Find's Treasure Forums

Welcome to Find's Treasure Forums, Guests!

You are viewing this forums as a guest which limits you to read only status.

Only registered members may post stories, questions, classifieds, reply to other posts, contact other members using built in messaging and use many other features found on these forums.

Why not register and join us today? It's free! (We don't share your email addresses with anyone.) We keep email addresses of our users to protect them and others from bad people posting things they shouldn't.

Click here to register!



Need Support Help?

Cannot log in?, click here to have new password emailed to you

IRON MASKING on Teknetics GAMMA

aSaSSino

New member
Hello,

I've seen hundreds of videos regarding coins between iron nails, and it seems that Teknetics MDs are capable to discriminate iron and still recognize the coin, even when rusty nails are on the coin. The strange thing is that the target ID is " 99 " most of the time... why ?

So... I made some try and, when the nail is in contact with the coin, the coin is still recognized but with lower target id. The problem is that, when I put the nail some inches on the top of the coin, in air test or in the soil (not uncommon in real search), the coin is totally invisible because the target id is in the IRON range.

Is there a solution for this? Or it is impossible, for ANY detector, to find a coin under an iron nail?

Sorry as usual for poor language :)
 
aSaSSino said:
I've seen hundreds of videos regarding coins between iron nails, and it seems that Teknetics MDs are capable to discriminate iron and still recognize the coin, even when rusty nails are on the coin.
Many of us have used the Coin BY and Coin UNDER a nail (or a few nails) demonstration for decades going back to the early '70s or so when using a traditional TR detector. Not a TR-Disc. model, but many of the standard TR's such as some from White's or Compass.

When we got some of our early TR-Disc. detectors, some had a provision to select straight TR or TR-Disc. and many times the minimum Disc. setting was enough to reject (not just 'ignore' like many early TR's) iron nails rather boldly. Some would still respond to a coin BY a nail or with the nail ON TOP of the coin. I've worked a lot of older sites, such as homesteads or town sites, that were heavily littered mainly with iron nails and did well using models such as a Compass 77B or 94B TR because they picked targets out in and around and immediately under some nails.

Not all modern VLF (TR) motion discriminator reject iron nails very cleanly but some do. I have enjoyed using some of my favorite competitors models in densely-littered iron nail environments, such as a White's Classic model, and for a year-and-a-half now the Teknetics T2, Omega, Gamma and G2 have been tackling those tasks very well.


aSaSSino said:
The strange thing is that the target ID is " 99 " most of the time... why ?
Visual Target ID is a response from the target's metal composition. When you have a close-proximity target, such as a bottle cap next to a coin, or a screw cap, or an iron nail, you will have a mixed-metal 'blend' of metals for the detector to respond to. A bigger challenge for target ID comes form the fact that IRON has a different effect on the electromagnetic field than does a NON-FERROS target. When these two sample targets are compared either adjacent or in contact, the Target ID/VDI numeric response will be skewed.

The best rule to acknowledge is this: When hunting in a mild-to-moderate ground environment, and when searching for a typical US coin, and if that coin is located relatively close to the search coil and in a favorable position (such as 'flat' to the coil), and if you like to use visual Target ID and VDI response, and IF there is not a close-by metal target to mask the desired targets signal, then it might be advantageous to refer to the visual information to support all the audio response received.

However, whenever you are hunting in very challenging ground mineralization, and when the target is ferrous or a non-ferrous target located close to a ferrous object, or when you know the site abounds with a lot of nails and similar junk, you can refer to the visual display, but realized that most (or all) detected targets might have a skewed response due to nearby target masking.


aSaSSino said:
So... I made some try and, when the nail is in contact with the coin, the coin is still recognized but with lower target id.
Very normal. A skewed response because the detector is responding to BOTH targets that are detected at the same time, and since they might be in contact, or very close on the same plane, the ferrous target is masking the favorable response from the non-ferrous coin.


aSaSSino said:
The problem is that, when I put the nail some inches on the top of the coin, in air test or in the soil (not uncommon in real search), the coin is totally invisible because the target id is in the IRON range.
A very common example of Target Masking. This is due to the fact that the stronger portion of the EMF (closer to the search coil) encounters the shallower iron nail and the response masks or eliminates the response from the deeper desired coin.

