Speaking of detector depth

I saw this video link over at Finds. I think it is pretty well done. They do about six detectors and keep it moving. Different dirt will give different results. We all know that. But it is nice to see some of the top models being compared. I think some of the limitations are worth observing more than just the depth results.

[www.youtube.com]

Thank you to the person at Findmall that posted the link.

Results looked something like this:

The narrow coils do indeed hit the coin between the nails better than the large coils.
When hunting mineral and iron infested ground, I usually opt for the 6" coil on the CTX.

As for the CTX not hitting that gold chain,.... hmmm.
Actually settings going for depth aren't usually the best for low conductors.
High noise cancel numbers on the CTX tend to work best from my experience.
If I'm after these kind of signals great care is taken setting up the unit and coil control.
Jumping from 50 conductive tones to combined isn't going to cut it.
Ferrous tone break needs to be dropped because you're listening for a signal which just bounces out of the ground signal with an FBS2 unit.
Instantly checking with the pinpoint feature often gives you a clear dig/no dig decission.

Goldbug 2 is a wonderfull piece of kit.
Video tells me I'm neglecting it too much LOL

These kind of videos going from low conductive surface targets, over complex targets down to deep targets.
They always seems like a bag of mixed nutts.
In any normal detecting situation, I'll probably hunt a site with different settings or different machines, trying to figure out what is down there.

The Deeptech machine seems like the one we all want.
Untill you decide a little discrimination is in order.

Nice bag of mixed nutts to watch though.

HH
Johnb

I kinda want a Gold Bug II now. I bet I'm late to the game, but it makes me wonder about how many small chains there might be on some of the freshwater beaches I hunt in the winter.

I dont like comparing one brand to another brand...Too many Iffy's....

Take the CTX, it is way better than most would suspect..yet it can easily look bad if your bins are not assigned the right tone's....The CTX can be a true eye opener when set up RIGHT!

The best settings I can give is to what ever machine you have get it to report a Bent nail and you will make finds in iron nail bed's and in dirt to better depth.....

If your discing a Bent nail your to agressive for unmasking agressively in nail's...the Smart will have an advantage in this scenario from the get go because of the WIDE rejection area of the iron it has....if you disc a bent nail right to the edge on the Smart it has a bit more of a chance to unmask than say a machine that trys to disc nail to copper in one turn of the dial....the wider the window of the range you are working in the better your unmasking will be ...The GMP has the same type WIDE window in nails....As DEUS...As DTVG.... You get the picture theres not alot of detectors with the WIDE nail reject area,,,but the ones that do seeem to be the best unmasker's in NAILS....RESOLUTION is of the utmost importance for any serious work...

If manufacturers were to offer you the SAME resolution on say a pull tab you would see tremendous coin find's gains in that single area...
In other words anywhere you have the WIDE resolution option on the target area's your most trying to reject (i.e nail's) the more finds will come to light.. and not by chance but by design..



Keith

Indeed we can never learn enough about this hobby and the tools of the trade and tip of the hat for the post.
Unfortunately operator abilities differ and if six guys did the test am sure results would differ but certainly good ballpark results...

Keith Southern Wrote:
-------------------------------------------------------
> I dont like comparing one brand to another
> brand...Too many Iffy's....
>
> Take the CTX, it is way better than most would
> suspect..yet it can easily look bad if your bins
> are not assigned the right tone's....The CTX can
> be a true eye opener when set up RIGHT!
>
> The best settings I can give is to what ever
> machine you have get it to report a Bent nail and
> you will make finds in iron nail bed's and in dirt
> to better depth.....
>
> If your discing a Bent nail your to agressive for
> unmasking agressively in nail's...the Smart will
> have an advantage in this scenario from the get go
> because of the WIDE rejection area of the iron it
> has....if you disc a bent nail right to the edge
> on the Smart it has a bit more of a chance to
> unmask than say a machine that trys to disc nail
> to copper in one turn of the dial....the wider the
> window of the range you are working in the better
> your unmasking will be ...The GMP has the same
> type WIDE window in nails....As DEUS...As DTVG....
> You get the picture theres not alot of detectors
> with the WIDE nail reject area,,,but the ones that
> do seeem to be the best unmasker's in
> NAILS....RESOLUTION is of the utmost importance
> for any serious work...
>
> If manufacturers were to offer you the SAME
> resolution on say a pull tab you would see
> tremendous coin find's gains in that single
> area...
> In other words anywhere you have the WIDE
> resolution option on the target area's your most
> trying to reject (i.e nail's) the more finds will
> come to light.. and not by chance but by design..
>
>
>
> Keith


