ADVANCED TRAINING

Isn't detector choice and hunt strategy about balancing many variables? EMI just being one of them (and maybe not the most important one at that particular site)? Iv'e always wanted to see a thread about "Hunt Strategy"...how does one approach hunting a particular site, choosing a particular machine, and why?

For instance, in NASA-Tom's initial post, time could have been saved by determining the amount of nail contamination first and eliminating the CZ right off the bat. Where does EMI mitigation fall on the priority list when determining hunt strategy for a particular site (other than the obvious EMI making it not possible to hunt there)?

Dean

Drew,

I've encountered this experience inside KellyCo (of whom has been sold/bought-out)…. in their showroom floor with customer detector stands set up.... for the customer to test/try different detectors. A (normally 12" capable) detector that would only air-test a coin to about 7"; yet, express no audible EMI...… but...… knowing EMI was the culprit. Other brand detectors would also show differing levels of EMI inhibiting performance.

Dean...…. I had no idea of the dirt conditions (carpets of nails) at this particular site.... before commencement; yet, would always attempt to start with a detector that would easily tell me of the existing hunt conditions...…. so I could then 'select wisely'.

And here I thought that darn ferrous masking/silent masking was the biggest concern. Yes the EMI factor is a big wake up call for me. (Certainly the "silent EMI")
I have several areas around my "home parks" where I have tried to work around the EMI issue.. I will gear down to 12 sens, pick the calmest channel... and realize a quarter 4" down barely comes thru. Then I finally say "what in the world am I doing here?!" LEAVE NOW should have been in the front of my mind.
I remember one particular park years ago had great potential, I always had in the back of my mind I will hunt that spot as soon as we have a power outage in the area!!

I hope metal detector manufacturers take this into consideration as our ever growing need for electricity rises. I have to think this is a "known factor" correct?? I would also think that something like this can be "tuned" out deep in the motherboard somewhere??

Great post Tom. I think you have just saved many folks countless wasted hours in the field. (And provided us another folder of information to help with our own search for "Intelligent Hunting".)

What was once impossible..... is now easy and obvious. BUT.......... if : You don't know...what you don't know........ it continues to appear/look impossible.
-Thomas Dankowski

OK, I have to ask a stupid question: how do you know if you have silent EMI if you can't hear it? How does one know it's affecting the detector? How do we deal with it? You probably have already discussed it in these posts but I am missing it.

martygene Wrote:
-------------------------------------------------------
> OK, I have to ask a stupid question: how do you kn
> ow if you have silent EMI if you can't hear it? Ho
> w does one know it's affecting the detector? How d
> o we deal with it? You probably have already discu
> ssed it in these posts but I am missing it.


If you know what your detector does in an emi free environment on a dime, then, at a particular site you air test it. If is less, then you know there is a silent depth killer.

Thanks Ozzie... I dig what you're saying now. Now I can re-read all the posts again and really get the proper info out of it.

ozzie Wrote:
-------------------------------------------------------
> martygene Wrote:
> --------------------------------------------------
> -----
> > OK, I have to ask a stupid question: how do you
> kn
> > ow if you have silent EMI if you can't hear it?
> Ho
> > w does one know it's affecting the detector? How
> d
> > o we deal with it? You probably have already dis
> cu
> > ssed it in these posts but I am missing it.
>
>
> If you know what your detector does in an emi free
> environment on a dime, then, at a particular site
> you air test it. If is less, then you know there i
> s a silent depth killer.

Quote

martygene Wrote:
-------------------------------------------------------
> OK, I have to ask a stupid question: how do you kn
> ow if you have silent EMI if you can't hear it? Ho
> w does one know it's affecting the detector? How d
> o we deal with it? You probably have already discu
> ssed it in these posts but I am missing it.

There are others here that can provide a better in depth answer than me. Having said that, if I can't air test a dime at or near the same depth as I can in my "non-EMI" location, then I can make a pretty good guess that is the issue. (Of course double checking my settings-freshly charged batteries ect...)

