Another way to do a masking test.

[jabbo]

My back yard is loaded with iron signals. I detected an iron object that has no other signals near it, pinpointed it and put a stone on it to mark the spot. Then I measured 6" from the stone and pounded a rod down to make a small hole 5" deep. Dropped a copper penny in and tamped it down and made sure it was laying flat. Turned on my detector, couldn't detect the penny. Took another penny, made a 5" deep hole on the opposite side of the iron object, this time at 8" away. Was getting a coin signal 50% of the time, depending which way I swung the coil. I don't know what the iron object is or how deep as I didn't disturb it but probably a rusty nail. Jabbo

 

[Elton]

n/t

 

[jabbo]

Used my Fisher ID Edge, zero discrimination. Will try it with my other detectors too.

 

[jabbo]

Did more testing with the ID Edge and Cortes. With careful short sweeps both detectors occasionally would flash a coin signal on the meter for the penny that is 6" from the iron object. The Cortes bars shifted to the right at times and flash # 95, and would sometimes give a depth reading, most iron targets usually give no depth readings, so a flashing depth reading is another clue that it could be a non-ferrous target. The ID Edge audio tone was high tone sometimes and # 36 flashed at times. This 2nd test was done with real careful short sweeps.

 

[dahut]

- - you see these iron masking tests all the time. Someone lays a ruler on the ground places a big honking nail on it and then moves a coin ever closer in increments, until the coin can no longer be detected. They video the whole thing, put it on YouTube and we all "oooh and aahhh" over the results. Shaking our heads knowingly, we make mental notes about how far from iron a detector can pick up goodies.

Then you come along with an in-ground test on bona-fide decomposed iron - real world stuff.

You have shown a result that is at least twice what we are accustomed to seeing. I mean, your penny has to be at least twice as far from the iron object than we see in those contrived tests.... and maybe more This is eye opening, really.

Anybody care to dispute the halo effect, now?

What size coil are you using? Is it the standard 8" Fisher spider coil? (please say it isn't....)

 

[jabbo]

Fisher 8" coil and 8" round coil on the Cortes.

 

[TURNMASTER]

But, how do you explain that wheat that was an inch from a nail. Or the dime with 2 nails and a penny in the same 6" hole.

Jabbowhat coil and machine combo are you using? Love to know,

Be interesting to discover how deep that iron is. If it was shallower would it have more effect on the pennies?

Thanks for the brain food.

HH
Jeff

 

[jabbo]

Jeff, I also sank a penny 3" deep at 6" away, got a good solid coin signal. Most likely is shallower than the iron or at same level maybe.

 

[TURNMASTER]

Jabbo do you run a DD on any of your machines? I hunted a super trashy spot with my 9" CC and found shallower stuff not a lot and 1 or 2 wheats in the 1950's. Went back over the same area with my new 6" DD and found a bunch more a couple inches deeper. Both times running in coin pattern with only iron notched out. I love that DD for the trash and heavy iron.

HH
Jeff

 

[jabbo]

Jeff, I have an 8" DD I bought for my Cortes. In air tests, it doesn't get the depth as the 8" concentric so I don't use it. After I bought it I found out that it is a great coil for highly minerized soil, but the soil in my area seems to be mild. Used it only a few times so I can't give any opinions. Some say it's great for separation but to me it seemed to be about the same as the 8" concentric in trash. I might have to give it another try, maybe I didn't spend enough time with it. Dave

 

[TURNMASTER]

Jabbo, I am new to all this. Started in april. I ran 1 and a half sets of bats thru my BH Landstar. Then I bought a X-terra 705 with the 9" CC and a 10x5 DD High Freq coil and found the DD to work well in the tight trashy stuff. I then picked up a 6" DD HF for the 705 and found it is even better in the trash. I know the smaller DD is better than the 5x10 because iI hunted the same 25 x 20 ft area and found a bunch more coins in holes with nails very close to them. As I was (still am) learning this hobby and machine this is an area that I have gone over with the 9" CC at 7.5khz before using either of the DD coils. This was just to see how much more I could pick out of an area I knew was full of junk and iron. Being new to all of this I will dig odd signals and jumpy TID #s. then I will go over the same area with a different coil just to learn what I dont know. I am probably just between 125 and 150 hours total. Getting to a few good finds though.

HH
Jeff

 

[jabbo]

Jeff, sounds like you got a good grip on using a detector in just 150 hours. It amazes me to see how much goodies the newbies are finding today. I mean, since the late 1960's a vast blanket of pulltabs was layed down gradually masking the older coins. I started in the early 70's and finding a tab was rare as I recall it. Back then, foil from gum wrappers was the problem, it was everywhere and I didn't have a discrminating machine, only a Heathkit All Metal mode detector and everything sounded the same. One day I started counting - junk vs. coins. I dug 9 pieces of foil to every coin. I don't know, maybe the odds haven't changed that much. I think as the old saying goes "the more things change the more they stay the same" applies more to detecting than to anything else. Today, newbies are starting right learning how deep silver sounds. When I started, a lot of silver was only 1" deep and I didn't have to try hard for it. So today, it's much easier for an old timer like me, than a newbie, to miss those weak coin signals. HH, Jabbo

 

[dahut]

One day I started counting - junk vs. coins. I dug 9 pieces of foil to every coin. I don't know, maybe the odds haven't changed that much. I think as the old saying goes "the more things change the more they stay the same" applies more to detecting than to anything else.
I dont believe they have. Only the types of trash have changed


Today, newbies are starting right learning how deep silver sounds. When I started, a lot of silver was only 1" deep and I didn't have to try hard for it. So today, it's much easier for an old timer like me, than a newbie, to miss those weak coin signals. HH, Jabbo
When silver can be found, that is. THAT in itself is becoming increasingly rare.