When we are rejecting the iron nails then we don't hear their response, but we also don't hear the good targets that are located below them and that's why there are still a lot of desired targets to be found in trashy sites. Those who use discrimination can't hear the deeper good stuff, so it is ignored. If you grid off an area that has a lot of iron nails and then make an effort to remove them all, there's a good chance that you'll find better targets below where the trash WAS.


aSaSSino said:
Is there a solution for this? Or it is impossible, for ANY detector, to find a coin under an iron nail?
You can generally presume that any desired good target that is located deeper than an unwanted target will be masked by the shallower trash and it will (and has gone) undetected. Remove the trash in heavily used and littered areas and you can get the older stuff.

Monte
 
Monte said:
When we are rejecting the iron nails then we don't hear their response, but we also don't hear the good targets that are located below them and that's why there are still a lot of desired targets to be found in trashy sites. Those who use discrimination can't hear the deeper good stuff, so it is ignored.

It seems that, if I use zero discrimination I may find the good target below the nail, but I tried the "All metal" mode and, of course, its response is still in the IRON field so, even without discrimination, the good target is masked... or I'm doing something wrong?

So the only solution seems to decontaminate the soil from all the iron, and re-check for good targets...
 
aSaSSino said:
It seems that, if I use zero discrimination I may find the good target below the nail, but I tried the "All metal" mode and, of course, its response is still in the IRON field so, even without discrimination, the good target is masked... or I'm doing something wrong?
If an IRON target is the biggest target in the detection field, or maybe the closest target in the detection field, then the detector, regardless of the operating mode, is going to primarily (or exclusively) respond to that target.

If an unwanted target, iron or not, is closer to the coil or positioned in such a way as to distort the signal from a desired good target, you will experience target masking. You could be looking for a small women's gold ring, but if it was laying close to, or under, or even just over a US silver 25
 
Here's how my Omega behaves.

U.S. dime one inch from a 2 inch long rusty nail - disc on 1. The dime will be detected provided I am swinging lateral accross the nail. If swinging the length of the nail, dime is not detected.
Same set-up as above with rusty bottlecap instead of nail. Dime will not be detected. Like Monte said......the bottlecap (iron) is larger than the dime.

Now if I do above test with a U.S. quarter instead of a dime next to the bottlecap.....then the quarter is detected. It's about the same size as the bottlecap. However, as the distance of the coil from the quarter/bottlecap increases, then the quarter becomes less detectable. More than if the quarter was by itself. The iron interferes with the quarter detection as coil distance increases.
 
Thank you everyone, I'll make some practice with this new knowledge, and with the Monte nail board... I made dozens of tests but it seems that everything was wrong, the nail board seems the most difficult test to try detectors!

See you!
 
and every other detector you ever get a hold of. That's what I do and it's helped me for 47 years of having fun! :)

aSaSSino said:
Thank you everyone, I'll make some practice with this new knowledge, and with the Monte nail board... I made dozens of tests but it seems that everything was wrong, the nail board seems the most difficult test to try detectors!
There are so many 'test' we can do that we set-up, but some of the best 'test' are those we encounter when out hunting in natural environments. Where nothing is 'controlled' and then the best we can do is duplicate an encounter, as close to exact as possible, and then learn from it.

I have hunted in and amongst iron nails especially since I first worked some of my favorite ghost towns in 1969. From 1965 thru '69 I was mainly hunting urban sites, such as parks, schools, yards, parking strips, etc., and while did come across iron nails, they were never in the abundance that I usually encounter in my preferred sites. Ghost towns, homesteads, building tear-down locations or where buildings have been destroyed by fire, renovation work where sidewalks have been torn up, old campground sites, and so on and so on.

