Separation Testing: Artificial Vs Realistic Conditions

[ColonelDan]

We’ve all seen numerous separation tests posted on YouTube and the vast majority that I’ve seen are simply air tests. I've conducted numerous separation tests over the years and one thing is most apparent....at least to me....air testing separation capabilities borders on a waste of time...for the most part.

Most recent example; I successfully separated good targets from bad using the Deus II in Beach Sensitive during an air test i.e. targets were exposed on the ground’s surface with approximately 1 inch separation. When I buried those same targets at the same distance, one from the other, at a depth of 3 and 6 inches, NO separation….and this is not unusual.

I pretty much ignore air tests of any kind. Why? That's obviously NOT the way we hunt. We detect targets that are buried in sand or soil don't we? I always abide by the Army approach from my day...."Train as you fight."

Can you get something out of air testing? Doubtful, maybe, sometimes, but don't take those results to the bank...if you do you'll be sorely disappointed when you apply those same parameters/results to buried targets.

Bottom line...for me: Tests that are conducted under the same realistic conditions that we find in the field will be much more reliable than those conducted under artificial conditions such as air tests...no matter how elaborate. I've seen far too many spurious results from tests conducted under artificial conditions.

 

Just the experience from my old foxhole....you may have a different experience.

 

[palzynski]

31 minutes ago, ColonelDan said:

...you may have a different experience.

No , I have exactly the same experience  ... 🙂 

I found the air separation tests to be not reliable and I ve done lots of them ...

For example , a Vanquish is better than a Deus on an air separation test . In the field it is a completely different story and a Vanquish is much more difficult to use than a Deus in my local ( French ) iron trashed areas ..

 

 

[King-Of-Bling]

I learned this long before YouTube and its menagerie of buffoons. If I relied on air tests , I would only be digging 10% of my targets.

[abenson]

For the most part I agree. However, we that hunt western ghost towns know that in areas that have been undisturbed, nails, coins and other artifacts basically lay right on top of the ground. So a test like Montes nail board has relevance. I can't even count the number of times I've got a signal and looked down to see the edge of a coin or token exposed from a thin layer of dust amongst a bunch of nails.

In the case of buried targets at different planes, I agree that air test have no use. In the wild, for the most part I've found that 90% of the targets in iron infested sites will be seen by most modern metal detectors. The best of the best get the remaining 10%. I've taken as many as 6 different metal detectors out at a time to compare countless signals in trashy sites and I think what I've stated above is pretty accurate.

[GB_Amateur]

One thing I learned a long time ago, too:  know the assumptions.  The problem isn't with air tests per-se, but the (mis-)interpretation when the assumptions aren't taken into account.

Going further, it's fairly easy to do an in-ground test with a single target only (meaning no nearby good OR bad targets).  How do you do a test with even just two targets?  You can bury them but they stay forever separated (in all three directions -- left/right, forward/backward, up/down) by the same amount.  What happens in the field?  All those distances vary, and sometimes you get even more than two metallic objects within the coils zone of influence.

So, are test garden results worthless?

Air tests have their value.  Test garden investigation has its value.  If you expect those to tell you everything about what will happen in the field....  But to blanket throw those tests in the trashcan is also sub-optimal.

[Jeff McClendon]

I mostly do separation tests and tests like Monte’s nail board test with the targets either laying on top of basically target free ground in the wild or on top of iron mineralized ground test samples so that ground balance and recovery speed settings actually have some realistic bearing on the testing. That is the type of ground I find most of the older pre 1900 targets in and it gives me at least a starting place for settings that might work and some indication of audio and target ID anomalies that might happen.  Otherwise, air separation tests only tell me very basic information which may or may not transfer over to real life detecting conditions where I detect. 

[EL NINO77]

With the separation test in the first row, you have to realize...what type of separation is involved....I divide separation into 3 types...

  ...The first type is a Flat 2D separation test - let's say a Monty performance nailboard type Test where the coin and the nails are placed in one plane... - and the places you meet are places like Ghost Town or even stones on the road ... where coins and keys and other iron are stored shallowly at approximately the same depth.

The tested detector must be able to handle 2D separation well...but often a smaller DD or concentric coil will help in this type of separation..the interesting thing is that the tested detector may not be good at 3D deep separation...-but it can be good at 2D separation..

The second type is the 2.5 D separation test, where the coin and the iron are on the surface from the side, but the coin is buried about 5-8 cm deeper... and at the deep ... level of the coin, additional iron can be deposited... In the field, you can very often encounter such a situation, mostly in the rocky terrain of a field or forest....but also in agricultural fields, which are often worn and in demand objects, but also iron in the ground, every time they modify their position, they often change their position...

In this test, the detector must handle the 2D separation well...but, among other things, it must also match the 3D separation well...to achieve good results in this test...coils of size 5-9" can prove themselves well in such a separation.

The 3rd type of separation is 3D depth separation where the coin is placed at a depth of 10,15,20. cm..and the iron is placed on the surface from the side or even several pieces of iron from several sides above the coin.. This is a typical ancient place where many lived civilizations and coins and iron are stored in different layers of the terrain ..... Only detectors with exceptional 3D depth separation will give really good results here... and such detectors can detect targets 15-20 or more cm deep .... between iron..
It may be a surprise that the best detection coils here are 9"-11"...

From my point of view, I do not underestimate any of these 3 types of separation test....and quite the opposite....if the tested detector successfully passes the 2D flat, 2.5D shallow and 3D deep separation test...then I consider this detector to be really successful. ..

...In real detection, the experience of testing that can optimize the detector setting for the best possible separation and correct sweeping with the coil ... will translate relatively quickly to good results in detection in such an environment..v. terrain heavily loaded with iron where good targets are still disguised...

In this video, I tested and detected with the detector on an old stone road... with a strongly set discrimination to + 26 so that I completely removed the aluminum foil signal... but still maintained excellent unmasking on very small silver hammered coins that give VDI 35-40...

Such a detector setting will allow you to fully concentrate on detecting the desired targets that have the right VDI targets....

 

 

[KD8GIS]

  When less is better.  Would you take your detector and set the 1-10 sensitivity settings down to 2?  Then turn the discrimination settings up most the way?  I think we all want to set everything up to maximum, Get every last inch and everything including large iron.  Half the time the detector is overloading, seeing 3D clutter, nulling out, masking.  Be honest. 

 I'll be first to admit it. We then go for smaller coils, narrow the search area for the detector to work with. Separation, Recovery speed is the talk, Are we asking too much of the detector? 

  "Back when" I didn't know what I would call that.   I did go about it in a manual way,  County fair grounds, over a 100 years old.  Layer after layer of targets and trash.  I knew the good stuff was there, I just had to work for it. Pick an area and take the loud big targets one by one and dig them out, go back over it and take the next layer out and start getting the silver, Each layer I cleaned out got better finds. There's no detector on the markets today, or ever for that matter that could sort thru that mess and pick out the good stuff.  Less can be better.