, coin & nails coplanar, nails
> pe
> > rpendicular to the sweep, and 3ft/s sweep speed,
> i
> > n the air (actually I have a wood test fixture).
> W
> > hile not a real-world test in the least, it is r
> ep
> > eatable by anyone anywhere, and does give a mean
> in
> > gful result in terms of recovery speed.
>
> Why don't you give us a demo Mr. instead of critic
> izing Keith.


Mickie----Do you know who you are talking to? (Geotech)

D&P-OR wrote:

> Mickie----Do you know who you are talking to? (Geo
> tech)


Obviously not del

Guy can’t tell the difference between criticism and valuable input either it seems.

It's probably me, but Geotech's post confuses me, as it seems contradictory.......No need to point it out..... to see if it jumps out on someone else.....No disrespect just questioning Geotech and yes I know who he is guys.

Thanks, Carl, for your input, but it raises more questions than it answers, for me anyway.

I think we need a definition of "co-located." Is it a function of distance, specific metals, or machine response?
Please name/define the two mechanisms you mention. You may have already done that. <g>
Please explain why there is a signal on the coin right next to the end of the nail (in Keith's video): co-locate, one target with coin VDI pulled down by nail (your explanation as I understand it) but NO signal at all when the coil is swept over the nail and coin with greater distance between them. I can only surmise that you are saying this represents two targets and recovery speed insufficient to signal on both targets? (I don't think that this is the case, but it aligns with what you have said, if I understood correctly.)

And this one is well over my head, but don't different detectors handle audio differently? I mean don't some take short interval "snapshots" of what's under the coil while others employ an "open audio gate" so that in the first case, the audio of one target can mask the presence of a closely located second target, while in the second case, the open audio gate signals both targets in quick succession, even to the point of blending the audio response of both targets if close enough together? Is this the same as recovery speed?

Wayne

Carl is merely stating: laws of (emotionless) physics...… with Zero human intervention.

When a electromagnetic field is exposed to iron...…. certain things happen...… and certain (other) things will not happen. Laws/principles of physics!

Mickie Wrote:
-------------------------------------------------------
> Why don't you give us a demo Mr. instead of criticizing Keith.

Not criticizing Keith, at all. I have tremendous respect for him. Just trying to explain the mechanisms going on.

ncwayne Wrote:
-------------------------------------------------------
> I think we need a definition of "co-located." Is it a function of distance, specific metals, or machine response?

A strict definition would be 2 targets on top of each other. But a nail is longer than a coin so in one direction its dipole response(s) aren't coincident with the coin. With a big enough nail and a wicked-fast recovery, it would be possible to resolve 2 targets (3, actually) when sweeping parallel to the nail. This is why I do my tests with the nail perpendicular to the sweep, so the dipole response is in the middle instead of at the tips.

> Please explain why there is a signal on the coin right next to the end of the nail (in Keith's video): co-locate,
> one target with coin VDI pulled down by nail (your explanation as I understand it) but NO signal at all when
> the coil is swept over the nail and coin with greater distance between them. I can only surmise that you are
> saying this represents two targets and recovery speed insufficient to signal on both targets?

There is always a signal on the coin, no matter where it is at. When close to the nail, the detector sees both targets as one. As the coin is moved away, it becomes a second response that is dropped due to insufficient recovery speed. As it is moved even further away, it gets detected again when the recovery speed allows it.

> And this one is well over my head, but don't different detectors handle audio differently?

Yes, the DSP and audio processing play a huge role in how co-located targets ID. As a coil is swept over a nail+coin the real-time vector response is a complex mess of squiggles as opposed to a normal clean line. Some detectors take a snapshot and report on the peak, which might be dominated by the eddy responses resulting in some kind of "good coin" TID. Other detectors try to follow the vector response which might produce a calliope of sounds. Ironically, a nail on a coin closely mimics a steel bottle cap so you have opposing goals: find coins in iron, but ignore bottle caps.

Its interesting that with all the advances in technology that a simple video can show the humbling facts of masking (various types).....using modern equipment. I know Tom has produced videos on the subject also. It is a continuous learning process and these videos are of incredible value to actually see all these physical laws in action vs just words on paper. Thanks to all the video producers. Let us not forget the basics of good metal detector usage...like sweeping more slowly. Don't let the fancy machine numb our minds to forget these principles.