Just thinking out loud about VDI resolution

Pete e said:

So how many have seen VDI numbers change as you dig your hole? Plenty of times I have seen a jumpy VDI of say 17 -18 firm up to a nice solid 20 after taking out a shovel full of soil?

What about targets that give different VDI at different sites? I have one sites were pistol balls come up at a consistent 16 but on other sites they are a 19?

This is with my Nox but have seen similar variations with my Racer 2 also...

I would love to be able to hunt primarily VDI only, but I know that I will miss a lot of good targets if I do, partly because our targets are so variable...

it *might* be a more practical approach for you folks who coin shoot for modern (post 1800) coins as the targets themselves are more consistent, but for people interested in older coins and relics, I can't see it working....

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Again, you're describing the very problem with these new detectors with only 30-50 VDI target segments. You don't see that jumpy VDI with the higher resolution detectors, and that is my point. Everyone has grown so accustomed to a jumpy unreliable VDI, they think that is the norm. It didn't use to be.

On the DFX, yes on deep target the VDI could get jumpy and less reliable. The E-Trac CO numbers start jumping on deep targets, but the FE number gives a very good indication of good vs bad. The $250 Simplex does not have a jumpy VDI. As I said, if it says 18-21 it WILL be a piece of foil, If on any swing it gives a higher number, say a 22, it will not be foil 90% of the time. If you get a 04 on every swing, it will be a piece of iron such as a paperclip, hairpin, tack etc. If on any one of the swings you get a VDI above 04, it will not be iron 90% of the time. The exception there is a bolt will sometimes read above a 04. I recover a lot of those steel $0.25 bubblegum machine rings because they read a 04 most of the time, but will get a VDI of 05-06 telling you it isn't foil. The 30-50 VDI detector will call it iron junk.

This conversation reminds me of the old school guitar player who rolls the tone knob and volume knob with his little finger and gets more results than the modern guitar player who has a mass of amps and foot pedals.
I have a Tesoro MicroMax with Garrett headphones with volume control. It only has a Sensitivity knob and a discrimination knob. After spending some time with it, I could roll those two knobs with my thumb and fairly accurately determine what the target was and the depth. It would produce different breaks and squawks in the tone. I need to get that detector back out.


https://www.youtube.com/watch?v=cmgAjkxq4Gc&t=20s

The reason vdi is insignificant to me is using an at pro as an example i have dug a gold ring corresponding to virtually every mid tone number from 40 to 75 and a couple honkers that crossed over into high tones i can't understand why people wouldn't dig an appropriate sized mid tone ,even if your main focus is coins i would think any place there is coins there's also the possibility of rings

The Lama said:

The reason vdi is insignificant to me is using an at pro as an example i have dug a gold ring corresponding to virtually every mid tone number from 40 to 75 and a couple honkers that crossed over into high tones i can't understand why people wouldn't dig an appropriate sized mid tone ,even if your main focus is coins i would think any place there is coins there's also the possibility of rings

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The reason I don't dig it all anymore is medical reasons. I have COPD, a repaired broken left hip, 5 hernia surgeries on the same side as my broken hip, and my left knee was mauled by a pit bull last year. Needless to say, my left side is shot. I'm, only good for about an hour of hunting, and in the hour I'm lucky to recover 4 targets. I have to make it every time I bend down count. That is why target identification is very important to me.

I have spent the last 5 years trying every detector I could get my hands on looking for the best target ID system. I have been very disappointed in the newer models which don't seem to put much emphasis on a good VDI system. Not like it was 20 years ago. I'm hoping the manufactures will see people more interested in a good VDI and put out a better one for us disabled hunters. But they won't do that unless there is enough interest in it. As you can see, most hunters care little about a good VDI system. That is why no one is making them anymore.

I mentioned this in another thread. Did Minelab intentionally cripple the Equinox because the Etrac and CTX were still being made and were the highest priced detectors they made? Both are the well known kings of silver identification both tonally, and V.I.D.. It would not have been smart for them to make a lower priced detector that was equal to them I.D. wise. Maybe it wasn't even possible to put Ferrous-Conductive on the Equinox.

I've swung over enough Etrac found targets to know at least on coins the Equinox does an outstanding job with it's fewer segments. You may have to massage the target more, and know the detector more by averaging the numbers in your head, but on coins I don't see the issue even on deeper coins.

