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On my mind -- Random Thoughts

Posted by NASA-Tom 
Re: On my mind -- Random Thoughts
June 06, 2022 01:17AM
Here is a "for example" thought:

((( Assuming about the same conductivity....... ---not that this portion really matters!--- )))

Is there a O-Scope trace signature delta/difference between a:

.54-Caliber lead Musket Ball
.54-Caliber aluminum ball of chewing gum foil
Re: On my mind -- Random Thoughts
June 06, 2022 01:54AM

I don't know enough about Oscilloscopes to know, but I would have to think there would be. That musket ball vs. ball of foil example is a very good one. Same thing between a rectangular tab, and a men's gold wedding ring. I would absolutely expect them to behave different, electrically.

My wedding ring registers 19 on the Equinox, in an air test. There are 2 or 3 different varieties of OLD rectangular tabs (a style that is no longer used, one which does not have a hole in the "tab" end) that registers EXACTLY like my wedding ring, both sound-wise, and VDI-wise. These same tabs register EXACTLY like my wedding ring on FBS units, also. I have worked REALLY hard to try to find some subtle hint or clue in the audio that, despite both targets being the same VDI, might allow a tiny bit of skilled differentiation between the two, and I simply cannot hear any such nuance. BUT -- obviously, there is a clear, substantial density difference between the two. I would love to think that some technology could be incorporated into a detector, such that this density difference could be at least "hinted at," with some degree of accuracy. Even if it reduced the pull-tab-to-gold-ring ratio in a trashy park from, say, 1000 to 1 (or whatever it is) down to something like, say, 50 to 1, that would be a monumental leap forward. It would allow us "dirt hunters" to actually focus on digging gold rings, and to do so with at least some hope of finding such rings, before tiring out after a pouch full of hundreds of pull tabs!

Re: On my mind -- Random Thoughts
June 06, 2022 11:32AM
Steve....... on most any flavor detector: The "audio" is the MASTER ........and the "VDI" is the SLAVE. Never once will the 'slave' NOT track the 'master'. ((((Actually......... there's something else in the electronics of detectors in final signal processing... that is MASTER....,,,,,,.......,,,,,,.......and the audio AND VDI (ID) are both SLAVES)))).

On a O-Scope........ a lead musket ball is presented by a very 'clear' trace.....that is very 'solid' ......well defined.
On a O-Scope........ a ball of foil of the same size is presented via a 'smeared' (blurry) trace.......(((especially the outer circumferential edges of the trace))).
Re: On my mind -- Random Thoughts
June 06, 2022 03:11PM
I think you need to put down your high dollar multi-freq units and spend a little time with some of the older models that do allow you to hear the pre-post amble density sounds.....

Go find yourself a Golden Sabre II and hunt it for about 4 hours in high alum trash sites to train your ear. There is a reason I still own one of of these, and it for the exact reason you are describing. You can hear the pre-post amble of the target.

For that matter, go get a cheap Bounty Hunter Tracker IV and do the same thing. It does it even better sometimes.

The main drawback of these old units that have that master audio is they have very limited depth. But you can darn sure hear the trash as trash.


Edited 1 time(s). Last edit at 06/06/2022 03:13PM by Mike_Hillis.
Re: On my mind -- Random Thoughts
June 06, 2022 06:35PM

Thanks for the explanation. I've kind of surmised that, over time, but I'm appreciative that you spelled out the "master" and "slave" relationship so clearly. So, it would then be correct to say that there's nothing in, say, the CTX "visual" output (like target trace attempting to show two separate targets, for example) that can't be ascertained, by a user with well-trained ear, from the audio output itself?

My thoughts on the separate visual output for "density" would -- in my mind -- require some separate, new approach to ascertain target density. And thus, I was not sure that whatever "separate approach" this would be, could be incorporated into the audio, or not. My preference would be for this specific aspect (if it could even be done) NOT to be included in the audio. I'd prefer it to be a separate screen, to be activated to allow additional "analysis/interrogation" of a given target. In my mind, this would allow the user -- once a target in question is located -- to learn things about the target beyond/in addition to the standard information gleaned from audio/VDI output. It would be a specific "density" screen, in my mind, with perhaps a graph, and possibly some "statistical" output, to show "likelihood" of the target being a "more dense" one, vs. a "less dense" one.

Just thinking out loud here...


Interesting post. And one that I find interesting, given that I consider you the "guru" when it comes to finding gold in turf-hunting scenarios.

So, let me ask you this. Do you feel -- say, with a Golden Sabre II -- that one could learn to differentiate between that specific pull tab that I mentioned, and my gold ring? Obviously, I don't expect it to be obvious, but are you saying that you feel that with enough practice, the machine offers enough of an audio subtlety that a skilled ear could learn to hear a difference between those two targets?


Edited 1 time(s). Last edit at 06/07/2022 02:40PM by steveg.
Re: On my mind -- Random Thoughts
June 07, 2022 02:00PM

With a concentric coil,....A higher karat gold band is such a smooth sound, as compared to the harsher, larger sound of a large tab, that yes....you can hear the difference in the older large tabs with the GSII. The new rounded square tabs with the two holes....those are more problematic...they are still a larger signal but the audio sounds good. Problem is when you add a crown setting to a ring, sometimes they stay smooth, sometimes they don't. But a crown makes a ring go veritical most of the time and what is really interesting is the vertical rings still keep their smooth audio where as a vertical tab is clearly junk. Vertical is easy to tell from tabs. Foil is clearly ratty until it gets thick, but if its got sharp corners it will stand out. One of the other attributes of the GSII/Pantera is that you can put the tone break on a large tab and get what i call a shiver tone on men's gold. When you hear it, you get a shiver up the spine. LOL. yeah...all you are really doing is putting a blended tone break on a target range, where most trash is just going to sound harsh, but that gold band is going to clearly stand out because due to the tightness/smoothness of the signal its going to play the tone break different. It really is a strange sound.