I am actually in the middle of my own crude EMI testing log. Checking typical areas I hunt and seeing where the best/worst zones are. This is going to save me a ton of time I would have wasted in bad locations. And maximize my detecting time in more favorable spots.
Peter

What was once impossible..... is now easy and obvious. BUT.......... if : You don't know...what you don't know........ it continues to appear/look impossible.
-Thomas Dankowski

martygene Wrote:
-------------------------------------------------------
> OK, I have to ask a stupid question: how do you kn
> ow if you have silent EMI if you can't hear it? Ho
> w does one know it's affecting the detector? How d
> o we deal with it? You probably have already discu
> ssed it in these posts but I am missing it.


If a detector with known settings will airtest a clad dime to say 12” away from coil in some locations, then you change locations and use same settings and the detector falls short of the 12” airtest on clad dime. User may or may not hear audible noise when testing in site. If you hear no noise yet detector falls short (airtest wise) one can presume Emi is causing. A user can try and mitigate Emi using whatever the detector model offers. Like noise cancel, manual frequency shift, changing frequencies altogether I.e. Nokta Impact, Anfibio, Deus.
In the end you may NOT be able to mitigate Emi to your liking for hunting a particular site. Like hunting in Florida with higher sink rates. Depth might be significant factor to base hunting a particular site. But if EMI precludes depth with a model detector, a user would be in a sense wasting their time, as a rehunt later with lower Emi (where airtest is greater than previously) would have a stronger chance to find the deeper and more fringe depth detectable targets in the site. THIS what I have said here is basically what NASA Tom has stated above.



Edited 2 time(s). Last edit at 12/11/2018 04:59PM by tnsharpshooter.

So then as it has been said earlier, one might need to have 2 or 3 detectors with them to see if one might be able to perform better than the others. So then my next golden question is: What 3 detectors are different enough for maybe one of them to be a little better at handling silent EMI ? I have only experience with Minelabs and Deus. Some of you have used detectors that I have never used. What 3 should we have in out arsenal?

tnsharpshooter Wrote:
-------------------------------------------------------
> martygene Wrote:
> --------------------------------------------------
> -----
> > OK, I have to ask a stupid question: how do you
> kn
> > ow if you have silent EMI if you can't hear it?
> Ho
> > w does one know it's affecting the detector? How
> d
> > o we deal with it? You probably have already dis
> cu
> > ssed it in these posts but I am missing it.
>
>
> If a detector with known settings will airtest a c
> lad dime to say 12” away from coil in some locatio
> ns, then you change locations and use same setting
> s and the detector falls short of the 12” airtest
> on clad dime. User may or may not hear audible no
> ise when testing in site. If you hear no noise ye
> t detector falls short (airtest wise) one can pre
> sume Emi is causing. A user can try and mitigate
> Emi using whatever the detector model offers. Lik
> e noise cancel, manual frequency shift, changing f
> requencies altogether I.e. Nokta Impact, Anfibio,
> Deus.
> In the end you may NOT be able to mitigate Emi to
> your liking for hunting a particular site. Like h
> unting in Florida with higher sink rates. Depth mi
> ght be significantly factor to base hunting a part
> icular site. But if EMI precludes depth with a mo
> del detector, a user would be in a sense wasting t
> heir time, as a rehunt later with lower Emi (where
> airtest is greater than previously) would have a s
> tronger chance to find the deeper and more fringe
> depth detectable targets in the site. THIS what I
> have said here is basically what NASA Tom has stat
> ed above.

