Iron masking

[Koala]

https://www.youtube.com/watch?v=6FFA...ature=youtu.be


Am I missing something in this video.

[Koala]

Kinda answered my own question.

On another forum I found this

"This test peaked my interest and was something fun to do tonight.

used an Australian shilling 925 silver bit smaller than a quarter and a 3" nail

just grabbed what I had set up and a couple swap outs.

Cibola with CSC : Pass

Vaquero with 6 x 8 Detech DD coil : Pass

Outlaw with 7" concentric coil : Fail

Compadre with 5.75" Concentric coil: Fail

Silver Micromax 4" Concentric coil: Fail

F19 10 x 5 Fisher DD coil : Pass

CTX 11 DD coil: Pass

Compadre 7" DD coil: Pass

Silver Micromax 7" DD coil :Pass

Silver Micromax 5.75" Concentric coil: Fail

Outlaw 7" DD coil: Pass"

Seems DD pass and concentrics fail this test but don't understand why

[Nupi]

Turn the nail 90 degrees and test it again!

[Koala]

Yep good spot Nupi. Quite a large rusty nail turned through 90 degrees above a Canadian dim is detected with my bandido and 6" concentric. But only if you swing slow and pinpoints 1.5" to the side.

[Arthur-Canada]

Wilson

Kinda answered my own question.

On another forum I found this

But the Wilson does not have a DD coil.
"This test peaked my interest and was something fun to do tonight.

used an Australian shilling 925 silver bit smaller than a quarter and a 3" nail

just grabbed what I had set up and a couple swap outs.

Cibola with CSC : Pass

Vaquero with 6 x 8 Detech DD coil : Pass

Outlaw with 7" concentric coil : Fail

Compadre with 5.75" Concentric coil: Fail

Silver Micromax 4" Concentric coil: Fail

F19 10 x 5 Fisher DD coil : Pass

CTX 11 DD coil: Pass

Compadre 7" DD coil: Pass

Silver Micromax 7" DD coil :Pass

Silver Micromax 5.75" Concentric coil: Fail

Outlaw 7" DD coil: Pass"

Seems DD pass and concentrics fail this test but don't understand why

But Wilson does not have a DD coil

[Koala]

But Wilson does not have a DD coil

Don't have a Wilson to test so can't find out what's going on.

I have tested the nail, coin and nail. Where the nails are 2" higher than the coins.

Tested with a IDX with a 10" DD and 8" concentric. The DD wins if I swinging down the nails and the concentric wins if I swing across the nails. So explains the results in the long list.

[Arthur-Canada]

Don't have a Wilson to test so can't find out what's going on.

I have tested the nail, coin and nail. Where the nails are 2" higher than the coins.

Tested with a IDX with a 10" DD and 8" concentric. The DD wins if I swinging down the nails and the concentric wins if I swing across the nails. So explains the results in the long list.

I would think that the concentric will always fail if you swing the length of the nail. Across the nail, the Wilson seemed to be the only one that could do it. All DD coil machines that I have tested have been able to do it across the nail. Never tried along the length of the nail with DD.

[ionut_mtb]

Recently i hunted on a roman field, settlement loaded with iron. Most of the coins found there were not deep, very close to the surface. Each year after the tractor plough the field, new targets appear. I have xp deus. Now, there are a lot of settings to adjust, but will not improve much. Who has experience with this, maybe can give some input. Looks like other detectors can see through iron, what is the explanation? Depth is not important, separation is.
On this thread: https://www.geotech1.com/forums/show...613#post213613
#314, #315 i found useful information.
Smaller coil can be a solution. What about frequency, signal amplitude?
Main targets are small silver coins, copper coins.

[Koala]

Recently i hunted on a roman field, settlement loaded with iron. Most of the coins found there were not deep, very close to the surface. Each year after the tractor plough the field, new targets appear. I have xp deus. Now, there are a lot of settings to adjust, but will not improve much. Who has experience with this, maybe can give some input. Looks like other detectors can see through iron, what is the explanation? Depth is not important, separation is.
On this thread: https://www.geotech1.com/forums/show...613#post213613
#314, #315 i found useful information.
Smaller coil can be a solution. What about frequency, signal amplitude?
Main targets are small silver coins, copper coins.

there's two different types of masking

recovery speed

separation


lets take separation. Place a large piece of iron on the ground. The place a tiny target next to it. No detector will see through the iron. The First it detected is at half the coil diameter. I have test lots of targets and machines and its always the same. Its always coil dependent

now let's take recovery speed. After seeing iron how long is it before it can detect again. Look on YouTube for Norfolk Wolf machine test. This is machine dependent. A fast recovery doesn't find any more targets, but does mean you can swing faster in iron.


There is no magic machine


There are plenty of "fake" YouTube videos implying a machine is better than any other. As an example there's a video say its the only detector that can see through iron. They place a coin on the ground and cover it with nails. Then swing across the nails. I have tried this for myself and any machine will pass this test. Swing down the nails it fails which isnt shown in the video.


There's loads like this. You can fudge the Monte nail test by changing the settings but would be unusable in a real field and so on.


Concentric and DD preform differently but one isnt better than the other.