I'm not a tot lot hunter or a beach hunter, but it seems to me the range of jewelry size and metal content is so broad it would not matter that much. The point about being about to know what junk reads and avoiding it would seem on the surface fruitless for the same reasons, but then again I don't target jewelry.

longbow62 said:

I mentioned this in another thread. Did Minelab intentionally cripple the Equinox because the Etrac and CTX were still being made and were the highest priced detectors they made? Both are the well known kings of silver identification both tonally, and V.I.D.. It would not have been smart for them to make a lower priced detector that was equal to them I.D. wise. Maybe it wasn't even possible to put Ferrous-Conductive on the Equinox.

I've swung over enough Etrac found targets to know at least on coins the Equinox does an outstanding job with it's fewer segments. You may have to massage the target more, and know the detector more by averaging the numbers in your head, but on coins I don't see the issue even on deeper coins.

I'm not a tot lot hunter or a beach hunter, but it seems to me the range of jewelry size and metal content is so broad it would not matter that much. The point about being about to know what junk reads and avoiding it would seem on the surface fruitless for the same reasons, but then again I don't target jewelry.

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I'm going to find out longbow. I've got another NOX 800 headed my way. I love the setup and the ergonomics of the Equinox 800, but when I took it to our city park I came home not impressed with the depth. I can take the E-Trac down there and go home with a few keepers almost every time, but they are deep. I see videos and I think I'm just not giving it the chance it needs to prove itself. I did that with the Explorer SE. I tried to follow up my DFX cleaning in that park with the Explorer SE and all the tones gave me fits and I sold it. Now having mastered the E-Trac, I realize I didn't give it a fair chance.

My biggest hurdle is my medical issues and the limited time I have for each hunt. If I can figure out what the NOX 800 VDI is trying to tell me it will all be good. I know it does a better job at unmasking coins down to the 6"-7" range, but I need it to hit 8"-10" and deeper coins and give me good odds at identification being right. We shall see.

mh9162013 said:

Of course! But current tech doesn't allow for that. Just increasing the number of segements will NOT automatically make it more reliable.

For example, if you had a ruler made out of play dough and it had 1 inch increments, what good is increasing it to 1/16 inch increments? The play dough is so soft, increasing its resolution would be meaningless. Only until the ruler was made out of a harder material, like wood, plastic, metal, etc. would boosting its resolution do any good.

And yes, the Simplex has more VDI resolution, but it's not SMF. So its VDIs are less consistent (especially in mineralized soil) as MIQ's VDIs. So all those extra VDI increments aren't as useful as they might otherwise be.

You're acting like it's easily done or that manufacturers can do it, but just don't realize it. I don't think either situation applies here.

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Why do you think simultaneous multi frequency makes a VDI more reliable than running a single frequency? So if I run the equinox in a single frequency the VDI will be sloppy compared to running it in simultaneous multi frequencies? I'm thinking that's not the case, simultaneous multi frequency has little to do with VDI readout vs running a single frequency.. VDI readout is more about how the machine processed that info,and not how many frequencies hit the target

woodbutcher said:

Why do you think simultaneous multi frequency makes a VDI more reliable than running a single frequency? So if I run the equinox in a single frequency the VDI will be sloppy compared to running it in simultaneous multi frequencies? I'm thinking that's not the case, simultaneous multi frequency has little to do with VDI readout vs running a single frequency.. VDI readout is more about how the machine processed that info,and not how many frequencies hit the target

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I just ran to my dedicated coin garden with the Equinox 600, cycled thru all frequency choices and the VDI was the same on my 6" buried quarter, in every frequency.

graybeard said:

So what you are saying is White's with the DFX had more intelligence than Minelab with the Equinox. I still use the DFX and find great targets. I no longer have the Equinox 800 that I had, to many EMI problems and terrible ID numbers.

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No, I'm not saying that at all.

woodbutcher said:

Why do you think simultaneous multi frequency makes a VDI more reliable than running a single frequency? So if I run the equinox in a single frequency the VDI will be sloppy compared to running it in simultaneous multi frequencies? I'm thinking that's not the case, simultaneous multi frequency has little to do with VDI readout vs running a single frequency.. VDI readout is more about how the machine processed that info,and not how many frequencies hit the target

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In difficult (mineralized or salty ground it does). In air tests, most tot lots or mild dirt, SMF is about the as single frequency...at least in my experience.