martygene Wrote:
-------------------------------------------------------
> So then as it has been said earlier, one might nee
> d to have 2 or 3 detectors with them to see if one
> might be able to perform better than the others. S
> o then my next golden question is: What 3 detector
> s are different enough for maybe one of them to be
> a little better at handling silent EMI ? I have on
> ly experience with Minelabs and Deus. Some of you
> have used detectors that I have never used. What 3
> should we have in out arsenal?
>
> tnsharpshooter Wrote:
> --------------------------------------------------
> -----
> > martygene Wrote:
> > ------------------------------------------------
> --
> > -----
> > > OK, I have to ask a stupid question: how do yo
> u
> > kn
> > > ow if you have silent EMI if you can't hear it
> ?
> > Ho
> > > w does one know it's affecting the detector? H
> ow
> > d
> > > o we deal with it? You probably have already d
> is
> > cu
> > > ssed it in these posts but I am missing it.
> >
> >
> > If a detector with known settings will airtest a
> c
> > lad dime to say 12” away from coil in some locat
> io
> > ns, then you change locations and use same setti
> ng
> > s and the detector falls short of the 12” airtes
> t
> > on clad dime. User may or may not hear audible
> no
> > ise when testing in site. If you hear no noise
> ye
> > t detector falls short (airtest wise) one can p
> re
> > sume Emi is causing. A user can try and mitiga
> te
> > Emi using whatever the detector model offers. L
> ik
> > e noise cancel, manual frequency shift, changing
> f
> > requencies altogether I.e. Nokta Impact, Anfibio
> ,
> > Deus.
> > In the end you may NOT be able to mitigate Emi t
> o
> > your liking for hunting a particular site. Like
> h
> > unting in Florida with higher sink rates. Depth
> mi
> > ght be significantly factor to base hunting a pa
> rt
> > icular site. But if EMI precludes depth with a
> mo
> > del detector, a user would be in a sense wasting
> t
> > heir time, as a rehunt later with lower Emi (whe
> re
> > airtest is greater than previously) would have a
> s
> > tronger chance to find the deeper and more fring
> e
> > depth detectable targets in the site. THIS what
> I
> > have said here is basically what NASA Tom has st
> at
> > ed above.

Martygene,
Notice which detectors NASA Tom mentions above in this thread. These detectors are purposely chosen by him due to flagship depth potential in milder ground. His sites, seems many are very mild.

So anyone else picking say 3 Detectors. If depth is primary goal, a person’s soil mineralization would be key to consider vs which detector models performance for depth in such soil mineralization.

For example CZ3d is not a good choice in my area due to ground minerals. Etrac, Equinox better choices.
But CZ3d is flagship deep in mild ground.
Nokta Anfibio is another flagship deep detector in mild ground.

So folks choices could vary.
And some models are meterless, hence for select digging maybe not best choices. But may indeed be grand choice for nonselect digging like relic hunting in site with little to no modern trash.



Edited 1 time(s). Last edit at 12/11/2018 05:33PM by tnsharpshooter.

Interestingly..... the CZ is one of the most EMI resilient detectors on planet Earth. Fortunately...…. it is a simultaneous multi-frequency unit...… that performs substantially better in bad mineralization...…. than nearly all single freq units; yet, certainly...… is not perfect. (And it's a late 1980's & 1990 technology platform). I still retain a few new-in-box units in my inventory.

Additional food-for-thought: I tested EQX in Prospecting Mode-2 ...at one of my remote test-gardens ...….. with the following air-test results on a clad dime:

Dec. 03 = 12" in Noise Cancel channel -6
Dec. 04 = 10" in Noise Cancel channel -6
Dec. 07 = 13" in Noise Cancel channel -6

No other settings were changed. All parameters were exactly the same. On Dec. 03 and Dec. 07...... absolutely zero audible EMI. On Dec. 04..... I could hear a very slight amount of EMI chatter. Certainly not enough for me to be concerned about. (((Or should I be!!))). Can you see were there's 'significance' in an air-test? Can you see were there's 'significance' in carrying a spare dime.... for a 15 second test?

At this same exact site...…. on Dec 09...…. I encountered the following resultant:

Noise Cancel channel '0' = 10"
Noise Cancel channel '7' = 13"

Soooooooooo………..by virtue of carrying a dime with me in the field...…. and taking 20 seconds to test the best (top two EMI-free) Noise Cancel channels.... in an air-test; subsequently to witness/experience a 10" noise-free channel...… and a 13" noise-free channel...……. do you think I should then proceed to hunt with the 10" channel???
Again...… can you see the importance of carrying a spare dime with you...in the field?
Changing MODES on the Equinox...…………. will express varying levels of EMI
Changing Freqs in each individual MODE ….. will express varying levels of EMI
The best EMI mitigation channel will not be the same channel..... for each MODE.... nor each frequency selection.
All data holds true for other types/brands of detectors.

