Best metal detector for masking and silent masking

[darktower007]

Now here's a scratchy subject.. (I'm here all night!)
Thinking VLF here in a park iron and trash density medium to high.
Hundreds of detectors many frequencies out there, but can any of them punch through the layer of crap masking our deep goodies?

My thought is no. They all work the same some just a little better than others.

Nasa Tom has a really good write up on this and the results were scary. I.e a dang staple completely masking out a coin!


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[Tom_in_CA]

... can any of them punch through the layer of crap masking our deep goodies? ......

A few issues here. I notice you are talking about "parks" (as opposed to relicky or ghost-town type places). At parks (unless you intend to "stripmine"), another masking issue is low conductors. If someone elects to pass foil and/or tabs for instance (to cherry pick for silver and high conductors) or to only dig deep signals (trying to pass shallow zinc or whatever), then iron-see through (the Dankowski article you speak of) is only 1 issue.

If you were talking strictly iron see through (to chase any and all conductors), there are plenty of machines that excel in that arena. However, the downside of any machine that sees/averages through iron better, is they tend to not be as deep in the process. OH SURE they may air test wickedly deep. And they may go wickedly deep when no masking is involved. But the minute they are tasked with seeing through/around iron, then the depth at-which it can do it, is not going to be as deep as an un-masked target. Also you will not get accurate TID/VDI .

And conversely, the power-house great TID machines (like Explorers) generally tend to lack iron-see-through ability. So it's a perpetual trade-off, eh ?

I say this because I notice , in the quote above, that you are asking about not only see-through, but also "deep". All in the same breath

 

[darktower007]

A few issues here. I notice you are talking about "parks" (as opposed to relicky or ghost-town type places). At parks (unless you intend to "stripmine"), another masking issue is low conductors. If someone elects to pass foil and/or tabs for instance (to cherry pick for silver and high conductors) or to only dig deep signals (trying to pass shallow zinc or whatever), then iron-see through (the Dankowski article you speak of) is only 1 issue.

If you were talking strictly iron see through (to chase any and all conductors), there are plenty of machines that excel in that arena. However, the downside of any machine that sees/averages through iron better, is they tend to not be as deep in the process. OH SURE they may air test wickedly deep. And they may go wickedly deep when no masking is involved. But the minute they are tasked with seeing through/around iron, then the depth at-which it can do it, is not going to be as deep as an un-masked target. Also you will not get accurate TID/VDI .

And conversely, the power-house great TID machines (like Explorers) generally tend to lack iron-see-through ability. So it's a perpetual trade-off, eh ?

I say this because I notice , in the quote above, that you are asking about not only see-through, but also "deep". All in the same breath

Correct. I reread NASA toms "Beneath the mask" I don't believe it's a frequency issue it's how metal detectors work as he stated. The key here is which one or method works best. DIGGER27 has researched the "blast through method" with the f70 in all metal mode every thing pegged out. Do others have other stories with different dectectos?
Im concerned in seeing through or picking up that masked coin at 7 inches vs a PI going 2 feet deep. I'd much rather have superior abilities at 8 inches of target I'd and separation vs explosive depth only in the middle of Kansas field (or Ohio you guys have fantastic glaciated soils!)


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[IDXMonster]

Just remember that besides a couple of machines, the transmit power is fixed, you can't "turn it up". You can let the machine tell you about everything it has ALREADY seen through adjustments. Not sure what the "blast through" thing is but it sounds like someone thinks they are turning up the TX power when they're not....

 

[digger27]

Just remember that besides a couple of machines, the transmit power is fixed, you can't "turn it up". You can let the machine tell you about everything it has ALREADY seen through adjustments. Not sure what the "blast through" thing is but it sounds like someone thinks they are turning up the TX power when they're not....

I think I am turning up the gain and threshold in all metal to max levels on an F70 in heavy iron infested sites.
I think I will call this the blast through method...but it s just a name.
I think this method has unmasked a shocking amount on non ferrous targets for me in many sites for the last few years.

 

[Patriot 1776]

The Minelab CTX 3030 nulls out iron with ease
Great Detector
call for a great price
dennis

 

[tesoroMex]

Can you share the information from Nasa Tom?
Thanks

 

[darktower007]

Can you share the information from Nasa Tom?
Thanks

Here you go.
http://www.dankowskidetectors.com/behindthemask.htm

Read every article he published its mind boggling!


