COIL Question for Reg.

[Frank-S]

Reg. you made a lot of coils,if you go from a small coil say about a 8'' coil and go to a 12'' or 18''
coil does the induction stay the same or increases, VLF or PI. Thanks
Frank.

 

[Dave J.]

I ain't Reg, but I've designed a few coils.

The inductance is proportional to the circumference of the actual winding, and to the square of the number of turns on the winding. This is skinny-winding air core coils of elliptical, D, or round shape like in searchcoils, not things like solenoids or ferrite core coils. The relationship isn't exact, but it's almost always a good starting point.

After you've wound the coil, then you throw an L-meter on it and see how ya done.

The resistance should also be close to that of the factory coil. In the case of single-frequency VLF type machines, it usually needs to be pretty close. Most multifreakers, not quite so critical. Most PI's can tolerate quite a bit of variation in resistance.

With induction balance searchcoils, the receiver winding inductance may or may not be critical depending on the machine. However the resistance usually isn't critical.

--Dave J.

 

[Frank-S]

Thanks Dave,
I have been trying to make a larger coil for my Troy X5, It has a small 7'' coil it will
detect a nickel at 14'' air test.Been trying to make 12'' coil go deeper,useing same induction
as 7'' coil,it has no PRE-AMP.all the coils i made will work,but they will not go deeper than
the 7'' stock coil,also used larger and smaller magnet wire. Also used more inductions (more turns of wire
and less turns of wire) and less inductions.I get the almost same dept.not deeper.
Thanks again for your reply
Frank-S