jasong

I think the wording is confusing. Metal detectors generally aren't licensed devices like radio transmitters, etc, they are a different class of device since the manufacturer doesn't want to waste money on licenses or risk leaks from the tests. What it's saying is that since it isn't licensed, you can't complain to the FCC about any interference from actual licensed devices like cell towers, wifi, bluetooth, emergency radios, etc. This is why these manufacturers don't get testing on anything but the Bluetooth tx/rx. 

But you certainly can try to prevent any of that EMI from entering the detector via shielding, or do signal processing, noise cancelling, frequency hopping, or any other noise reduction techniques available. As long as doing them doesn't interfere with the licensed products, and you can't complain if the licensed products interfere with you. 

Every time I get a hair away from pulling the trigger on a 900 or Manticore, I read something that makes go back to thinking I should just find a used 800 and wait for something better. Well keep up the reports, curious to hear if any planned or potential updates help, and if there is any compelling reason to use one of these newer machines for prospecting over an 800. I like new stuff, but not stuff that doesn't work well. 

Situation normal. 

One large prospecting Youtube channel that for reasons beyond me many people find to be reputable (and I see still occasionally posted here too) both fakes finds as well as charges people for gold tours to places I am well acquainted with and know are being salted. Like 1st time detectorists using 20 year old coin machines, 6 inches off the ground, and finding 1/4 and 1/2 ouncers buried 1 inch deep in places gridded by hard core, full time gold detectorists for 40 years - that level of ridiculousness. The fact it's being done where I literally recognized the exact washes, bushes, trees, etc was just the icing on the cake. 

Yet when I tried to point this out to the very people I thought were being victimized, I was told I was the liar and demonized. Not one "thank you for letting me know I'm being ripped off".

Learned a lesson quick there. People generally want to believe every color of BS. And if you are the one ruining their dream, you are the a-hole, not the snake oil salesman. This, among other thievery, lying, and cheating were a big reason I decided to stop making videos myself, and remove myself from social media for the most part, aside from this forum, it's all toxic these days IMO, and not representing actual reality. I prefer to live in reality myself.

59 minutes ago, Mike_Hillis said:

Rutus Altrex has a screen that shows you what freq has the most EMI interference.

Cool...this is almost exactly the type of thing I was talking about wanting to see. 

So even with VLF's it is possible to basically do a real time background EMI scan, at least to some degree. So technically, you could have a "quick press" noise cancel button that just hops to the current best channel as it constantly analyzes in the background. 

It occurs to me (re: the coil up, coil down scan) that if external EMI is the problem, you don't technically need to use the coil itself to run a background scan. You could simply scan for EMI constantly with another antenna at the control box instead of the coil. This approach itself could be interesting because you could then run the coil signals and the EMI antenna signals through something like a differentiator so you could instantly know the difference between EMI and a target/ground noise (since the target/ground signals would be absent at the EMI antenna on the control box). Then cancel out anything that isn't a target/ground noise through standard signal processing. 

Yeah I was just commenting in this thread because lately it's only recently that I've seen anyone but myself beat the drum for EMI/noise reduction in the forefront of newer detector tech developments on new machines and being something to really discuss. It's something I've been saying and asking for for over a decade though. And I'm passionate about it because after a tally, I'm around $25k spent on metal detectors at this point, and probably about to be $35k after the new 8000 (or whatever) comes out, so I'm getting impatient. 😄

So I wanted to add to the discussion here too because usually when I've mentioned similar things in the past it's mostly ignored or a few lukewarm responses at best, but now people seem to be paying attention. Maybe a manufacturer is too, who knows.

That said, I am going to buy a Manticore or 900 or something, maybe just an 800, here soon for gold prospecting and to detect old abandoned cabins and investment property yards. So I hope I can get a bit more up to date on them by this summer too.

18 minutes ago, GB_Amateur said:

Does it reveal it's doing that?  This idea being blasted that Noise Cancel on the ML Manticore is secretly reducing the sensitivity (note:  on the Manticore the 2 digit sensitivity value is always on display on the left side of the screen and I've yet to see that value go down when I do a long Noise Cancel procedure -- has anyone??) seems over the top, to put it mildly.

A lot of the accusations being hypothesized here about the Manticore can be tested by the antagonists.  I'd like to see more of that compared to the current unsubstantiated accusations.

No, the 6000 doesn't reveal any specifics because all it's settings are hidden. But auto reduction of sensitivity, auto adjusting ground balance, etc that's the general concept behind "Geosense". Plus it's easy to test, and I've tested it and witnessed the sensitivity decrease firsthand. Anyone else could do the same with this machine, it's instantly observable, though the degree to which it auto adjusts and how long it retains those adjustments has so far been semi random from what I can tell.

