What do you think of this article (re: iron masking)?

[TrpnBils]

Can a standard office staple completely mask a silver dime?

I found this in another forum and a quick read is kind of discouraging, but I find myself wondering how accurate it is. Several members there said they tried the same test and were able to see right through the offending staple.

What do you all think? FYI - this article was written in 2009 I believe so it's a bit dated.

http://detectorstuff.com/beneath-the-mask-nasa-tom/

 

[sprchng]

It couldn't be truer.

 

[Chris(SoCenWI)]

I don't know how long you been reading these forums, but when the Minelab Explorer came out a decade and a half ago the amount of finds from "Worked out" sites was spectacular. I believe this is almost entirely due to the fact the explorer was one of the first equipped with a DD coil. With a traditional coil the electro-magnetic field is shaped like an inverted traffic cone. Anything metal anywhere in the cone shaped field will mask anything below it. With a DD coil the field is pretty much only under the center web of the coil. This means a good target is MUCH less likely to be masked by adjacent trash.

http://www.dankowskidetectors.com/discussions/read.php?2,47415,50063

This link was posted on the CTX forum recently and shows how a DD coil works with adjacent trash.

Even though a DD does much better at finding targets that were previously undetectable with older detectors, there is still a lot of coins we miss because of masking. I've worked enough construction sites to see that when a couple inches of top soil is removed the finds can be amazing. It's not because the coins were too deep to have been detected before the evacuation, but because fifty years of trash has been removed from above the coins and they are no longer masked.

Chris(SoCenWI)

 

[Gary Clark]

Very interesting article , guess we will always have something to dig for. I hate the thought of digging all the lead shot out there just over the top of Pulltab masking a zinc penny.

 

[TrpnBils]

I don't know how long you been reading these forums, but when the Minelab Explorer came out a decade and a half ago the amount of finds from "Worked out" sites was spectacular. I believe this is almost entirely due to the fact the explorer was one of the first equipped with a DD coil. With a traditional coil the electro-magnetic field is shaped like an inverted traffic cone. Anything metal anywhere in the cone shaped field will mask anything below it. With a DD coil the field is pretty much only under the center web of the coil. This means a good target is MUCH less likely to be masked by adjacent trash.

Chris(SoCenWI)

I've only been around this forum for a couple of years I think (although on another forum I found out today that I registered there like 9 years ago and only posted 10 times so who knows), so I missed that wave of new technology. I was wondering about the difference between the DD and concentric coil fields though and how the different shape might affect this type of thing, but it makes sense...

 

[sprchng]

Take that image of the concentric coil pattern and reverse it and you will be looking at the amount of ground that becomes shielded below an undesirable target , regardless of the coil.
A masking item near the surface blocks the readings to the detection depth of the particular detector for the whole length of the pass.
It's the reason the best unmaskers are the machines with the fastest recovery speeds.

 

[surfchunker]

I pulled a dime out of a whole that had 5 roofing nails and a small battery that I knew had a dime in there too ... so nope it's not true

 

[TrpnBils]

I pulled a dime out of a whole that had 5 roofing nails and a small battery that I knew had a dime in there too ... so nope it's not true

\

out of curiosity where was the dime depth-wise in relation to all of that?

 

[surfchunker]

it was the last target I found so it must have been below it all. it wasn't a solid hit but enough of a good hit to know something good was there. that was with the Coiltek 10x5 coil

 

[Southwind]

It's not as simple as the article makes it out to be. Masking isn't a simple black & white Yes or No situation. It can vary from detector to detector, one condition to another and the settings you have. I've done several videos showing an old DFX hitting coins on the side of and even underneath a rusted iron nail. A staple will mask a good target when all conditions are right for it to do so. When set correctly a staple does not mask much if anything.

 

[ironsight]

It's not as simple as the article makes it out to be. Masking isn't a simple black & white Yes or No situation. It can vary from detector to detector, one condition to another and the settings you have. I've done several videos showing an old DFX hitting coins on the side of and even underneath a rusted iron nail. A staple will mask a good target when all conditions are right for it to do so. When set correctly a staple does not mask much if anything.

Agreed! There are all kinds of variables involved with a good target masked by junk. Is the junk touching the target? Is the junk below the target? Is the junk above the target? And if so how high above the good target? How large is the piece of junk? Is the junk off to the side? The junk metal? Is it discriminated out? etc. etc.

I've dug coins with corroded nails above and to the side. I've also probably walked over a lot of good targets because of junk mask.
Most times i found a keeper below or closely around junk is when using an open screen, digesting all the clues then going with an experienced hunch!
An open or partially open screen will tell you a lot, the whole picture in fact, warts, keepers and all!
Just got to know how to de-cypher it all.

 

[Dale(Ia)]

It's not as simple as the article makes it out to be. Masking isn't a simple black & white Yes or No situation. It can vary from detector to detector, one condition to another and the settings you have. I've done several videos showing an old DFX hitting coins on the side of and even underneath a rusted iron nail. A staple will mask a good target when all conditions are right for it to do so. When set correctly a staple does not mask much if anything.

Agreed! There are all kinds of variables involved with a good target masked by junk. Is the junk touching the target? Is the junk below the target? Is the junk above the target? And if so how high above the good target? How large is the piece of junk? Is the junk off to the side? The junk metal? Is it discriminated out? etc. etc.

I've dug coins with corroded nails above and to the side. I've also probably walked over a lot of good targets because of junk mask.
Most times i found a keeper below or closely around junk is when using an open screen, digesting all the clues then going with an experienced hunch!
An open or partially open screen will tell you a lot, the whole picture in fact, warts, keepers and all!
Just got to know how to de-cypher it all.

That's it in a nutshell, Ironsight!

Iowa Dale