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Up Averaging

Bowie

New member
Didnt know really where to post this, thought maybe technology forum, so if Ive posted in wrong forum,I am sorry.
I know,believe if trash is over a target, then, I believe a machine will never see it.
But when trash is beside target or off to the side,maybe touching, a detector will up average that signal, more likely, still a non text book signal but still higher than what the trash is beside that target.
In your opinion,experience; have you found a machine that better up averages these type of scenarios?
If so would you share?
Thanks,
John
 

Tom_in_CA

New member
John, there is two factors at play here: Not only machines that tend to "average" better, but also a factor of "target separation" (speed of processing between signals).

A detector that has fast target separation will do better at seeing close-by targets as separate, but may not necessarily be good at "averaging", for example.

And it depends on what type targets you're talking about. Like: to see through and around iron? to see through and around low-conductors? (like if you were nixing out foil in junky parks, for example).

Usually the "power-house" detectors we all love, d/t their depth and great TIDs, will wain in the target separation and see-through (averaging dept). So for example: the Explorer (in that "power-house" category) is not going to fare too well in ghost-town nail/iron-riddled environments. Or won't fare as well under bleachers where perhaps you're nixing out tabs and foil in your quest for silver. However a Tesoro Silver sabre (or some such related 2-filter machine) will excell in that ghost town environment, and under bleachers to snipe out silver from the ocean of aluminum. However, you will loose depth with that 2-filter machine, and will not have the fun TID's perhaps, etc... that the power-house class machines have. So as you can see, there's trade-offs depending on where you hunt, your goals, tolerance, etc....

The ability to "average" well need not necessarily be when two targets are close or touching. It can also be when the offending target (a nail, for example) is right ON TOP of the coin. You will not necessarily strictly see *only* the nail, as I think your post says is the case. There are machines that will indeed see through the nail (ie.: "average well") to get a conductive hit on the target beneath. In fact, the old all-metal TRs could do this trick with up to 3 nails laid exactly on top of a coin (whereas all modern discriminators would have long since "lost" that coin, eh? :)) However, the benefits end there. In all other ways it's a dinasour to try to use. Poor in minerals, poor depth, a bear to keep balanced, etc....
 

REVIER

Well-known member
Bowie said:
Didnt know really where to post this, thought maybe technology forum, so if Ive posted in wrong forum,I am sorry.
I know,believe if trash is over a target, then, I believe a machine will never see it.
But when trash is beside target or off to the side,maybe touching, a detector will up average that signal, more likely, still a non text book signal but still higher than what the trash is beside that target.
In your opinion,experience; have you found a machine that better up averages these type of scenarios?
If so would you share?
Thanks,
John

My opinion...
That statement about trash being over a target you will never hear it is incorrect.
I have 2 Tesoro's, an F2 and an old Compass TR unit.

There are videos out there about how well some Tesoros can pick out good targets below trash like this one.

[video]http://www.youtube.com/watch?v=DtxB1lnTXps[/video]

Now nothing is is stone and depending on depth of these objects, soil type and other things your mileage may very, but the Tesoros and some other brands can do this well.
I also know that one advantage of my Compass is these kind of detectors, even though the technology is decades old, have a great advantage in iron infested sites because if adjusted correctly they can "see" right through iron and pick up high conductive targets laying below.
This type of technology is usually not all that deep, but I have tested mine with way more and thicker pieces of iron on top and surrounding a coin then that nail in the video and it is like that iron is not even there.
A good example of how these detectors work in this vid...

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

Changing over to my F2, a more modest starter unit, (it is said but don't believe it), the target separation is just fantastic and this set of targets proved that to me one day.
This was with the 8" standard coil and not the smaller sniper which probably would have had an even easier time doing this.

Strolling along, swung over all three of these...big noise.
Numbers jumping all over the place from foil to tab, but right in the middle, as I scanned from left to right and from right to left I could see a solid 33 right there on my screen that kept popping up where the other numbers jumped a little.
By slightly moving that coil north and south I managed to get that 33 to stay there and it was a solid "coin tone" so I knew there was a nickel here.
I knew something else was going on so I dug that nickel and also found these trash objects at exactly the locations you see here.

The nickel was 2 inches deep, the tab was about 3-4, the piece of foil was laying on top of the soil but hidden in the grass.