That said, I'm just talking about the detectors I own and use, I don't know anything about the Manticore or any other recent VLF releases from other companies either.

I'm also not talking about noise cancels specifically in my prior posts, I'm talking about a range of topics. In terms of anything Manticore specific, I'm not the one to talk to. The topic was next gen detectors in general though, which is why I was speaking about machines other than the Manticore or whatever other VLF's people are talking about in the VLF world that I'm not connected to much.

The auto-adjustment on the GPX 6000 definitely uses sensitivity decrease to deal with EMI too. Down to unfortunate levels in some cases, it seems.

Hopefully better methods emerge, but I guess if R&D ends up decreasing due to less demand, they may not. I think the general idea with noise reduction in the future should be to lower the noise floor so you can boost sensitivity, not lower it. Approaches that lower sensitivity just seem like a temporary bandaid and not a longer term solution.

Nice call @Againstmywill That looks like a likely ID. I learned about a new manmade material too.

It's hard to know what's going on inside some of these modern detectors specifically without just guessing, but from a wider noise cancellation perspective, you can tell the difference pretty easily between some EMI and a target just by looking at periodicity (for instance, a sine wave) - a 60hz power signal, etc. VLF's I'm less sure about than PI's, but I imagine you can differentiate by frequency too, similarly.

Harder would be to tell the difference between a target and random noise, spherics for instance. You could enable some of this potential on a detector by the inclusion of an accelerometer so that it knows when the coil is moving, and if it's not moving (in the case of a PI anyways), then noise should be noise and not a target. In these cases the transient time - speed of signal - can be used to differentiate between a target and a noise event. Again, an accelerometer in the coil would help here since the target "size" could be esitmated as function of swing speed (targets would be "wide", lightning would be "short"). This would enable some degree of effective noise cancellation with the coil on the ground. Smoothing does this.

The problem is that more noise cancelling = more potential for noise cancelling a target. That's what Smoothing does on the GPZ, even without accelerometers to gauge coil movement or not. There are definitely times to use Smoothing, and times to know when not to use it. The key is understanding what it does and when it helps or hurts.

Minelab has recently patented designs incorporating accelerometers, so I suspect they might be able to improve smoothing and general noise cancelling with the coil on the ground, using some ideas like these.

1 hour ago, phrunt said:

I don't think we should get used to these lightning fast 3-5 second noise cancels though, good things take time and the most effective detectors at the moment for noise cancels take time, the GPX 4500 seems like it takes about a minute if not more to go through its 254 channels while you're holding your heavy GPX coil up in the air.  The GPZ 7000 although slightly quicker still feels like about 30 seconds.  Both these detectors recommend you hold your coil up above the ground.

I think they could have 0 second noise cancels if someone spent the time to incorporate such a feature. There is enough CPU power to run a program that does nothing but scans noise/channels constantly when the detector is on. And either auto adjusts to the quietest channel, or gives you the option to adjust to current quietest channel instantly with a button push.

The holding the coil thing in the air is to direct the detector to the loudest EMI source. But that also puts it with the coil 90 degrees off from other sources of EMI that might actually affect the detector more when using it on the ground. So while it often helps, I don't think it's absolutely necessary to have the coil in the air and an automated scanning program could probably do about as well with the coil flat on the ground as you detect too.

I can't say for certain because I have no idea what they have going on in the actual detector software or how many resources they are using. But even if they have the FPGA maxed out, a 2nd FPGA only costs like $10-15, so they could easily add another dedicated to nothing but noise/signal processing. 

Here's a link to .kmz map of snow depth/cover on Google Earth for those wondering where the snow is melting off or not yet in your areas of interest. 

It doesn't show local smaller show drifts, snow filled washes, small snow patches, etc. It's mostly bigger fields of snow. But still, you can get a rough idea and potentially save a trip to someplace covered with many feet of snow still.

This winter was crazy. I just read an Wyoming Game and Fish report that estimates half of all the antelope in the state died this winter due to the record colds and snow.

2 hours ago, FarTraveller said:

How about a solar powered AI driven autonomous drone that drives around obstacles to scan every inch if a site to map every likely gold signal?

These language based AI's are not good for that stuff. But clearly we have self driving cars, delivery robots, etc that can handle spatial coordinates and real time visual data. But those are specialized cases, not stuff easy for the public to access like ChatGPT, etc.

