BEST DISPOSITION TO BUILD A COIL

[Marcello]

http://www.thunting.com/geotech/forum/tech/images/COIL2.jpg


WHICH IS THE BEST DISPOSITION TO BUILD A COIL FOR A METAL DETECTOR VLF? (IN PHOTO I HAVE REALIZED TWO PROTOTYPES FOR THE MAGNUM).

THANKS!

[Dave J.]

Of the two you show, I recommend the 3-coil coplanar system. It'll be more stable than the "kinked transmitter" design.

You'll get slightly better sensitivity and stability if you increase the diameter of the inner reverse-field transmitter, which is usually called the "feedback coil", so that it almost touches the receiver.

--Dave J.

[Marcello]

Thanks,
does he know me to say if there are formulas for the approximate calculation of the diameters of the coils, to get the maximum sensibility?
or the ideal position?