 

[TURNMASTER]

I've dug
30 or so wheats
1 indian cent 1898
1 V nickel 1899
2 Buffalos 1914 and 1925
3 Mercs
3 rosies
1 1951 Quarter
and a Bunch of clad and junk. Haven't totaled my clad yet. I am not done for the year yet, close though

Jeff

 

[jabbo]

Hey dahut, someone here once said more older coins are masked and still in the ground then ever was dug up. He could be right, but I dread digging iffy signals, keep choosing the wrong ones. Going back to searching mainly for gold jewelry and clad again. Will be digging a lot of tabs but I'll have to say I did real good finding gold during the past 5 years. Hey Jeff, you're doing good for a newbie.

 

[UK Brian]

Has anyone ever disputed iron halo ? Your right re the YouTube tests. Majority are contrived. An interesting masking test is to use a tiny staple and see what that masks out.

 

[TURNMASTER]

Thanks, I like to think that I am a quick study.
Jeff

 

[go-rebels]

Has anyone ever disputed iron halo ? Your right re the YouTube tests. Majority are contrived. An interesting masking test is to use a tiny staple and see what that masks out.

"Contrived?"

What do you mean?

 

[Monte]

My back yard is loaded with iron signals.

Actual in-the-field sites are the best for "testing," as a rule. At least they are in my opinion. However, if your yard is "loaded" with iron trash, you might have multiple trash targets close together, either side-by-side or one on top of another. This can make finding a desireable target quite a challenge. Also, if loaded with iron you should probably be using a smaller-than-stock coil for best potential results.

I detected an iron object that has no other signals near it, pinpointed it and put a stone on it to mark the spot.

Was/it just one iron target, or more than one so close you can't isolate the two? Also, I presume you used the All Metal mode to find these iron trash targets, right?

Then I measured 6" from the stone and pounded a rod down to make a small hole 5" deep. Dropped a copper penny in and tamped it down and made sure it was laying flat. Turned on my detector, couldn't detect the penny.

First question: Did you fill the hole with dirt? Probably not since you tamped the existing dirt down. Just doing that would make that particular spot of ground read/respond differently than the surrounding matrix. Also, no dirt in the hole makes a difference.

Without knowing the actual depth & size of the iron trash target, it is difficult to imagine the effect it might have on a near-by desired targets. The odds are that the iron trash was shallower than the 5" deep coin which would cause some very serious masking challenges!

Took another penny, made a 5" deep hole on the opposite side of the iron object, this time at 8" away. Was getting a coin signal 50% of the time, depending which way I swung the coil.

That additional 2" of distance (space) between the marked iron trash and the new test coin could make the difference in it signaling. Also, the first coil that is 6" away from the marked iron target might also be close to another hunk of ferrous junk and that could also mask it.

I don't know what the iron object is or how deep as I didn't disturb it but probably a rusty nail.

nataurally, and as I read below, this brings up comments about a "halo effect." I've stated my learned opinions on forums in the past, so I''ll just briefly state that there is virtually no functional "halo" to be found about most coins or good jewelry because they are made of very noble metals. There needs to be a LOT in play for there ot be any halo at all, if any, and it is functionally insignificant.

Now, an "iron halo" is a completely different topic here for two reasons. One, ferrous object will decay/breakdown over time and can (potentially) result in a condition where any halo present might have an effect on the generated electromagnetic field. Might. This is especially true if the ground down to and all about the rusted iron junk is well wetted/saturated.

The simple fact of the matter is that ferrous has a different effect on an electromagnetic field than do non-ferrous targets. Since iron has an enhancing effect, it make it a bigger problem when you get into evaluating "target masking."

Other things come into play as well, such as search coil used, search coil sweep speed, search coil presentation (from a particular direction), control settings, etc., etc., etc.

What is most satisfying to me is the fact they you're taking the time to learn more and master you detector(s) and, in the end, it will make YOU the better detectorist for the time spent.

Monte

 

[dahut]

Hey dahut, someone here once said more older coins are masked and still in the ground then ever was dug up. He could be right, but I dread digging iffy signals, I keep choosing the wrong ones. Going back to searching mainly for gold jewelry and clad again. Will be digging a lot of tabs but I'll have to say I did real good finding gold during the past 5 years. Hey Jeff, you're doing good for a newbie.

Or he could be wrong. There is always some wag to make statements like that. Here's another people love to spout:

"A good operator with a bad detector will beat a bad operator with a good detector."

These things sound so clever and dogmatic, but they have no basis in fact. What they do is play to our desires - it's how they sell detectors, after all.

So, perhaps you aren't choosing the wrong iffy signals to dig at all. Rather, if you are digging them, you may be finding out a truth: in that particular spot, the old coins are gone or never existed.

You gotta go with what is real, and avoid hanging your success on pithy epithets.

If clad and jewelry are working for you then it sounds to ME that you have discovered a working solution. There is no shame in that. In fact, I would love to hunt with you some day and pick up a few pointers.