Recently...….. I wanted to perform a curiosity-test with the Anfibio at a beat-to-death site. I had 'finished' this site with the Anfibio…….. with the best EMI-mitigation day...presenting 10.5" on a clad dime air-test. When I showed up on this particular day..... ready to commence my 'curiosity-test'...…. my initial set-up protocol expressed a 13" air-test on a clad dime..... after implementing best EMI mitigation procedures. I was startled. This instantly prompted cancellation of my 'curiosity-test'. I immediately commenced detecting this small (90' x 80') parcel. In 70 minutes...… I had dug 31 coins …… all coins exclusively within the depth strata of 10.5" - 12.5" (and no deeper...nor shallower)......….with the newest coin being 1917. EDUCATION #1
EDUCATION #2 = At the 70 minute mark...…. the detector instantly started 'chattering'. EMI. I attempted to mitigate EMI...… to no avail. I had completed 90' x 60' of the 90' x 80' parcel of land. I still had (and..... to this day...…. still have)…… a high-producing 90' x 20' remaining strip of parcel to complete.
I have hunted this site 8 times … in my life..... thus far.,.,.,.,.,.,., and with various detectors...… mostly proto's. Collectively..... all 8 hunts had produced 7 coins total. Soooooo…… to find 31 coins in 70 minutes...….. is nothing short of stupendous.
Is depth important?
Is EMI mitigation important?
Is bad mineralization mitigation important?

I have every intent to talk about bad dirt. Need to find the time!
If you can not mitigate bad EMI FIRST...…. then bad mineralization may be a moot point. . . . . (hardly matters). In other words: If you cannot handle the ""AIR""...…. then...….. lowering the coil to the ""GROUND"" …… is irrelevant.
Air first...….. then ground.

Unless the EMI limits the detector to 8 inches and the mineralization limits it to 6 inches. Just sayin'

Tom I know we've discussed EMI to a great extent in the past here, it's always been an interesting topic and it's an eye opener when you get shut down by EMI just how fragile detector electronics are to the real world.

We've all been to sites with the same detector and had days where you can't make a find to save your life, then go back the next day to the same site with the same detector, and the site was on fire. No doubt EMI related.

When I worked in commercial WiFi I used a spectrum analyzer called a WiSpy. It was a fairly inexpensive USB device you plugged into a laptop that would sniff the air. Great and inexpensive tool for channel planning and trying to sniff out RF related issues. I always wondered why that same technology couldn't be built into a detector, and something like an Equinox (which interestingly Tom stated is a full ONE INCH deeper then the F75 in case nobody caught that) that has the ability to use different SMF technology could potentially dynamically auto-tune frequencies to work around the RF noise.

This shows air tests that are reported don't have much meaning.

Now we should keep an eye on First Texas. They may now come up with a detector that takes care of emi.

Rick

Ok some detectors air test deep but doesn't mean they go deeper in the ground. Other don't air test deep and go deep in the ground. So how does air testing for emi affect different detectors for best depth in the ground.

I guess you need the detectors that go deep to begin with. But still does the best air test mean it will go deeper in the ground. Yes I guess it would. If it only air test 7" you wouldn't want use. So it all depends on what your detector can air test in the best situation.

Never mind. I talked myself out of this thought lol.

Rick



Edited 2 time(s). Last edit at 12/12/2018 12:59AM by Rick, N. MI.

Cal_cobra Wrote:
-------------------------------------------------------
> Tom I know we've discussed EMI to a great extent i
> n the past here, it's always been an interesting t
> opic and it's an eye opener when you get shut down
> by EMI just how fragile detector electronics are t
> o the real world.
>
> We've all been to sites with the same detector and
> had days where you can't make a find to save your
> life, then go back the next day to the same site w
> ith the same detector, and the site was on fire.
> No doubt EMI related.
>
> When I worked in commercial WiFi I used a spectrum
> analyzer called a WiSpy. It was a fairly inexpens
> ive USB device you plugged into a laptop that woul
> d sniff the air. Great and inexpensive tool for c
> hannel planning and trying to sniff out RF related
> issues. I always wondered why that same technolog
> y couldn't be built into a detector, and something
> like an Equinox (which interestingly Tom stated is
> a full ONE INCH deeper then the F75 in case nobody
> caught that) that has the ability to use different
> SMF technology could potentially dynamically auto-
> tune frequencies to work around the RF noise.

Yes that’s what I was kind of alluding to in my previous post.
I don’t see why manufacturers can’t include some type of EMI Tracking Mode.
We have ground tracking, it only makes since to have continual Air tracking too.