Once I shifted to hunting older town sites and similar places in the spring of 1969 i began learning how best to deal with hunting in iron. It's a little tougher today due to our modern detectors, or at least a lot of them. The Nail Board performance Test is an absolute copy of an easy-to-duplicate encounter in the old ghost town of Frisco, Utah.

It was Memorial Day Weekend of 1994 and the abundance of iron nails were scattered on the ground at the hill-top where the old school used to stand. Laying there ion the surface and in plain view, and boxed-in by four (4) different-sized iron nails, was an Indian Head penny. I relate the story in an article on the www.ahrps.org website under Tips & Techniques and how I knew which makes present would detect the visible Indian Head, and which one probably wouldn't (sometimes based upon the higher level of Discrimination they were using.

I had my note paper with me as I was doing some field evaluation so I just placed a sheet of paper on top of the coin and nails. Then picked them all up and I was able to get them placed on a sheet of thin cardboard, and I have used this for 17 years now in seminars, one-on-one demonstrations, or just when evaluating detectors.

I had it duplicated in the exact position and now this exact placement is duplicated on the Nail Board Performance Test 'kit' that I offer. It is very easy to see it, and easy to adjust a detector so that the iron nails are rejected, then when the coin is placed in the marked location between the nails, it can be an eye opener for many who have not experienced hunting in iron nails (or other small iron).

Yes, the Nail Board performance test is quite a challenge, but when I do four tests for an audience to learn whet their detectors can do, the other three test conditions, along with the Nail Board, can do a lot to help educate folks as to the 'How To' to try and get the best performance, as well as let them learn the limitations many makes and models have in some challenging conditions.

If you get an actual Nail Board Performance Test kit, I'd like to hear your response to how the Gamma (or other models) work for you.

Monte
 
Hello Monte,

I printed your board on an A4 sheet and found some nail of the right size, next Sunday I will try the board and record a video to post here...

In the meantime I've seen a G2 test using the concentric coil of the Greek series on this site and I tried the same test... with the nail at 12 o clock, touching the gold wedding band, even with D1 tone and discrimination set to 1, the Gamma don't make any sound. In AT mode, no VDI is shown.... I'll make a video and post here, too...

See you
 
[video]http://www.youtube.com/embed/7Qn4EjRJe7Y[/video]

Here is the test with a rusty nail and a 18kt gold wedding ring... as you can see, when the rusty nail is vertically on the top of the ring, the metal is mute (or overload)... when in AT mode the metal is not mute, but don't show VDI... :(
 
It seems a very good test, I will try it with the nail board...
 
Cannot believe to my eyes, my Gamma cannot see the 10 euro cents between the nails, this Omega sounds completely different...

I don't think that the elliptical coil can make this difference... I will record the same nail test and put it on youtube :-(
 
Hello, here is the video I made... this video shows that the GAMMA 6000 is MUTE, even with D1/D2 tones and Disc. set to 1 ... when in ALL METAL, the VDI is not shown...

[video]http://www.youtube.com/watch?v=zmpeiPOnNus[/video]

And this is the video of the same test on the Gold Century 1025... it's a little better...

[video]http://www.youtube.com/watch?v=HSJdoLMcEmg[/video]

This is the MONTE nail board test:

[video]http://www.youtube.com/watch?v=n8tLb9mO89A[/video]

Please help me, I don't know if my GAMMA 6000 is running correctly :(
 
test on the new coil omega 9.5'' NEL
very small nickel coin
[video]http://www.youtube.com/watch?v=lMVVRg8r8kM[/video]
 
This is a new test from one of my friends with another Gamma:

<iframe width="480" height="390" src="http://www.youtube.com/embed/z1ZvCyJwJuo" frameborder="0" allowfullscreen></iframe>

As you can see, with nail at 12 o'clock, the metal is almost always mute or in overload... My reseller has wrote to teknetics and we are awaiting for a reply but I'd like to know if this problem is also at alpha delta and omega or only a gamma issue...

Thank you :(
 
Oops here is the video:

[video]http://www.youtube.com/watch?v=z1ZvCyJwJuo[/video]

Hope it will run, now...
 
Top