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Reliable Test For Comparing Target Separation Capabilities?


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While we're all abuzz with the announcement and advertised feature and performance characteristics of the XP Deus II, I'm wondering about tests that distinguish between detectors' target separation abilities.  'Word on the street' is that in trashy iron sites, the original Deus is still the best available.  Presumably those reports are based upon in-field testing, which of course is the real proof.  But the downside is, (AFAIK) these are qualitative observations, not quantitative.  Subjectivity involved?  Unfortunately, yes.

We do have Monte's Nail Board Test for a special case -- iron nails near a single coin, all in the same plane and typically all on the surface of the ground.  Add depth combined with some mineralization (burying the MNB) and you've included another real world dimension.  But in the field, multiple nearby targets are seldom in the same plane.

So you hopefully see the purpose of this post.  Has anyone seen/tried other methods to better simulate actual in-field conditions to differentiate between competing detectors to best be able to handle trashy sites?

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I have several set ups in my test garden that mixes targets/trash at varying depths & orientations. I try to simulate different sites I hunt. It is very informative & shows each detector/coil/frequency's capabilities at various settings.

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I think a good test ,, is a relatively simple 3D separation test ... where the coin is placed on 10-11 cm in the ground ... and the nail is placed on the surface of the terrain .... as close as possible to the center of the target./ v deep-seated coin ... where the tested detector can separate the nail well ... and put a good signal on a relatively deep-seated coin ..

In this test, Atrex can separate 3 grams of iron nail from 14 mm -0.5 grams of silver hammered coin / placed at a depth of 11 cm / at a distance of 13 cm ... This is a really great result. - so this detector has a really good 3D separation predisposition ...

There are enough detectors that have a problem separating such a nail even at a distance of 30 cm from the coin in this 3D test ...!!!

3D separation Excellent detectors can deal with a nail somewhere in the range of 13-18cm..from the place-center ..where the coin is stored ..

Another important thing ..
   At the end of the test, I still have a control test for the correctness of discrimination ... where the signal on the nail itself is right in the tone of iron ... and the signal on a separate coin is a nice non-ferrous signal ..

Everything must be clear and distinct in such a test ...

In such a 3D test I use at least 2 small types of coins .. low conductive silver coin and high conductive copper small coin .... 

 

 

 

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You could make a depth test bucket which could also function as a 3D separation test bucket and fill it with whatever sand or soil you need to test in to try multiple different scenarios.

 

Depth-Separation-Test-Bucket.jpg

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I did quantitative tests this summer in the field in an iron infested area , a comparative test between a Deus HF 9in , an Apex Ripper and a Vanquish 540V8.  I dont use experimental separation tests any more because I found them not reliable enough , due to the complexity to reproduce a real iron trashed soil environment . 

1 - Gold medal  XP Deus Lite WS4 HF 9in , 7 coins found during 1h20 ---> 5 coins / hour

2 - Silver medal Garrett Apex Ripper        , 6 coins found during 2h     ---> 3 coins / hour

3 - Bronze medal Minelab Vanquish 540 V8  , 3 coins during 2h         --->  1,5 coin / hour

 There is no better simulation than ... reality  🙂🙂

Notice that there are huge differences between the detectors , this is not the case with pure depth tests in clean soil where the differences never exceed 20% 

 

Look at the following thread below for more details , last post :

 

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I'm currently working on this very issue. I intend to use Monte's Nail Board, but modify it so the board is a few inches thick so I can place the penny or dime on the same plane as the nails or on a lower plane. I intend to use this to compare the Equinox 600 to the Garrett AT Max and maybe my Vanquish 340 and Fisher F2.

If I get around to building and testing it, I'll let you know how it works out.

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As an engineer, I like and appreciate the experimental method as a means to seek absolute truth. Not only is it a fun exercise to solve the problems associated with devising a valid experimental method but it can also enhance learning.  

