Science or Snake Oil

[DeepThought]

I will ask it again: for all the commentary about different detectors' performance, why is there no standard to compare them against? Depth = a function of electromagnetic field strength, target size/orientation and surface area. Of these, there is a lot of talk about the last two and absolutely none on the first (as a function of the transmitting oscillator). A lot like comparing sports car performance without ever talking about HP to the ground. OK design engineers...feel free to chime in. Or provide a copy of your metal detector design schematic and chip sets...

 

Amazon Forum Fav 👍

Minelab PRO-FIND 35 Waterproof Pinpointer Metal Detector for Experts with Tone ID & Adjustable Sensitivity - Grab it through Amazon!

[Tom_in_CA]

also, I'm no engineer, but to take a stab at this question of yours:

" ...explain to me why 2 different detectors (same coil size, same operating freq, no discrimination, same positioning and orientation) will have 2 different detection depths for the same size and orientation target?..."

It's a lot more factors in each machine, beyond just a few factors of "coil size", "frequency", etc.... There's more components inside, that all work together. You know, like one computer and another may have the same software, same processor, etc... Yet one computer is faster than another. Because there's various parts of the "chain", that lead to the ultimate picture you see on your computer screen. And the computer is only as fast as its slowest component, no matter HOW much "memory" or how fast your modem is, etc...

I knew a fellow who, for a short time, tried to design coils and probes. Thinking he could branch off into a new career to "build a better mousetrap", and sell to the after-market of detector enthusiasts. Oh boy did he get a hard lesson! In his experimental tries at making various probes and coils, he learned that a minor nuance of thousandths-of-an-inch length of the copper wire windings, or how tightly he wound, etc... could make a difference in the outcome. So in today's exacting automated assembly, they can make those things robottically, where everything coming off the assembly line is measured to the umpteenth degree, etc.. But to apply that to your question, you can see that two different machine you might *think* have the same "components, frequencies, etc...", yet ... can have different results based on the interaction and spec's of the rest of the components that they interact with.

 

Amazon Forum Fav 👍

A Handbook of Civil War Bullets and Cartridges - Grab it through Amazon!

[beerguy]

When I first got out of college, I was a radio tech, working on VHF radios for aircraft. What a huge lesson in RF! A transmitter output was affected by the shape of the cover over the final amplifier stages. We would 'tune' older radios with a screwdriver by rapping the handle on the cover. The right dent in the right place could tweak the power output enough to make it pass, or detune it so you would have to try again!

I have also tried to make a 'better' detector and gave up way before I was even close to making any components.

Rather than buy a spectrum analyzer, you could buy a few of the finest machines out there!

 

[lucky larry]

I have read all your threads and have a deeper appreciation for the depth (no pun intended) and breadth of your knowledge about the workings of detectors. I also appreciate the amount of time spent writing the responses.
To add my 2 wheaties to the discussion, albeit highly UNTECHNICAL, companies often purposely avoid agreeing on a codified measurement or omit data from cut sheets so consumers can't compare apples to apples; there is little incentive for them to do so. I suppose it then falls to independent evaluators to design tests that allow equal comparisons. Not sure if this has been done with detectors. If there are too few consumers who care enough to spend money to by Consumer Reports...then why would they do it? I apologize if these points were made in other posts, I might have missed them in all the tech talk.

 

[lookindown]

Two detectors of the exact same model can come out of the factory with different depth capabilities...that's why you here of a "Hot machine". My family has raced cars on oval tracks for years. The most horse power does not mean the fastest lap times...you need the right gears, suspension, tires and so on...so many different variables.

 

[Tom_in_CA]

Two detectors of the exact same model can come out of the factory with different depth capabilities...that's why you here of a "Hot machine". My family has raced cars on oval tracks for years. The most horse power does not mean the fastest lap times...you need the right gears, suspension, tires and so on...so many different variables.

good comparison lookin-down. Let's see if that sinks in.

 

[JunkShopFiddler]

Man, the mental capacity, knowledge, and intelligence of all the T-netters on this thread is truly awe-striking! The ability to express themselves everyone has shown is truly impressive! I haven't learned anything definitive but is sure is exciting reading about race cars, two foot deep dimes, rebounding signals, and treasure objects floating in the air! This is like Albert Einstein vs the Myth Busters! E=MCTnet...More please, please, please. I still have popcorn left!!!!

