Too High Gold ID Problem

[Skull diver]

2 hours ago, midalake said:

I think there are some people that would debate depth loss. On a 3030. 

Certainly there are so many variables between setting and terrain that it is impossible to pit one tool against the other.

However, when I saw the distance from the coil at which the signal begins to manifest on the D2, I realized the potential effectiveness on low conductors.

Although air tests are worth as much as toilet paper, gold remains gold, and there are pieces that barely play stuck to the coil of the Ctx...

I use it, I keep it, but the occasions of erosion where it might make a difference are becoming increasingly rare.

[palzynski]

On 2/10/2024 at 10:17 AM, Skull diver said:

...

The ring you observe in the photo, is an ordinary wedding ring that probably because of its thickness, responds with a solid 80.

Forgive my assertion, but this is damning, considering the multitude of coins and leads that fall within those figures.

...

I agree , when I started with the D2 I was surprised that the D2's conductivity ID works very differently from my previous detectors ( Deus1 , Equinox , Vanquish540 for example ) 

As you said the D2 low conductivity range is spread out and the high conductivities are compressed . 

For example a schrapnell ( around 10g lead ) IDs 75/99 on the D2 ( at the right side of the scale ) where it says 17/40 on a Vanquish 540 ( at the middle of the scale ) , see pics below  ...

I have been a little disturbed by this at the beginning , now I am used to it , 
but I would have preferred less compressed high conductivities on the D2 ...
 

1) the target : 1st WW schrapnell 10g lead 

 

2) Deus2 , ID 75/99 for the schrappnell  ( blue arrow ) , at the right side of the scale

 

3) ML Vanquish 540 , ID 17/40 for the same schrappnell ( blue arrow ) , at the middle of the scale

[The_Stalker]

Just tested 8 gold rings, from a small thin 10k band to a very large class ring and everything in between.  The Deus 2 had a spread of 48 on the lowest to an 88 for the class ring.  For what it's worth, the Tarsacci had a spread of 5 to 17 for the same gold ring collection.  I think this just goes to show how difficult it is to cherry pick with any detector, but I agree the Deus 2 is the hardest to cherry pick gold because of the huge numerical spread that it presents as gold.

[palzynski]

There is something specific to rings too , they are circular which increases their conductivity vs "compact" ( non circular ) targets .. 

[Skull diver]

@palzynski

Logically, with a more compressed ID scale, I would justify more objects falling under the same numerical group.

That's the oddity on Deus2, just the final group that includes coins, leads of about 30 grams and above, and silver, includes 18K gold over 5 grams.

The funny thing? Approaching the coil to a stove I have in my shed, the steel of the cooktop sounds a perfect 80 exactly like that wedding ring.

The problem is that it is a mass the size of a washing machine.

I have no words.

[Skull diver]

@The_Stalker

I think it is possible to fix this behavior with an update.

I vaguely remember a few users noticing a difference in the past between the very early versions and 1.0.

It was a matter of a few coins however, rather than gold.

[EL NINO77]

On objects of the ring type, the eddy currents are very well concentrated around the circumference of the ring - and therefore such an object can obtain slightly better detection properties than a coin of the same diameter.

Regarding the dispersion of VDI numbers, other things are important, such as the purity of the gold, as well as the size and shape...

[JCR]

This topic is certainly getting into the weeds of professional level detecting. That is why this Forum is so special.

The selectable TID scale vs normalized TID offered as an option on some former top of the line units(Deus I, Impact/Anfibio Multi & Rutus Alter 71/Atrex) would help to some extent. That user choice is missing from the current top releases. I would like to have it back, just because it may be useful in certain situations.

[Chase Goldman]

On 2/11/2024 at 12:58 PM, Skull diver said:

The problem is that it is a mass the size of a washing machine.

I have no words.

I understand the frustration regarding TID scaling in general, and the specifics of the Deus/Deus 2 scaling which indeed compresses the high end of the TID scale (high conductors) while giving a huge range on mid-conductive targets from 20 through 80.  However, this example, which is valid, is also a great reminder that a detectorist should not rely solely on TID to make a decision.  Large steel targets do indeed ring up high, as well as large aluminum targets.  As far as these large targets are concerned, pitch audio or pinpoint help to readily unmask their true nature through elongated audio or huge pinpoint mode footprints so they can be readily bypassed if looking for jewelry or coin-sized targets.  Furthermore, as Jeff McClendon pointed out, target audio quality or purity is also a great "discriminator" between round or symmetric targets vs. junk, irregular targets that sound more distorted.  Of course, damaged jewelry and coins, and non-continuous precious metal loops such as broken rings or earrings can also affect this outcome in both audio and target ID indications.   

It all comes down to the fact that no TID scaling option is necessarily going to be universally acceptable to all detectorists because target objectives vary.  Enabling some end-user customization of TID scaling, as JCR suggested, in certain "regions" of the scale depending on the detectorists needs would be a welcome feature addition.

In the absence of such a feature, and to be frank, no TID scaling scheme is going to be "perfect" regardless how much customization is allowed, then the detectorist who has neither the luxury nor will to "dig it all" will have to "play the odds" as they have had to do forever.  They will need weigh for themselves whether that 80 TID is worth chasing based on the classic risk/reward assessment that accounts for the likelihood of occurrence and the return on "investment" should you chose to chase the targets at either TID extreme.  Is the occasional honker that rings up 80 WORTH digging up thousands of junk or low value coin targets, or is your time best spent simply recovering the bulk of the valuable targets that fall in a narrow range of TIDs, than wasting time on digging potential "white whales".  The math is really not all that hard once you have a sufficient data to understand how valued targets are distributed across the range.  As a "professional" it makes sense to do this kind of data assessment in addition to the hard physical work of dive recovery to make your recovery efforts as efficient and lucrative as possible.

 

[Skull diver]

@JCR @EL NINO77

This is what happened today.

I started the session with D2 in a promising area.

About two hours and two medium-sized rings (both under 5 grams).

Tool change and back in the water with the Excalibur.

After two minutes I dig out the third snake-shaped ring, perhaps the thinnest and lightest of the three.

This is overwhelming evidence that a screen and an ID, can make a difference if they respond correctly to the object, but as long as you dig outside the range of interest, you lose useful time for other targets.

I fear I will soon have to fall back on yet another detector and the choice is really narrow.