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Gotta ask this question

woodbutcher

woodbutcher

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Seems everytime something new comes out and there's a problem I read posts from guys who have all the answers. ..Fair enough,maybe they're right but maybe not. .. But now this ( silent EMI) seems to be all the talk,and the reason these guys are saying the D2 has issues..And I've read that the equinox also suffers from (silent EMI) now..Seems to be the diagnosis if your machine isn't upto par nowadays..
Ok,here's my big question,,,if the EMI is silent how does anyone know it exists,,,and I've never heard of noisey EMI so what the hell, I mean where are these new theories coming from?
 
A few months ago I was out hunting and got a nice signal on my D2. Called my buddy Jeff over to listen to it on his Nox 800. As he walked over and got within 10 ft of me, the signal completely disappeared. Nothing! Once he walked away, it came back. To test it a little more, I tossed a silver quarter on the ground and continuously scanned it as he approached with his Nox. Once again, my signal completely disappeared when he got within ten or twelve feet from me. The silent EMI from the Nox to the D2 is definitely a thing. Doesn’t seem to be as bad around other detectors.


Sent from my iPhone using Tapatalk
 
Rattlehead said:
A few months ago I was out hunting and got a nice signal on my D2. Called my buddy Jeff over to listen to it on his Nox 800. As he walked over and got within 10 ft of me, the signal completely disappeared. Nothing! Once he walked away, it came back. To test it a little more, I tossed a silver quarter on the ground and continuously scanned it as he approached with his Nox. Once again, my signal completely disappeared when he got within ten or twelve feet from me. The silent EMI from the Nox to the D2 is definitely a thing. Doesn’t seem to be as bad around other detectors.


Sent from my iPhone using Tapatalk
Click to expand...

I've always heard that as crosstalk, and I've experienced it as well. That's not what I'm talking about tho,these guys are going to sites and calling silent EMI when there's no other detectors around..
 
It stands to reason that if another detector can cause silent EMI, then something else running similar frequencies could also cause it. No?

FWIW, there was no cross talk or chatter. The signal just went away. Both machines completely silent.


Sent from my iPhone using Tapatalk
 
I believe I've seen NASA Tom talk about silent EMI fairly often. The concept makes sense, however since it is silent wouldn't that mean that most of the time there is no indication of EMI issues? Rattlehead's example is interesting as he never would have known about interference if he wasn't actively scanning a target as the other detectorist approached and silenced his signal. Other than unique situations such as that how are we to know if we are impacted by silent EMI?
 
I don't know if this is emi or what but I have days when many strong over the air tv stations won't come in. A lot of those times, for a few hours, I'll start receiving stations from other cities that I usually never get ANY signal from Crazy things go on in the atmosphere whether man made or mother nature.
 
I would wager so-called "silent-EMI" is the noise-canceling algorithms encountering an issue that causes it to over subtract / over silence the original signal.

Meaning, silent EMI isn't a naturally occurring electromagnetic phenomenon emitted by some mysterious source, but a behavior that arises in the programming of the detector itself when it encounters an input that produces an undesirable output.

Detectors will subtract observably periodic signals (sine wave style EMI) and it is possible that the EMI mitigating algorithms interpret another detector as a signal with a periodic behavior, then subtracts that signal from it's own, resulting in "silence". If a subtracted EMI signal is approximately equal to the generated signal (e.g. subtracting one detectors periodic signal from another detector's very similar periodic signal), then via the superposition principle the resulting signal will be ineffective at detection.
 
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woodbutcher said:
Seems everytime something new comes out and there's a problem I read posts from guys who have all the answers. ..Fair enough,maybe they're right but maybe not. .. But now this ( silent EMI) seems to be all the talk,and the reason these guys are saying the D2 has issues..And I've read that the equinox also suffers from (silent EMI) now..Seems to be the diagnosis if your machine isn't upto par nowadays..
Ok,here's my big question,,,if the EMI is silent how does anyone know it exists,,,and I've never heard of noisey EMI so what the hell, I mean where are these new theories coming from?
Click to expand...

LOL nailed it woodbutcher.

"Silent EMI" like Bigfoot, has no proof, needs no proof apparently. First time I heard mention of this "silent EMI" I thought it was a joke and then I started seeing people take it seriously. I think the only reason is the idea came from this certain person that likes to be associated as some space scientist with all the answers to try and explain something with no answer.

Isn't "Silent EMI" like an oxymoraon?
 
