Splitting Hairs On Ring VDI Numbers

[deerman]

BUT if you don't dig all the signals you get in the gold range you just might miss a $10,000 or higher value ring that becouse of the numbers comes
in above or below what you have as a good set of numbers as there are alot of small rings with BIG diamonds in them??? just my thoughts
also with gold at the price it is even the small rings are worth $$$$$

 

[Critterhunter]

This has been beat to death before. Like I've said countless times, I'm not arguing the digging it all isn't the most thorough solution. What I'm saying is that when land hunting and it would require you a life time to dig all the tabs out of a large park then I'd rather improve my ring to trash (tab) ratio but avoiding most of the common tab numbers. Yea, you can just watch the number on the VDI and not run a notch but that gets real distracting to me in a sea of trash. By shutting those tabs up via the notch set properly the machine quiets down and allows me to investigate each and every other signal that falls outside that notch zone. I'll then be more inclined to really check everything else out, and will dig what sounds smooth and consistant with VDI from any direction to further discriminate out trash non-uniform in shape. It's real easy to tell by either the jumpy VDI or the sick sounding audio when it's NOT a gold ring, unless of course that ring is crushed and/or cut up. I further discriminate in areas loaded with small bits of foil or aluminum by bringing the discrimination up to kill everything below about 90 on the VDI. Otherwise it's a non stop random ramble of constant tones in some of the most trashy spots I hunt, such as right around picnic tables.

Today I decided to try the above settings in a really trashy old park. Managed to dig 3 deep nickles that I bet I would have missed had I also been hearing the tons of pulltabs laying around them in that very trashy area. When I keep hearing a bunch of tones right near nickle it's easy for me to not even look at the VDI and just to try to wander out of it as fast as possible. I'm sure a lot of people do that, but by using the notch I could cut "all the voices" down to the ones I wanted to hear and investigate- that being anything but another lousy pull tab.

 

[Critterhunter]

My next little project is to create a graph on the computer that shows where all the random tabs I sampled fell within the VDI number ranges. I've already sort of posted this information in condensed form with percentages, but it's interesting to see the bell curve of those tabs and how they are more heavily concentrated within the meat of the number range. I have this on graph paper from when I did the sampling, but I didn't enter it on a computer. It even shows what are round and what are square tabs, which is sort of interesting in it's self.

I should be getting the book within the next few days and look forward to reading and comparing their findings to mine on rings. This is the sort of stuff I really enjoy...

 

[Critterhunter]

I created the graph with the random tab samples to illistrate where the majority fall....

Also, I've finished reading that book where over 1000 rings were scanned in for the Sovereign/Excalibur. I found it interesting that they mostly concentrated on the discrimination dial and what percentage of rings would be found with various settings of that. Notch seems much more useful in that respect to me yet it was hardly mentioned. They did provide pictures of the rings and a little information in respect to the discrimination setting but beyond that the vast majority of the booklet is very basic and was nothing more than mildy interesting to me. About the only thing I'll have to say about it in comparison is where they found the discrimination dial would still allow all the rings they recovered to be found, which I'll have to review before posting. However, what they didn't cover is whether the test pool of rings they used was a true random sample dug by digging anything above iron, or if some of which were found by digging only certain targets over the years. They can greatly bias the test pool. The over 100 rings I used were found with an Excalibur by a friend while water hunting at several locations, so they are both not biased by site specific activities or by only digging desired zones. Same deal with the tabs posted in the chart below...

 

[Critterhunter]

Just re-reviewed the booklet on over 1000 rings being scanned. The thing I found to be of most interest to me was the fact that all the rings scanned (with the exception of some steel "junk" rings) would be accepted with the discrimination as high as 3 on the dial. This was on I believe a Sovereign XS, so that setting might differ on other models. The lowest reading non-steel rings scanned read somewhere below 79 on the VDI, though they weren't specific on where those started in VDI value. This conforms nicely to the rings I sampled, because the lowest value they started at was 75 and went up from there. As I've previously said, in spots where tiny bits of foil or aluminum from things like can slaw exist I like to set my discrimination at about 90 to silence the majority of them.