The problem is anything wheeled runs into rocks, bushes, etc. Anything with a coil that needs to touch the ground runs into the same issue. And anything flying drone based cannot get a coil real close to the ground, plus it's own motors create a ton of noise that makes things like detectors hard to use.

I have a few other solutions to larger scale, semi-automated prospecting. But it'd require a lot of tinkering/research/building/failures, and at this point in life I doubt I'll ever have the time to do it since the payoff isn't that great compared to other things I could spend time on. 

9 hours ago, phrunt said:

Could it be the self generated EMI hindering performance?  They may have sounded about the same but doesn't mean they are.

As far as I know the 7000 doesn't auto adjust sensitivity down due to EMI though. So if he had the sensitivity set equal on both machines, one should just be quieter than the other. I'm not sure how one machine is that much deeper than the other just by making it slightly quieter though, I can't see the mechanism for which that might happen. The purpose of making machines quieter is being able to boost sensitivity (and to reduce target masking), but he doesn't appear to be boosting sensitivity.

Target masking can occur with too much noise, but that doesn't appear to be happening here as it's the same target in open air, with similar noise levels, and on one machine it's simply being detected much deeper with very similar noise levels. Dunno... I'm a bit skeptical though, maybe he'll explain it all further?

I personally don't believe the 6000 was inconsistent among different owners. My observation has been some people simply didn't recognize it. The problem with it existed on literally every single 6000 I've ever come into contact with. In many cases the owners themselves were unaware, or saying they didn't see the issue - until I used it and showed them. Most of these people were primarily headphone users, or people who insisted excessive noise on detectors is "part of the game", etc.  I haven't encountered a single 6000 that didn't have that issue, so I doubt it was unreliable components, I think it was a design flaw with unshielded components on every 6000 made up until a certain point. At least, I haven't yet seen any evidence to prove otherwise, but I'd be pretty curious to see a 6000 in person that was bought before the cut-off date which doesn't have this issue when in my own hands, if anyone in the US wants to show me one in the field here. 

But yeah...as to Woody mods, I'm skeptical. If he is reading here, it'd be interesting for him to post and answer some questions maybe. I too find it hard to believe ML would make such basic, correctable errors... But they did seem to do exactly that with the 6000 unshielded components, so...

That Woody hasn't found the EMI/speaker/whatever issue on the 6000 himself, when this appears to be his primary job, makes me wonder too. Or maybe he has a newer 6000 with the fix already in place?

Also thought similar re: your last sentence - I think they probably did leave some gas in the tank for whatever the 7000 successor will be, easy gains in combination with lighter weight. But with this long between models, I'd sure hope for something else good in terms of advancements. 8 years is an eon in the tech world. 

3 hours ago, Goldseeker5000 said:

That's very interesting Jasong, keep us posted as you get into more advanced questions for it. Maybe ask it some questions about placer gold deposits and Mass Wasting. For kicks ask it about Gold Skarns and how to hunt them. Heck, even just see what it even comes up with about Gold Skarns would be entertaining . 

I've pretty much abandoned using these GPT AI's alone for anything prospecting related. They are ok for asking questions, but for some of the work I wanted to do with them, they aren't sufficient at this stage. 

Too complicated to explain here, but the problem is with the general design where they are language model AI's, and the way they interpret language. They are ok for ingestion of large amounts of language based data, like reading and summarizing a lot of papers - which is one thing I wanted to do.

But they fail entirely with spatial recognition and certain number based computation. So for exploration work, they are no where close to sufficient as standalone tools and require other API's as well as other AI's, and the whole project has gotten beyond my technical ability.

That said, in the process of research I did find some pretty interesting hybrid-AI type tools that look promising for prospecting/exploration. But I just don't have the time to learn tangential stuff with no immediate application right now as I have too much other stuff to take care of first. When I get more time to learn these things I'll try to post on them if I can make them useful. 

He's posted the results of the modded 7000, first one I've ever heard about. 

He's getting like 3" more depth on a AUS 20 cent coin, looks about like a US quarter? That would be exceptional if so. A big stress on the "if". 

I'm skeptical though, because the only mod he said he did was reduce the self generated power supply noise. Less noise should allow you to run more sensitivity, but he tested a stock and modded GPZ both on 16 gain, so no sensitivity increase.

So where is the depth gain coming from? The stock machine sounded pretty similar in terms of EMI to the modded machine too. Anyone got a better idea of what is happening here? I'm not quite understanding where the depth gain is coming from.

