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Iron Bias Fe Versus Fe2

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1 hour ago, Steve Herschbach said:

None of this information about how FE and FE2 relate to each other is anything other than speculative and should be taken with a huge grain of salt. The only thing I know for sure is the FE2 range is far more aggressive than the original and kicks in earlier than I thought based on what Tom had said.

I love this discussion.  What I find interesting based on Steve and Jeff's testing how little FE affects certain mixed targets.  I think it is just tough to compare FE with F2.  Perhaps they react differently to different types of targets.  If I take Steve's latest theory on the FE to F2 scale comparison the following observations come to mind (which I am dubbing the Herschbach IB scale to differentiate it from the Dankowski IB Scale):

1.  If FE indeed reacts so minimally compared to F2,  I wonder why ML chose to retain FE other than to avoid complaints from Equinox users about removing desired capability.  I know that personally, I have never invoked FE ever since F2 showed up in the Ver 2.X update.

2.  Steve's theory might also support the notion that Fe 0 and F2 0 actually both represent completely turning off the IB filter.  That notion sort of went out the window when I first embraced the "Dankowski IB Scale" that showed FE 0 ~ F2 4.

3.  Finally, I find it interesting that ML took care to select different FE IB default settings for different modes including "0" for Park 2, Field 1, and Field 2 and 6 for everything else.  And, counterintuitively, set the F2 IB default to 6 across the board.  Hmm...

BTW Using the 3.0 update.

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I've used the F2 setting pegged at 9 quite a bit and haven't seen any down side to doing it......yet anyway. I'm still getting tiny foil non-ferrous readings of 1 in modes Park 1 and 2; Field 2, and Beach 1 and 2. I'll try to remember to experiment with Field 1 (which I almost never use) and the Gold modes. My only concern might be what effect it would have at depth.....or maybe in depth would be a better term. In using F2 @9 I don't "feel" it's detrimental, but, maybe it is and I haven't noticed it.

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7 hours ago, cudamark said:

I've used the F2 setting pegged at 9 quite a bit and haven't seen any down side to doing it......yet anyway. I'm still getting tiny foil non-ferrous readings of 1 in modes Park 1 and 2; Field 2, and Beach 1 and 2. I'll try to remember to experiment with Field 1 (which I almost never use) and the Gold modes. My only concern might be what effect it would have at depth.....or maybe in depth would be a better term. In using F2 @9 I don't "feel" it's detrimental, but, maybe it is and I haven't noticed it.

I would consider an F2-9 IB setting detrimental to my type of hunting, which is trashy parks.....I wouldn’t feel comfortable with that high of a setting because I have tested the F2 IB on deeper targets (6-10”) in trashy, iron infested turf, and have noticed a difference between an  F2-4 and an F2-0 on real iffy targets... F2-0 IB hangs on to the non-ferrous signal “longer” than F2-4 (while doing the Minelab wiggle on your coil)....so I’d imagine F2-9 would be even more obscure on the non-ferrous response than F2-4 would be.

Higher iron bias settings favor the ferrous response of the target more than the non-ferrous response. 

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I just came back from a beach hunt.  Mind you conditions are not right at the beach for a lot of targets so I took it slow and easy on the first few 'tests.'  I used B1, 23, 6, F2 0 and then saved F2 9 and switched back and forth on the find, during the dig and after recovery.  I would have to say that several of the targets were the same on both with the 15" coil.  Lead seemed very similar.  Before I got to the wet sand I had a target and the 9 clearly had an effect on it.  It kept it in the negative numbers and sound and it was a dry bottle cap.  That was the best test where I could see a clear difference.  If other targets had responded the same way I'd use some F2 but I found a jumpiness with it that would take a learning curve to interpret.  I'm familiar with 0 sounds and expected targets.  F2 9 will not be something I use often, maybe in a park but that would be all.  I tried a bit of F2 5 and it was much less jumpy on the little swings.  I just didn't feel like the time it would take to switch back and forth would be worth it.  I'd already have dug the target.

I think I should try the difference between B1 and B2 rather than FE or F2.


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I never set F2 above 4, because otherwise our most valueable clad (2€) tends to render ferrous - they're composed out of two different Materials. Even then I still don't feel 100% comfortable I don't miss something... :unsure:

FE on the other hand always felt useless to me, with the kind of targets I have to deal with on my beaches..



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I tested the differences between Iron Bias FE and Iron Bias F2 last year right after upgrading equinox to soft 2.0.

The tests included a field depth test + signal repeatability in 10 sweeps with a coil over a deep target, a separation test..... and tests to eliminate 3 differently corroded bottle caps ...

the results..