I was playing around with some randomly generated numbers for both ring values and the number of rings and tabs existing in a theoretical area just for fun. I feel pretty confident to say now that if you are digging all the tabs in a large area loaded with them, but do not intend to dig all of the tabs out of the site over the months or years it may take, then you are grossly hurting your chances of recovering a gold ring compared to eliminating the most common tabs present. In a situation like this where you don't have the time or motivation to dig everything you greatly increase your odds of recovering gold rings while eliminating the need to dig most of the tabs. To me it's no longer a way to be lazy and still hope to get a few rings, but a great tool to use to my advantage to find more rings than I would have otherwise.

 

[Rob in (Ca)]

Last year I changed my hunting style to what like crazyman posted above ..... and have found well over $3K worth of jewelry, Dig It All....just be in the place.

 

[jbow]

I found a white gold circlet with small diamonds all around it that read in the 90s... but the tone was sweet and the number was stable from 4 directions.... that is the Sovereign though.

J

 

[Critterhunter]

Here's the link to the coin chart which also condenses the ring parameter numbers as well as the tab percentages into chart form to carry around. My next addition will be to add to the chart what percentage of rings fall within what number ranges. Also note that there are several numbers in the tab chart that are empty. I'd dig those and other "odd" numbers in the hopes of rings as well as a good find, such as a silver 3 cent piece that I think (from memory, didn't check) reads 166. I also like to dig those 170 and 171 numbers that are just below penny yet give solid/locking tones. Anybody else have a certain number they like to key in on?

http://www.findmall.com/read.php?21,1131790,1171945#msg-1171945

 

[Critterhunter]

Just wanted to link this thread to the other current one as they both contain related information along with more ring hunting tips...

http://www.findmall.com/read.php?21,1311376

 

[Critterhunter]

This might prove of interest concerning some form of trash to ring ratio. Ran across this little nugget of information on another website by Tom in CA. Since I

 

[Critterhunter]

I've been doing some research for a project I'm working on and thought a little of the coincidental subject matter at hand might prove of interest to those ring hunters reading this thread. These excerpts are from

 

[Critterhunter]

A recent question in this thread...

http://www.findmall.com/read.php?21,1311376,page=1

about calibrating the notch for pull tabs gave me an idea. For those of you who own Sovereigns but don't have a meter who would like to try this ring program (notch setting), I'll send you a 165 reading pull tab for calibration. Just PM me an address to mail it to and your name. I doubt I'll need to use this disclaimer but I will anyway...If I get too many requests for this I'll have to cut it off at some point. Next time I'm out hunting I'll save some 165 tabs and mail them to you. More than likely these will be round tabs with the next area I intend to hunt.

You'll want to raise the notch slowly as you sweep back and fourth over the tab until it just barely kills the audio. If your notch is 12.5 digits wide like my GT then it will then kill down to 152.5, knocking out about 84% of all round and square tabs. Adjust it slightly higher or lower as you hunt if you are digging a bunch of tabs just above or below the notch. Mainly setting it to 165 for me seems to work just fine for both old and new sites I hunt.

I realize many (including myself) often don't want to use any form of discrimination if old coin or ring hunting due to the potential for masking and also because many deep fringe coin signals might initially appear in the tab range until properly swept over with short sweeps to draw out the best ID and audio. Many also like to hear the tab range in case one sounds different in some way that sets it apart from other targets in that number range. However, when the amount of tabs I'm hearing is so numerous to the point of severe distraction, that's when I like to use the notch. If I'm not planning on digging tabs when coin or ring hunting and they are present by the thousands then this greatly helps my concentration. I've said it before, my nickle count goes way up because now I'm prone to pay attention to those when otherwise I might mistakenly ignore them as just another tab. Also, just like running sensitivity too high can cause you to miss signals because of the constant noise, hearing tabs by the billions might cause you to miss a deep coin or other signal when you are just trying to hunt your way out of a mess of tabs. It's like having three people talking to you at once, and when that happens you don't really hear what any of them are telling you.

