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Why are the numbers different?

H Desert Digger

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Does anyone know why Minelab has the -9 thru 40 target ID system when a lot of the other companies seem to use the somewhat "standard" 0-99 target ID?

After a few yeas on the AT Pro, I find myself getting lost with the Nox's Target ID numbers.

HDD
 
Does anyone know why Minelab has the -9 thru 40 target ID system when a lot of the other companies seem to use the somewhat "standard" 0-99 target ID?

After a few yeas on the AT Pro, I find myself getting lost with the Nox's Target ID numbers.

HDD

ToySoldier gives the best explanation out there, in my opinion.

Thanks for the shout out. I wrote that post because it drove me crazy each time somebody said the -9 to 40 scale has half as many segments as 0-99, and therefore it has half as much detail or twice as much compression. Anybody who has used both hopefully noticed when the same piece of foil that might hit at 0 on a Nox then hits at 40 on an AT Pro. 10 segments up from the bottom versus 40. Clearly, something's going on other than 2 to 1. Long story short, Minelab's scale of 50 is not liner relative to Garrett's 99. There's more compression than 2 to 1 in some ranges and none in others. In other words, Minelab thinks more detail is useful in certain ranges.
 
Thanks for the shout out. I wrote that post because it drove me crazy each time somebody said the -9 to 40 scale has half as many segments as 0-99, and therefore it has half as much detail or twice as much compression. Anybody who has used both hopefully noticed when the same piece of foil that might hit at 0 on a Nox then hits at 40 on an AT Pro. 10 segments up from the bottom versus 40. Clearly, something's going on other than 2 to 1. Long story short, Minelab's scale of 50 is not liner relative to Garrett's 99. There's more compression than 2 to 1 in some ranges and none in others. In other words, Minelab thinks more detail is useful in certain ranges.

Your explanation makes great sense. I only started detecting last March and I spent most of the time using a Simplex. I picked up a Vanquish 540 for beach use. I really did not mesh with it until I spent a full week at the beach with it then I totally appreciated it. I just bought a NOX 600 last week and had it out for the first time on Friday. Was really easy to jump from the Vanquish to the NOX and I have to say I am pretty much sold on them now.
 
That was very interesting data ToySoldier thanks for taking the time to investigate and share that. I suppose there is a lot to be said about being accurate and having the proper information at hand.

It's just a matter of spending more time hunting with the Nox I suppose. In the mean time, I feel like I'm using a Metric tool in a SAE environment.

HDD
 
It's just a matter of spending more time hunting with the Nox I suppose. In the mean time, I feel like I'm using a Metric tool in a SAE environment.

HDD

When I first used the Vanquish I felt the exact same way, now after using the Vanquish a while, I feel that way when I use the Simplex.

To try and simplify this scale even further, hunting in say Park 1 drops the first couple segments out so you are only basically hunting from 1 to 40 at that point.
 
H Desert Digger: said:
Does anyone know why Minelab has the -9 thru 40 target ID system when a lot of the other companies seem to use the somewhat "standard" 0-99 target ID?

After a few yeas on the AT Pro, I find myself getting lost with the Nox's Target ID numbers.

HDD
Knowing 'WHY' a lot of manufacturers do some of the things they do has always been a bit puzzling. Matter-of-fact, it's also a mystery why some engineered designs don't do some things, or why they omit some features, modes or functions on a detector.:?:

Your question points to one of the more uncommon things we all learn to figure out along the way. Minelab hasn't always used a -9 to +40 VDI reference, and not all manufacturers use a 0-99, either. There is no 'standard' as such but it would be nice. Take my White's XLT , for example, that uses a VDI range from -95 to +95 which makes 191 VDI numbers, when you include the '0' at mid-point. My 'Bushwhack' program accepts all Disc. 'segments' or 'notches' or 'VDI Numbers' from -40 up to +95.

The MX Sport and MX-7 also use the -95 to +95 scale, but the '0' is off to the left because the -95 to '0' has a more compressed scale and the '0' to +95 is a more open or broader scale.

Then you have others that rely on that '0' to '99' scale you mentioned, but they have different numeric VDI readouts or assignments. My Fisher F5 has the Ferrous / Non-Ferrous break at '15' as does my Nokta / Makro Simplex +. But my Nokta FORS CoRe has that break-point at '40', the Nokta FORS Relic at '20' and the 'Makro Racer 2 at '10.'

The Teknetics T2's have a Ferrous break-point at '40' as do their Omega 6000 and Omega 8500, but all three of then have a different Iron Nail rejection point. Using the same three iron nails for comparison, the Omega 8000 rejected them with a VDI of about '16'-'17' and the T2's at about '21' while the Omega 8500 needed an increase to about '37' to '39' or almost the Ferrous break-point.

A US 5¢ coin makes a very good test target, too. I look to see where each detector model I use registers them on THEIR VDI scale in an 'air test' or on the ground in a metal-free area. That gives me a rough or general idea how a particular desired target, of a uniform size, shape and alloy content, might register in an ideal condition and within a reasonable coil-to-target distance .. better known as 'depth.'

The next step is so simulate in-the-field encounters you have made, or perhaps make up some tests of what you think you might come across, and always be inquisitive when out detecting of any suspicious signals caused by good targets and a masking target. For example, I have a US Nickel I can look at, but when I sweep the V-540 over it I get a rock-solid lock-on that is almost always '15'. In a series of perhaps 7 to 9 passes I might get a '14' but the rest of the time it registers '15', and that is not what you'd expect from a 5¢ piece.

Why? I duplicated an in-the-field encounter I made at a RR ghost town of an 186? Shield Nickel that I eyeballed on-the-ground but the response was good on my unit, but didn't respond to my friend's detector. The cause? A RR spike was directly below the coin an inch of so, and he used a different older model with more Discrimination that I did.

On that particular test I was doing yesterday, the V-540 did give a tighter and closer-to-correct VDI than some of my other models, but it was still an errant, higher read-out.

I DO like the EQ. and Vanquish VDI display, and I also know it can be closer in many cases than other brands and models, but it can also be wrong quite often, too. In the end, having an assortment off makes and models helps keep me on-my-toes to remember the differences in design and read-out of desirable targets from model-to-model because they can differ.

Monte
 
I think the only thing I did not like about the Nox VDI is that it is just darn near impossible to tell if you have a copper penny or a dime under the coil. I can spot a pulltab vs a nickel with probably a 90% degree of success, but copper pennies vs clad dimes in particular is a 50-50 tossup on my machine and the soil here.
 
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