When I Ground Balance a detector, what does the ground balance number tell me? (Air tests results added)

My Minelab Xterra 705 ground balances in my ground at 60. Does that number tell me if my ground is high, medium, or low, mineralized???
My unit locks on a silver Rosie Dime at 4 inches. At 5 or 6 inches, it reports it as iron with occasional chirps.
I have 58 cal Minie Bullets buried at 7,8, and 9 inches. It reports them as iron tones (-6 to -8 ) but chirps occasionally as it seems to know that they are something a little different from plain iron. But I don't want to digress from my main question. Can I send a soil sample off and have it analyzed (agricultural office?) to see if its full of that iron stuff??? Thanks. kevin



Edited 1 time(s). Last edit at 11/23/2012 03:19PM by Kevin B.

Something isn't adding up Kevin.
1 year may not be enough time for minerals to settle from digging out a hole to put item in.

Does it air test ok?
It should id correctly over most of the range of an air test.
If it doesn't air test and id correctly you may have a bad coil, etc.

Perhaps you should do some air tests and observations and let someone who has this unit compare.

According to Digger, the higher the number, the lower mineral content.
My ground in my yard gbed at 18, at other sites,10 at other sites 28 to 35.

Perhaps iron content in ground could cause higher gb numbers, I dunno.



Edited 1 time(s). Last edit at 11/23/2012 06:32AM by Steve(MS).

Steve(MS) yes, this has me puzzled. That is why I became concerned about my Ground Blalance number being 60 and yet anything over a 4 inch dime (in the soil) gets an iron tone assignment. I may have something set wrong. I will do a ground balance for sure.
But I WILL say this: Keith Southern stated in a post that, in an air test, a Nickel will "chirp". But not with my unit. I will post air test numbers shortly in the thread. Maybe someone can help me sort through this. Buy the way, it just started raining outside. Maybe that will help settle my new test garden.

All I know is you should get that silver dime at 7-8 inches in most cases...Certainly not a depth demon like some other units but something is wrong somewhere...

As far as the numbers let the techies chime in as I don't have a prayer and just ground balance my units spot on...

Mike Hillis Wrote:
-------------------------------------------------------
> HI Dan,
> Everyone on this forum uses a Minelab FBS detector
> and doesn't have to do any ground canceling.
>
> Just kidding. Don't get mad.
>
> Regards ground canceling, there is plenty of
> technical stuff floating around. JB's Baron site
> has some good articles about ground canceling by
> George Payne. Dave Johnson has some good stuff
> in various papers, as do others.
>
> Very simply put, one end of the ground balance
> range is toward conductive salt, the other end is
> toward ferrite minerals. You can get an idea of
> what TYPE of ground you are hunting in based upon
> where in the ground balance range your ground
> acutally cancels out at. You can't measure the
> AMOUNT of mineralization by the ground balance
> setting, but you can get an idea of the TYPE.
> This is true for all metal detectors that use a
> ground cancelling circuit that you can interact
> with, either by manually setting the ground
> canceling point, or by viewing a setting on a
> display. Today, FTP puts all this info in their
> detector manuals. Just pull up one of their
> manuals online and read all about it.
>
> The main mineral that I have to contend with is
> black sand. My ground balance settings reflect
> that. The CZ's balance somewhere between 2.25 and
> 2.75 in my soil conditions and I can find place
> where it will balance below 2 however they
> wouldn't be very useful. (1 - CZ3D, 2 - CZ70).
> That ground balance setting affect performance on
> high conductors both in the ground and in the air.
>
>
> HH
> Mike

AIR TESTS Results. I accepted the least bit of repeatable chirp.
1973 Copper penney: 9.5 inches
1971 Clad Dime: 9 inches
1934 Merc Dime: 8.5 inches
1986 Clad Nickel: 11.5 inches
2000 Clad quarter: 10.5 inches
1948 Wash. silver quarter: 10.5 inches
2 Cent Shield Coin (nickel sized); 11 inches
Yes, the air tests are nothing to write home about. I do these is a dark room, where i air test my other units. The other detectors, for instance, the CZ-3d that I bought from Tom air tested a dime at 12.5 inches (stated by NasaTom) and when I go it home and in this same room, sure enough, it air tested a dime at 12.5 inches. Just saying this so that I can rule out : "Well, it was in a bad place to be air tested!" If anyone here has a Xterra 705 and would take the time to do a bit of air testing so that I can get a idea of performance. Something tells me that the Xterra is working as it should. Heck, even with a 15 inch CoilTek DD coil, it was only hitting silver dimes at 10.5 inches in an air tests. That was with the 7.5khz and 18.75 khz coils. The air tests info for the three 15 inch DD Coil Tek coils are posted as a sticky over on the Xterra Findmall site. Check them out if ya get a chance. For a coil that size, I would have expected a bit more. But by no means am I trying to turn this into an Xterra bashing. Heck, I own one. And if I sell it, I sure don't want to post a bunch of negative crap about it.
I had similar results with my Etrac. I buried a silver quarter at 6 inches and the Etrac couldn't hit it. I tried two tone ferrous, open pattern, everything. I sold it to a guy in Missouri, and it works fine for him. He still has it. I found a Barber 1902 quarter with it. The Barber was about 5 inches down. Choppy signal.