I have a friend who's been at the diamond park in Arkansas for like a month or two and he's been doing pretty well with a saruca out there, like well enough that he's just ended up staying for a while after it was just going to be a short trip at first I think. 

I built a low budget saruca out of some mesh I had last year, took it to the diamond fields in WY, spent like 8 hours staring at endless quartz bits, thinking...is this a diamond, is this a diamond, is this a diamond haha. If I could find a way to automate and process lots more gravel I think I'd give it more of a go, since there are rubies here too (also not really gem quality though).

Do you have an outlet to sell sapphires you find? I wouldn't know other than jewelers, but jewelers around here don't want to buy anything gold, gems or otherwise. 

I found a pale blue sapphire deposit in Wyoming a few summers back. Crystals about the size of the tip of my pinky. There are kinda low quality in situ, but been thinking about taking a drywasher in the wash below the deposit to look at some of the stuff eroded from older parts of the deposit.

Figure if the drywasher catches garnets en masse, it should catch sapphires too? Probably miss more than I catch, but probably not many gem quality ones there anyways.

3 hours ago, GB_Amateur said:

What's the replenishment timescale, though?  (You know better than I that...)

...

I read a  decent book (Field Guide to Meteors and Meteorites by Norton and Chitwood -- for some reason I can seem to find the link atttach icon in the post headings...) on the subject and it surprises me the low number of estimated falls and even recovered samples listed for the various known finds by classification.

I don't know much really, I don't specifically look for them, I find them by accident. The people I know who meteorite hunt seriously spend a lot of time looking for fresh falls though, so it must be at least somewhat frequent.

But from prospecting in general I can say I've found meteorites in 2 states that were unknown falls, cold discoveries while prospecting for gold (both were clearly old though, 100's or 1000's of years). I haven't reported any of them to be classified. I don't really want my full name out there for the bad elements to know, and I don't want some places I'm actively working to be known either, so no classifications for me. I suspect there is a good number of meteorites found that go unreported for similar reasons, I personally know other people who've also made finds and not reported them for those reasons. 

While they are rare, I doubt the slim number of recorded instances represent the actual occurence/distribution of them on the Earth. The amount of land people have run coils over is diminishingly small. Both cold finds I made were in places no one would ever metal detect, and probably never will again, because there was no indicators there of prior habitation or gold mineralization.  Endless more land like that available... That leads me to believe that meteorite hunting probably could be a fairly doable hobby with a metal detector, for people with a ton of patience. At this point, if I had to really make a living off detecting and didn't want to mess with jewelry, I think I'd probably choose to do meteorite detecting as it gets me into the wilds and exploring and away from people same as gold. 

That said, I doubt it will ever be a significant source of revenue for detector manufacturers....but it's something I guess. 

37 minutes ago, Digalicious said:

Coins are diminishing and more and more people are wearing cheap jewelry that looks as good as the real thing. Due to those, I can see veteran hunters prematurely giving up, and new detectorists becoming frustrated and giving up. If all that is taken into account, as well as what you said, then I imagine there is little desire to put profits into substantial R&D.

Ever since I started detecting there were always arguments that there was no payoff in R&D though, which is why some US companies stagnated, yet Minelab proved them wrong.

But it does feel different this time, feels the growth curve is bending downwards now. So I agree, we'll probably see decreasing R&D too, unfortunately. 

Nugget depletion is a one way, irreversible vector. It's why I've spent so much time diversifying into geology and using the detector as a tool to help identify larger, commercial deposits. I'm not sure there is an equivalent for coin/jewelry/relic detecting though, it'll likely decrease in growth too. Meteorites are an interesting case that gets replenished however, and can be quite valuable, but they are highly niche and require a ton of patience to find, not for most people.

1 hour ago, Digalicious said:

The cheap power chips haven't just been in abundance "today". They've been around for a good couple of decades. Yet, the engineers haven't incorporated real time EMI filtering. I think they haven't done so because it wouldn't make any difference. 

Detector engineers didn't incorporate anything modern into metal detectors for decades. It's a recent development, relatively speaking.

No offense to detector engineers, but aside from Minelab, or maybe a few other companies recently, most of these machines looked like stuff designed by electronics techs and hobbysists turned pro, not by a team of PhD electrical engineers, computer scientists, and physicists. 20 years ago, fresh out of school and ready to change the world, I asked on a forum why everything seemed primarily analog still and no one was really using modern MCU's with built in signal processing - I was told there was no reason to, by actual detector engineers. And the companies proceeded to release the same models with old circuitry and new names/paint for another 10 years while tech was making great leaps forward, and some went out of business because of it. Detectors are always 10-15 years behind the rest of tech. In some case, more - some of those old detector designs were straight out of the 80's or early 90's and 30-40 years behind the time. 