AccurateCalls said:
Meaning, silent EMI isn't a naturally occurring electromagnetic phenomenon emitted by some mysterious source, but a behavior that arises in the programming of the detector itself when it encounters an input that produces an undesirable output.
Click to expand...

Exactly.



Silent EMI is merely referring to EMI that for whatever reason, the detector blocks from being heard through the speaker. It could be due to the specific algorithms being used, or possibly an overload state that causes the detector to be silent, while barely able to detect a coin near the surface.

For example, in my backyard, I have 3 high power lines in the alley, and a 240V line running diagonally across the yard to my house. All my SF and SMF detectors are not only extremely noisy in my backyard, but I lose a significant amount of depth. If I use a SF of around 5 and 10 khz, the noise is diminished slightly, but it's not until I start using around 15 khz that the noise starts to significantly be diminished. At 20 and 40 khz, the noise is gone. However, even with those SF's, and the detector being silent, I'm losing about 30% to 50% of depth due to EMI. It's closer to 50% with small targets such as deep coins, and shallow edged coins. I know this because I can take my detectors well outside of the city to sites that have little EMI, and my detectors will detect coins much further in the air, and in the ground, compared to high EMI sites.

One of the first things I do at a site, is bury a target deep, then go through the SMF and SF modes to see what hits the target the best. EDIT: The other thing I do is go into the closest thing to an all metal mode and start swinging to find out what cr-p in the ground I've got to deal with :)
 
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Rattlehead said:
A The silent EMI from the Nox to the D2 is definitely a thing. Doesn’t seem to be as bad around other detectors.
Click to expand...
That's a weapon against the D2 that Minelab developed and went out with their latest Equinox update! :lol:
 
So, the only evidence of "silent EMI" is your detector gets less depth? OK!

I understand the interference between two detectors, heck I witness it all the time, but that is not silence at all. You can hear it.

Seems to me the only way to document such a theory.... is to hunt with two detectors in the same area and see if you get less depth. Of course, first, you would need to test the ground conditions to make sure that isn't to blame. You know, moisture content, etc.

Hey, I'd say we have given manufacturers a new feature. A detector that eliminates silent EMI altogether. But the key is, how do you know when it is working? You send in your detector claiming the S-EMI is not working, and your evidence is you're not getting the depth you should. LOL
 
Detector said:
So, the only evidence of "silent EMI" is your detector gets less depth? OK!

I understand the interference between two detectors, heck I witness it all the time, but that is not silence at all. You can hear it.
Click to expand...

So wind doesn't exist because we can't see wind:) Yet, we know wind exists because we experience its effects.
 
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FelixtheCat said:
That's a weapon against the D2 that Minelab developed and went out with their latest Equinox update! :lol:
Click to expand...

That's exactly what Jeff told me. He said it was going to be his new secrete weapon. Said he was just going to turn on his Nox and put it near me when I'm hunting, then go back and hunt that spot after I leave. :lol:

Detector said:
I understand the interference between two detectors, heck I witness it all the time, but that is not silence at all. You can hear it.
Click to expand...

The interference I mentioned was indeed complete silence. No chatter on either machine. The D2 wouldn't detect the target at all, regardless of depth.
 
Rattlehead said:
That's exactly what Jeff told me. He said it was going to be his new secrete weapon. Said he was just going to turn on his Nox and put it near me when I'm hunting, then go back and hunt that spot after I leave. :lol:



The interference I mentioned was indeed complete silence. No chatter on either machine. The D2 wouldn't detect the target at all, regardless of depth.
Click to expand...

That's really weird. My friend and I swap on and off using my D2 and Equinox 800 and other than really loud noticeable EMI when the coils are rather close to one another, I have yet to experience silent EMI on either detector. There is also frequently a Simplex in the mix too, with all 3 detectors being basically unaffected at distance >1m. All detectors are running the latest version.

I know for a fact both detectors are working because we frequently compare signals from the two machines and both of them always get the target.
 
LOL considering that EMI is just a generic name for anything that causes interference with a magnetic field, Silent EMI could be from a nearby wireless/Bluetooth system or so many other devices I guess you can call it what you want.

I'll know next time I'm not getting good depth I can blame the darn silent EMI. pfft.
 
What I've found is that my Silver Umax, Legend, Simplex and Tracker 4, all lose a significant amount of depth in EMI. More specifically, when I took those detectors to a site well outside of the city that has almost no EMI noise, the detectors air tested much better than in high EMI sites like my own backyard.

It's exactly what Dankowski experienced when he said the following in the worst ever forum format lol:

"Back to EMI. Let's say I have a particular field that presents serious potential.... for my intended quest. It may be a several-hour round-trip to this special site. I want the best equipment that is the most technologically advanced.... that will present maximum potential for success.