 

[jmoller99]

I am an EE and used to design RF gear (and avionics). I recall tuning some RF gear with a ball peen hammer to get them just right.

As for coil sizes, I have an older Whites 5900 that happens to run at the same frequency that most Bounty Hunter detectors operate at (6.8 Khz) and I have adapted a number of the Bounty Hunter coils for its use. The Stock 9 1/2 inch coil that came with the 5900 DiPro/Sl is deeper than the 10 inch BH coil on this machine (I attribute that to inductive and capacitance differences in the transmit circuit load design versus how the coil was built), however, the 4 inch BH coil really works well on this 5900 in very trashy areas. I may convert one of the 11 inch BH DD coils (like the one on the Fisher F4), since it also works at the same frequency (and can use the regular BH coils - note: Fisher has many different detectors that operate at different frequencies, the F2 and F4 happen to run at 6.8 Khz, like the Whites 5900 and 6000 do).

I have wound a few of my own coils and while they worked (getting the fariday shield right is not easy) , my time is better spent detecting with known entities.

 

[beerguy]

Jmoller, nice post.

My experience was in the 80's, tuning the King 9000 VHF radio's to adhere to the 25kHz spacing. Good times.

I would love to try and fab a coil, but I found that I like digging in the dirt better as well.

Junk shop, now I have to go make me some popcorn as well. Just got back from the park with the family and now they ALL want their own detectors. so that will be the only snack food I can afford now.

 

[lucky larry]

Man, the mental capacity, knowledge, and intelligence of all the T-netters on this thread is truly awe-striking! The ability to express themselves everyone has shown is truly impressive! I haven't learned anything definitive but is sure is exciting reading about race cars, two foot deep dimes, rebounding signals, and treasure objects floating in the air! This is like Albert Einstein vs the Myth Busters! E=MCTnet...More please, please, please. I still have popcorn left!!!!

JAF - could you give backstory of your icon, eg pin with an "E"?

 

[Carl-NC]

Tom in CA - bad day?? Point: forget environment, forget usage preferences -- they're transparent to our test. Take 2 VLF detectors and lay them side-by-side on a bench. same orientation .... same target. The Tesoro will go deeper (emit a greater signal strength) than the Bounty Hunter in air tests. Why - the Tesoro emits a greater EMF signal strength (power output at the coil). And yes, depth is also a function of signal wavelength (inverse of frequency). With this info, I can quickly assess the expected detector performance for a given application.

No, actually, you can't.

 

[Chris Miller]

Interesting post.... I quit detecting 15 years ago because it all seemed like snake oil to me. I probably just never truly learned what the heck I was doing because others around me were having great success.

I let it go for 15 years and just jumped back in because I thought the technology had improved. Apparently my conditions are not ideal now though because I now have highly mineralized ground. So I go out and buy a new ACE 350 and an AT Pro and both are acting like complete idiots out here. Not sure whether to throw in the towel or try yet another machine. Now I don't fully understand all of the different technology that is currently available but one thing is for sure... the machines I have seem to be nearly worthless in this part of the country. Unless you just enjoy digging strong signals to 8-10 inches non stop only to find the signal disappears. My girls are treating me like I am a special kind of stupid for investing so much into something that seems to be totally bipolar.

 

[MinnesotaStateUniversity]

Wrong forum,

Activity Stream - Geotech Forums

 

[snokid]

I just got back from the ocean, I was using my Excalibur and I just dug a paperclip at 15-18" I bet if I turned it up I could find them at 30"... I also have a Fisher F5 seems like the limit of that thing is about 10" in dirt. My garrett doesn't go as deep but it's turn on and go...
I have used my Excalibur at a tot lot (not a good idea) but digging down thru the woodchips to find the staple they used to hold the weed block isn't the best use of time either....
So the moral of the story is the right tool for the right job...
So at the beach it's the minelab
out in the woods or the tot lot it's the fisher
when someone wants to try it out I hand them the garrett...

 

[Muddyhandz]

a) how high did the tester run the sens? And no, there's no "calibrated" sensitivities between manufacturers, that 2/3 up the dial is the same calibrated point on each. For example, there's the 1266 which has an upper 1/2 of the dial that all but unusable anywhere, except clean white sand. Everywhere else, you can't run over 1/2 sens. So what fairness is there to say 2/3 of the dial strengh for each air-tested machine? See?).

