Anyone Know The Truth About Fe Numbers?

[MHirschmann]

I have read quite a bit about Fe numbers not always being accurate. Quite a few people have mentioned that the conductive numbers are far more accurate/stable. We all know that numbers can sometimes be inaccurate/unstable when a target is deep/small but thats not what I'm talking about. When a target comes up at Fe 18,19,20-Co 45, would you dig it or walk away? I hunt primarily with my ears and use my eyes only to support what my ears are telling me. One thing that I have noticed is that lately I have been digging more "iffy" Fe numbers. I don't know if I have just been getting lucky on a few occasions or if it's really true that Fe numbers are not nearly as accurate/stable as Co numbers. Either way, I will always primarily be an auditory hunter, it would just be interesting to know if there is truth to the occasional inaccuracy of Fe numbers as I often use the visual input of my machine to make my "to dig or not to dig" decision. I would really appreciate any input. -Marc

 

[JJ]

fer

 

[Southwind]

I think all of us hunt by sound and then use the numbers, to varying degrees, to determine to recover or not. Myself I pay little to no attention to the FE numbers. On shallow targets that rear 12-12 I will recover based on the FE but not on the deeper stuff.

 

[Ken in Georgia]

The G2 has the same Fe reading for all metal, it will help you id gold or try to help anyway.

 

[EtracTom-AdirondacksNY]

I'm in Southwinds camp here I don't care at all what the ferrous number is. I only go by sounds and the co. no. hints at me what my target may be and the cursor location when I flip to wide open quick mask to get a better cleaner reading on the signal/sounds and then lastly the cursor location while in pinpoint mode I will give a quick glance at to concur while hunting in coins discrimination mode.

I have seen that cursor while in pinpoint mode be at the bottom right hand corner hiding out in all that black in the coins discrimination mode telling me it may be iron so that is one of the reasons I go into quickmask wide open to double check. Sometimes I do it before pinpointing and other times after depends on what the other things are telling me about the target.

Remember in Andy's book he said that targets that were good fell to as low as FERROUS 27 on that scale/screen so that is way down there and your only seeing ferrous 18-19-20 you stated so got a deeper ways to go yet. Flip to quick mask wide open and then see what it reads and the cursor does. If it goes to the far bottom right hand corner and stays there while sweeping over the target it is most likely iron. If it's up off the bottom by 1/4 of the way or more higher up or tries to bounce up higher towards the middle area of the screen it may be a good target dig it at least that is what I have found in the soil around here and it usually is a coin lots of times wheaties or silver corroded over trying to fool you .

 

[MHirschmann]

Thank you everyone for your input. I will try digging more of these random Fe valued targets and I will let you know what I find. I really appreciate all the help on here all the time. I also really wonder what I may have been skipping over by trusting my eyes over my ears when it comes to these random Fe values. Sure will be interesting to find out. Thanks again and happy hunting! -Marc

 

[NebTrac]

Each site can be different Marc. The only way one can tell for sure is to dig some "iffies" and evaluate your target or Fe level there. I run Andy's program, so my Fe is open down to 27. Most of the time if it drops below 20, the target is a bent nail, fencing staple or rusted barbwire. BUT, I have had coins come in with a Fe of 27.

So there are places for sure I'll dig a +20 Fe and places I won't. Only after digging some there to confirm.

NebTrac

 

[MHirschmann]

Thanks NebTrac, I also usually run either Andy's coin program or TTF. Your approach with "sampling," if you will, makes sense. I will give it a try and see what happens. Merry Christmas to you and everyone else on here! -Marc

 

[moonshine]

When a target comes up at Fe 18,19,20-Co 45, would you dig it or walk away?

If it was repeatable and had some depth I would dig that target every time. I would imagine what you would really see is something like 18-45, 15-44, 22-45, 14-45, 15-44, etc. but it would be a nice repeatable signal. i would be all over that target. at least, from my experience this past season, some deeper targets do that. i would almost just disregard the numbers completely and just listen to the machine.

 

[DirtAngler]

The Etrac is kinda based on the FE 12 line. That being said though, the ferrous number like the conductive number are not always going to be accurate due to many variables. With both numbers you have to allow for a margin of error and experiment with digging until you have a grasp of what you think they are telling you. Sound first, meter to try to verify. JMHO.

 

[EtracTom-AdirondacksNY]

Right but the 12 line I believe is based on the conductive range scale going across opened to a range of 50 from 32 from the Explorers to give us a better ID on targets so they are more spread apart. Somewhere on here or in Andy's book he says that the cond and fe numbers mean nothing that it was just a way to for Minelab to quantify on the screen in a grid mask format so you have something to see or use for possiable idea. Just like most all other detectors do horizontally across their screens for instance Whites machines for target reference idea no ferrous number on any of these other detector manufacturers machines just conductive numbers for an idea of the target.

 

[TheMarshall]

Right but the 12 line I believe is based on the conductive range scale going across opened to a range of 50 from 32 from the Explorers to give us a better ID on targets so they are more spread apart. Somewhere on here or in Andy's book he says that the cond and fe numbers mean nothing that it was just a way to for Minelab to quantify on the screen in a grid mask format so you have something to see or use for possiable idea. Just like most all other detectors do horizontally across their screens for instance Whites machines for target reference idea no ferrous number on any of these other detector manufacturers machines just conductive numbers for an idea of the target.

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Regarding the emphasized parts in the above quote.

If Andy did make that comment then he is either over generalising on the significance of the Fe/Con indicators, or not understanding too well ,their derivation.

You must understand the basic fact of a metal detector's functionality.

It is that a detector reports on what it senses in its TOTAL magnetic sphere of transmitted flux.

That is NOT what is commonly, (and misleadingly,) shown as a conical shaped image/field..

It is a larger, 'circular' field of magnetic flux.......'like an aura surrounding the search-head.

So therefore.....the Fe and Conductive numbers represent the TOTAL summation of the two electrical properties of the enveloped MASS....

That MASS consisting of ground and target resistance, and the ground's magnetic properties due to Ferro contents and mineralisation, plus the targets own Power-factor (phase).

That is a heavy, rough, definition of what's involved.

A Whites detector has the same raw data in its X and R channels, but displays it in a different, less sophisticated, way/presentation.

0 to +94 indicates the conductance of the 'sphere of detection and all targets within it'

-1 to -95 represents the 'inductive' influence of the progressive dominance of any ferro components of target and ground, combined.

That is a short over-view of what these numbers are about.

Anyone who says the numbers are meaningless, has some way to go, in improving his understanding of metal detecting principles.

I'm still learning after almost 45 years of the hobby.

TheMarshall.

 

[TheMarshall]

Moonshine. In my opinion, you have expressed the business of TTF (or ?TF) in a concise and accurate way

"Well done", and I hope folks take it on-board as they see fit, to compliment their preferences and experiences.

Detecting methods are a culmination of many variables for each individual and location, so whilst basic principles don't change much, environmental condition do, and it is wise to be aware of the alternative ways to combat those.

I am impressed by the level of thoughtful opinions and comments of the E-Trac forum participant's.

May any difference in opinions between us, never be allowed to detract from the goal of seeking more knowledge.

Thanks to all......TheMarshall....Matt