EDIT: I just thought of this. I friend came down with his White MXT with the big round coil that has a big round hole in it, and tested my 7,8, and 9 inch bullets and couldn't hit them. They rang out as iron. I remember that he said to himself in a low voice: "This isn't good." I then took my Deus and hit them all three with hi tones. But my Xterra results would mirrored his on my bullets. I know THIS much. I don't know WHAT is in my ground that drastically reduces a VLF capabilities, whether iron, or conductive salt, but SOMETHING in it stunts the performance of VLF detectors.



Edited 2 time(s). Last edit at 11/23/2012 03:46PM by Kevin B.

The ground is wet this morning. We got some rain. Goodie. Anyway, I ground balanced several times. Always between 60 and 61. I went over to my 7,8, and 9 inch bullets. The Xterra did better on the bullets. I would get a one way hi one (I'm in 2 tones) on the 7 and 8 inch. On the 7 inch, I even got a two way hit as i circled the bullet. This result is on par with my other detectors (discluding the Deus, which always hits them with hi tones, two way...all directions) I am beginning to believe that ground balance numbers have nothing to do with iron content in the soil. (I know that I took a leap when I said that, but maybe it will get me some feedback) Thanks. kevin

Kevin---I'm just curious---How did that CZ-3D that you purchased from Tom that air tested 12.5" on a dime do (read/hit) on the buried targets in your test garden?----------Del

Del good question.... if you get close to the air test in a test garden planted for years with the CZ your unit is fault...if not you just have some real bad ground is my opinion...

I have a 10" dime and burried in my dirt and no machine will hit it unless the ground bal is manipulated but then you might think it's ground noise...the Explorer hit's it with a high tone but then the high tone it gives mimic's the high tone hot rock ring...Etrac nulls the Dime.Thinking it's mineral with wide open screen max sens...CZ-6a super hot one calls it iron when it reports..

the X-terra will low tone it on every other swing alternating with no tone...

I have an 8 inch nickle that is very tough but the size helps and also the shallower depth...but still a hard target..

Now with all that said...The recenlty burried target's will not give you accurate response..epsecially on the terra...

A nickle will airtest with a chirp on the 705 with elliptical high freq max sens all metal 2 tone 15.5"
A dime will airtest with a chirp on the 705 with elliptical high freq max sens all metal 2-tone 13"

On the terra I find and it may not be right!! that the all metal 2-tone is different than say a disc mode rejecting nothing......I know they are both still disc modes with the all metal just being an open screen....but the all metal seems to also except an area below the first notch and above the last notch...the wrap around area that is not assigned in a pattern mode disc, even wide open...

Now I may be wrong on that but it seems to be more noisy in the dirt and get better depth in 2 tone all metal than it does with say 2 tone accept all pattern disc...they should be the same yet I am not sure they are...The pattern mode MIGHT be nulling some areas in the wrap zone ....Again not sure but ever so slightly seems like that...

The 705 I find to be deep in my dirt..slighlty deeper than the MXT..coil size for coil size...Some other's do not report depth with the 705...Not sure why?...The 705 is noisy in minerals for sure compared to some...especially exposed dirt that's had the top layer removed and packed...like old roadbed's still in use..

The 7.5kHz coil in 10.5 DD is really the deepest coil for coin sized object's...it will get on down there....I have found 3 ringer's with that coil well past a foot..in good dirt...


The ground balance on the 705 is backwards from other detector's... the lower the numbers the worse the dirt....Mine balances at 18...which is like 80 range on the F75/T2..So 60 range would be like 40 range on the F75/T2....but ground balance number's are not everything...I have some dirt that is on the 50's but high iron content 3-4 fe bar's and it just shut's detector's down...as bad as 80 dirt on a t2 with 5 -fe bars..