Once again Tom, could you please post about detectors you know something about?
I've been using the 1266x for 20 years and have ALWAYS cranked the sensitivity to the max in every place I've hunted. What you call unusable or unstable is something that you cannot understand.
It is sending too much audio information for you to handle. My brain is the microprocessor and it has been trained to sort through all the audio information. I could take that machine to anyone's "hunted out" spot and pull out goodies providing there's enough iron and junk to mask targets. Most people prefer a silent search detector. To me, silent search means a lot of nulling and many good targets missed. I would give up detecting altogether if I couldn't hear the "chatter" that most people don't like to hear.
I can't even count the times I've gone into a hunted out spot, got cluster of "clacks and pops" (rejected nails, bottle caps, etc.) and was able to tell that there was a good non-ferrous target in that rat's nest.
In fact, that happens ALL THE TIME when I hunt. The mighty $1500 machines suck in those situations, which is why there's lots of goodies waiting for me to find. They are glorified cherry pickers and are in demand because most don't want to spend the mental energy to determine whether they dig or not. Those machines don't even have a true all-metal setting.
Your "Hitting a brick wall at 6 inches" (that you've said many times before) is so wrong. I get incredible depth all the time with that old beast and well beyond your 6 inches and I rarely hunt in white sand!
You always seem to talk about the '66 and I just can't let it go. You have very little experience with that detector and I've mastered it and still continue to hunt with it to this day.
I'd love to hear you talk about the machines listed in your profile. I'm sure you have a lot of good info to share about those detectors.
Cheers,
Dave.
P.S. Please don't refer to me as one of the "cult followers" of the 1266X. It's the best tool for the places I hunt and I know it better than I know myself.

 

[scotty544]

Interesting post.... I quit detecting 15 years ago because it all seemed like snake oil to me. I probably just never truly learned what the heck I was doing because others around me were having great success.

I let it go for 15 years and just jumped back in because I thought the technology had improved. Apparently my conditions are not ideal now though because I now have highly mineralized ground. So I go out and buy a new ACE 350 and an AT Pro and both are acting like complete idiots out here. Not sure whether to throw in the towel or try yet another machine. Now I don't fully understand all of the different technology that is currently available but one thing is for sure... the machines I have seem to be nearly worthless in this part of the country. Unless you just enjoy digging strong signals to 8-10 inches non stop only to find the signal disappears. My girls are treating me like I am a special kind of stupid for investing so much into something that seems to be totally bipolar.

You need a pinpointer and a V3i.

 

[Carl-NC]

Interesting post.... I quit detecting 15 years ago because it all seemed like snake oil to me. I probably just never truly learned what the heck I was doing because others around me were having great success.

I let it go for 15 years and just jumped back in because I thought the technology had improved. Apparently my conditions are not ideal now though because I now have highly mineralized ground. So I go out and buy a new ACE 350 and an AT Pro and both are acting like complete idiots out here. Not sure whether to throw in the towel or try yet another machine. Now I don't fully understand all of the different technology that is currently available but one thing is for sure... the machines I have seem to be nearly worthless in this part of the country. Unless you just enjoy digging strong signals to 8-10 inches non stop only to find the signal disappears. My girls are treating me like I am a special kind of stupid for investing so much into something that seems to be totally bipolar.

My guess is that both detectors will work just fine. Try to find someone experienced to go hunting with, they can help you get dialed in.

 

[DeepThought]

Jmoller - you understand, then the many requirements and IV&V stringent in the aircraft field - especially rotary wing. Imagine a single test garden in which different metal detectors are tested against common conditions by user and manufacturer alike - instead of multiple gardens/tests done by multiple people under different conditions. Every field test I've read to-date is always a personal assessment of usability and recap of manufacturer claims - not a comparative scorecard. Point: some folks have been very vocal about the inability to determine detector performance this way - under controlled conditions. Yet they make recommendations of MD performance and purchase - from under uncontrolled and various conditions. IV&V.

That said - I get it: apples and oranges. A MD isn't a $10 million annual cost that folks lives are dependent on. It is a great hobby that enables me to carve out a spot and drop some of this stress and do so for only a few hundred bucks. Heck .....I'm greatful.

In the end, it's all about location, location, location. If it's there, I will find it .....to the extent technique & my MD's depth will enable me <s>. Thanks, all

 

[jmoller99]

There are no standards in test gardens. I recall reading that Fisher (before it had business problems, and was bought out by First Texas) actually created an elaborate test garden with soil trucked in from all over the place, so they could go out and compare their detectors out on their test areas to address issues that people would find out in the wild. I don't know of any other company who did this. Everyones ground is a bit different, so there are always challenges in setting up standard tests.

