Homemade coil

[Reg]

Re: Eric: Coil Question?

Hi bbsailor,

I deliberately do not critically align my coils so minor movement doesn't hurt. I will lace the two windings together at the crossover points using either synthetic sinew, or a small plastic tyrap. This will keep most everything in the proper place. I am careful to use a tywrap that has no metal in them. Some do.

DD coils for a PI are very forgiving in many ways as long as the damping is correct. Usually, I have a couple of usecs extra headroom so if things do change a little, the coil will still work just fine.

Reg

[Kev]

Re: Homemade coil

Hi Rob,
I've tried to find a proper datasheet for Epiglass epoxy products without much joy, have you any idea what constant this material displays.

I may need to buy some and check it on the TDR. It comes in large cans though, so I'm stuck with it if it proves to be hopeless.

Tis true, any detectors only as good as its coil. We see it even with the top of the range Minelab units, they can all be tweaked with the addition of a well designed target specific coil.

Cheers
Kev.

[Robby_H]

Re: Homemade coil

Hi Kev,
I can't help you with info on Epiglass. A quick Google didn't reveal a website. Epirez is at...
http://www.epirez.com.au/driver.asp?page=main/products
You have to wade thru a lot of stuff to get the info needed but it isn't stated for most of their products and the old tins in my shed have numbers that are no longer listed on their site.

I measured a large stock of Minelab pi compatible coils and the variation is much more than one would expect. The crystal mod on a 2000 can show the difference in coils rather well at the higher frequency/shorter delay settings and these would benefit if a coil was made specifically for them.
On another note, I just inherited a huge roll of what appears to be metalised plastic (originally 12857mt x 1mt!) which is only conductive on one side. A quick attempt at introducing static failed but the air is quite wet here at the moment. A piece approx 1' square gives a reading between corners of around 10 ohms and doesn't give a signal above the electrical interference here on a 2200 so will have to go bush to re-check this. The cro shows that this 1' sheet has at least a 6usec decay but needs checking further to see how far it actually extends. It might be ok for a bit of a play maybe.
Rob.