You dont have the beach mode turned on do you Kevin? The umbrella at the top of the screen on or off...

Keith



Edited 1 time(s). Last edit at 11/23/2012 06:02PM by Keith Southern.

No, the beech mode is off. Tell ya what I'm gonna do. For those of you that know the Deus, I am gonna go out and Ground Balance that machine and also observe the bars. I'll report back in this post with an edit.
I am in All Metal. Two tones. I even tried tracking with offset on both sides of 60. Those 5 and 6 inch deep dimes are are just not gonna be hit. I TRIED to make my Gold Pack hit a nickel at 14 inches. Not a peep. I am going to re-air test outside. But heck...I got all day.

My XP Deus Ground balances at 73 and the little bars on the far right of the screen fluctuate between a quarter and a half. Now what does that tell me??? Absoluetly nothing. I an fast learning that I have learned very little about VLF's. Guess I never gave each one a chance. Oh well. I'll order a 10.5 inch DD 7 khz coil Monday since UPS decided to take two days off this week. See what it does.
You know what? If I had just stuck with my freakin ACE 250, I'd be money ahead. That is what a sesible person would conclude. But it's not ALL ABOUT finding as many relics and coins as possible. Oh don't get me wrong....it comprises a LARGE percentage of why I metal detect and buy detectors. But trying new units is fun too. And attempting to solve mysteries. Such as: All of this time I have been calling my dirt mineralised, when now the Xterra, which Ground balances at 60 in my dirt, seems to say that I have LOW mineralization.
But when you air test a unit and it gives a good tone on a dime at 9 inches, and then put it in dirt and it only reaches it at 4 inches.....there is SOMETHING in my dirt that is distorting the detectors ability to read the target!!!! The reddish brown color of my dirt makes me think that its iron. But I could be wrong. I have a good mind to send a dirt sample off for a complete analysis.

Something is askew Kevin...If the DEUS is saying 73 then the terra should be saying like 25-30 or so...they should not be that close...unless they have redone the ground balance system on the latest one's? they read backwards,,,if the 705 reads that high on the ground bal it would not need a DD coil...you need dd's below 30 ...Something does not sound right...

How are you ground balancing the 705 detector...are you letting it track in auto?...thats the best way to the the 705 it cuts down on iron falsing also...

My 705 in my dirt is around 10-30 on the g.b. most of the time...

Keith

Oh NUTS! It would be just my luck to get a freakin DUD!!! And then have to send it back to Minelab and WAIT!!! Okay, to your questions Keith. I ground balance via auto (pumping) and I also have learned how to ground balance via Tracking. Heck i even know how to off-set the Tracking ground balance. I am going to take it back outside and see why it's not ground balancing properly. AFTER i perform a factory reset. I am using 4 alkaline batteries. I am going to reread the instructions. I mean.....what are the chances of buying a detector from a company like Minelab....and then getting a dud that will not ground balance properly. I'm starting to get irritated. But NOT at ANYBODY. Just at my sour luck.
Keith, the report that I gave you concerning my Deus readings: Does that inidicate mineralized ground????
(by the way, that is TWICE that I have heard this morning that "something doesn't seem right." And I am starting to agree!!) Thanks for jumping in here and helping me with this. I am going to perform a factory reset, and then ground balance again.

EDIT: I just went back outside after resetting everything. I ground balanced by pumping in Coin and treasure mode. I didn't let the coil go lower than three inches towards the ground. The Ground Balance number is 68!!! I went to the three bullets (7,8, and 9 inch) and actually got better hits on them. More hi tones mixed with the iron grunt. I tstill hits a 7 inch Eagle I button (freshly buried) strongly and a fresh 7 inch bullet strongly with hi tones. But heck, I don't know which coil to get now. I had a Concentric coil on a CZ-3D that Tom calibrated and sold me. My dirt would not allow it to hit a silver dime past 6 inches!!!! Same with F75SE. I cannot remember the exact depths, I just remember wondering why my detectors wouldn't reach deeper with a hi tone and everything was giving iron tones when below 6 or 7 inches. Keith S., what did your Deus ground balance at in the ground where your Xterra GB's in the 20's????? Man this is confusing. If EVER I needed some technical advice, its now. I think I'll call Minelab and ask them about the latest Ground Balance numbers and what they mean.



Edited 1 time(s). Last edit at 11/23/2012 09:00PM by Kevin B.