Hi Keith, Are you saying that if a detector has like a set of numbers you can just knot out pulltabs and still find rings and coins in with them. Hope this makes sence. Dean

Hey flintstone..

What was reffering to is if we had a machine that would offer the RESOLUTION in the pulltab range like the gmp...deus...dtvg offers in the nail range we would dig less pulltabs and more coins...in other wordsthe more exact you could say reject a pulltab the less chance you would have of also rejecting deeper indian head or 3 center and such..

The ultimate would be to have a machine with a high resolution notch system...lay a pull tab down and open the notch window up and really narrow up the rejection zone to a partial hit above and below on say the square tabs...the do the same for the beaver ones...yet leave the areas between them wide open for rings...a digital machine should be able to do this..

Keith



Edited 1 time(s). Last edit at 10/19/2013 02:30AM by Keith Southern.

Good point, Keith. That is exactly why I followed your guys' advice on this forum and run my F75 at 6 disc. at all times. If I'm running into pull tabs, I can usually "mentally" disc. their numbers out "for the given location". I have found one solid square tab in my area that will ring up as a zinc and reach greater depths due to it's thicker design. I can usually tell that it isn't a coin, but dig anyways as it is in Indian Head territory. I still dig bent square nails, and the ocassional deep nail, but that just let's me know I'm not missing targets. Great info., great post. But now that I think about it, isn't that the premise of the Golden Umax? I know it's not a depth monster, but I had considered that detector in the past due to it's wider notch system with pull tabs/rings.....

The Golden Umax does have soem nice notch features...but the way im talking about would offer even more resolution.....Imagine having 100 points if resolution anywhere on the spectrum of conductance to DIAL in your machine for razor edge performance....

Say were in a setting hunting and there's an abundance of a certain type trash item we dont want to dig or cant dig but theres also some valuable rings and coins in the mix ....the site has been hunted hard already...But its it a area that does not alow exploratory digging...

the targets could be say aluminum rivets from old bleacher's.. they sound just like lets say a penny/dime...Well wiht the right amount of resolution the aluminum rivet could be removed but not totally..allow it to bleed a bit... then the deeper older coins could be found that the other machine's with less resolution would of left thinking they were the annoying rivet.....

I could see a machine with resolution wherever you require it on the conductance scale...Not just in the iron scale like the handful are doing now...

Resolution when coupled with tight coils fast processors and such can open sites back up....

High resolution notching sytems could be eye opening...and have it so you can open up as many areas you like in the magnified zones....

The more goodies you can get with the least amount of digging is the key in certian site's...

How many indian heads are dug in 100 year old park's/Yard's.???theres tons of them out there but the I.D. systems will drop an indian head into the screwcap range or lower...allow us to magnify that screw cap range or whatever to recover more goodies that would otherwise be called screwcap..

I know theres tons of indian out there because when I work old house sites around here that does not give up silver and the such .. theres alway's indian heads lurking in there usually dated around the late 1880's to 1900 ...so if these silver free houses in the deep wood are silver free but hold indian's..I am sure the old parks that are hunted for Silver mainly are holding tons of Indian's that are passed over daily because of false I.D.

Not sure they will ever give us more full band resolution but it would be a useful tool .. Well at least on paper!

Oh yeah and the rejected targets I want to hear them even if its a pulltab...but give me a volume control for the rejected target's....I want the audio gate open all the time...

Could you imagine being able to design your own machine ....Who Knows maybe one day we can!

Keith



Edited 1 time(s). Last edit at 10/19/2013 02:23AM by Keith Southern.

