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Detector Technology and Electronics and new detectors => Detector Coils => Topic started by: Doug on Friday March 1 2019 10:21:26 AEDT AM



Title: Coaxail coplanar coils for Pi's?
Post by: Doug on Friday March 1 2019 10:21:26 AEDT AM
Coaxail coplanar coils for Pi's?
What are the pro's and the cons?
doug ::419::


Title: Re: Coaxail coplanar coils for Pi's?
Post by: Dontbstme on Friday March 1 2019 17:08:50 AEDT PM
  
Coaxail coplanar coils for Pi's?
What are the pro's and the cons?
doug ::419::
Only folks who used them would be able to say something beyond the theories. I'm curious.


Title: Re: Coaxail coplanar coils for Pi's?
Post by: WM6 on Friday March 1 2019 21:12:04 AEDT PM
  

Coaxail coplanar coils for Pi's?


Coaxail versus coplanar  or  Coaxail and coplanar at the same time?

Do we even know what is such coil design (construction)?

Are there any drawing (intersection) of such coil, to speak about the same design?


Title: Re: Coaxail coplanar coils for Pi's?
Post by: Dontbstme on Saturday March 2 2019 03:01:09 AEDT AM
  
  

Coaxail coplanar coils for Pi's?


Coaxail versus coplanar  or  Coaxail and coplanar at the same time?

Do we even know what is such coil design (construction)?

Are there any drawing (intersection) of such coil, to speak about the same design?

In the IB detectors the coaxial coplanar coil is a system that consist of usually round loops 3 or more that are of the same diameter and placed above each other forming a construction that resembles a cylinder. It can be made with 2 TX, 1RX or the other way round.
They suffer similar ground noise problems as CC on IB detectors.
I have not designed or made any of these as they are not practical for sales due to bulky appearance.

By the basics of their construction the coaxial coils will have one distinct advantage to all other IB coils short of the two box system. The coaxial arrangement can eliminate the near field ground interference (the positive field) making these coils to work much like a mono coil on PI, but this will inhibit the discrimination severely as all IB detectors need this near field interference zone to produce accurate discrimination.

I can not possibly see what benefit these coils can add to the PI performance, but then I am no expert on PI.


Title: Re: Coaxail coplanar coils for Pi's?
Post by: Doug on Saturday March 2 2019 09:48:20 AEDT AM
Came across this.Might be in the wrong thread?
Active induction balance method for metal detector sensing head utilizing transmitter-bucking and dual current source
https://iopscience.iop.org/article/10.1088/1742-6596/450/1/012047
doug ::419::


Title: Re: Coaxail coplanar coils for Pi's?
Post by: IBGold on Saturday March 2 2019 16:15:49 AEDT PM
Hi Doug,

I have built an 18" one to Aziz's formula a few years back and tested it while testing the QED,s in actual goldfield conditions and did not find any distinct advantages and its bulk was its main disadvantage so I did not go any further I will post a picture if any one is interested as it is still sitting in my workshop.

I have also built a few non induction balanced ones that were Erik or Dave Emery's formulas from memory they were quiet good but have not been fully tested yet too many projects I seem to get derailed.

Regards, Ian. ::62::


Title: Re: Coaxail coplanar coils for Pi's?
Post by: Dontbstme on Sunday March 3 2019 01:56:17 AEDT AM
  
Came across this.Might be in the wrong thread?
Active induction balance method for metal detector sensing head utilizing transmitter-bucking and dual current source
https://iopscience.iop.org/article/10.1088/1742-6596/450/1/012047
doug ::419::
I believe this article is related to another that you have posted a month ago on another thread.
They claim to have resolved the high mineral interference issue with IB detectors.