This Schematic need to try

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http://www.aa5tb.com/loop.html

https://www.e-magnetica.pl/doku.php/al_value

https://ozdisan.com/p/884?ids=10336;495510&groupids=10336&propids=495510&sayfaAdedi=20

https://www.atd-shop.com/x1610-en/ferrite-core_-b65805j0000r087

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I agree with shielding from noise. But then you need to change the power. Otherwise, the screen will become an element of Antena. I liked the idea myself, and the principle of work looks like an IHA-1 device, but a mortgage and mee are inevitable. I think that if the generator is adjusted to the frequency of 700-900 Hz, you can try to look for voids.

I think that with distance between Antenna to circuit this problem will solved , or also so will not be affected , need to Try for best position .
Yes this circuit can use for search Voids , also with using different Frequency posible is Find of
precious Metals. Need to Try .
In Realy I not build it , I only created this Sch and tested with Simulation , Works wery well .