Keith, would it be possible for a manufacturer to make the scale 200 points, instead of 100. Expand the range to double somehow, not just add more numbers. I think the sunray meter for the sovereign series had 200 numbers if I remember correctly way back then.

Determining the targets composition using conductance has an unavoidable Achilles heal---the dirt.
It's like the ineffeciency of high energy lasers in a hazy atmosphere.
Simply folding a pulltab on either axis changes it's conductivity,,,the number of numbers is irrelavent
The breakthrough in detector technology we all look for will be in using something besides conductivity to determine compositions coupled with more effective ground cancellation , until then the best TID will continue to be the in hand identification method.

Possum!

Why 200 how about 1000 !!!!!

the DEUS does the first 10 in 10th's so that's 100 for the first 10 so 1000 would really get exact tight...

But yes I think it's doable...its just how much does the manufacturer think we want?

as the machines progress though I can see the resolution easily becoming full scale...

funny you mention the Sovereign...

I might of been the only one on the planet who saw the original bar grap meter as the best one they made .. remember you could expand the nickle segment to the full graph...

I dug alot of nickles in trashy spots wiht that bar graph!!

Keith



Edited 1 time(s). Last edit at 10/19/2013 02:20AM by Keith Southern.

Keith, , , , that was the exact intent (and success) of the CZ-3D......... BUT............. since most detectorists are fairly non-technical (except our own forum members)........and may not figure out a fine-tune/wide-span Disc control.......... so I made sure to deliberately create a 'fixed' set-point....... to exacting/hair-splitting accuracy........... (already done for the user/operator) for finding many, many more old-generation coins. It is a 'specific purpose' detector..... targeted for 'general purpose' users/hunters. This is to say: Creating a 'specific purpose' detector.... does indeed limit the market. But............ I would be remiss (due to changing times/mindsets) if I did not state for the record........ that 'specific purpose/specialty' detectors are now truly catching on.... to the point of generating (creating) large target-market audiences. This is ALSO to say that: We are creating a human 'mindset shift' by virtue of "discovering the unknown". As of the last decade...... it has come to light that: There are MORE non-ferrous targets than could have ever been (previously) imagined in carpets of nails....... than (collectively/combined) most all other areas on planet Earth that are fairly nail-free. Simply said: Maximum nails = Maximum habitation.

"Micro-jewelry" hunting is another example.

Years ago, we (FRL) were working on 1270-X HRID & HRAD prototyping.
HRID = High Resolution Iron Discrimination
HRAD = High Resolution Aluminum Discrimination

The (targeted market) HRID was to be the public enlightening "eye-opener" ...... as to "opening up square nail sites" and 'start' to expose the unsuspecting (richness of nail infested sites)....... subsequently redirect the 'mindset' of relic hunters...... which................. in turn............ would open up the 'eyes' of the 'general purpose' (especially old coin) hunters.
PROBLEM............ The 1270 HRID was analog electronics coupled with a concentric/coplanar (unfocused) coil.
RESULTANT = No joy!
(((Then along came the advent of the Teknetics T2........ success/mission accomplished.... on 1st Generation basis/creation))).

Corporate steam had run out (for many political/fallible human mental endurance weakness reasonings) when (attempted) energy was put forth towards HRAD.

Allow me to be a killjoy for a moment. While a digital display can map out the target response to exact bins and has the power to differentiate better, it can't do miracles or defy physics.

Consider, a common pull-tab in the ground and lying in different orientations, at differing depths, surrounded by differing mineral/iron concentrations might display a variety of Co value from say 10 -14. We'd expect the values within this range coming up 90% of the time to be a pull-tab. Perhaps a buffalo nickel gives a Co range of from 11-15 and within this range it would be a nickel 90% of the time. There is overlap between signatures, like this:

.........10, 11, 12, 13, 14......... for the pull-tab.
................11, 12, 13, 14, 15...for the coin.

Now, to gain more resolution let's widen the display by 10x (instead of having 50 Co values you'll get 500).