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[Tom_in_CA]

The Minelab CTX 3030 nulls out iron with ease
Great Detector
call for a great price
dennis

Uhhh, don't confuse "nulls out" (discriminates out) with "see through (allows averaging up).

There are PLENTY of machines (like the CTX) that, yes, effortlessly pass (null out) on iron. But that's not the subject of this post. It's a question on seeing through and around.

 

[darktower007]

Bring new this phenomenon is perplexing to me. I thought "man all these silver posts I bet I can find them too!" Yeah right it's tough!


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[digger27]

Bring new this phenomenon is perplexing to me. I thought "man all these silver posts I bet I can find them too!" Yeah right it's tough!


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Tough, sometimes, but doable.
It's a matter of several things.
Using a decent tool, learning it well, understanding how targets behave under all kinds of conditions and situations...plus maybe a little luck.

In a permission lawn I have been hunting for like a year I have found much but eventually signals got sparse.
Kept coming back and dug every trash signal that wasn't iron over time just in case, lots of the iron ones too.
I was positive I got it all but the house is close to mine and I walk right by it every time I visit my neighborhood park so now I use this as a little laboratory.
If I change coils, try new settings, think about things differently then before this is a great place to try them.

One day I walked by and hit this lawn one more time and on this visit there was a change, a few days before I had realized that what I thought I knew about target behavior in the sites I hunt which are usually infested with huge amounts of iron was wrong, it was lacking so I changed my way of thinking about target behavior and opened up my horizons a bit more.
Started digging more of the iffy signals I hadn't in the past, tried to look for other indicators and behavior in all this iron I had dismissed in the past because I thought I had a pretty good handle on understanding my rough dirt and the things that are hiding within it but actually didn't.
On this hunt on this day I got a signal that was mostly iron and I am sure I passed by probably dozens of times before but this time with a new attitude for some reason I noticed something a bit different.
In the small 3" wide hole I opened there were three targets in it close to each other...two bad and one good.
This is why I continue to try to learn new things and get better on every hunt and why I don't believe any site is ever really hunted out.

The same F70 tool with the same coil I had used uncountable times before using settings I have used in the past too but this time the change was a different attitude and a little extra knowledge.
Success in this hobby is a combination of different things and you never know exactly which component in that equation is the important one so change it up from time to time and always keep learning.

 

[Vern2]

Good writeup, digger27.

 

[luvsdux]

To my way of thinking, if you don't want to miss anything, hunt in all metal. Yes, you'll wear yourself out digging junk, but the fact that every target will sound off will ultimately reveal the goodies near the trash target as long as you recheck the hole before filling.
luvsdux

 

[bigscoop]

I think the terms "pass through" and/or "power through" are a bit misleading. I live in trash infested properties, even seek them out, as in my neck of the world these are some of the last untapped metal detecting frontiers simply because they are so trash infested, other hunters simply avoiding them like the plague. However, I often do quite well hunting them though this type of hunting is much slower with a very dedicated approach/method. I use the Minelab Excalibur and/or the Sovereign Gt with the stock 8" coil, which is actually only about 7 1/4".

I run the machine threshold to just under audible in Disc mode, the sensitivity somewhere around 1/2 (just depends on what I can get away with), the machine volume all the way up, and the machine disc setting between 1 & 3 depending on conditions. The Excal has built in iron mask so it is on all the time. This is my "primary mode" of operation though I'm constantly switching back and forth between Disc and PP mode to help with target separation, etc. As Tom already noted, you can forget about depth unless the search field is clean of other conductive debris, which isn't very likely due to all the tiny and/or deteriorating metals in the ground. Whenever the processor has to work harder you lose depth.

"See through" and "pass through"....is it possible? Only if there is some way to see through and/or around the masking agents. This means holes, exposed edges, the masking agent sitting at such and angle that it allows for deflection, or the masking agent is very thin and not solid, such as halos, scattered grains, etc. If the masking agent is dense/solid and of larger diameter then the masked object then you can't see through or around to that masked item. In other words, that masked target has to be, in some way, visible to the search field.