I arrive.
Turn F75LTD 'on'. Individually run through all the noise-cancel channels..... and find the one that presents the least EMI. I learn that 3 of the noise-cancel channels present no audible EMI. Channel 2, 3 and 5. Even though these three channels present no audible EMI...… I air-test the unit on a clad dime. Channel 2 allows detection of clad dime to a air-test distance of 9". Channel 3 allows for a air-test distance of 8". Channel 5 expresses 9.5". Even though I can hear no audible EMI...… the "silent EMI" restricts my best performance to a maximum of 9.5". Knowing the F75 ….. under normal circumstances...… will air-test a clad dime to 12"; now expresses reduced performance to 9.5". My "no-go" decision is implemented. . . . . due to my (minimum) 10" requirement.

I then swap detectors to the Equinox. Perform Auto noise-cancel. Then verify the auto noise cancel selection..... by individually testing each one of the noise-cancel channels...… manually. I find 2 channels that are better than the auto noise-cancel selection. Then...………… I perform the required/standardized clad dime air-test..... utilizing the three best noise-cancel channels. One channel presents 7" air-test. Another channel presents 9". And the 3rd channel presents 9.5". In an EMI-free area.... the EQX will air-test a clad dime to 13". Again...…. "no-go" decision is implemented.


Site 2.
This time...… the EQX air-tests a clad dime to 10.5" …… expressing minimal 'audible' EMI. . . . on it's best noise-cancel channel. Interestingly (educationally): one of the other noise-cancel channels presents no audible EMI also; yet, air-test performance is only 7". Silent EMI is crippling.
Click to expand...



https://www.dankowskidetectors.com/discussions/read.php?2,156756,156834
 
AccurateCalls said:
That's really weird. My friend and I swap on and off using my D2 and Equinox 800 and other than really loud noticeable EMI when the coils are rather close to one another, I have yet to experience silent EMI on either detector. There is also frequently a Simplex in the mix too, with all 3 detectors being basically unaffected at distance >1m. All detectors are running the latest version.

I know for a fact both detectors are working because we frequently compare signals from the two machines and both of them always get the target.
Click to expand...

Next time Jeff and I are out hunting I'll try to get a short video demonstrating it. I imagine it depends on which programs are being used. If memory serves, I was using Fast and he was using one of the two Park programs.

I remember Gigmaster noticed a similar issue when he first got his D2. I don't recall what the new video posting rules are, so I won't link to it.. But if you go to YouTube and search Gigmaster EMI it should pop up.

{EDIT} Its titled Deus II Silent EMI reproduced on the Beach. You can see it at about the 8:50 mark.
 
Digalicious said:
What I've found is that my Silver Umax, Legend, Simplex and Tracker 4, all lose a significant amount of depth in EMI. More specifically, when I took those detectors to a site well outside of the city that has almost no EMI noise, the detectors air tested much better than in high EMI sites like my own backyard.

It's exactly what Dankowski experienced when he said the following in the worst ever forum format lol:

https://www.dankowskidetectors.com/discussions/read.php?2,156756,156834
Click to expand...

Agreed that EMI does in fact cause problems with depth. However, I don't sgree that "silent EMI" is the problem. There can be so many factors that affect detector depth without making any noise that has nothing to do with EMI. Now if there is some EMI emitter that you can turn on & off and truly note a difference in the depth on your detector and no noise, that would be proof of silent EMI. I don't think it exists. Not saying I'm 100% right, but I do know enough about electronics to be dangerous.

The fan club of the site scares me LOL. I went to the site many years ago and dared to question the Master of all that is metal detecting. I was pounced on by the fan club like flies on feces. How dare I call into question the Master. LOL I ran and never looked back. It wasn't a detecting site, it was a fan club site.
 
Detector said:
Agreed that EMI does in fact cause problems with depth. However, I don't sgree that "silent EMI" is the problem. There can be so many factors that affect detector depth without making any noise that has nothing to do with EMI.
Click to expand...

The only differentiating factor in what I, Dankowski, and others have experienced, is the major difference in EMI between the test sites. If you know of any other factor that could explain the significant depth loss, I'm all ears.

BTW- I don't know anything about Dankowski. The first I heard of him was when I got back into detecting a few years ago after a long absence. I was taken aback at the amount of EMI noise and performance issues that I was experiencing, that I never experienced back in the day. So, I looked into the EMI issue, and that posting by him popped up. I remembered it, because I experienced the same thing.
 
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