I picked the F2 as a backup unit over others because of the rapid recovery and great target separation, and this is exactly why.

All detectors are different, some have the ability to separate these multiple signals better than others.
Money should rule in this case and the more expensive units should all be able to do this better and better as you move up the line in price points but in real life that might not be the case.
My under $200 Compadre can do this, also my Compass, my $400 plus Vaquero can too, and so can my $200 F2.

Others will chime in with opinions on other units soon, I am sure.
 

BarberBill

New member
One cure for the masking problem is to hunt in all metal and dig it all. Yes, I know how frustrating and tedious that usually is, but all metal will tell you there is a metal target under the coil and when you dig you will quickly know whether it is junk or good or both in the same basic location.
BB
 

chuck ky

Active member
i found several clad quarters with the t-2 that read 86-87 when the normally read 88-89. i decided it was the rebar in the sidewalk that was bringing them down. i don't think i've had any machine that brought the i.d. up.
 

Goldstrike

Active member
In addition to what's been said, smaller coils also aid in target separation when it comes to good targets surrounded by and in trashy ground. As all of us know already, a smaller coil has the ability to separate and pick out individual targets whether they be iron or a silver or gold coin etc;. but ONLY if you swing much slower and let the detector (whatever make it may be) to identify the target.
While some detectors have perhaps more of an ability to get around the iron, no detector will be 100% effective but there are techniques (coupled with a smaller coil) that will help to at least identify and of course together with the mixed signals and then you need to decide to dig or not to dig! There are a lot of variables on this subject alone but I just wanted to share my 2 cents on this!!
 
chuck said:
i found several clad quarters with the t-2 that read 86-87 when the normally read 88-89. i decided it was the rebar in the sidewalk that was bringing them down. i don't think i've had any machine that brought the i.d. up.

The OP was stating it from the viewpoint of many trash targets, a few of which were upsampled by a nearby good target. The other perspective is that good items are downsampled by nearby trash. Either way of expressing it is correct. It's all about ID averaging no matter how its stated. Faster machines or a small coil can pick these multiple signals apart.

Unless you are familiar with it, many may overlook coin signals mixed with trash that have moved down to the zinc or pulltab range, while gold and other desirable low conductors can be moved upwards in ID by a higher-conducting trash item.

Using zero disc helps one to hear it all and maybe discern the difference. Otherwise, lacking a fast machine, all-metal no-motion is the best way to dissect multiple targets without digging. The few detectors that offer ID in their no-motion modes are another nice feature to have.

Besides using a slower sweep, a far shorter sweep that is centered right over the target and doesn't extend much past it can also help separate multiple items.

-Ed
 

Bowie

New member
Thank you for the replies. I have thought about it as up averaging but know a piece a trash will bring the signal/tdi down.
I havent used as many detectors as most of you, so I was wanting to know,if possibly there was something out there that excelled.
At the moment, I use an ETrac and F75SE. One is slower responding and the other is faster.
Ive found coins in amongst trash with the ETrac, but I havent found anything deeper than 6-7 inches with it. I have found targets with the F75 at 9 to 10 inches but not just coins, as I relic hunt with the F75 plus I cant recall pulling a good target out amongst trash with the F 75 (but Ive only had the F75 for a couple months now and havent really had a lot of hunt time with it).
I had a M6,fast responder, and found coins with nails/trash in the same hole.
Like you guys,I have dug my share of trash.
Thankfully one thing I havent had to deal with is bad ground.
I believe Im on the same page with you guys, wanted to make sure. Ive employed the same swing techniques as most of you and have used all metal or no disc in some cases as a particular machine didnt have all metal.
Masking is a major concern for us, just keep hoping some company will come up with the magic wand,lol.
Let me ask another question. If you are hunting a site full of trash, whether it be just iron or one with all the modern trash as well. What is your priority, just target seperation or depth? How do you set up your machine/hunt in a site like this, what are your priorities? Mine is seperation, but I always wonder if Ive missing that hint of a coin next to trash. Are you the same way?
Thanks,
John
 

WIHawker

New member
My AT pro will average up and down. I have dug multiple nickle quarter spills and they read 78-80. I thinking im dugging a penny but find a quarter and a nickel. I have dug many double quarters. They read as high 90-94. I also came across a couple coin spills that sounded like a bottle cap hi lo tone jumpy numbers or no number at all just alot of noise. One such spill was 3 quarters, a dime, a nickle, 4 pennies about 1 inch after i popped them all out re swung and got a rosie at 5 inches a bout 1 inch left of the hole. I had a quarter nail i dug once. one way i got a solid quarter signal the other way i got a crappy signal. I move 90 degres and got no signal at all. I still dug and got a quarter at 4 inches. the nail was resting on top of it.