1..Train field depth test - Iron bias F2 had much better signal repeatability than Iron bias FE when iron bias was set to a higher value. For example Iron bias value 7 ...... F2 got 7 good sweeps from 10 max. FE had 4-5 sweeps from 10 max ...

when setting iron bias FEa F2 to 0 ... the results were very similar .... with little advantage for Iron bias F2 ..- emotionally ..


2. Highly demanding Separation...." Monte performance nailboard Test" on a 13mm hammered coin .... that's why Equinox is tested on a small 6 "coill" ...

 In this test you can safely set iron bias F2 to the value F2 = 3 .... and the separation results will be reduced by only 1/2 point / 6 points out of 8 points max / compared to Iron bias F2 = 0 ... /6.5 points out of 8 points Max / ..
even the higher setting of iron bias F2 is less aggressive ... on Iron bias F2 = 6 you still get 4.5 -5-points out of 8 points max ...

When setting Iron bias FE, there is only one effective setting, and that is FE = 0 .... where it achieves the results in the separation on a small coin with 6 points out of 8 points max ...

Already when Iron bias FE is set to 1 .... this setting will severely limit the separation ..because you will only achieve 3-3.5 points out of 8 points in the separation ...

 From this separation test it is clear to see the advantages of setting Iron bias F2 ..

IMG_20200903_133545 (2).jpg


3 .Test is a test to eliminate 3 botle caps with varying degrees of corrosion ....

Iron bias F2 set to 4 can eliminate 2 bottle caps out of 3 ....
And when F2 is set to 6-7, it can reliably eliminate all 3 bottle caps.

Iron Bias FE cannot reliably eliminate all 3 bottle caps even with the value Iron Bias FE = 9 max .. still hear parasitic signals as well as mixed ID ..

After these 3 tests I can state ... is Iron Bias F2 is the second and strongly improved generation of Iron Bias settings at Equinox ...


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2 hours ago, EL NINO77 said:

After these 3 tests I can state ... is Iron Bias F2 is the second and strongly improved generation of Iron Bias settings at Equinox .

Very good write up/tests! 👍🏼  Could you also conclude after doing your tests that FE-0 and F2-0 are pretty much identical, meaning a 0 value for either iron bias filter setting is as close to “Off” as one can achieve, or will you still give a slight  advantage to F2-0 with regards to non-ferrous unmasking and deeper iffy targets??

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23 hours ago, Steve Herschbach said:

The chart was originally posted here created from information Tom Dankowski posted based on what he thinks he knows about the control. I’d say based on my simple test that the information is now suspect.


Tom said the new FE2 vastly expands the control range both higher and lower, with the original FE setting spanning the middle of the new range. Tom is equating Iron Bias 0 with the F2 setting of 4 and Iron Bias of 9 with F2 setting of 6. 

However, in my video you can see that a FE2 setting as low as 1 has more effect that a FE setting of 9. The FE2 setting of 2 makes it very obvious. Based on my simple test it looks like a FE setting of 9 is more like a FE2 setting of 0.9

So is FE2 setting of zero actually applying less bias than the FE setting of zero? Tom says so, but my current answer is “I don’t know” until I create a scenario that proves it. That would mean a FE2 setting of zero would have to produce a nonferrous reading on a target that the regular FE setting of zero called ferrous. Right now that seems a poor bet since all FE settings appear to fall in the FE2 region between 0 and 1.

Based purely in my video the FE settings of 0 - 9 appear to equate to FE2 settings of 0.0, 0.1, 0.2, 0.3, 0.4, all the way to 0.9

Or another way to look at it is that if the original FE setting tops out at FE9, then the FE2 setting of 1 would be the equivalent of FE10.

I do appreciate this -- please don't take this the wrong way.  But it has my head spinning.  The diagram (possibly wrong) is easier for me to understand.  So let me ask this (specifically my understanding/intepretation of what you said) and please tell me if I got it right:

Start with the diagram as shown above.  Move the top scale (orignal FE Iron Bias) all the way to the left.  This means the left edges of both zero bins line up.  Then scrunch the FE (top) scale down so that the right edge of the FE (top) scale is just inside the 0-->1 border of the F2 (lower) scale.

Is that consistent with what you've said?

