Will The Next Gen Detectors Address Emi ???

[jasong]

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. 

[Past Member]

5 minutes ago, jasong said:

 

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. 

I obviously agree that large leaps need to be made in EMI mitigation, because I see current EMI mitigation to be almost laughable. What I can't see however, is how it can be legitimately accomplished with software, without an equal negative effect occurring.

In regards to the rest of your post, well those are great points. Something else to consider is that hobbyist detecting is a niche market. 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.

[jasong]

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.

[GB_Amateur]

1 hour ago, jasong said:

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.

What's the replenishment timescale, though?  (You know better than I that...) there are a couple strewn fields at Gold Basin which have produced quite a bit, yet those falls occurred thousands of years ago, I think.  We hear about fireball sightings and their subsequent meteorite searches, but how frequent are those -- about as frequent as Medieval Europe cache finds?  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.  And many of those, like the Gold Basin finds, are from falls which occurred long ago.

There are things quoted about the number of tons of meteoroid material that hits the earth's upper atmosphere everyday.  However, how much of that makes it to the surface and what is the resulting size distribution?   (BTW, these questions are more than rhetorical.  I've looked for answers to them and not been successful.  Someone has at least a reasonable idea; maybe even someone here.)

Maybe getting off-topic here, but from much of what I've read on this thread, there's a good reason for that.  ?

[UT Dave]

10 hours ago, UT Dave said:

One of the absolute worst parks for EMI is the one closest to my house.  I have to run the Nox at 20Khz and sens 16 to get it to quiet down.  Maybe I'll take them both over there this afternoon and do a side by side to satisfy some of my curiosity.

Didn't quite happen.  I took both machines over there, but was short on time and wanted to get in a quick hunt with the Manticore then do a side by side EMI comparison before leaving.  Started raining about an hour in and when I got back to the truck I didn't feel like standing out in the rain to compare EMI.

Manticore in Multi, ATG, default ferrous limits, one region all tones, ran quiet and stable at 18-21 sensitivity depending on which part of the park I was in.   And just nailed the nickels.  I continue to be impressed with how easily the Manticore calls nickels over the 800.  And I think the 800 calls them pretty good.  But I only dug 18 coins and 9 of them were nickels and I dug only 2 square tabs that were both only half a square tab.  One junk stainless and one mangled .925.  

Since, I don't know for anything like a fact that Manticore sensitivity 20 equals Nox 800 on 20 sensitivity, a static comparison would have been uncertain anyway.  Comparing wild targets both tuned for EMI would be a lot better.  But, honestly, I don't see myself bothering.  I'm feeling pretty confident the Manticore is working better in EMI and would rather just hunt with it than do tests against the 800.  I likely will still do the static compare at this park anyway, it's easy and won't take long.  Just need it not to rain ?.

- Dave

[jasong]

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. 

[FloridaSon]

UT Dave good report. Do you use the ‘long press’ when noise canceling? I have found a quarter about 12 inches deep directly under the power lines behind my house. I have noticed the EMI from power lines changes throughout the day.

Regards

[GB_Amateur]

12 hours ago, jasong said:

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.

Yes, even though we think of primo sites (whether for native gold or coins and relics) as seriously picked over, that is a small fraction of the earth's non-ocean surface.  The deserts (including Antarctica) presumably have the exposed and shallowest meteorites; seems less likely for plant covered areas, though.

I know it's been mentioned before, but still an interesting thing to contemplate -- how many meteorites, small fragments in particular, have been detected but ignored as simply hot/cold rocks (by native gold detectorists) or even nails or other waste iron bits (by coin&relic detectorists)?

Coincidentally when the 11:00 news came on last night the first item covered was the reports coming in from Central Indiana of a bright flash and sonic boom that had occurred a few hours earlier.  Most skies in the area were unfortunately overcast but a morning news program (see the link I just posted) shows a perported image -- I initially am a bit skeptical that this is the event, given the sky conditions I was experiencing as well as some people's unscrupulous efforts to get their 15 minutes of fame.  Hope I'm wrong and if so there should be other videos showing up to confirm that one.

[phrunt]

I watched a TV show on Antartica meteorites once, it's the easiest place to find them, dark colours really stand out on white and it's not soft snow, it's often rock hard ice.

If I encountered one I'd likely call it another stupid hotrock and kick it away, I doubt I'd recognise one.

We've had a couple of them in NZ already this year caught on CCTV cameras with the bright flash and object flying across the sky.  I've only seen two in my lifetime, one quite big one in Brisbane, Australia at about 3am after getting off a plane, we were driving back from the airport to the mother in laws house, no cars at all on the road, most properties with lights out, the place was asleep and a massive flash that I thought a speed camera got me, then we see the object flying in the sky but it's angle looked like it was going to hit the ground pretty close, it wasn't going across the sky more coming downwards..

The other I was just sitting in my Spa at night time again in Brisbane and there was a much smaller flash and an object flying across the sky on a downwards trajectory.    Nothing at all like the previous one I mentioned though.

I'd love to find one, I doubt I ever will.

I think EMI mitigation is the final frontier for metal detectors, many in the know have commented depth levels have been maxed out for years, target ID stability was maxed out with the CTX and now we are heading backwards to less stable to improve other aspects of detector performance I guess, tiny gold performance peaked with the GB2 back when I was a school kid.    EMI seems one area where improvements could be made, and in a way have to be made as EMI gets worse every year for almost every detectorist.  Frequency shifting to me seems the best solution for VLF's, and now with most modern detectors being multi frequency they have coils more suitable for moving frequencies.   They should be able to establish during a "EMI noise scan" procedure which frequencies in their pre-programmed modes are being affected by EMI and shft off them slightly until the noise clears while leaving the quiet frequencies alone.   Older detectors like the T2 where I do my frequency shift in a previous video on this thread perfectly demonstrate how well frequency shifts work, even tiny ones like the T2 has under 1kHz can make a huge difference.

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 personally have found noise cancels most effective holding coils above the ground in maximum sensitivity to get the most EMI into the detector, then after it thinks its done as good as it can with the noise cancel I move my sensitivity to the desired level.