Depth test

[ghound]

I'd say 12" coins are a rare wild dig, i've one field where the soil is good and i dig coins to 10" no problem.
I've a test pit at home, the type with holes drilled in horizontal at different depths so as the soil is undisturbed.
I can get a solid signal you'd dig on small dime size silver at 8", bigger coins at 10"
When you start to go deeper say 12", it takes very little to mask the coin, but i also find i can hit the same depth coins better in my test garden that's been there a fair few years.
Some detectors can do better in disturbed soil, as in a freshly buried coin, than others.

 

[woodbutcher]

Im gonna say something,and this is not my uneducated guess,this comes straight from electrical and magnetic engineers with degrees in this field,with metal detector r and d.. if anyone takes the time to look it up and read it,then a lot of uneducated guesses would end.
A coin,trash,gold ring,etc is penetrated by what's called a eddy current,which is then passed back to the coil and the brains of the machine tells you what conductivity the metal is..Key word here is penetrated..it is absolutely impossible for the eddy current to penetrate ground that's been bled into and a (halo) created..It must be a solid form for the eddy current to penetrate it,,and report back.
And yes I'm absolutely saying a fresh coin picks up better than a old buried coin,and that's not my uneducated guess either,comes from the same electrical and magnetic engineers saying it.
And a deus,f75,v3i,impact or racer don't stand a chance at a 12 inch coin undisturbed.Maybe a multi frequency like a Minelab with a large coil possibily,but no single frequency machine will.A lot of fish stories goin on,,and when you think you got a 8 inch coin it's really 6 inches,,I'm guilty of that myself.

 

[Florida Tabdigger]

One day you will dig a 9+ inch coin and scratch your head wondering how that happened.

 

[ghound]

I can show you my detector picking up a fresh buried 12" coin no probs. My wife has an hounors degree in engineering, works for a top US firm, but she's the last person i'd ask advice on metal detecting lol.

Im gonna say something,and this is not my uneducated guess,this comes straight from electrical and magnetic engineers with degrees in this field,with metal detector r and d.. if anyone takes the time to look it up and read it,then a lot of uneducated guesses would end.
A coin,trash,gold ring,etc is penetrated by what's called a eddy current,which is then passed back to the coil and the brains of the machine tells you what conductivity the metal is..Key word here is penetrated..it is absolutely impossible for the eddy current to penetrate ground that's been bled into and a (halo) created..It must be a solid form for the eddy current to penetrate it,,and report back.
And yes I'm absolutely saying a fresh coin picks up better than a old buried coin,and that's not my uneducated guess either,comes from the same electrical and magnetic engineers saying it.
And a deus,f75,v3i,impact or racer don't stand a chance at a 12 inch coin undisturbed.Maybe a multi frequency like a Minelab with a large coil possibily,but no single frequency machine will.A lot of fish stories goin on,,and when you think you got a 8 inch coin it's really 6 inches,,I'm guilty of that myself.

 

[Florida Tabdigger]

How solid is solid enough to absorb or reject an eddy current. Coal is not very solid and will give a signal. I have dug wheats that have leached into the surrounding soil and left a brown crystalline area extending a half an inch around the coin. It is this not-so-solid area that increases the target size to the detector. That is your halo effect. In the last 20+ years of hunting, I have only found about 3 maybe 4 coins over 9 inches. Which is why you won't see myriads of you-tube vids finding them unless they have been planted. A couple weeks ago I found a 1943 GW that had been buried for over 70 years and it was barely 3 inches deep. Coins usually don't settle so deep. But one day you will find one that is, and all that technical information isn't going to explain why.

 

[woodbutcher]

How solid is solid enough to absorb or reject an eddy current. Coal is not very solid and will give a signal. I have dug wheats that have leached into the surrounding soil and left a brown crystalline area extending a half an inch around the coin. It is this not-so-solid area that increases the target size to the detector. That is your halo effect. In the last 20+ years of hunting, I have only found about 3 maybe 4 coins over 9 inches. Which is why you won't see myriads of you-tube vids finding them unless they have been planted. A couple weeks ago I found a 1943 GW that had been buried for over 70 years and it was barely 3 inches deep. Coins usually don't settle so deep. But one day you will find one that is, and all that technical information isn't going to explain why.

Florida tabdigger,just google how metal detectors work,and get ready to read some very good information.Im not a know it all,but I do read and get expert information on how things work.Itll all come together for you and make more sense when you read ..hey,and maybe it'll help you understand more about your machine,and lead to more finds? It can't hurt to read up.
And I have dug many coppers that left large black stains in the ground ,but that is not what my machine hit on,it hit on the coin.Unless the eddy current penetrated a solid metallic object it will report nothing.And hot rocks are solid magnetic objects.

 

[woodbutcher]

I can show you my detector picking up a fresh buried 12" coin no probs. My wife has an hounors degree in engineering, works for a top US firm, but she's the last person i'd ask advice on metal detecting lol.

I will agree a machine will pick up a fresh buried 12 inch coin..no question.But my point is a coin dropped 100 years ago,say in 1917 and has sunk to 12 inches for whatever reason,and has been undisturbed,,,you will never even get a peep on it.
I don't and never claim to know it all,don't want to know it all.lol..but I'm sure on this fact,if someone's digging a 12 inch coin it's fallen back in the hole a few times.

 

[Florida Tabdigger]

Eddie currents penetrate everything. If it gets absorbed then it's Ferris (iron), if it rejects, not absorbed, then it's non-Ferris. That's why the older machines with the meter either went one way or the other. You didn't touch on coal. It's non metal, why does it respond? And why does moisture effect it's response? Why does salt effect eddy currents? Ever swept your detector on a saltwater beach? It doesn't take a solid object to effect eddy currents. As I stated earlier, you will eventually learn from experience that not all signals are from solid objects and soil conditions effect it very much. You HAVE come across as a know it all, to the point where you said I am kidding myself and that I don't know 6" from 9". I'm telling you, eventually you will be a believer. Just need more time in the field.