Comparing my Equinox 600 to AT Max or Fisher F2, the former had far more stable VDIs at depth in my highly mineralized soil.

All detectors struggle at depth. As for the Equinox at a salt beach. I would say anything past 5" has suspect VDI's depending on nonferrous type and size. Add black sand and EMI, all bets are off.
Good thing I do not rely on the Equinox VDI's, rather more just to identify the target as ferrous or nonferrous.

Beachhunt1 said:

All detectors struggle at depth. As for the Equinox at a salt beach. I would say anything past 5" has suspect VDI's depending on nonferrous type and size. Add black sand and EMI, all bets are off.
Good thing I do not rely on the Equinox VDI's, rather more just to identify the target as ferrous or nonferrous.

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And that has become the excepted norm for many.

On the E-Trac, you have the CO (Conductive) VDI, and the FE (ferrous) VDI. I have found the CO VDI to be a good indicator down to roughly 8" depending on conditions. At that point, the FE becomes important because rusted iron will fool the CO once you get down to that depth, but the FE continues to give you the information to tell the rusted iron from a conductive target. If the FE ever reads to 17 or above, you can be pretty sure it is junk. If the FE remains at 12 or below, you can be pretty sure you have a conductive target like a coin.

Now that is FBS as opposed to SMF and maybe that is the difference, but if it can be done with a detector that, supposedly, uses 28 frequencies at once, why not 5 of the SMF?

FBS didn't process 28freqs at once nor 5 freqs in SMF, this is old ground

Detector said:

And that has become the excepted norm for many.

On the E-Trac, you have the CO (Conductive) VDI, and the FE (ferrous) VDI. I have found the CO VDI to be a good indicator down to roughly 8" depending on conditions. At that point, the FE becomes important because rusted iron will fool the CO once you get down to that depth, but the FE continues to give you the information to tell the rusted iron from a conductive target. If the FE ever reads to 17 or above, you can be pretty sure it is junk. If the FE remains at 12 or below, you can be pretty sure you have a conductive target like a coin.

Now that is FBS as opposed to SMF and maybe that is the difference, but if it can be done with a detector that, supposedly, uses 28 frequencies at once, why not 5 of the SMF?

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Beachhunt1 said:

All detectors struggle at depth. As for the Equinox at a salt beach. I would say anything past 5" has suspect VDI's depending on nonferrous type and size. Add black sand and EMI, all bets are off.
Good thing I do not rely on the Equinox VDI's, rather more just to identify the target as ferrous or nonferrous.

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True, but some struggle more than others.

Detector said:

And that has become the excepted norm for many.

On the E-Trac, you have the CO (Conductive) VDI, and the FE (ferrous) VDI. I have found the CO VDI to be a good indicator down to roughly 8" depending on conditions. At that point, the FE becomes important because rusted iron will fool the CO once you get down to that depth, but the FE continues to give you the information to tell the rusted iron from a conductive target. If the FE ever reads to 17 or above, you can be pretty sure it is junk. If the FE remains at 12 or below, you can be pretty sure you have a conductive target like a coin.

Now that is FBS as opposed to SMF and maybe that is the difference, but if it can be done with a detector that, supposedly, uses 28 frequencies at once, why not 5 of the SMF?

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Almost no one (outside of Minelab or Codan) knows for sure how many frequencies an FBS or MIQ detector is processing at once. Based on marketing of both techs (and the slower recovery speeds of FBS and FBS2), I think FBS processes more frequencies at once than MIQ. But that's just a hunch.

The amount of freqs processed by FBS already been proven, it's old news.

mh9162013 said:

Almost no one (outside of Minelab or Codan) knows for sure how many frequencies an FBS or MIQ detector is processing at once. Based on marketing of both techs (and the slower recovery speeds of FBS and FBS2), I think FBS processes more frequencies at once than MIQ. But that's just a hunch.

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ghound said:

The amount of freqs processed by FBS already been proven, it's old news.

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Do you have a link? I'm curious to learn more about how FBS works.

Detector said:

Again, you're describing the very problem with these new detectors with only 30-50 VDI target segments. You don't see that jumpy VDI with the higher resolution detectors, and that is my point. Everyone has grown so accustomed to a jumpy unreliable VDI, they think that is the norm. It didn't use to be.