Iron Mask, this is tricky because in order for it to actually work the masked iron object can't leave the search field and then re-enter it again as the processor will reset each time this happens, the slow recovery speed of Disc Mode not allowing for full filtering of the iron, or unmasking of the masked target, if the coil passes over this masked area too quickly. If the coil passes over too quickly at best you might get a very quick chirp or bark, the "edge" of these responses being very sharp. This is when you have to really slow the coil down, allow it to hover over the null area so that the processor can complete its duties, and then impart a very tight coil motion, or "wiggle" as it is often referred. Quite often you will get something similar to a bottle cap response, switching to PP mode and counting the number of edges within the returns will often expose a multiple target situation, or masked target situation.

This is how i go about hunting extremely trashy areas and I've come to look forward to it, especially when water hunting old beaches, mainly those areas of those beaches that have become silted in, weedy, or around the docks where trash is often discarded and collects. Targets have been collecting here for years and years, detectorist avoiding them at all cost. This is just my personal experience in regards to the terms "see through"..."pass through" and/or "see/pass around."

 

[Tom_in_CA]

Good write-up Bigscoop.

..... If the masking agent is dense/solid and of larger diameter then the masked object then you can't see through or around to that masked item. In other words, that masked target has to be, in some way, visible to the search field. ...

I dunno about this. Wont' some machines allow for "averaging" at this point ? So for example if a tab read 28. And a dime read 79, then you might get a ~53 (albeit garbled, etc...). So that if you were electing to "pass tabs and foil" in this case, and had set your disc. to about 50, you'd get a coin UNDER (and completely obscured by) the tab. Right ?

Machines models/brands differ in their ability in this dept.

 

[bigscoop]

Good write-up Bigscoop.



I dunno about this. Wont' some machines allow for "averaging" at this point ? So for example if a tab read 28. And a dime read 79, then you might get a ~53 (albeit garbled, etc...). So that if you were electing to "pass tabs and foil" in this case, and had set your disc. to about 50, you'd get a coin UNDER (and completely obscured by) the tab. Right ?

Machines models/brands differ in their ability in this dept.

Here's my thoughts/experience with the subject of averaging. In order to generate an average then the processor has to have information regarding both targets, right? This means that the search field has to have access to both targets, keep this in mind as we explore this whole "pass through" theory.

So here we are, on our favorite trashy beach or in our favorite trashy park sweeping our coil in search of masked targets. But what about those rare thin individual targets that we discover in perfectly clean ground. If our machine has the ability to pass through these items then why do we still get good, strong, and accurate ID on this targets? Why don't our sends pass right through them and generate very faint and/or weak returns? Yes, we do get broader and flatter returns from these thin items but this isn't the same thing as a truly weak return, the actual returns still being very strong and sometimes at surprising depths in very soft soils.

I just don't believe "pass through" is a practical concept, even with the very best of machines capable of averaging unless both items, or portions of them, can be cleanly accessed. If "pass through" was as capable as advertised then the accuracy of many individual targets would be seriously flawed, especially those thin and oddly shaped items, etc. But this is just me based on my own experiences in hunting these trash infested areas.

 

[Tom_in_CA]

Here's my thoughts/experience with the subject of averaging. In order to generate an average then the processor has to have information regarding both targets, right? This means that the search field has to have access to both targets, keep this in mind as we explore this whole "pass through" theory.

So here we are, on our favorite trashy beach or in our favorite trashy park sweeping our coil in search of masked targets. But what about those rare thin individual targets that we discover in perfectly clean ground. If our machine has the ability to pass through these items then why do we still get good, strong, and accurate ID on this targets? Why don't our sends pass right through them and generate very faint and/or weak returns? Yes, we do get broader and flatter returns from these thin items but this isn't the same thing as a truly weak return, the actual returns still being very strong and sometimes at surprising depths in very soft soils.

I just don't believe "pass through" is a practical concept, even with the very best of machines capable of averaging unless both items, or portions of them, can be cleanly accessed. If "pass through" was as capable as advertised then the accuracy of many individual targets would be seriously flawed, especially those thin and oddly shaped items, etc. But this is just me based on my own experiences in hunting these trash infested areas.

As usual, bravo on another good write up. I get what you are saying. And the "averaging" is really only tell-tale when objects are A) shallow, and B) preferably touching (or very close together anyhow).

I've hunted underneath bleacher grandstand tearout before (which dated to the 1920s), which was an OCEAN of aluminum tabs and foil. All of which was in shallow hardpan (d/t it had been in perpetual dank dark conditions for ~70 yrs.). Thus depth wasn't the issue. And d/t the millions of tabs and foil (and the limited time we had to work before const. on the new grandstands started) we were forced to go high disc. Yup, kiss nickels and gold goodbye. We were angling for copper/silver.

