Can pinpointer detecting thin chain?

[Nupi]

Hi, Polymer.
I'm doing well, thanks.
I am now busy with other things.

"Does anyone else happen to have this problem?"

I do not know if it's a problem if you looking for a good thermometer then it's a blessing.
I have also slightly affected by but not extreme.
I'm not sure but it would also be the type of ferrite that you are using.

[Polymer]

Hello Nupi,

Thank You for your reply.

I will be trying different ferrites once I get them and new wire ( I have ran out).

One thing has puzzled me for a while, but I never asked. It is regarding L1 (1600µH) + L2 (330µH) = 3300µH in your wonderful drawing.

Are not Inductive things added in series? Like the result should be 1930µH ~ 2mH.

What have I not understood here

Thank You Nupi,

[chemelec]

It Doesn't Work that way, When Both windings are on the Same Ferrite.
Or also when Two Inductors are placed Close Together.

[Nupi]

Hello Nupi,

Thank You for your reply.

I will be trying different ferrites once I get them and new wire ( I have ran out).

One thing has puzzled me for a while, but I never asked. It is regarding L1 (1600µH) + L2 (330µH) = 3300µH in your wonderful drawing.

Are not Inductive things added in series? Like the result should be 1930µH ~ 2mH.

What have I not understood here

Thank You Nupi,

Hi Polymer,

"Are not Inductive things added in series? Like the result should be 1930µH ~ 2mH."

That is correct if they are connected in series and have no magnetic interconnection with each other. But in the pinpointer the coils do have a magnetic coupling with each other.

SERIES INDUCTORS WITHOUT MAGNETIC COUPLING
Ltotal = L 1 + L 2

SERIES INDUCTORS WITH MAGNETIC COUPLING
When two inductors in series are so arranged that the field of one links the other, the combined inductance is determined as follows:
Ltotal = L 1 + L 2 + 2M

On this website I think they explain in an understandable way how it works.
Regards, nupi.


http://www.electronics-tutorials.ws/...inductors.html

[Polymer]

Thank You Chemelec & Nupi for your replies!
I now understand and calculated a similar number with k=1 Yippee ...

For future reference: it is called "mutual inductance"

Most pages I found did not show how to figure out M, so I'll jot it down here:

M = k times square root of (L1timesL2) How the hell do I get math notations in here?

k can be from zero to one. k=0 is no mutual inductance & k=1 is complete mutual inductance.
I used 1 for the NUPI coils on ferrite core and got 3384uH as the result.

SERIES INDUCTORS WITH MAGNETIC COUPLING
When two inductors in series are so arranged that the field of one links the other, the combined inductance is determined as follows:
Ltotal = L 1 + L 2 + 2M

Hope this is understandable.

Happy Tinkering

[Qiaozhi]

M = k times square root of (L1timesL2) How the hell do I get math notations in here?

You need to use LaTeX. It's embedded in the forum.

For example:
Enter: [latex]M = k * \sqrt{L_1*L_2}[/latex]

to display:

Syntax guides can be found here:
https://en.wikibooks.org/wiki/LaTeX/Mathematics
and here:
https://wch.github.io/latexsheet/latexsheet.pdf
https://wch.github.io/latexsheet/latexsheet-a4.pdf

[Polymer]

Thanks Qiaozhi. Great! I will try it now.

Total Inductance =

Mutual Inductance M:



Can I preview this message to see if it works without having it put up in the forum straight away?

[Qiaozhi]

Thanks Qiaozhi. Great! I will try it now.

Total Inductance =

Mutual Inductance M:



Can I preview this message to see if it works without having it put up in the forum straight away?

Yes - click on the Go Advanced button. There is a Preview Post button there.

[Qiaozhi]

Total Inductance =

Note you can use "\pm" for plus/minus and "\mp" for minus/plus.



Also to add some white space, you can use "\ ".

[6666]

Hi ionut_mtb

did you make the pinpointer ?

off topic but, I cruised on Carnival legend in Nov 2015, nice ship, and in Feb this year went back to Isle of pines on Pacific Jewel.