Bryan

One of the things I noticed about the wireless coil on the Deus. Another place for EMI to infiltrate easily into the detector. I hunted in some places that drove the Deus crazy.

a big 10-4 on that goodmore. many times i cannot use the Deus due to EMI. there is nothing that i can do to settle it down.

goodmore Wrote:
-------------------------------------------------------
> One of the things I noticed about the wireless coi
> l on the Deus. Another place for EMI to infiltrate
> easily into the detector. I hunted in some places
> that drove the Deus crazy.

A detector that air tests at 7" on a dime but finds a dime 12" in the ground would be highly suspect of having been air tested with restrictive EMI present. EMI is probably the culprit responsible for making people think their detector goes deeper into the ground (where they are detecting in the open away from EMI) than in the air (near their house). There might be a case for vertically distributed elongated iron in the ground collecting and enhancing the magnetic field density that happenstance results in a deeper non-ferrous target to be illuminated, but that should be a relatively rare event.

Tom,

As you prepare for a site by 'emi' testing, are you assuming that audible EMI is more detrimental to detector performance than 'silent' EMI, or have you already proven this to yourself and are thus able to skip the step of testing all available channels for best performance and then 'dealing' with any nuisance noise that may be present?


Rich (Utah)

------------------------------------------------------------------

Just one more good target before I go.

Troy Galloway and I discussed this same phenomena one day over the phone...some time after the X5 had came out. Troy actually kept a coin attached to his shoe laces so that he could do checks in the field. He had came up with some filter box that plugged into the control box that shielded it from external EMI. You couldn't detect with it but its purpose was to do full machine diagnostic checks to see if it was functioning to standard...i.e. starting to get circuitry noise at a proper position on the dial, etc while inside of a building with lights, etc.

As relic hunters, we had discussed things that had happened in the field of which at the time, we had no way to explain it. Things like...why at certain sites, it would be really producing and then suddenly stop. The common thought would be "well we played this site out" but then in going back at a later date with the same machine, targets started appearing, within easy depths and make you wonder "how did we miss that?".

NASA-Tom,

What you shared here, is really, really fascinating -- and extremely instructional. Just extraordinary information, in my books. And the resultant? 31 coins -- which, on 8 prior hunts, had netted a COMBINED TOTAL of just 7 coins? Wow! And all from a strata of soil that you would not have reached, had you not taken such a meticulous, intelligent approach...

You are really making the wheels turn in my science-oriented brain...forcing me to think...about an aspect of detecting (EMI mitigation) that I have CLEARLY not given sufficient attention to. Auto noise cancel (my normal routine) is CLEARLY insufficient...by a LONG shot...

My only curiosity is, WHAT WAS the "curiosity test" you had in mind that day, with the Anfibio, but which the optimal detecting conditions you discovered resulted in you abandoning the testing, and opting for what turned out to be a very productive and informative "plan B?!"