Now the pull-tab zone is from 100.......................................140.....................
and the nickel zone is from...........................110............................................150

Instead of having only a difference from 10-11 or 14-15 as non-overlap areas to differentiate between a pull-tab from a coin, now you'll have from 100-110 and 140-150 as non-overlapping signal areas (90% of the time). Seems like a great idea.

But..... also the detector must now define each individual range bin 10 times more accurately (or precisely) or you gain nothing. All detectors use signal processing that averages results from individual pulses (15 kHz is 15,000 views per second into the ground) which requires the detector to average pulses together - then process the averaged gates and display only the stable received values. The designers could make the machine more reactive by displaying narrower gates and increasing processor speed, more information would be passed, but the TID would become increasingly jumpy until it was unusable (and cost would increase).

The point is there seems to be a limit that detector design can be pushed past which the operator receives too much uncorrelated data. Though the extra 100 data points will display returns in that area which are likely to indicate your desired target - it would be erratic with many hits simply representing minor variation in the signal. Without smoothed data gained from the wider signal averaging the detector could become (if pushed too far) a nightmare to use.

So, I'm not sure if most modern high-end digital detectors aren't already displaying the best information they can at this point. Perhaps it can be tweaked more, but one would suppose if it could have been done - it would've been done already.

If Minelab (or any other manufacture) could create a 350 x 500 target resolution display (not pixel) instead of 35x50 it would probably have been worth doing. While a cheap detector might only resolve signal results onto 20 LCD points to save money while another detector may spread the phase values over 100 LCD points - which is better, there is a point of diminishing returns, where unintended consequences ruin any further increases.

It is likely the inherent difficulty in processing the signal without increasing unwanted signal noise and producing an erratic target ID (which only serves to confuse most operators, like turning up the sens until the display is jumping all about) is the main issue. You can't sell such an animal. Otherwise, engineers could design a detector that displays nearly every signal returned using enormously high processing speeds and have a display that looks like a bunch of lightning bugs blinking everywhere. Not too useful. Well, that was just a thought.

Johhny I like to look at it as being able to remove parts of the targets I dont want but not all of the target ...

If I completely remove pulltab theres more of a chance of masking a Coin......if I partially remove a pulltab it gives the coin more chance of a diggable signal...

Now I look at this in my Known area of working nails...and the more resolution I have in the nail range the more finds I can make....

I think the same thing could carry over to other KNOWN troublesome target's that are in quantity that are not iron related...

I could very well be wrong and I see where you are coming from... But resolution does so much when its used to advantage...

thank's for your insight..

Keith



Edited 1 time(s). Last edit at 10/19/2013 02:19AM by Keith Southern.

Food-for-thought:

Nails ..... vs ..... button/bullet/buckshot/bullion/buckle
..... is to say:
Ferromagnetic ..... vs ..... Diamagnetic/Paramagnetic

--------------------------------------------------------------------------------------------

Coins/rings ..... vs ..... pulltabs
..... is to say:
Diamagnetic/paramagnetic ..... vs ..... paramagnetic

--------------------------------------------------------------------------------------------

In the first example.......... there is a dramatic delinable differential (electronically/electromagnetically).
In the second example..... there is minimal delinable differential (electronically/electromagnetically).

Very interesting guys. I'm with you's so far, I think. Can you go further into the subject?
Tom, I think you talked about ferromagnetic vs diamagnetic/paramagnetic a couple years ago, if memory serves me....sounds like another area to be used in conjunction, for a better clue if a good target is hidden. Can it be done? heck if I know.

Doesn't Minelab e-trac and the 30-30 with the ferrous and conductive numbers fine tune this .....and with combining the custom off/on coordinates of X and Y, (excuse my laymen's terms, I'm far out of my area) give a better picture of the target? I imagine a faster processor needs to back up the other side to make it work.

Jonny, I see what your saying about the percentages being the same. I think Keith wants to be able to see/hear a thinner slice of the loaf so to speak.....a tiny hint more, if something is hiding in the nails.

But then the human brain has to be able to keep up, hmmm........... Am I on the right track?