However you loose all this with a DD coil.

Wish CZ Dan and Gene R. were still around to post on the GSII audio attributes.

Tom-CA will come on now and blast all this. LOL.


Edited 1 time(s). Last edit at 06/07/2022 02:03PM by Mike_Hillis.
Re: On my mind -- Random Thoughts
June 07, 2022 02:40PM
Interesting stuff, Mike. Having never used an old analog machine (nor have I used a round concentric coil before), I can't imagine the audio nuances you describe. I think there would be a pretty steep learning curve there, in my case, but maybe it's something to think about.

At least, until this new "density" capability might come to fruition...

Re: On my mind -- Random Thoughts
June 07, 2022 09:01PM
Well, if the density of the target form were to be done, perhaps in the future, the approximate volume of the target could be determined with multiple sweeps from differing angles, similar to the Garrett GTI series, but more accurately. Then the phase shift would relate to the conductivity of at least the surface composition of the metal to the eddy skin depth. The assumed metal type and approximate volume would give an approximate target density. A foil ball of the same volume as a mini-ball would display a much lower density, assuming the composition difference between foil and lead could be determined accurately enough.
Re: On my mind -- Random Thoughts
June 08, 2022 01:22AM
Mike H. ....... exactly. QUITE a bit was lost..... when Multi xxxx coupled with DD xxxx coupled with 'digital cleanup' xxxx coupled with Filtered(s) ...............etc................etc ...,,,...,,,...,,, took place. YET......... SOOOOoooooooo much was gained in another arena (that we ---oh-so--- love).

Steve G. .... the CTX presents some interesting/applicable attributes AND detriments. The target-trace is a 'forward-direction'....... yet, some of the filtering (and DD coil) and processing .,.,.,.,., takes a toll!

(((Withholding information....does not constitute a lie))). Soooo........... I need to 'come clean' and explain a additional step. I have been comparing a certain caliber ball of foil.......to the same caliber lead musket ball. There's a large delta (on a tracible O-Scope) between the two discrete visual (and easily convertible to 'audio') signatures. BUT.......... if you compare a modern square-tab (stay-tab) to a woman's gold wedding band..........,,,,,,,,,.......... the delta/delineation/differentiation reduces......,,,,,,,, a huge amount. About 80% 'gap-closure'. BUT........ the remaining 20% delta...... is still more than enough (electronically) to delineate/differentiate.

John........... correct; yet a accelerometer then becomes a mandatory requirement. (Certainly NOT impossible...... with today's technology).
Re: On my mind -- Random Thoughts
June 08, 2022 01:35AM
this is correct! take any single tone Tesoro,and hear the audio!.it takes some commitment, but the
detector will "talk to you" if you listen to it, and "most" single tone Tesoros WILL get down around 7.0r 8" or so with a small concentric coil on board!
the 180 disc. on a tesoro is very 'tight" in ferrous trash, and outstanding in iron "most" good audio will indicate a "softer" deeper, "'modulated" hit on a
non-ferrous target.the 12 kHz frequency is an excellent compromise in trash, but the key is in "learning" the audio.


Edited 1 time(s). Last edit at 06/08/2022 01:39AM by jmaryt.
Re: On my mind -- Random Thoughts
June 08, 2022 02:01PM
I'll be the negative Nancy on the Tesoro thing. I say if their machines were that accurate at IDing gold from trash, then they would still be around today instead of not being in business. There would surely be a huge market for machines that people could go out and, with a little learnin', be able to hear those nuances and ignore most all the trash and dig only gold. And surely by now, somebody would have done videos on doing exactly that, calling the shots and doing live digs to showcase how good they are at doing it. All I've ever heard and seen from it from people, were excuses. I liken it to this right here. When I look for native artifacts, I carry a flipping stick with me, to save me from bending down to every piece of flint I see. During periods of slow times between finds, I will tap my boot out of boredom with my stick...and then suddenly I will spot a point. I could say I have a lucky stick and that every time I tap my boot with it, I find an arrow head. In reality...there are FAR more times I tap my boot and NOT find anything, than when I tap it and actually spot an arrowhead. In detecting...you're not going to have a high percentage of accuracy calling your shots in trash. There's just too many variables. Too many different pieces and shapes of trash...too many different pieces and shapes of jewelry. You may call it right SOME time but I'm betting you're wrong MOST of the time. Even a clock with dead batteries is correct twice a day.
Re: On my mind -- Random Thoughts
June 08, 2022 05:39PM
For Density display....off the audio....using delta pitch audio....could you have a single line display that would show 'thin' vs 'thick', using the line size for a density check? "Thin" line corresponds to a tight signal, vs 'Thick' corresponding to a more spattered signal.....maybe rolling like the old QXT signal display or the V3 rolling pinpoint display...????..maybe coming off the all metal channel even...

The problem with filtered disc modes is you don't even get a response until after the signal peaks and starts to decay....for real time, it would need to be independent of the filtered disc mode or some sort of mixed mode....but it needs to be clear what you are looking at..

Signal intensity is currently a pretty clear graphic...perhaps ramp up/ramp down could be appended to that???

I dunno...

Re: On my mind -- Random Thoughts
August 22, 2022 06:09PM
BEACH = The Design Engineer of whom tackles SALT the best = WINS
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