Been awhile since I had an X-Terra but I thought the entire range of GB numeric values was between 1 and 32? Keith is correct....the GB number only tells the general type of ground but that doesn't indicate the iron and or minerals. That's where the Fe3O4 meters on the FT detectors shine. There is a way to sorta get the mineralization info with the XT but the (somewhat secret) sequence of pushing certain buttons needed for it to display is no longer in my memory banks.

go-rebels already posted the answer. The ground balance setting tells you what type of mineralization you are dealing with, not the amount of that mineralization.

Various detectors can also tell you the amount, most people here being familiar with the T2 and F75 bar graph for mineral amount. I tend to use the old fashioned method - stab a super magnet in the ground and see how much soil it grabs.

I have found the 705 to be extremely powerful in Prospect Mode but only a middling performer in any "not Prospect" mode. They really screwed the pooch when they started calling disc modes with no disc "all metal". The Ace 250 and others do it also. Now we have to explain how the all metal mode on the 705 is really not the all metal mode, it is a disc mode with filters engaged and set to accept all targets.

So what do we call true threshold based all metal modes now? The 705 calls it Prospect mode but that's not going to work.

Steve Herschbach

Prospecting Since 1972 at DetectorProspector.com

Steve's Mining Journal - - Gold Prospecting & Metal Detecting "How To" Guides - - Equipment Information & Reviews - - Public Gold Prospecting & Metal Detecting Sites - - Gold Mining Claims For Sale or Lease - - Steve's Guide to Gold Nugget Detectors



Edited 1 time(s). Last edit at 04/19/2013 03:01PM by Steve Herschbach.

On the Deus in my yard dirt the G.B. number is 88 on 18kHz.
On the 705 in my yard dirt the G.B. number is 15 on 18.75 kHz.

Ground balance numbers are different on the DEUS for different freq's, the lower the freq the lower the G.B. also the lower the freq the ower the Fe3O4 number's.

same on the omega vs the G2 when using the same coil's the Omega G.B's lower than the G2. And show's lower Fe3O4 number's...


G2 is 90 in my yard dirt
Omega is 58 in my yard dirt with same coil's..

Dont expect one machine from one manufacturer to ground bal to the same numbers as another machine from another manufacturer even if the machines are on the same freq..but they will be in the ball park usually..but there is no set in stone standard for what they can mean...

But the xterra numbers do run backwards from the norm...and the 705 does use 100 point's for G.B range, the 505 I believe uses the 32 point ground bal number as Brad stated...

Keith

Well, the only reason that really started me to worrying about it was when I read an Ebook that said to use the DD coils ONLY iwhen Ground "Phase" readings where 30 and below, or somewhere thereabouts. And use their concentric coils above that. I yelly..I have NEVER had any luck from concentric cioils in my dirt. Where as DD coils where much better. So I didn't want to oder the worng coil. But I am going to go against the E-books advice and order a 7 khz DD 10.5 COIL. B elieve this or not, the detector is starting to Ground blanace in the 50's now. And in part of the yard, in Tracking mode, it got down to 44. I would spot check as I walked along swinging and sometimes pumping. As powerful as my unit is in Prospecting mode, it has a very easy to interpret True All metal mode (prospecting mode). On an 8 or 9 inch bullet, the detector's pitch rises dramatically and the falls as I pass over the target. But as far as searching in old homeplaces.....the Deus really seems to have no problem trumping this machine. But please bear in mind that I have not had the Xterra long. The 7.5 coil may fool me and do some outstanding things.

The DEUS will be hard to beat in a iron site Kevin...
You will find the 705 deep with the 10.5 MF coil...

Sort of sound's like your yard is filled...the way the numbers are jumping could it be that the dirt is flipped?

Unless you are just into experimenting with machines the DEUS is about all you will need till say you find a exact need for a certian machine...

That could include the need for a prospecting unit...
or the need for a true all metal threshold based mode...
Or a P.I. is a machine you might really consider having besides the DEUS...

VLF's are very close in the ground...
In bad ground a P.I. machine will unlock target's you thought were not there...
As P.I.'s evolve and hopefully a bit better disc is added..(JUST FOR IRON I.D.) bad dirt hunter's are going to be quite surprised at what certain areas we are walking over actually hold....

Every one needs to understand the P.I. technology...And learn where to use it and when....

A Deus and a P.I. like the Infinium or TDI will cover alot bases..and SOOOOO Much information will be learned...I dont recomend P.I.'s to people on purpose.. but if you are serious about learning metal detector's a Pulse is a great tool,yet at the same time confusing to some ..I know people who use them and have yet to come to grips with them..they still lack the basic understanding of the technology...