Steve

NASA-Tom Wrote:
-------------------------------------------------------
> Interestingly..... the CZ is one of the most EMI r
> esilient detectors on planet Earth. Fortunately...
> …. it is a simultaneous multi-frequency unit...… t
> hat performs substantially better in bad mineraliz
> ation...…. than nearly all single freq units; yet,
> certainly...… is not perfect. (And it's a late 198
> 0's & 1990 technology platform). I still retain a
> few new-in-box units in my inventory.
>
> Additional food-for-thought: I tested EQX in Pros
> pecting Mode-2 ...at one of my remote test-gardens
> ...….. with the following air-test results on a cl
> ad dime:
>
> Dec. 03 = 12" in Noise Cancel channel -6
> Dec. 04 = 10" in Noise Cancel channel -6
> Dec. 07 = 13" in Noise Cancel channel -6
>
> No other settings were changed. All parameters wer
> e exactly the same. On Dec. 03 and Dec. 07...... a
> bsolutely zero audible EMI. On Dec. 04..... I coul
> d hear a very slight amount of EMI chatter. Certai
> nly not enough for me to be concerned about. (((Or
> should I be!!))). Can you see were there's 'signif
> icance' in an air-test? Can you see were there's '
> significance' in carrying a spare dime.... for a 1
> 5 second test?
>
> At this same exact site...…. on Dec 09...…. I enco
> untered the following resultant:
>
> Noise Cancel channel '0' = 10"
> Noise Cancel channel '7' = 13"
>
> Soooooooooo………..by virtue of carrying a dime with
> me in the field...…. and taking 20 seconds to test
> the best (top two EMI-free) Noise Cancel channels.
> ... in an air-test; subsequently to witness/experi
> ence a 10" noise-free channel...… and a 13" noise-
> free channel...……. do you think I should then proc
> eed to hunt with the 10" channel???
> Again...… can you see the importance of carrying a
> spare dime with you...in the field?
> Changing MODES on the Equinox...…………. will express
> varying levels of EMI
> Changing Freqs in each individual MODE ….. will ex
> press varying levels of EMI
> The best EMI mitigation channel will not be the sa
> me channel..... for each MODE.... nor each frequen
> cy selection.
> All data holds true for other types/brands of dete
> ctors.
>
> Recently...….. I wanted to perform a curiosity-tes
> t with the Anfibio at a beat-to-death site. I had
> 'finished' this site with the Anfibio…….. with the
> best EMI-mitigation day...presenting 10.5" on a cl
> ad dime air-test. When I showed up on this particu
> lar day..... ready to commence my 'curiosity-test'
> ...…. my initial set-up protocol expressed a 13" a
> ir-test on a clad dime..... after implementing bes
> t EMI mitigation procedures. I was startled. This
> instantly prompted cancellation of my 'curiosity-t
> est'. I immediately commenced detecting this small
> (90' x 80') parcel. In 70 minutes...… I had dug
> 31 coins …… all coins exclusively within the depth
> strata of 10.5" - 12.5" (and no deeper...nor shall
> ower)......….with the newest coin being 1917. EDUC
> ATION #1
> EDUCATION #2 = At the 70 minute mark...…. the dete
> ctor instantly started 'chattering'. EMI. I atte
> mpted to mitigate EMI...… to no avail. I had comp
> leted 90' x 60' of the 90' x 80' parcel of land. I
> still had (and..... to this day...…. still have)……
> a high-producing 90' x 20' remaining strip of parc
> el to complete.
> I have hunted this site 8 times … in my life.....
> thus far.,.,.,.,.,.,., and with various detectors.
> ..… mostly proto's. Collectively..... all 8 hunts
> had produced 7 coins total. Soooooo…… to find 31 c
> oins in 70 minutes...….. is nothing short of stupe
> ndous.
> Is depth important?
> Is EMI mitigation important?
> Is bad mineralization mitigation important?
>
> I have every intent to talk about bad dirt. Need t
> o find the time!
> If you can not mitigate bad EMI FIRST...…. then ba
> d mineralization may be a moot point. . . . . (har
> dly matters). In other words: If you cannot handl
> e the ""AIR""...…. then...….. lowering the coil to
> the ""GROUND"" …… is irrelevant.
> Air first...….. then ground.

Tom Slick...…….. If you walk into a hunt-site and turn your detector 'on'...……. and it's chattering like crazy.,.,.,.,.,.,., what are you going to do? You MUST mitigate EMI first..... in order to get your detector UP TO the 8" air-test...….. so you then may be able to go 5" or 6" deep … in bad dirt. Air first. Then ground secondly.

Rick...… yes...… absolutely! It is so easy to perform an air-test for a 'variables-removed' base-reference data...…… yet; unsuspectingly..... being inhibited by EMI; subsequently, unknowingly skewing resultant.

Rich...….. you bring up a VERY good point(s).
First...….. Audible EMI (so far) has always been more detrimental than silent EMI.
Second... Silent EMI is (nearly always) not as crippling as audible EMI; yet, due to its unsuspecting nature..... can cause a detectorist to have reduced performance..... blissfully in-the-blind.
Third...… Silent EMI will have certain noise-abatement channels that perform better (silently) …. over other noise-abatement channels (silently). And...…. you would never know/suspect...… unless you perform a validating test. ""What you can't hear..... WILL hurt you..... unsuspectingly!""

1. First: Get rid of AUDIBLE EMI.
2. Secondly: Find the "best" SILENT EMI channel.

Steveg……… My 'curiosity-test' was to dig the low conductors (searching for Nickels.... and trinkets)…… to see if the deeper depth targets were ID 'up-averaging' or ID 'down-averaging'. Up to this point (in this particular field...…. old one-room school house)……. I had found several coins; yet, only the high conductive coins. No 'lunch money' Nickels yet.