[ionut_mtb]

hello 6666, hello guys.
yes i made the pinpointer, i found a picture in my comp, attached,
I also insert this inside a pvc tube and one potentiometer (500ohm- for sensitivity) with knob outside where battery is. I had same problem with temperature, unstability when touching the cold ground/mud, needed adjustment. Two outside pot's is good solution. After i brought deus and did not make any other projects, it's easy to pinpoint, just dragging the coil over the target and see where the signal stop. and the target is in front of the coil.
I would like to try malish fm2, as does not need external adjustments. more stability but not so sensitive like nupi.
regards!

[Polymer]

Hi ionut_mtb,

I like the compact build of your nupi PP!

I received my hollow ferrites and will be playing around with those.

I have extensively used my Nupi PP in temperatures from 0°C to 25°C in the meantime.
A great help for me finding good stuff!

Everytime the sun comes out between clouds, I have to re-adjust & vice-versa.
I am using external 1k & 50k multiturn pots at the moment.

I do get great distances on a nickel & gold ring (14-16cm) on my test bench, but it is not very stable.

I'm looking into how to deal with or counter the extreme temperature drift I have and find the main causes (Coil, ferrite, capacitors, transistor).

@NUPI: can you offer some insights into this?

I tried to understand how this oscillator works. It seems like a Hartley but not exactly , so I am over my head here ... any explanations?

Thank You, have a great day!

[Polymer]

Hello Nupi,

You may not have read my last question or maybe have no time or interest.

I am experimenting with getting the temperature drift down considerably with simple methods, but
my electronics knowledge is just not good enough.

Since this is not a publicly open forum, do you mind if I post your schematic with questions on an
open electronics forum?

[bklein]

Yes sure. Cooper, silver, iron chains can be found even if they are relatively small. But to gold chains without heavy lock, ring or medallion on it at least smaller 4 mm. wide we have so say bye bye.
May be some $4000 nugget detector can see gold chain 3.5mm or 3 mm. or even 2.95 mm. wide. I have no one and can't test.
I guess using such nugget detector to look for small gold chains first let you find all bits of aluminum foil starting 2-3mm in diameter.

Hey, how well do nugget detectors like goldbug, GMT, various minelab gold detectors do with a gold chain? The Minelab propointer sucks detecting gold nuggets so I asume bad with chains.

[Nupi]

Hello Polymer,

Sorry, for the late response.
It's not that I have no interest to answer your questions.
I have not received notice of Geotech that there was activity, or I have not seen it.
I always answer the questions they ask me or they must behave like *******s a**h***s.
I have not been on the "Thread: Can pinpointer detecting thin chain?" for a long time but often at the forum and have posted the necessary crap!!
So the next time if I do not answer within a week, please send me a personal message, okay?
To answer your first questio.
" I'm looking into how to deal with or counter the extreme temperature drift I have and find the main causes (Coil, ferrite, capacitors, transistor). @NUPI: can you offer some insights into this? ".
---- My first problem is that my electronics knowledge is not so big to explain clearly all the details.
---- My second problem, and probably the biggest, is that my English is
not so good to explain clearly all the details.
What I can say is that the oscillator is a derivative of a Hartley and that the coil is sensitive to temperature variations also because of the few turns which the coil counted.

But those who can explain more with certainty, the are the following persons:
Carl-NC, Teleno, Ferric Toes, Davor, Skippy, Dave J., Qiaozhi....................
There will certainly be more, but these are a few that come to mind I think that want to help you.

" Since this is not a publicly open forum, do you mind if I post your schematic with questions on an open electronics forum? "
I think that is fine, if you its origin mentioned. (http://www.geotech1.com/forums/showt...345#post224345)

P.S. I'm working on a new version of the PP in SMD pieces will be smaller and more stable.
Then I want to start the project VLF / IB M.D. for Geotech forum which will have the qualities of the previously described detectors that have been appointed / discussed in this forum. This is a big project and I need to have help. First to answer the questions in clear and good English, therwise it will be impossible to let it become a success. This is also how to continue my health.
Have a nice weekend.