Nail board test are flawed

In my opinion nail board test are NOT like actually detecting in lots of trash, unless a person is going to detect every square foot from every direction, the test shows you nothing. The test are staged because you know the position of your target and the trash around it.

Not really flawed but as you say not real world either. When comparing machines in the field the one that reveals the squeakers from off angles that the other doesn't is what I look for. Unit A against Unit B. Recovery speed doesn't always equate to see-thru, it's only part of the equation.

Tom

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In a democracy, it is difficult to win fellow citizens over to your own side, or to build public support to remedy injustices that remain all too real when you fundamentally misunderstand how they see the world.

Tom...... good/correct response.

Tom

Appreciate you covering this aspect (rotation around targets) in your field report notes on the Impact. Highly informative and Keith's "squeakers". LOL

____________________________________________________________________________________________________________
In a democracy, it is difficult to win fellow citizens over to your own side, or to build public support to remedy injustices that remain all too real when you fundamentally misunderstand how they see the world.



Edited 1 time(s). Last edit at 02/23/2017 12:25PM by Jackpine.

I use the nail board test as a guage to tell me of a machine has the ability to handle the basic scenario of a desired object on the same plane as the unwanted objects. Tesoros have historically done well on this test, better than most machines out there. In the western US where climate has been dry, targets do not sink fast where you have areas where what was dropped over 100 years ago can still be seen just laying on top the ground, (nails, flat tin, buttons, coins etc) the tesoros excel. So depending on the location you are hunting, certain machines will outperform others and vice versa.

Yeah I say it's useless also especially when moisture content in the dirt comes into play. Drier = Better target separation.

I can see it being a useful guide for shallow hunting around small iron, personally i find the 3d tests far more useful/realistic to my detecting, something along the lines of Ziggys test tub, as i find more iron either above or below my finds, rather than on the same plane.



Edited 1 time(s). Last edit at 02/23/2017 01:02PM by ghound.

Nail board testing and airtesting are just very very basic tests that can be carried out in any part of the world and still give the same basic results ie i could test a Tesoro with a 8'' polo coil in London and New York and still get the same result either using the nailboard test or airtesting and just gives you some idea what the machine can do,the results are not set in stone.

But the test can then vary by a massive margin if used for 'in ground' testing,as luck would have it here in the UK our ground conditions are pretty mild,of course some location they can be on the wild side,i had access too a a prime roman site that was about as bad as it gets mineralization wise in fact it was that bad folks use to take samples home in ice crean containers etc and see if a new detector could penetrate through and pick up a coin underneath.Gary from Gary's detecting had some of this bad soil for a few of his test on other model aprt from XP ones.The trouble with this soil it was like wet black sand from the beach but 60-70 miles inland.

I guess its pretty easy to replicate a nail board test just using rusty nails and UK coinage or use coinage from your relevant country as part of the test,no good having US coinage if your main targets are silver hammered coins from a trashy saxon site.So a nailboard test and air testing is additional help in providing information about a detector,but certainly should not be used as the main buying criteria for sure.

deadeye,
I appreciate watching the various nailboard tests that folks post from the standpoint that when they define their settings, it helps me understand what a detector will do in a particular circumstance. Buying a detector off of someone's word from a place that I cant try it out...i have to depend on something. Listening to the tests, hearing the audio while seeing targets under the coil gives me a sense of "pleasing to my ear" for wanting to hunt with it for 4 hrs.

My version of nail tests is putting down junk targets I dug from prior hunts that fooled me (thought it was good) or big nasty thick rusty blob nails and putting coins and buttons next to/under those to see what those larger objects mask like, and how my detector (f75 in this case) performs.

I got an Indian Head cent on Sunday because even though I got a one way signal for at least 25% one way, turning a bit over 90 deg past it broke up bit, switched to FA since it was fairly shallow, and got a jangle of hits, now including a better high both ways back where I was getting the one way. I was looking for old, deep coins..got an 1889 shallow coin only 5" deep. I had been fooling around with one way signals a few weeks back on junk targets and dimes, and I don't think I would have stopped prior.

The only annoying thing about the IH, is that Ozzie called the date as a 1889 before either of us looked at it. The man is uncanny.

That's about as dead on as it gets Deadeye

1 foot 2x4 with a rusty bent 2-3" nail gopped in the middle and dime gooped on the bottom at one end and a nickel at the other end.
More useful and realistic,,my compadre want even come close,my cz 6a does the best of all.
Next best is my gamma 6000 and gold bug se 29er

------------"Cz's still bad to the bone".------------
Living on a big ass Astroid.
The woman that got my rib,I want it back.

No test is going to be applicable to any real-world situation that isn't exactly like the test arrangement. Vary the coin and nail(s) depth relation, inter-related 3D orientations ... vary the soil moisture, soil type, mineral/salt content and stratification ... vary the EMI - you'll get a widely different result - quite unpredictable with many unaccounted variables.

In other words, no test is good for anything except showing how detectors fare against each other within the framework of the test. Which is important. Because, that's all any test can do. They all mimic some tiny fraction of the real world inexactly. So, knowing this, I say design a variety of tests including nail board test and extrapolate the result to the real world in any way you'd like, hopefully without bias. The testing is objective, it is accurate, it is the truth for the domain of the test. The conclusions when applied to the real world are subjective - perhaps right, perhaps wrong.