Disclaimer:

I am not advocating you go out and buy a Pulse unit Kevin...LOL!

Keith



Edited 1 time(s). Last edit at 11/24/2012 03:14AM by Keith Southern.

Kevin, I personally didn't like the default tone for prospecting mode, I changed it to the lowest pitch...this has zero effect on performance.
Even with the 6" coil, in prospecting mode, that joker would go deep...in fact deeper than the deepest all-metal mode of a bunch of older detectors that I have used in the past.
I always thought if I could have mastered the prospecting mode, since it was a deep mother...that would have been depth to be reckoned with.
But alas, I never was able to unlock its secrets in telling enough about deep targets to be able to pick which ones to dig.
And who wants to dig many 10"+ holes if they are bits of iron?

That's not to say it isn't possible for someone else to find out.
I heard early on of a particular relic hunter pulling out bullet after bullet with prospecting mode up in Virginia...that was years ago
and haven't hear it since.
I think he was using that eliptical DD high freq. coil also.

Likely you need to take it out in a clean field somewhere and see if the gb numbers are more in line with what is to be expected.

LOL@!!!!!!!! Too late!!!! You done hooked me!!! LOL i's just kidding. Heck Keith, truth is I just like buying and playing with a new unit. I REALLY wish that I had bought a F5 with DD coil but still, the Prospecting mode on this unit could prove valuable for hunting battle ground sites and hunting the woods where everything gets a dig. But then again, you might see the Xterra 705 Gold Pack up for sale is a few days. Who knows. But I am keep the Deus. I am actually starting to learn its behaviors. I dug a couple of deep Minie Bullets last week with it. IN TRASH!! I barely heard the bullets.
Having said that.....if anyone has been wanting a brand new Xterra 705 Gold Pack to fiddle with, you might find a GREAT DEAL on this forum this weekend. Just depends on if I want to spend another $175 for another coil because that is what I'll do if I keep it. I don't know, Minelab and me just don't mesh real well. I tried the Etrac. Sold it in 3 weeks, but I didn't give it ample time to learn.
My yard is a about 5 acres. It has been plowed but that was 45 years ago. It has only been mowed since then. You can sweep the gound, even in clean areas in All Metal with the Xterra and you'll here tiny iron tones fairly regularly. But when you swing back over them they are gone. This is NOT in Tracking Ground Balance, but in pumping ground balance. Every 15 yards or so. But this eveing, when the ground balance was reading 44, the 7,8, and 9 inch bullets where coming in clearer. This dirt has NEVER let me have great depth on coins. With anything. The Deus accepted. I buried a silver dime at 6.5 inches last year while I had my first F75SE. I tweaked and tweaked and tweaked with that thing and all I got was an iron grunt. And I made CERTAIN that I was on clean ground. But I buried one at 5 inches about 30 yards away, and all my detectors hit it well!!!! This dit just seems to have particulates of something that distorts the transmit field and stymies it and keeps it from reaching deep for coins. Heck, I may try reburying tomorrow when I come out of the deer woods (frozen of course) and add some salt water like NasaTom did when making his test garden,

Steve(MS), I posted before I read your posts. Sorry about that. You know that is a GREAT idea. I'll take it out in the morning to the old school field, and several more places and record the ground balance on a sheet of paper. I called Minelab this afternoon ( they were closed) and left a message with customer service asking them about what exactly does the GB numbers inidicate. Steve, you have been very helpful in all of this and I appreciate it. Several others have as well....Keith Southern, and several others. I need to run to wal mart and get some botttled water so I gotta post quick. Thanks for all of yoru suggestions.

Hi Kevin,

I really enjoy your posts. In addition to what has been said above, I’ll give you some background information, make a suggestion or two, and tell you what happens here when doing similar tests over disturbed ground targets in a testplot. Maybe it’ll help you sort things out…and hope I’ve not overlooked anything obvious… but first a question…

As regards your 705… when you ground balance the unit regardless of the GB readout… is it actually ground-balanced to the soil?

I suggest that you don’t spend time evaluating target ID and / or discrimination capability, and to a lesser extent detection depth over disturbed ground test plot targets. Detector performance … especially target ID… should be evaluated over naturally settled targets in undisturbed ground. Test plots are disturbed ground, and may act accordingly for many years… at least here in somewhat elevated “moderate” ground. Yes there are techniques used by some who claim these mitigate the effects of disturbed ground testplot targets and I do not dispute those claims. Different ground conditions in different areas… and what works well here may not work so well elsewhere. My test plot targets do not respond as well re: depth / sensitivity, and target ID/ discrimination performance is abysmal compared to that which can be had over naturally settled targets in undisturbed ground.