That being said, when it comes to detecting, I have concluded that no physical test can cover every situation and variable. Take Monte’s nail board test.  How often in the wild are targets all lined up on the same horizontal plane.  Furthermore, we are at the point of splitting hairs on detector performance to the point of crowning one king over another is somewhat pointless.  I don’t expect the Deus II to significantly out perform my Deus or Equinox on separation.  I still plan on getting a Deus II for reasons I will explain in detail in a more appropriate thread but it has less to with performance and more to do with versatility, ergonomics, and an interface that enables settings to be efficiently and quickly manipulated on-the-fly to enhance rapid target interrogation techniques.

Other than existing solely as a crude pre-season detector “op check” test bed, I no longer use my test garden as means to benchmark and compare detector performance.  As a result, what I have gravitated towards is learning a small core of 3 or so detectors inside and out (VLF and PI) and hone skills associated with coil control and manipulating settings to enhance target interrogation and identification under realistic field detecting situations (real world learning).

To really achieve a useful means of evaluating detector capabilities, I think the best approach is building detailed digital analytical models of detectors and representative challenging target “problem” situations.  Digital models enable controlled manipulation of both detector parameters and target situation variables (e.g., material composition, shape, mass, depth, soil characteristics, masking ferrous and non-ferrous trash, EMI sources, etc) to see which detectors excel under specific controlled conditions without the practical physical limitations a test bed presents.  Again, this takes significant investment and knowhow (including access to potentially proprietary detector information) such that it is also a likely unrealistically achievable.

Anyway, not trying to suppress innovation or experimentation here, just explaining why I have moved on from such endeavors.  Especially in regards to the futility of evaluating performance for the purpose of answering the question “what detector is best”.  The answer to that question, quite simply, is the detector you use the most and that is a subjective, personal decision that is more about feel than it is about specs.
 
Still interested in seeing what folks come up with, though.  It makes for interesting reading at least even if concrete, objective and irrefutable results are unlikely.

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1 hour ago, Chase Goldman said:

To really achieve a useful means of evaluating detector capabilities, I think the best approach is building detailed digital analytical models of detectors and representative challenging target “problem” situations.  Digital models enable controlled manipulation of both detector parameters and target situation variables (e.g., material composition, shape, mass, depth, soil characteristics, masking ferrous and non-ferrous trash, EMI sources, etc) to see which detectors excel under specific controlled conditions without the practical physical limitations a test bed presents.  Again, this takes significant investment and knowhow (including access to potentially proprietary detector information) such that it is also a likely unrealistically achievable.

Yes, and yes.  Consider weather modelling (a much more difficult problem for sure, but also one that gets 100's of millions of $ of annual support because it impacts the entire poplulation of the world, not the miniscule subset of metal detectorists, let alone the minute number of that group who even care about this subject).  Knowledge of weather was known at some level for millenia yet it is only in the last decade or so that computer models have become reliable for short term (1 day to maybe 3 days?) and a week or longer predictions have large uncertainties.

1 hour ago, Chase Goldman said:

Still interested in seeing what folks come up with, though.  It makes for interesting reading at least even if concrete, objective and irrefutable results are unlikely.

IMO there is little doubt a continuous spectrum of objectivity exists, and the more data the better.  As far as irrefutable, the only time that happens is with problems so trivial their results aren't impactful or someone is burying his/her head in the sand accepting nothing more than beliefs.

Is the Monte Nail Board Test of value?  Is that as far as we can go to get meaningful results??  Finally, is it worth the effort???  (hint:  More question marks at the end of a sentence indicates it's a tougher question.  😄)

 

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I’m with Chase on this also. I had a very basic test garden at our old house.  Now that we’ve moved I have no intention of making another. After 3.5 years of at least weekly hunts with my nox I like digging weird, iffy signals just to learn what they are.  I wish I had done this more when I first got it.  Just too many variables out there to just dig textbook signals.  

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