Because of all the variables i would take depth over seperation.

This is a great thread!
 

WV62

Well-known member
I worked the better part of my hunt day just trying to work on something like averaging to get some of this silver out of the ground. I was running my F75Ltd and I started by cleaning a small area in the park where I have found silver. So a lot of digging and still no silver I started thinking in the direction of this post for coins with trash right on top of coins. My machine would give a low coin number and high pull tab number. Then I thought what if a coin and trash have a little space between them. This is where you get low number in one direction and a higher number in the other direction. I found that if you short stroke or just bump the item on the high side you will get a good coin reading and if you do the same on the other side you will get a pull tab reading being that is what I was using for my trash item. Now if you rotate 90 degrees and cross both at the same time you will get close to your coin reading depending on the coin size. A dime and a pull tab will be harder to tell because the pull tab will pull you number down, but if you put quarter down the quarter will win out and you will get a number very close to just a quarter.

Hope this helps,

Ron in WV
 

Critterhunter

New member
This is what I always believed for years- that to unmask one needed a fast recovery speed and minimal or no iron rejection (any form of discrimination). Since then I've seen with my own eyes and ears in numerous head to heads in the field that there are more than one way to skin that unmasking cat. Comparing a machine with a faster recovery speed and low or no iron rejection being set, to that of one with built in iron rejection and a slow recovery speed...Both machines have seen badly masked coins before digging just as well as each other. And I'm talking some coins so badly masked that they were a complete null all the way around them (even for the low iron rejection setup) and would only sing "COIN" from one very tight angle for both machines.

The difference? The slow machine is using a quality DD coil with a super sharp DD line (SEF 12x10). Not once in numerous comparisons over a few years have we seen a lick of difference between them, circling around the target and comparing the signals with both machines. Simply put, a machine can't see what the coil can't see separately.

Now, I don't argue any one approach (low or no iron rejection, faster recovery speed, or a sharp DD line) is better than the other, but I do now believe the end result, as far as what my own eyes and ears have shown me, is pretty much a wash on whichever path you take. A few years back I believed the complete reverse of that, in that the only true way to unmask was with faster recovery speed and low or no iron rejection.

This might be somewhat controversial to say, but let's add a little more fuel to that fire...Think about low iron rejection. Is it really allowing you to see a coin in iron better and thus sounding off to the coin only because the iron rejection has been zeroed out? Not IMO. Detection fields, far as I always read, stop and interact with the first (meaning shallowest) object in the field and it's game over after that. I don't really think in most instances the field is seeing the iron and coin at the same time, but rather low iron rejection is just decreasing the lag time between "rejection mode" of the iron to "acceptance mode" of the coin, and thus you are able to hear the coin where as otherwise it might be silent as the machine resets from rejection to accept in it's processing.

By using a quality coil with a sharp DD line you are then more cleanly going from "I see the nail" rejection mode to "I see the coin" acceptance mode. In a sense then, you've found another way to increase "recovery speed", or better put perhaps you've turned the page more cleanly from one (the nail) to the other (the coin) as the coil moves. By lowering iron rejection you are eliminating the lag time between reject and accept, or by using a sharp detection field you are in a sense doing the exact same thing.

From what I've read, it appears it is possible to gleam the ferrous (nail)/ non-ferrous (coin, tab, ring, etc) traits from a detection field in a mixed target "as one" signal. Minelab has appearantly figured out how to do this, and I would suspect is then the reason why they just built in fixed iron rejection on the BBS units, as lowering it wasn't so much of any issue anymore. That's what I suspect anyway, and the ability to pull coins out of nails does appear rather good to me.

But in terms of being able to tell a mixed non-ferrous/non-ferrous two target signal, far as I've read over the years that's an impossibility as to what a detection field can tell you. Only the ferrous/non-ferrous aspects are what detection fields appear to be able to tell a detector, from what I've read anyway, but would welcome any links to the contrary on both these points.