Some units do much better over disturbed ground targets than others… particularly in discrimination modes where any discrimination is employed. In such comparisons, the results have little or no relevance to detector performance over naturally settled targets in undisturbed ground. I suggest locating suitable targets… and doing target ID comparisons in particular… in the field.

My testplot is used for target separation tests, or side-by-side relative depth comparisons in true all metal mode between different models of detectors. But that’s it. For example, any coin below maybe 3 to 4 inches will target ID all over the map. Beyond that depth they all read as iron… specifically target ID in the upper iron range consistently at “14” on the F75. Those figures don’t compare with hunting down at the local park where a 6” to 7” penny properly identified is nothing unusual. Same soil conditions, but undisturbed ground.

Here’s some background information as your first question was “what does the ground balance number tell me”? The direct answer is that the ground balance readout represents a weighted-average phase measurement of all soil minerals under the searchcoil at any given sampling point. Ground phase can be viewed as a ground "target ID" measurement based on phase shift similar to any other target ID measurement such as a coin. However, sometimes a “penny” readout may not be a penny but some other target with a similar target ID. And so it is with soil minerals because there is room for overlap as to how individual or groups of various iron minerals will target ID. So in a general sense it can apply to specific mineral types at times, but frequently it is not a definitive technique to identify exact soil minerals beneath the coil. There are too many possibilities in different geographic regions. In your soil a relatively “high” GB readout on your 705 indicating lighter mineralization does not necessarily correlate to how tough those ground minerals are to detector performance. As discussed below, maghemite soils read moderately on the GB scale but are highly magnetic susceptible soils that play havoc with metal detectors. When wet, such soil may become more reactive at reducing EMF penetration.

Ground phase has other uses in a prospecting application, but its main purpose is to adjust the ground balance control to effectively cancel out interfering ground signals. The ground balance control should be viewed as a separate discrimination control for this purpose. Proper ground balance results in improved detection depth, more accurate target ID, and more stable operation.

That said, keep in mind that iron minerals continue to inhibit EMF (electromagnetic field) penetration and warp the EMF despite proper ground balance settings. Ground-balancing permits us to detect targets to the best of a given unit’s ability within the constraints imposed by ground minerals. This explains why better depth can be had in light magnetic strength soil minerals as contrasted to reduced depths experienced over increased magnetic susceptible soil minerals.

And so we come to the subject of iron mineral magnetic susceptibility as per the Fe3O4 bar graph readouts on some of the Fisher units such as F75. Magnetic susceptibility in a metal detecting context refers to the ability of a soil’s iron minerals to attract a magnetic field. The Fe3O4 bar graph on the F75 or other units measures the strength of the ground’s magnetic susceptibility.

As the strength of magnetic susceptible iron mineralization increases, the electromagnetic field (EMF) penetration into the ground is reduced, thereby decreasing detection depth and effective target ID depth. These magnetic minerals further compound target ID reliability by distorting target signals. Some minerals such as magnetite… and to a slightly lesser degree maghemite… are highly magnetic susceptible but occupy different placements on a ground balance scale. For example magnetite occupies the elevated ferrite or most non-conductive end of the GB scale whereas maghemite generally occupies the middle of the GB scale. So we can see that an iron mineral’s ground balance setting may have no direct relationship to its magnetic susceptibility. For example, hematite also occupies the ferrite portion of the GB scale, but has a low magnetic susceptibility such that it has little effect on metal detectors.

Hence the Fe3O4 bar graph at a glance… offers a good indication of the strength or severity of iron mineral magnetic susceptibility with which an operator will have to contend. High soil magnetics also means there will be a “tight” ground balance window compared to that experienced in more moderate or lighter magnetic mineral soils. There will be less “give” in the vertical latitude available with coil elevation differences as you scan the searchcoil before the ground minerals start to give spurious signals.

That about it for now Kevin, hope it’s of some value to you… I think your problem is working with disturbed ground targets… the inconsistencies between units or even the modes on the same unit can give you a headache if you don’t realize what is happening.

Jim.

Jim, I just woke up and read your post and I must say that I totally appreciate that explanation. It sets me at rest. This afternoon, I will carry the Xterra on her maiden voyage to a place where coins might be present and try her out. I truly appreciate the clarity that you have brough into this. Wow....now there's some good knowledge. And I appreciate it.

JimHem..... again......... with much gratitude.

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