And I had set my Eagle SL II to reject ~47 and downwards. So that I'd *just* loose the beefy type square tabs. And I noticed that even though penny/dimes start at the high 70s, yet I'd get the benefit of "averaging", by choosing a lower # (as long as it wasn't low enough to start allowing in the trash I didn't want). I've sometimes get a coin under tabs.

But , of course, who's to say there wasn't a "peak" of the coin? Who's to say if the coin was touching the tab(s) or not ? Another machine I've used for this purpose, which seems to "average", is various 2 filter tesoros (Sabre, Bandido, etc...). But yes, it probably only works when shallow, and coin close to the tab/foil above it.

 

[darktower007]

Here's my thoughts/experience with the subject of averaging. In order to generate an average then the processor has to have information regarding both targets, right? This means that the search field has to have access to both targets, keep this in mind as we explore this whole "pass through" theory.

So here we are, on our favorite trashy beach or in our favorite trashy park sweeping our coil in search of masked targets. But what about those rare thin individual targets that we discover in perfectly clean ground. If our machine has the ability to pass through these items then why do we still get good, strong, and accurate ID on this targets? Why don't our sends pass right through them and generate very faint and/or weak returns? Yes, we do get broader and flatter returns from these thin items but this isn't the same thing as a truly weak return, the actual returns still being very strong and sometimes at surprising depths in very soft soils.

I just don't believe "pass through" is a practical concept, even with the very best of machines capable of averaging unless both items, or portions of them, can be cleanly accessed. If "pass through" was as capable as advertised then the accuracy of many individual targets would be seriously flawed, especially those thin and oddly shaped items, etc. But this is just me based on my own experiences in hunting these trash infested areas.

Man thanks for all the replies folks!

It has a lot to do with soil I'm learning. As a new detectorist I have discovered soil has s HUGE influence on so much more than I realized. In Tennessee (Chattanooga) we have mid clay and Loam content soil plus a ton of chert. When I was in Ohio last week overseeing some groundwater well drilling I was feeling of the wonderful glaciated soils there. Wonderful loose soil compared to Tennessee.




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[bigscoop]

Man thanks for all the replies folks!

It has a lot to do with soil I'm learning. As a new detectorist I have discovered soil has s HUGE influence on so much more than I realized. In Tennessee (Chattanooga) we have mid clay and Loam content soil plus a ton of chert. When I was in Ohio last week overseeing some groundwater well drilling I was feeling of the wonderful glaciated soils there. Wonderful loose soil compared to Tennessee.




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Soil can change everything, for sure, sometimes drastically. When I moved back to Indiana this was one of the first things I noticed.

 

[bigscoop]

As usual, bravo on another good write up. I get what you are saying. And the "averaging" is really only tell-tale when objects are A) shallow, and B) preferably touching (or very close together anyhow).

I've hunted underneath bleacher grandstand tearout before (which dated to the 1920s), which was an OCEAN of aluminum tabs and foil. All of which was in shallow hardpan (d/t it had been in perpetual dank dark conditions for ~70 yrs.). Thus depth wasn't the issue. And d/t the millions of tabs and foil (and the limited time we had to work before const. on the new grandstands started) we were forced to go high disc. Yup, kiss nickels and gold goodbye. We were angling for copper/silver.

And I had set my Eagle SL II to reject ~47 and downwards. So that I'd *just* loose the beefy type square tabs. And I noticed that even though penny/dimes start at the high 70s, yet I'd get the benefit of "averaging", by choosing a lower # (as long as it wasn't low enough to start allowing in the trash I didn't want). I've sometimes get a coin under tabs.

But , of course, who's to say there wasn't a "peak" of the coin? Who's to say if the coin was touching the tab(s) or not ? Another machine I've used for this purpose, which seems to "average", is various 2 filter tesoros (Sabre, Bandido, etc...). But yes, it probably only works when shallow, and coin close to the tab/foil above it.

I did a video exploring this very thing, mainly iron mask feature, but it's the same with about any alloy. I did this with the Excal and a borrowed CTX and E-Trac, the video I did with the Excal. Here is that video:



Notice what happens each time the machine is allowed to reset, notice what happens after resetting as the iron and silver ring are passed through the search field at the same moment, just as they would be in the field.