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I did some field testing yesterday in a particular very iron trash rich ~ 20 sq. m. section of a park I've been hunting for five years.  Every IB/VLF detector I own has gotten at least a short workout in this spot.  The first couple years I found the good targets (including a Mercury dime and an Indian Head penny), but since then it's difficult to even find non-ferrous.  I always use this for a tough trashy iron workout and thus playing with the Equinox 800's Iron Bias feature, it seemed like the right place.  Here are the settings used:


In retrospect I should have done a ground grab on all four modes.  I was not getting any ground noise from any set at 0 so just left them there.

My procedure was to set all modes at F2 = 0, search in Park 1, and then investigate in Park 1 with F2 = 9 as well as other modes at both F2 = 0 and F2 = 9.  Here is a photo of the targets I eventually dug after doing those investigations:


Now I list those targets, noting how they sounded and what visual TIDs' they showed:

1) ~3" deep bent aluminum clip (lower center of photo) -- gave a bit jumpy TID around 17 in all four modes.  All gave mainly clean signals regardless of FE2 setting (0 or 9).  I did notice that in Park 1, FE = 9 that I got more iron noise from surrounding weak targets, but there wasn't any confusion given the size and depth of the aluminum target.

2) ~7"-8" deep aluminum foil -- (Note:  this target was likely all in one piece but it broke during recovery.  I tried to remove all of it but possibly a few shards remained in the ground.)  All four modes showed TID's of 7-9 and all sounded good (no iron confusion) at both F2 = 0 and F2 = 9.

3) unknown deep target -- (Note:  I've been fooled by this target so many times that I now know it's location, but I wanted to see what IB changes would do.  From multiple recovery tries -- not this time! -- I get down about 10" and handheld pinpointers tell me there is still more distance (> 2") to go.  Recall I'm in a park so I don't want to dig a grave.)  Park 1 gave a consistent 40 TID with no iron sounds at all.  The other modes gave 39-40, also without any iron grunts.  Strong and seemingly localized signal.  Short of someone burying a silver bar there I suspect it's a large piece of iron farm equipment.  This once was part of a farm lot and I've found many pieces of discarded farming tools, etc.  When I switched all modes to F2 = 9 they still gave no indication or hints of grunting and kept the same TID's.

4) ~6" deep, very rusty iron bracket (lower right item in photo.  The picture doesn't show that the cross section is a flat rectangle, about 1/2" side by 1/8" thick.) -- Park 1 and Field 1 (IB minimized) gave target ID's in the low 20's.  Park 2 and Field 2 said high teens.  I only checked F2 = 9 for Park 1 and Field 2 but both gave noticeable iron grunting then but still showed (now jumpy with negative numbers occasionally mixed in) the same TID's as before.

5) ~3" deep, 5" long square nail near a ~2-3" deep bent, round cross section nail.  (The distance between them was ~4"-5" and I got fooled into thinking this was a single target.  The square nail was pointing towards the bent nail and I think its 'sharp' tip was giving the non-ferrous signal.  The bent nail may have contributed to that, though.)  Unfortunately I didn't record TID's other than noting that with F2 = 0, all gave mixed ferrous and non=ferrous.  When I checked Park 1 and Field 2 (only) with F2 = 9, both just resorted to ferrous tones, no longer showing any non-ferrous.

6) vertical nail, tip up, with tip ~6" deep.  All four modes gave TID's 19-21 without noticeable iron grunts.  With F2 = 9 there was a hint of iron but the non-ferrous was still sounding good.  (Note:  I was never able to recover this so it's not in the picture.  I just wasn't able to break the nail loose as its head was buried much deeper and I was digging in mixed crushed stone and soil.  I was able to feel the tip easily with my bare hand so I know what it was, and estimate it's length as ~3"-4", possibly a 16d size.)

For the other two targets pictured (~1" long finishing nail and a second bent nail) I didn't take notes sufficient to report.

In summary, the two non-ferrous recovered targets didn't false much, if at all, with F2 = 9.  However, they were pretty strong signals to begin with.  Some of the iron (such as the rusty bracket -- item 4) did give more grunting with F2 = 9, but they were already showing that at F2 = 0.  Still, an increase in grunting could help as long as it's for actual ferrous (as in this case)....  The evil vertical nail, IMO, is not one that I would ever ignore at either F2 = 0 or F2 = 9.  In my experience, vertical nails always sound good, especially if the head is up (not the case here).

Bottom line is that my tests don't give Iron bias F2 a gold star for these common relic hunting trash targets.  After performing this exercise I read Steve's post that the overlap of the two scales (original FE and the F2 that was included starting with update 2.x) apparently is different than previously indicated.  If I understand the new comparison correctly it could be that FE could help better ID'ing the targets I recovered under those in-field conditions.  I may have to do another experiment.

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