On the DFX, yes on deep target the VDI could get jumpy and less reliable. The E-Trac CO numbers start jumping on deep targets, but the FE number gives a very good indication of good vs bad. The $250 Simplex does not have a jumpy VDI........

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(emphasis added by me)

That's simply not true.

Here's a two part video of a guy air testing common metal detecting finds with his Simplex. Objects that don't bounce between two or more numbers are the exception. Plus, as with every detector, different examples of the same object, including coins, hit different VDI from each other.

Lower conductors/trash/jewelry
https://www.youtube.com/watch?v=s0TaLagGlHg
Higher conductors/coins
https://www.youtube.com/watch?v=zXzong68NIc

(In the description there are links to different objects.)

Here's a completely random video I found of a guy doing a typical yard hunt with his Simplex. I just clicked on one of the first videos that came up in the search:

https://youtu.be/B0ZRc6SQSbI?t=24

Wheat pennies and clad coins jumping 4 to 8 numbers. I slowed down the video on his first and second targets.

First target, with each tight swing: 16,84,65,83,78,85,85,77,90,80,75,89, etc... It was a 2-3 inch clad dime.

Second target:
76,77,74,74,81,77,82, etc....

I have an AT Pro (99 scale VDI) and the VDI is jumpy. I've done plenty of back to back tests on targets pre dig with the Equinox. The AT Pro bounces just as much as the Simplex and more than the Equinox on the same targets. The At Pro gets me to dig more, which can be a good thing sometimes. It has other great features. It's rugged, waterproof, very descriptive audio as far as how solid and round an object is, and great for when I'm up for digging pretty much anything.

Also, when you're facing fairly clean dirt, being able to swing a dozen times over each promising signal is reasonable. Either to allow the detector to dial in a VDI or just doing it mentally.

What's more important when there's three or four non-iron signals for every swing is what you hear on the first pass or two. Again, in my own testing on targets pre-dig, the Equinox more often finds something close to the true reading on the first pass or two, and has more ways to relay that over audio.

On that same note, while FBS-based Explorer II isn't my main machine, I also disagree that the CO number gets jumpy at depth. If anything, the strong point of FBS is that it hits deep high conductors with a very high, stable CO. When that happens, it's a coin.

So, don't say these 100 scale machines don't have jumpy VDI. You've repeatedly said that 'people don't care about VDI' and something along the lines of VDI being nearly useless. No, people care about VDI, it is arguably better than it's ever been, it is extremely useful, and we'd all like for it to be as good as the limitations of the underlying science allows.

woodbutcher said:

Why do you think simultaneous multi frequency makes a VDI more reliable than running a single frequency?..........

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Detector said:

..........On the DFX, yes on deep target the VDI could get jumpy and less reliable. ..........

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Reliability (getting the same reading over and over) is only part of the equation.

What we ultimately want are 'reliably valid' readings delivered quickly, and it's nice if we have some flexible controls and high precision would be welcome. The level of precision possible or practical is debatable because of the limitations of the underlying technology and the wide variation in targets and ground conditions.

So, there's:

Validity
Speed
Reliability
Flexibility
Precision

When hunting old coins and relics in old yards with both rusty iron and some modern trash under nearly every swing, I'd rank them in that same order of importance, although they're all important of course.

The focus on number of segments puts too much emphasis on what I think is not only the least important variable but also the one with the least possible return on investment given the realities and limitations of the underlying technology.

Multi-IQ is Minelab's excellent attempt at improving the VALIDITY of a single VDI within the first pass or two on a large easy to read screen. An unprecedented fast processing of a wide range of frequencies.

If that's not enough, they gave the user control over recovery speed and iron bias, the weighting of the frequencies in different search modes, as well as the option of highly customizing the tones of those 50 segments.

ghound said:

FBS didn't process 28freqs at once nor 5 freqs in SMF, this is old ground

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From the Minelab site.

Minelab’s FBS technology simultaneously transmits 28 multiple frequencies from 1.5kHz to 100kHz.

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It also has been shown to be a "time-domain" technology which is why a slow-moving coil is needed. With the newer faster processors, even time domain can be processed at a greater speed, meaning a slow swing is not as necessary.