Thank's Tom.. for the insight to the 1270 workings ..I like your HRAD idea!!

And I think I can see that the ability to differentiate between metals of like conductance and makeup is tougher than metals that are magnetic and non magnetic?

So in my train of thought the more FINE/EXACT disc line you have the more distinguishing can take place...

Me being strictly a relic hunter at heart I dont venture in modern trash all that much Becasue I hate to dig it all and I have to if I am looking for relics intermningled in modern trash...So hence the Thinking I am doing now on MORE RESOLUTION...Theres an awfull awfull lot of Good Artifacts of the past intermingled in modern trash but very very hard to get them out of it...I find some of my best Buckles lying in beer cans for a reason!!!


Keith



Edited 2 time(s). Last edit at 10/19/2013 02:38AM by Keith Southern.

Ozzie the 30/30 is opening new doors just with the faster proccesor combined with the Co-Fe I.D. system...

I like to think the 30/30 is what the engineers actually had in mind a decade ago but took till know to finalize...

Yet it could be so much more..

Keith



Edited 1 time(s). Last edit at 10/19/2013 02:17AM by Keith Southern.

Keith Southern Wrote:
-------------------------------------------------------
> Thank's Tom.. for the insight to the 1270 workings
> ..
>
> And I think I can see that the ability to
> differentiate between metals of like condcutance
> and makeup is tougher than metals that are
> magnetic and non magnetic?
>
> So in my train of thought the more FINE/EXACT disc
> line you have the more distinguishing can take
> place...
>
> Keith

That's the problem/flaw I see with your desire (mine too!) in wanting a detector that will discern "like" metals more efficiently Keith

it's easy (well - with todays tech anyway) to differentiate/separate targets of magnetic (iron) VS non magnetic (copper/aluminum/etc.) with speed and complete accuracy

that is to say - resolution, reactivity, and all the rest of the tech built into today's machines (the better ones) have made it an easy task to separate iron/non ferrous metals even when mixed together

but

to differentiate/separate say (a thin white gold ring from a wadded up piece of tinfoil) in the same sense/fashion that an F75/T2 or GMP or Deus or DTVG can separate/differentiate a coin from iron mixed rgt in iron is a whole nother story!

It would be a giant leap forward if they could figure out a way to do it but I dunno - as I was telling Tom in another thread on this subject

the only way I see it working is when they build a machine that can do true spectrum analysis (and I don't mean the Whites wanna be spectroGraph) I mean (Gas chromatography–mass spectrometry) (that is to say) when they invent a portable hand held detector/machine that can send a signal into the ground in a nanosecond that burns the metal to release gases while at the same time sending a signal back to the machine after analyzing the composition of metal based on the gases released/reported in the analyzation (used in labs for forensics currently - but is a drawn out process and not portable by any means) but - at that point - we'll have what we seek!

Has to be a specific test though. A specific test positively identifies the actual presence of a particular substance in a given sample (say you're looking for gold) you'd have to be able to set the machine to analyze for gold so it will tell you IF there's gold present or not in any given target you come across... A non-specific test merely indicates that a substance falls into a category of substances (that is to say) if you are doing non specific test - you may as well use the detectors we use now because the test will only give an indication of "possible" targets (ie - gold, aluminum, tin, etc.) the same as the machines we use today do!

P.S.

The way it analyzes the gases is thru the measurement of light passing thru the gas/es in the metal when heated/burned. The measuring of light refraction as it passes thru the gas/es.

I'd imagine a machine like that would be out of reach of even the most hardcore detectorist though - the cost (if they could invent/utilize the tech into a hand held) would probably be in the $100,000.00 range or more most likely!



Edited 3 time(s). Last edit at 10/19/2013 02:16AM by MichiganRelicHunter.

Dang Tom, we are not all rocket scientist, lol. But I think I got the jist of what you said.

Hey Michigan....

Your really thinking outside the box on those methods for sure !!

I applaud you for such thought process!

I am thinking in Archaic ways compared to your Idea...!!While your in the Quantum realm!