 

[woodbutcher]

Eddie currents penetrate everything. If it gets absorbed then it's Ferris (iron), if it rejects, not absorbed, then it's non-Ferris. That's why the older machines with the meter either went one way or the other. You didn't touch on coal. It's non metal, why does it respond? And why does moisture effect it's response? Why does salt effect eddy currents? It doesn't take a solid object to effect eddy currents. As I stated earlier, you will eventually learn from experience that not all signals are from solid objects and soil conditions effect it very much. You have come across as a know it all, to the point where you said I am kidding myself and that I don't know 6" from 9". I'm telling you, eventually you will be a believer. Just need more time in the field.

Not the way I read it. No eddy current Is rejected?Salt does not rejest a Eddy current, you are confused.Eddy current is what penetrates the metal, not necessarily the outgoing or incoming signal.

 

[Florida Tabdigger]

Normally I would not participate in this kind of tit-for-tat argument, but your misleading other members who are following. If non-medal objects did not respond to the detector, then why make a pulse induction units for salt water? Salt isn't metal. It's all about conductivity, not just, is it metal or not. Why does a rusty nail give a non-ferrous reading in the ground and once dug, not? And that wrap-around term just irks me. It's the oxidized area around it, halo, that rejects the Eddie currents that gives it a non-Ferris signal.

 

[Florida Tabdigger]

The detector receives back a difference of what is sent out. It knows what has been absorbed, and what has been rejected. Gold has no, or extremely little magnetic properties. Iron absorbes it well and will become saturated. Oxidized soil will not saturate. Therefore the false non-Ferris signal.

 

[Florida Tabdigger]

I'm growing weary of this argument.... I bow out, you win.

 

[woodbutcher]

I'm growing weary of this argument.... I bow out, you win.

10 4. Me too..good luck

 

[BottleCapKing]

How solid is solid enough to absorb or reject an eddy current.

What is a "rejection" of an Eddy Current? I don't believe this topic was ever covered in my Electomechanics or Electromagnetics classes. I did skip class more than I should have, so I may have been absent that day.

 

[Florida Tabdigger]

Good luck to you too.

What is a "rejection" of an Eddy Current? I don't believe this topic was ever covered in my Electomechanics or Electromagnetics classes. I did skip class more than I should have, so I may have been absent that day.

Nooooo!!!!
I'm done.

 

[ohiochris]

Perhaps yours, not all.

It will vary a little depending on soil type , but all vlf detectors operate the same basic way and Ive had quite a few over the years. The point is , long buried coins can be detected deeper than fresh buried coins. While there is at times some disagreement as to exactly " why " , ...the principle is a well known fact.

 

[ohiochris]

Normally I would not participate in this kind of tit-for-tat argument, but your misleading other members who are following. If non-medal objects did not respond to the detector, then why make a pulse induction units for salt water? Salt isn't metal. It's all about conductivity, not just, is it metal or not. Why does a rusty nail give a non-ferrous reading in the ground and once dug, not? And that wrap-around term just irks me. It's the oxidized area around it, halo, that rejects the Eddie currents that gives it a non-Ferris signal.

Metal detectors are in reality " conductive mineral detectors" , since metal is a concentration of conductive minerals it happens to stick out above the interference from the background minerals contained in the soil itself.....and that's a "simplified" explanation of why metal detectors work the way they do. When base metals leech out from a target in the ground it changes the conductive profile of that target enough that it appears larger and will often if not always return a better signal to the detector.

Then , there is also the issue of how the metal target reacts to other minerals like salt , and what that does to the signal coming from the detector. And how mineral saturation can really screw with a raido signal.

 

[ohiochris]

Im gonna say something,and this is not my uneducated guess,this comes straight from electrical and magnetic engineers with degrees in this field,with metal detector r and d.. if anyone takes the time to look it up and read it,then a lot of uneducated guesses would end.
A coin,trash,gold ring,etc is penetrated by what's called a eddy current,which is then passed back to the coil and the brains of the machine tells you what conductivity the metal is..Key word here is penetrated..it is absolutely impossible for the eddy current to penetrate ground that's been bled into and a (halo) created..It must be a solid form for the eddy current to penetrate it,,and report back.
And yes I'm absolutely saying a fresh coin picks up better than a old buried coin,and that's not my uneducated guess either,comes from the same electrical and magnetic engineers saying it.
And a deus,f75,v3i,impact or racer don't stand a chance at a 12 inch coin undisturbed.Maybe a multi frequency like a Minelab with a large coil possibily,but no single frequency machine will.A lot of fish stories goin on,,and when you think you got a 8 inch coin it's really 6 inches,,I'm guilty of that myself.

Honestly...... you have gotten some bad information somewhere.

Experience with metal detectors appears to prove exactly the opposite , ......consistently.

 

[woodbutcher]

Honestly...... you have gotten some bad information somewhere.

Experience with metal detectors appears to prove exactly the opposite , ......consistently.

Nope. Not bad info at all. Its all on the web, and its all the same report from various sites.My experiences are exactly what I've said and read, but I won't debate because yours ate probably different experiences, and that's cool.Whatever works right.

 

[ohiochris]

Nope. Not bad info at all. Its all on the web, and its all the same report from various sites.My experiences are exactly what I've said and read, but I won't debate because yours ate probably different experiences, and that's cool.Whatever works right.

One of these days I am gonna have to see those reports backing your position , but to this day even though I have been on the internet since it first began and have been detecting 20+ years I haven't seen anything like that ....only the opposite. But I will drop it though , not worth arguing about