NASA-Tom,

Thanks for the info. Very interesting...

So you had in the past TRIED to dig nickels, in the "nickel range," with no success, suggesting deeper nickels at this site (which should be present) may be registering outside of the normal "nickel range?"

Very interesting, how you think...

Steve

Thank you for the clarification of "air first then ground" . Of course, we do this automatically (air first) as part of our start up routine when we auto tune then hunt and assume all is good.
Living in the very mineralized SW I am (was) always more concerned about mineralization mitigation than anything else. Obviously to my detriment.

Thank you, Tom, for the education! Much appreciated.

I look forward to your ground mitigation strategy.

Also, I would assume, that silent EMI affects all detectors? Specifically, PI (GPX)? If so, could one perform the same "best channel" test with a gold nugget out in the field prior to nugget shooting? Thanks again!

Dean

Great topic Tom!
I live in SW Colorado where the mineralization in the ground is very high but I still go by EMI first before choosing a detector to hunt with and the type of hunting I am doing that day and where.
For example if I am going relic hunting to old rail camps alongside the train tracks I only choose an analog detector to take with me because I know that the emi coming off the tracks and the telephone
lines that follow them make my digital detectors go nuts.
Hence the VQQ, Smart plus, MXT pro, or a Tesoro fairs this environment a lot better. Now if I am going to a new site I will take my best digital machines and one analog with me to make sure all my
bases are covered and I am not stuck hunting with a detriment.
Now if I am going old coin hunting in old parks I always carry a CZ with me because as Tom alluded to they are the best at handling all forms of EMI do to the analog nature of their design. (Thank you Tom
for trying to perform surgery to get my old deep girl performing again)
My CTX handles the emi ok but only allows for depth of 8 to 9 inches in my soil. My CZ6a hit an SLQ at 11in in my local park that the CTX barely chirped on, would never have found it with just using the CTX.
When testing the NOX 800 in my local old parks I wasn't finding anything past 6 to 7 in so I went to the truck and got my CZ and located an coin target that pegged the depth gauge and then ran
the NOX over the target and nothing, no matter what I did, manual noise channel change, nothing. The NOX was running smooth but I chalked it up to silent emi seems to affect the NOX more than regular emi with
depth. 9in down was a wheat penny.
Moral of the story, analog technology may be old but in certain circumstances, it outperforms digital. Hopefully one day that will change. My CZs are getting up there in age, not sure how long
they will last.lol

This is a very interesting thread - thank you for sharing. I am not well versed in electronics but I do have a question concerning "noise cancelling"

On my Equinox, I can AUTO noise cancel and get a different number each and every time I use the function. (I can push the button 5 times and get five different numbers that the machine settles on) Is EMI / silent EMI causing it to change that much in a matter of minutes?


Is there any way to incorporate an onboard diagnostics / EMI monitoring system to constantly adjust (ever so slightly) the frequency or frequencies being transmitted?


Just thinking out loud.

EPL II Wrote:
-------------------------------------------------------
> This is a very interesting thread - thank you for
> sharing. I am not well versed in electronics but
> I do have a question concerning "noise cancelling"
>
> On my Equinox, I can AUTO noise cancel and get a
> different number each and every time I use the fun
> ction. (I can push the button 5 times and get five
> different numbers that the machine settles on) Is
> EMI / silent EMI causing it to change that much in
> a matter of minutes?
>
>
> Is there any way to incorporate an onboard diagnos

> tics / EMI monitoring system to constantly adjust
> (ever so slightly) the frequency or frequencies be
> ing transmitted?
>
>
> Just thinking out loud.

Same here, I've been wondering about that.

tabman

EPL II Wrote:
-------------------------------------------------------
> On my Equinox, I can AUTO noise cancel and get a different number each and every time I use the function
> (I can push the button 5 times and get five different numbers that the machine settles on) Is EMI / silent EMI
> causing it to change that much in a matter of minutes?

Probably means the EMI is close to equally prevalent in those channels so it's a random choice. If you don't trust the auto-select, put it in all-metal and do it manually.

> Is there any way to incorporate an onboard diagnostics / EMI monitoring system to constantly adjust
> (ever so slightly) the frequency or frequencies being transmitted?

Ground and target signals would screw it up.

Is there any small handheld emi detection meter a person could carry in a pocket, on the market?