As a side note, I have yet to really use this "program" to see how well it works in any real intense manner yet. I always seem to find other things I want to hunt for (mainly old coins), or get in one of those moods where I feel like digging everything above iron for any potential rings or masked coins. I haven't used it nearly enough to see if rings start popping up with out having to dig nearly as many tabs. In fact, I'd say I've used it more while coin hunting than ring hunting thus far, wanting to notice potential old nickle signals while ignoring most other junk. If anybody ends up finding a ring or two with this calibration method please at least shoot me a PM and tell me about it.

 

[Critterhunter]

Here's some percentages from somebody sampling over 100 rings like we did. My only question is did he aquire those rings by digging everything above iron? If not then the test pool is biased. We've found they are pretty evenly spread from foil (about 76) all the way up to about zinc penny, after which they thin out a bit. These were rings recovered with an Excal digging everything above iron water hunting over the course of about 6 years.

 

[synthnut]

" My only question is did he aquire those rings by digging everything above iron? "

This is a collection of Gold rings of various shapes and sizes ..... The ranges were given for the 161 rings ..... No tricks , no excuses .....They are a collection of rings found, and the respective range that they were in ...... Nothing more , nothing less .... I don't know how you can say that this is biased if this is what the man found, and the ranges are what he posted ......??????.....What does IRON have to do with anything ? ..... He's giving raw data ....How can raw data be biased ? ......He's not trying to prove anything ....He's merely posting data ....... ..Jim

 

[Critterhunter]

I'm saying simply this- If those rings weren't found by digging every single signal above iron then they are a biased test pool. I don't know if they were found that way or not, I'm simply asking the question since the specifics were not posted. If I were to sample rings from "a collection" then I gurantee you that it will be slanted in numbers. Why? Because many people key in on certain zones. Nickles, tabs, or specific number ranges. Even if 100 of those rings were found digging all signals above iron but the rest were found when somebody was being selective in some way while say land hunting then you might as well throw out any results you get.

Here's another example....Let's say I key in on digging coins 7" or deeper and end up after a few weeks with about 40 wheats and 6 silver coins, along with about 20 clads. Can I then say that my average for old coin hunting is 20 clads for every 6 silvers, or 40 wheats per 20 clads? Of course not, since I've biased the numbers by technique. Same deal with rings. If you are selective in ANY way the numbers mean nothing.

Now, I'm not saying his test pool is biased or not. I have no idea. He might very well have found all those rings digging every signal above iron. I'm simply asking the question. Without the answer to that it's just a curiosity and not anything to use as a guide.

 

[Critterhunter]

As another example of statistical bias, which will probably be all I have to say on the matter (can't make my position any more clear)...Let's say you take the percentage of people infected with AIDs in the US and calculate prevailing infection rates via sampling. If the people surveyed were homosexual men or drug users then the corresponding infection level results would of course be much higher than if a random sample of the entire US population was used.

I'll even draw the distinction out to something more refined. If I were to go to a jewelry store and sample all the gold rings at that store then I still don't have an unbiased random test pool of rings to chart numbers by. Why? Because stores cater to certain types of clientele. Some stores are high end, having more rings of specific styles and at higher K values, while other stores cater to lower end customers, having rings again of different style and perhaps lower K values. Still yet, some of them deal in rings from specific wholesalers who's product line only ranges a certain amount in quality and style.

The only way to insure an unbiased test pool of rings would be to sample them from several different stores of differing clientele/cost/styles. In metal detecting, the only way to provide a true random test pool of rings would be to dig every single signal above iron at numerous locations. Not to dig what sounds good, is stable in VDI, is above or lower than a certain tone or VDI range, and so on.

Now, I'll make an even finer distinction here. Because my friend dug these rings water hunting mostly in one state, one could argue that even this test pool of rings is biased. Culture varies to some degree from state to state, average incomes, etc. You could even go so far as to say this test pool is biased to some small degree by the type of person who swims versus those who never do. However, that may be "splitting hairs" at the microscopic level, beyond the need for realistic results.