If my detector fails the nail board test (it does) I won't expect it to do very well amongst randomly dispersed nails (it doesn't), that's going to be my subjective conclusion of the objective testing. Going head-to-head side-by-side in a nail-strewn field against another detector would validate the subjective conclusion.

The nail board test isn't wrong, it was accurate, even if the field tests yields different results. It simply means the tests do not correlated well, they aren't testing the same thing. So, again, the testing is accurate, it's the truth, but the real world scenario out in the field are often sufficiently different as to result in two different testing methods (that's to be expected) which end up yielding two different, but accurate, results (the results are not mutually exclusive as they test different aspects of the detector).

The short of it is ... I believe any test done faithfully and without bias is useful information. If the results are applied correctly to the real world and perhaps bolstered by unbiased field testing, that is the all that any testing can achieve. Other than this all you have is anecdotal accounts and exciting stories of fabled depths achieved meant to shock and awe. I prefer more scientific methods than glowing accounts of amazing performance in the field ... first show it can air test well, handle a board test, produce in a test garden, and uncover in a head-to-head field test ... then perhaps the amazing performance and glowing reviews are warranted - err maybe (are the results reproducible by others - if not, I'll wait for more evidence).

-Johnnyanglo

Knowing if and how my detector will respond to targets in various situations allows me to make better DIG decisions in the field. It will also influence my choice of detectors to keep on hand and to use for a particular site.

But my best education comes from actual recovery of real targets in the field in the infinite number of different scenarios/conditions. This is where ones' expertise/knowledge of your detector pays off.


Rich -

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Just one more good target before I go.

If the detector does not pass the test Nail Board it and real conditions on heavy trash will not work ...

The nearest thing i have to a nail board test, a coin at 10" with several nails at the same depth.

ghound Wrote:
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> The nearest thing i have to a nail board test, a c
> oin at 10" with several nails at the same depth.
>
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> 345_zps5hv1irmb.jpg[/IMG][/URL]


Ok------What detector/coil combo picks it up?

John........ absolutely exacting.

I can get it good with my GM5, 9" round or 10"x12", DD, ground is med/high mineralization.
Surprising just how loud those small nails sound off at that depth.

D&P-OR Wrote:
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> ghound Wrote:
> --------------------------------------------------
> -----
> > The nearest thing i have to a nail board test, a
> c
> > oin at 10" with several nails at the same depth.
> >
> > [URL=http://s89.photobucket.com/user/robertkirkw
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> > d/media/Mobile%20Uploads/20160731_140345_zps5hv1
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> > /k211/robertkirkwood/Mobile%20Uploads/20160731_1
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> > 345_zps5hv1irmb.jpg[/IMG][/URL]
>
>
> Ok------What detector/coil combo picks it up?

I agree with J&D and ghound,, Those Hammered coins are way harder to pick out on the nail board test than standard US and UK Coins, That's where the GM5 and the XP machines really shine,

You can compare getting a signal on Hammered Coins to trying to get a good signal from half a Beaver Tail from a ring pull while doing the Nail Board test, Almost all detectors can do the nail board test using normal coins, But throw a Hammered Cut Half on to the Nail Board and that will destroy your faith in to 80 to 90% of Detectors that are on the market, Find a machine that can do the Hammered Cut Half / Nail Board test and no matter what comes on the market the machine that you have will not be bettered.

John.

Just look at it as a data point from the multitude of data sets (tests) out there.

Do you want to hunt with a machine that cannot pass a basic test like the nail board test?

-Cal

Yes, on shallow targets you need something that can cut it in nails/junk, but if you want to pull out bigger targets in iron at depth, 12"-20"+ you will probably be better with a detector that ignores the small shallow stuff altogether.



Edited 1 time(s). Last edit at 02/25/2017 06:05AM by ghound.

Flawed???.

But it still offers some sort of STANDARD that the industry really does not have..


a simple standard is grab a 16d nail non galvanized and a zinc penny and do a down the barrell test..

Lots of units wont do that and usually there the ones that are more sluggish in iron making finds..

Keith

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

The nail board test is a good first attempt at having some type of standard for horizontal discrimination. It would be better if we settled on a standard nail(s) and making sure that they are new and not rusted. Rusted nails may give a completely different result and the question would be what standard of rusty nail should we use. Therefore, new nails should be used....

Sometimes, however, the nail board tests results can be baffling. The Nokta with 5" coil passes it with flying colors. My MX Sport with 10" coil isn't consistent at detecting a coin down the pipe. However, My Sport was able to detect 5 CW bullets that my Nokta had missed with a 5" coil in a very small trashy area.

It's time we have a 3D standard test.

I know the nail board test is about the only test most people use. I would say if you hunt in lots of trash, locate a coin and dig 4 inches to all sides and 3 or 4 inches below it flip it over, then see if your detector can locate it. If you did that 10 times, I would say your detector would fail most of the time.

Be serious how do you duplicate nails buried 100years...