Now we've moved beyond basic MCU's and we have ultra customizable FPGAs and whatnot, with many magnitudes more power. And even that is on the cusp of being "old news" IMO. Honestly, I think a lot of digital hardware approaches are about to be obsoleted by AI signal processing. 

I've seen first hand some of the magic you can do with modern tech with a team of qualified, educated people working on products. The company has to be willing to pay for that skillset though, it takes a whole team now. Most US detector companies never were, until maybe recently. I wouldn't count Minelab out though, as much as they frustrate me, I have to hand it to them for staying modern and supporting their own science/engineering grads in a way US companies refused to, and they are reaping the benefits of it. They are suffering from the ill advice of their modern marketing grads now though, but that's a different story. 😅💩

Meanwhile, for any companies willing to pay for real development, EMI/noise mitigation is IMO definitely one of the areas detectors can absolutely still benefit and improve by large leaps, just my opinion but I'm pretty sure of it. 

56 minutes ago, Digalicious said:

With that said, I also wonder why exactly the smaller coils are less suspectable to EMI. More specifically, is it simply a matter of the small coil's much tighter field being more "closed" and impenetrable to the EMI?

It's because coils are antennas too, meaning they can couple with both magnetic and electric fields. Generally, with loop antennas for receiving EM radiation, the rule of thumb is that bigger diameter = more sensitivity. It's more complicated than that since certain sizes/shapes are more sensitive to certain frequencies, 1/2 frequencies, 1/4 frequencies, etc, but that's a basic idea anyways. Close to a loop, the magnetic field dominates, and sensitivity is a matter of flux density, so smaller coils are more sensitive to smaller targets, but less sensitive to EM. Well, with PI's anyways, I don't know a lot about VLF's, but a loop is a loop.

I think a lot of research could be put into reducing noise just with proper coil design. Some detectors seem to still be using generic sorts of coils from decades ago that appear to have very little modern design consideration for EMI reduction included.

For top tier detectors (definitely the $6-$10k gold detectors anyways) I think the entire control unit should be carbon fiber too. Both for weight reduction, but also because it's conductive and thus has the potential to act as a shield itself. I can detect my phone while off next to the side of the 6000 control box, it clearly lacks any shielding at all. 

Same for coils, for PI's anyways, I'm curious if carbon fiber tops/sides and plastic bottoms might be a good method to shield without gaining weight - maybe even losing weight. This is stuff I've mentioned for over a decade though - knowing Minelab reads the forums - and they don't seem to do it ever though, so maybe it just doesn't work. 

I think the whole concept of a "noise cancel" button is obsolete though. Modern computing power is in abundance for cheap on chips today. No reason EMI filtering/noise cancelling/channel scanning can't go on in the background 24/7 and auto adjust as needed rather than press a button. IMO anyways.

Ok, he has to be reading these posts. 😄

His latest video shows some similar things about the 6000 as I was saying in prior posts about desensitizing and staying desensitized. His just caused by EMI, but I know big iron also affects it too and I think he'll discover that soon with more experiments as well. The problem is when the auto adjustments are sticking around rather than being auto readjusted back up when the EMI/iron goes away, and you never know if you're running dumbed down (mine were 3-4" reduced in my brief tests) all day from an auto adjustment event potentially hours prior, because there is no way to check. Trust in a detector is paramount to do good work, this is bad.

One EMI/iron event might cause you to run desensitized for the rest of the day? Do we have to reboot every 5 minutes to avoid that? Even after rebooting I was still desensitized sometimes in my brief tests, but that too was unpredictable. It was happening in "manual" too, more problematic. 

* Bleh, deleted paragraphs of me ranting. It's Minelab. It is what it is. I'm not going to go on another single man crusade to fix yet another thing for a detector which I am just going to retire the first chance I get to get something better anyways. I don't get paid or free detectors, not happy about doing free work for them. People can draw their own conclusions, but I know what I've seen in the field and the 6000 definitely misses a lot of gold well within it's technical range to hit, due to unpredictable adjustments, even when operated by experienced detectorists.

😅👌

For wear parts do you guys stick with stuff like ABS on 3d printers, or has anyone tried resin printers to see how durable they are for things like knuckles, etc? The resin printers seem pretty interesting for detail work, or things like experimenting with fine detail sluice riffle or pan bottom designs.

Dolomite is a likely candidate.

$16/ton as crushed road base here, you're halfway to being a hundredaire in pennies.