Again, as I've said several times already, I am not saying his test pool is biased. It may very well not be, but I would very much like to know how they were obtained in order for the information to prove more useful. I'm simply saying that if you are going to graph percentages as any kind of guide post to follow then you need to know exactly how the test pool was acquired. Without that information I can not rely on the results as a useful tool. Even if the test pool wasn't obtained by digging everything above iron it could still be helpful, but then I'd at least have to know exactly what criteria was used in finding those rings. Was it by solid ID lock and good audio? What types of locations were hunted? Were specific conductivity ranges targeted? And so on...

Simple as that. The numbers posted could be useful even if they were biased in some way, but I would at least need data relating to how (method or criteria of targets dug) and where they were acquired. At least then I could use the information as some form of guideline. Lacking that it gives me nothing to judge similar expected results by.

 

[synthnut]

Crtiter ,
You are now putting words in someone elses mouth ..... He is not saying anything about precentages .....YOU ARE !!.....He is putting down what he found .....He's not saying how he dug them , or where he dug them , and he is not making any claimes at all about percientages ....He is compililing data , and YOU ARE THE ONE MAKING CLAIMS , not him !!......YOU are making up your own criteria .....He is just presenting data ...... YOU are the one jumping to conclusions ...... If I said that I went to the beach on Saturday, and found 2 gold rings ........I then went to the same beach on Sunday , and found 3 Gold rings ........ I went to the beach on Tuesday and dug 5 Gold rings ......These are all just statements .....How can there be a bias ........ They are only satements ......Jim

 

[Critterhunter]

Ooops, forgot to post the link for future reference...

http://www.findmall.com/read.php?21,1324202

 

[EZrider]

I took my wife's jewelry box "more like a vault" PR women like gold. I air tested every piece she had with the ET just to get the numbers. The % of what Andy came up with are spot on. No need to over anal ize anything. I used to enjoy coming to this forum and learn solid info from people. Now it seems i have to wade through lectures and theory crafting. The info Synthnut posted was solid.

 

[Critterhunter]

Here's the percentages by common trash numbers, based on a known test pool of truly random and unbiased rings...

Pay close attention to the numbers. Do you see any thing out of the norm in terms of what people keep spouting as common knowledge? Namely the myth that most gold rings fall into the nickle zone. I believe two factors contribute to this-

One, many machines don't have the needed resolution in this zone, and so the "nickle zone" on those machines is much wider, taking in foil and some tabs.

Two, the old saying is "if you want to find gold rings then you have to dig the nickle zone". That prophecy is then self-fulfilling, because the more you dig "the nickle zone" while ignoring others the more rings you are bound to dig in that zone. Hence one of the more common reasons why test pools get biased. That, and people digging the tab zone.

The next major flaw in conventional wisdom is that most rings fall into the tab zone. Taking "zones" as a whole in relation to which conductivity ranges certain types of common trash can be found, one can see that by far most rings can be found in the "foil" to can shard range of numbers. Not in the nickle zone, and not in the tab zone.

I have a feeling that most sample bases acquired by land hunting would skew less towards the foil range, since if people are going to be selective about digging then usually the foil range is the first to go (not be dug).

So long as people keep just repeating the old "rules of thumb" in metal detecting without challenging results and thinking for themselves, proving things one way or the other, myths like this will continue to be replicated. I can't tell you how many times I've had to correct people who think better batteries mean better performance, or that the S-12 coil is the lightest coil in that size range.

The problem with rocking the boat by not buying whatever people choose to ram down your throat in terms of beliefs is that it often steps on toes, hurts feelings, and rubs people the wrong way who have too much invested or built around certain things. I'm not hear to please anyone (lord knows we all know that! ), just to try to make them question things or look at them in a new way. They can choose to ignore that information and smear me as promoting propaganda, or they can re-think their beliefs and maybe find out that all the "common knowledge" or "conventional thinking" out there was indeed the propaganda in the first place. Decide for yourselves. To each his own...

(Give me a minute to get this file uploaded. I have to convert it to a JPeg from a Word File)...