But whether either one is true or not as said above, the laws of physics the govern detection fields appear that both targets have to be at the same depth and so close to each other they'll priobably be touching or overlapping, because the field stops and warps around/interacts with the first metal object it hits from all I've ever heard on the subject. You can see this demonstrated to the extreme as a test article once showed, in that even something as small as a staple will mask a coin deeper below it in the field. And once the staple gets deep enough you no longer will even hear the iron or null from it, which means now you don't even have a clue that something was under the coil that might be masking something else. For that reason many believe (myself included) that there are still tons of silver coins out there left to be found at spots long since given up by hunters as "dead".

Even if the two targets are at the same depth, once they get a certain distance from each other in the horizontal aspect, the field is going to hit and only see one or the other. Think of it like a mouth to a flame. For that reason a sharp DD line is of primary important to me, and also because a shallower trash item can be well off to the side of the coil while a deeper coin is directly under it, and you'll never hear that coin. First metal object hit and it's lights out IMO.

Recovery speed IS an issue to me only if I'm in the mood to swing fast, but so long as I control my sweep speed it's far more important to me to have a sharp detection field. If you simply have to swing fast then yes, you need a fast machine. On the other hand, for my style of hunting these days at dead sites I prefer to work the coil slowly and sniff in and out of iron or other trash looking for any hints of a high tone. You just can't do that with some fast machines, or at least moving the coil too slow might cost you performance in depth or discrimination ability if the machine isn't built to be used slow.

Besides, I feel a slow recovery speed gives me the extra time to really drink in and take the best look I can at a target without the machine trying to reset on me or clip the audio short when I'm after the finer traits of the target. To me this also becomes important when I'm trying to suck up the hardest hit on a target at fringe depth. I think of it as trying to read a street sign at 100mph vs only doing 35. I feel the longer hovering look at depth gets me that extra bit of depth to pull the best ID/audio I can out of the target. You can see this in play on some machines that have the ability to change the SAT (self adjusting threshold). Too fast a setting and depth suffers. Too slow and stability might suffer. In trying to be one or the other you often do neither well. Better to use a machine (fast or slow) that suits your style and stick with it.

Final thought, and part of your question I think- Do some machines have the ability to hold onto the right conductivity better of two non-ferrous mixed targets in the field (again, same depth then and very close for the perfect storm of masking)? Yes, I believe so. In truth in a mixed non-ferrous signal the machine doesn't know it's got two targets under the coil (it doesn't either with a nail and a coin, only that some machines can see the ferrous/non-ferrous aspects of the signal to some extent), and so what usually happens is the conductivity is summed between the two. Tab and silver dime= conductivity (ID) is placed on a average between the two (like say as a zinc penny then perhaps or a bit lower). But this averaging is also based on the size of both targets. Bigger piece of foil vs smaller silver dime= probably the ID shows much nearer to the foil range, like say in the nickel range or so.

But to answer your question- I've used machines that seemed better at holding onto the higher conductive properties of the silver dime and not allowing the VDI to be dragged down, or at least as much (to say a zinc penny signal perhaps), or at the very least as often as I've experience with prior machines. Why? You're guess is as good as mine. My only stab at a guess is this- As you wiggle the coil the field will still see one or the other separately here and there (with a sharp field anyway), and perhaps the VDI and tone processing of the machine tries to hang onto and offer up the highest conductive signal it saw in those split micro seconds between seeing one or the other, and then continues to show that as both are then washed in the field most of the time?

This concept can be seen in volt meters. Some have split second display stabilization where a constant up/down voltage quickly pusling is ignored and instead the highest voltage reading is the only thing seen on the screen. Despite all that, the audio still knows. You might not see the finer change from one to the other thanks to the buffering of the VDI, but the audio on a good machine will still warble a bit and say "something ain't right here, you've got a less than pure signal that changes a bit under the coil." :biggrin:

All the above said, this is just my working theories with some reading and experience over the years in this hobby. I'm sure there are others who strongly differ with some or all of what I just said above, and I can fully understand, as it wasn't too long ago I would have been the one arguing with myself, in particular on the various paths to unmasking and how important each were in the final outcome. I would love to read any articles or links that offer differing points of view on all this, as I don't claim to have all the final answers.
 
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