I, however, have a test garden that has a lot of targets in it. It was very easy to create and once in, the only maintenance I have is to mow the grass over it occasionally. I don't know why more people don't make the effort to dig a few holes and drop a few dollars worth of coins and other targets at different (measured) depths and use that to compare detectors with. For sure, the gold samples will only be detected by a very few detectors, but the rest are pretty easy to use to compare against. I use the area to teach people how to use their detectors (I don't sell detectors, its just a hobby of mine). I don't care what brand they use, or what model. I have found a lot of detectors work really well (that some people here disparge) once you understand what is telling you. Also, many people have unrealistic expectations about what they will find (and really just want to have the detector tell them what it is, how deep and exactly where to dig).

I don't intentionally coin shoot anymore. A lot of detectors have features that really does not help me all that much (I don't hate VDIs, but they often tell you things that are combinations of targets that you might assume is a single target, and you might skip it because of that).

I prospect for gold - it was over a year before I found my first tiny nugget with a detector, but I dug lots of trash (1000:1 is a normal ratio of trash to gold for me). I also listen for different things now than I used to and while I still dig lots of trash, I have hit quite a few good gold targets in places that other people told me were barren. I practice in my test garden before picking up a detector I have not used in a while. Likely, that's why I am getting some reasonable results. If all I was to do was show up and start detecting (with one of my 9 detectors) it would take me a while to get productive. I might miss some targets at the beginning, or forget quirks of the detector during the entire effort.

I do relic hunt - in that case you have no idea what a good target at that site might be. I have dug Mini-balls at army camp (from the time of the civil war in Kearney Nebraska) all very low conductivity - most people would think its trash from what their detector told them - but that's often a relic that I am interested in (I came to dig targets, not to complain about how everything reads like trash - some of those turn out to be the real prizes of the trip).

Why don't I coin shoot? I lost interest in finding lost coins. I found some silver, but mostly clad and more recent coins. I have plenty of that stuff in coin bowls around the house. If there was some historical content to the coins I found, that would interest me, but typically that's not what is here in Colorado. I don't put as much weight in peoples opinions of their detector as how it reacts in my garden when I try it. As I have said, there are a lot of Bounty Hunter detectors that are quite capable (BH is brand that many people mock without having anything to back their judgement on).

I pick all of my detectors to have special qualities that the others I have may not be as good at. That allows me to focus my detection efforts on what I think is worth finding at the sites I visit (typically places that were abandoned 100 or more years ago). I do require most of my detectors to be able to be ground balanced because of all the mineralization that occurs at the sites I visit.

I also find that smaller coils, while you get less depth, often help you work areas more effectively. Not everyone takes this approach.

It's all in what your goals are.

 

[Tom_in_CA]

There are no standards in test gardens......

Jmoller, even if "test gardens" could be erected, as you say (or better yet, flagged un-disturbed naturally occuring signals in the ground, that a multitude of machines are tested on, and then the target is dug to see what-it-is), are still bound to be obscured, arbitrary, biased, etc...

I have, even myself, tried to compare signals in this way. Either for my own use (my own self trying each subsequent machine over a flagged signal), or to show it to buddies with other machines, for them to sample.


The problem then becomes, is that it's FAR TOO EASY for the next person to simply say "yeah I hear it" and "yeah I'd dig it", and so forth. Why? Because they've just been pointed out an exact spot, so OF COURSE they're going to be craning their ears, criss-crossing multiple ways, etc.... When you *already know* something's there, then you're going to be subconscsiously already interpretting any flutter as being a "yeah I hear it".

For example: One time I was hunting in a jet-black-mineralized cesspool of a gully wash where rain water/culverts had eroded a path to the beach, on a So. CA beach. It crossed right under one of the historic piers. And as I saw this erosion, I could see lots of nails exposed (reddish rusty little lines all scattered through the gully-wash-channel). I hopped down into the mess, and found that my humble Whites Eagle could barely get 2" deep in the jet black salt minerals! But no problem, as least I could knock out those nails with ease, so I proceeded to pick out coins (even some older silver) from the mess.

