If M.L. Hinds can't answer the question, then maybe Jbow can................"Viva l'E-Trac".MattR.UK

[MattR]

Mr Hinds, can you please tell the forum what the magnetic permeability is of 'iron' and 'steel', compared to that of silver or copper items.

Then explain how your detector sees THROUGH such ferrous materials, and by your own experiences, 'ignores them in preference to non-ferrous metals.

************************************​

Just for the records; I detect regularly with my E-trac, meeting these ferrous/coins situations often.

By experience and good practice, I find the optimum direction and technique necessary to expose the good from the bad.

My E-trac doesn't see THROUGH the iron, but rather depends on sufficient lines of flux by-passing and reaching the nearby 'coin', but in close conformity to those adjacent lines of fux that are attracted into the iron, .

The dominance then of one target over the other, is a matter of many parameters, all of which are unique to that particular moment in time and place.

NOTE:- The iron can assist in an indirect way, if the object

 

[Rigit]

My E-Track can see through 6ft of lead as well as iron so there!

 

[M.L. Hinds]

The relative permeability of ferromagnetic materials increases as the magnetizing field increases, reaches a maximum, and then decreases. Pure iron and some alloys have relative permeabilities of 100,000 or more. Matt I do not understand why we are carrying this any further I admited that my post was taken out of context because of how I wrote and if you read under that post I posted my mistake! I am an electrician by trade not an engineer.. I do wish I could design such a piece of work but my electronics background it very limited so as far as knowing exactly how every detail works I am limited!! Never claimed to be a rocket scientist just love detecting!!

Have a good day, M.L. Hinds

 

[digitrich]

It's for him to know, and you to find out.......nanny, nanny.....boo, boo

 

[jimpugh]

Magnetic Susceptibilities of Paramagnetic and Diamagnetic Materials at 20

 

[jbow]

n/t

 

[jbow]

You are getting hung up on semantics... it is just a figure of speech... have a pint and go dig up something.

Julien

 

[jbow]

much ado about nothing me thinks....

J

 

[jimpugh]

According to the graph we should be finding fast amounts of Iron .........Now MY Minelab must be defective I should be finding four fold the amount of platinum to the shredded Aluminum targets AND enough Uranium to put the Arabs out of the oil business......Actually it is miraculous these Minelabs defy the laws of physics Now do not be hard on ole MATT he is finding LOTS and laughing all the way to the bank ......after all he is a Good Hunter and has access to world class fields!
Now for a proper Target Who put the HEX on "Beach Combers" Machine......I think if it where mine... I get me little tool kit out and carefully look to see if the power jack was loose or the touch pad membrane connector was Ajar........It would be to much for me to be E_TRACLESS ....

Happy Trails
Jim Pugh

 

[Jim upstate NY]

its a matter of being to see one while rejecting another at the same time.. There is no doubt that you can get a good clean coin hit in some situations on a coin near iron if you have enough iron accepted. However there is also no doubt that a signal coin near a nail that the two are seen as one, and a balance of ferrousity of the two is shown... The secret is getting to the point of where you can get the coin to sound better than the nail, without having a nail to sound good too. I keep trying to get to that balance, but the best results in air test are no good in the field, even if you can tell on most nails after playing around enough, it still is very distracting to hear a good tone every swing and even 4 or 5 decent hits in some of my spots..

FE 30 seems to be the spot that the nail will crackle in air tests and the coin will read solid, but in the field the nails hit pretty darn good with it opened up that far.. When I have the screen accepted up to 30 the coins surrounded by nails generally hit 29-46 of course they bounce around also, but no way you will get a signal at all except perhaps a blip that sounds like any other false in coin mode. So if your hunting in the iron you have to accept as much as possible without driving you nuts.

With the Explorer in iron mask I could accept all but one line of open screen and still get mainly low tones on iron with an occasional high tone while in FE audio. being limited to the 2 or 4 tones on the Etrac hurts in this case, because it seems both coins and nails bunce around about the same when mixed together with the Etrac. if you see what I am saying.. It was much much easier for me to tell a coin from an iron iffy... now I can only listen to a couple tones and they seem to be about the same, especially opened up to only one notch of disc.

Now it does seems to me that the Etrac does a better job of locking onto coins in iron, but also reads nails in the coin range more often, and its just too bad they have such close conductive values.

I am wondering why Minelab chose 12 as the FE readings for coins, I think if they read up in the 01-04 range, that we could reject more iron and they would not average so low, this less iron falses when running just iron reject.


if single nails read 34 and coins read 12, then the average of the two is 23, and that is exactly the reading I am getting on a lot of the coins I have found in iron are reading. in tests with multiple nails I get them as low as 29.

So it makes sense to me that if coins read even 4 FE, then the average would be 18 and maybe get down to the 23 in extreme cases, but if we can reject 27 even, that cleans up many of the nails that hit very solid in many cases.

Anyway I am running Conductive now, I cant seem to find a good way to use fe.. I still dont know why they took the multii mode FE audio away... I dont see any point of them doing that... surely its possible since it can do it in conductive.. even if they think its not the way to go.. let us decide what we like, and audio tones in FE would not affect in the least for people that use conductive anyway

 

[jbow]

Why don't you jump up where the sun don't shine... leave my name out of your posts. You know full well what was being said and chose to make an issue out a non-issue.

J

 

[vlad]

Iron or steel is the frequency of the detector, and operating method.
Check with Steve(MS) on his extensive testing using an older Compass at a very high frequency
that will detect a coin when surrounded by nails on all sides, and nails above & below the coin.
He has a test scenario using the above parameters that exemplify this perfectly.
You do not need to be an engineer to see quantifiable results in a test anyone can do.
But I must give credit where credit is due; Matt is the best person I know when it comes
to masking truths in the same manner a trash target might mask a good target. And he is,
by his nature and to this I must also give praise, overly generous-every time he opens his mouth
he shows his ignorance.