[ivconic]

Recently i hunted on a roman field, settlement loaded with iron. Most of the coins found there were not deep, very close to the surface. Each year after the tractor plough the field, new targets appear. I have xp deus. Now, there are a lot of settings to adjust, but will not improve much. Who has experience with this, maybe can give some input. Looks like other detectors can see through iron, what is the explanation? Depth is not important, separation is.
On this thread: https://www.geotech1.com/forums/show...613#post213613
#314, #315 i found useful information.
Smaller coil can be a solution. What about frequency, signal amplitude?
Main targets are small silver coins, copper coins.

I will tell you how i search with the Deus under such conditions.
First to mention that i have also lot of such sites here.
When i step on such site, as you described; first i do proper ground balancing, manually, by bobbing a coil and adjusting GB until is balanced well.
Next i switch to Deus Fast preset. Rise sensitivity to 94. Iron volume 3-4. Disc at 4.
Reactivity 2.5-3. But MOST IMPORTANT is silencer. I rise it to 3 and often to 4. In case i don't want to hear iron trash.
In case i want to hear all the signals; silencer -1 to 0.
And than i do the fast but short swinging over each target. Crossing and swinging.
You have to listen carefully the response.
No matter the detector; most of the job is done by "human factor" and experience.
Such sites are pretty tricky but in my book those are most desirable type of sites and most interesting to search.
XP Deus is good and can handle such sites very well.
But only if you add the "human factor".

[waltr]

And than i do the fast but short swinging over each target. Crossing and swinging.
You have to listen carefully the response.
No matter the detector; most of the job is done by "human factor" and experience.
Such sites are pretty tricky but in my book those are most desirable type of sites and most interesting to search.
XP Deus is good and can handle such sites very well.
But only if you add the "human factor".

This part is very important regardless of which detector you use.
Here in the eastern USA I detect old farms. Lots of iron trash but also many good targets mixed in.
It is the 'human factor' that finds the good targets.

[ionut_mtb]

I will tell you how i search with the Deus under such conditions.
First to mention that i have also lot of such sites here.
When i step on such site, as you described; first i do proper ground balancing, manually, by bobbing a coil and adjusting GB until is balanced well.
Next i switch to Deus Fast preset. Rise sensitivity to 94. Iron volume 3-4. Disc at 4.
Reactivity 2.5-3. But MOST IMPORTANT is silencer. I rise it to 3 and often to 4. In case i don't want to hear iron trash.
In case i want to hear all the signals; silencer -1 to 0.
And than i do the fast but short swinging over each target. Crossing and swinging.
You have to listen carefully the response.
No matter the detector; most of the job is done by "human factor" and experience.
Such sites are pretty tricky but in my book those are most desirable type of sites and most interesting to search.
XP Deus is good and can handle such sites very well.
But only if you add the "human factor".

I use same settings like you, but silencer i use -1 almost every time, because, i think, if is iron infested, some good targets can give scratchy sound. GB every time. I also noted that 9” is better than 11” ( of course..). In the future i’m planning to make one smaller coil (round or oval) as i have two boards (one lf one hf from broken coils). What about frequency and tx power? So many setting to try with deus

[EL NINO]

Separation in iron can be divided into 3 groups:


Group 1 is "Signal averaging" - nail up and coin 2-3 down - this is well shown in the video .. with Wilson ..


2nd group 2D shallow separation - a classic and very good example is .. "Monte Performance Nailboard Test" ...


3. The group is a 3D deep separation ... and not every detector has such a * 3D predisposition.

[Melbeta]

I am not quite sure just what they do to IRON MASK. I thought it was more or less an method of filtering out a particular frequency, either with an unique circuit or a notch like circuit, to eliminate an particular resonant frequency. In other words they are not really masking the iron, but in circuits actually discriminating the iron they want to mask OUT???

Maybe one or both of the moderators can fill us in with this explanation???
Melbeta

[Carl-NC]

El Nino has the best response. Let's look closer...

"Recovery Speed" and "Separation" are really talking about the same thing, namely how fast a detector can detect a target, respond to it, and get reset for the next target. This can be 2 desired targets (say, 2 silver coins) or it can be a desired target next to a discriminated target like a nail. With many detectors the disc'd target has its audio blanked out so if the detector does not respond fast enough the silent nail can completely mask out the silver coin. I call this "recovery masking." If you get a good signal swinging the coil in one direction but no signal in the other direction it is likely because of this scenario.

I like to test recovery speed by placing a US silver quarter between (2) 16p nails and, while sweeping the coil at 1 m/s, decrease the spacing between the nails and the coin until the detector no longer issues 3 distinct responses. An average detector will give 3 responses down to 4"/10cm or so. An exceptional detector can get down below 2"/5cm. Any given detector will always perform better at this with a smaller coil. This test is what El Nino calls "2D shallow separation" because all targets are in the same plane, like Monte's nail board.

Once you get below the distance where the detector can give 3 distinct responses you begin to see a combined response. This is El Nino's "Signal averaging" case. If a nail normally has an ID of 20 and a silver coin is normally 85, then a silver coin and a nail together might ID at, say, 50. This is also a form of masking but it has nothing to do with recovery speed; no detector can recover fast enough to separate 2 targets exactly co-located. Let's call this "average masking."

El Nino's 3rd case -- "3D separation" -- is when you have, say, a shallow nail and a deep silver coin. Or vice versa. This can alter the recovery speed because, for example, a strong nail may more easily mask a deep/weak coin, so you need more distance between them in order to get the coin response. Also affects average masking as a strong nail and weak coin will have an average that is closer to the nail.