Yet till newer transmission methods are developed...and espacially ones that can penetrate the Ground we move on evolving as we go..Ground penetration is going to be the main problem I would imagine when trying to depart known VLF for something New...


Great insight

Keith

One thing not mentioned here is EMI and how it can change the detection depth of every machine to a certain percentage.
An example is in order.
This past summer I had the opportunity to compare detection depth between the Fisher F75, Whites DFX and V3i and finally the CTX 3030.
In areas where EMI was not an issue each machine could detect with a certain margin of accuracy coins down to the 8" level with little difficulty. Now moving on to areas of medium to high EMI and over half of the machines mention could not detect a dime at 6" regardless of settings. Please keep in mind, before each machine was tried the others were turned off and stored over 50' away from the location. High EMI can change the detection capabilities of every machine regardless of brand. I won't go into the specifics of which did better or worse, but will say each has their strong and weak points. Just my thoughts on the matter. I love this hobby............

markg Wrote:
-------------------------------------------------------
> One thing not mentioned here is EMI and how it can
> change the detection depth of every machine to a
> certain percentage.
> An example is in order.
> This past summer I had the opportunity to compare
> detection depth between the Fisher F75, Whites DFX
> and V3i and finally the CTX 3030.
> In areas where EMI was not an issue each machine
> could detect with a certain margin of accuracy
> coins down to the 8" level with little difficulty.
> Now moving on to areas of medium to high EMI and
> over half of the machines mention could not detect
> a dime at 6" regardless of settings. Please keep
> in mind, before each machine was tried the others
> were turned off and stored over 50' away from the
> location. High EMI can change the detection
> capabilities of every machine regardless of brand.
> I won't go into the specifics of which did better
> or worse, but will say each has their strong and
> weak points. Just my thoughts on the matter. I
> love this hobby............


Over half----I think we could guess that the CTX did the best in that regard (EMI).-----Right??

Whats really bad is when your machine is encountering EMI and your not even aware of it!

Good info Mark!

Keith



Edited 1 time(s). Last edit at 10/19/2013 09:05PM by Keith Southern.

Regarding emi and depth capabilities:

Both of the Whites detectors (Spectra series) I have owned, as well as an SE Pro, handled emi very well. Although I'm pretty confident that my F75 could run at half power (to negate emi) and still obtain decent depths. These (Fisher/TK) machines vary so much from detector to detector. Therin is the problem, trying to maintain a constant variable in order to properly analyze the independent/dependent variables....

CTX handled EMI the best.
Second I carry a couple targets to check my machine when I suspect EMI. Sometimes I'll check to see if my performance has downgraded whether EMI is audible or not.

Tom,

Don't know much so feel free to correct, but I think you are saying the +X inductive nature of the iron nail is more easily determined against a -X diamagnetic component. The +X and -X components have different phase polarities and are less problematic to resolve.

The weaker paramagnetic (small magnetic moments), such as as a pull-tab produces a -X diamagnetic-like component (opposing secondary field) that must be distinguished from the other similar -X components in a non-ferrous coin.

Thus, if you wanted to make a high resolution aluminum discrimination you'd have your hands full.

That is correct.
When dealing with the need to differentiate between ferrous vs non-ferrous...... the phase characteristics are much easier to ID (((although iron has multiple characteristics that have/produce a different world of ambiguities..... whereby inducing multiple opportunities for ID failure))). Dealing with paramagnetic/diamagnetic targets...... and splitting hairs with a fine-tune Disc span to differentiate between aluminum (paramagnetic) targets vs coins (primarily diamagnetic)....... induces a different set of electronic/electromagnetic difficulties towards ID delineation.
Although paramagnetic materials pose 'some' permeability characteristics (and mild hysteresis) whilst the external electromagnetic field is being applied......... and diamagnetic materials nearly strictly presents no magnetisable characteristics,,,,,,,,,,,,,, to be able to differentiate (electromagnetically) between the two...... especially with 'motion' discrimination (at current mindset/technology) is not feasible.

((((( As long as we remain incarcerated (within the confines) of electromagnetic detection devices ))))).