Along the beach comes a guy swinging a Garrett. He sees me digging targets in the channel, and asks if he can join me. I see that he's swinging a particular Garrett that I knew, for a fact, was very poor in minerals. So I told him that , yes, he could join in, but that .... be prepared for some nasty black sand. I sorta wanted to see how his machine would compare. At that exact moment, I was getting a conductive signal. So I tell him: "here's one now as a matter of fact, let me know if you can hear it". He jumps down in, turns on his machine, and swings over the spot I'd just shown him. And he got it LOUD AND CLEAR. With "room-to-spare" as a matter of fact. I could even hear it coming in over his headphones. So he turns to me and says "yes I hear it". Boy was I impressed. But I was also suspicious. So I say, "how about over here?". And as he starts to swing his coil elsewhere, the problem became immediately evident: He was getting signals EVERYWHERE d/t the black sand, and had assumed that the "signal" he was getting where I'd pointed, was .... a differentiable signal. He didn't last more than 5 min. in that mess, and left for greener grounds.

Oh, and by the way, a pulse guy came along too, and saw me in my little honey hole. I invited him in too, knowing that since he had a pulse, that the minerals would give him no problems. But I warned him: there's lots of nails in here". To which he says: "no problem, I can tell them by their sounds!" Well .... 15 nails later ... he too left for greener grounds. Doh!

Another time, I was given a CZ6 to test at a particular park where I knew deep silver lay. I started with my Whites, and was able to flag a particular signal that .... in my experience of this park, was probably going to be a deep wheatie or silver. Then I took the CZ6, and waved it over the same spot, with a variety of different settings, swing speeds, directions, etc... I was ABSOLUTELY AMAZED that the CZ6 not only got the target with ease, but also got it with room-to-spare, correct ID, etc.... I was very impressed. Dug it up, and it was, as expected, a deeep silver or wheatie. So then I proceed to swing the CZ6 elswhere around that spot, and get immediate hits, that sound and read exactly the same as the signal I just dug. But upon digging those, they were various other things like deep nails that were fooling the TID, or teensy eraser tops or odd-ball things.

Now I know, with the CZ6 illistration I just gave, that no doubt, CZ6 fans would come on saying that there are tricks to knowing those deep nail falses. Or tricks to knowing shallow vs deep clad/oldies. And they would justifiably "take issue" with the observations that I made. I'm fully aware of that. Or they'd argue that I wasn't experienced enough, and so forth. I'm fully aware of that, and the truths that do come with experience of nebulous nuances of each machine. BUT THAT'S JUST THE POINT! The point being, is that it becomes HIGHLY speculative, arbitrary, individual, etc... NOT things which can be simply measured on a 1 to 10 scale, and so forth.

 

[lookindown]

Once again Tom, could you please post about detectors you know something about?
I've been using the 1266x for 20 years and have ALWAYS cranked the sensitivity to the max in every place I've hunted. What you call unusable or unstable is something that you cannot understand.
It is sending too much audio information for you to handle. My brain is the microprocessor and it has been trained to sort through all the audio information. I could take that machine to anyone's "hunted out" spot and pull out goodies providing there's enough iron and junk to mask targets. Most people prefer a silent search detector. To me, silent search means a lot of nulling and many good targets missed. I would give up detecting altogether if I couldn't hear the "chatter" that most people don't like to hear.
I can't even count the times I've gone into a hunted out spot, got cluster of "clacks and pops" (rejected nails, bottle caps, etc.) and was able to tell that there was a good non-ferrous target in that rat's nest.
In fact, that happens ALL THE TIME when I hunt. The mighty $1500 machines suck in those situations, which is why there's lots of goodies waiting for me to find. They are glorified cherry pickers and are in demand because most don't want to spend the mental energy to determine whether they dig or not. Those machines don't even have a true all-metal setting.
Your "Hitting a brick wall at 6 inches" (that you've said many times before) is so wrong. I get incredible depth all the time with that old beast and well beyond your 6 inches and I rarely hunt in white sand!
You always seem to talk about the '66 and I just can't let it go. You have very little experience with that detector and I've mastered it and still continue to hunt with it to this day.
I'd love to hear you talk about the machines listed in your profile. I'm sure you have a lot of good info to share about those detectors.
Cheers,
Dave.
P.S. Please don't refer to me as one of the "cult followers" of the 1266X. It's the best tool for the places I hunt and I know it better than I know myself.

All detectors aren't the same...your 1266 may be special.