A 30AWG Radial Coil

[chemelec]

Just Curious if I could Wind This Radial Coil.
LOTS OF FUN, But turned out Very Good!

30 AWG wire, 5.25" ID and 6" OD.
Inductance 350uH
DC Resistance is 5.7 Ohms.
I Didn't count the Exact Turns yet, But I will.

**Finished weight is 6.5 Grams.

Than comes to Test it on my PI.

[joop]

Nice...

did you glue the wires together? Looks like it... Did you do any measurements besides resistance and inductance? What about the self-resonance frequency?

[satdaveuk]

Hi Garry
Had to edit this post because I was saying that coil was equal to Garrys builds which after I realized infact it was one of your builds lol
Nice to see your still at it
All the best

Regards

[golfnut]

General coil question..

When I make coils on a wooden peg former - then bind the turns with cord, the turns are bundled - no set place for the turns.

When I have in the past made or modified a Transformer or commericial coil, the turns are all arranged neatly - side by side...
For greater efficiency.


If I can summon up some motivation, I may wind one with 'neat turns' where the each turn is 'in its proper place'.

Any views - S

[chemelec]

Nice...

did you glue the wires together? Looks like it... Did you do any measurements besides resistance and inductance? What about the self-resonance frequency?

As Close as I can determine, the Self Resonant Frequency is 2.56 Mhz.
The Coil has 32 Turns, 30 AWG.

[joop]

That's a really good figure, thanks!

[chemelec]

This coil was wound in This Jig, using the .010" thin PCB as a center piece.
First Attempt to wind this Failed badly, It Fell apart on removal from jig.

Second attempt was wound in 2 Minutes.
However Epoxy Coatings and Drying times too over 3 Hours to finish it.

I measured the Interwire Capacitance to be 10pF.

On my detector, it detected a 1 Gram Gold Nugget at 3 Inches
And a 1/2 gram at about 1 1/4 Inches.

[TH Jim]

I measured the Interwire Capacitance to be 10pF.

WOW! That is seriously low! The self resonance is seriously high! This coil is seriously fast!

Can you give us some detection depth data on usual targets like rings, chains and coins etc please Gary?

Regards Jim.

[chemelec]

WOW! That is seriously low! The self resonance is seriously high! This coil is seriously fast!

Can you give us some detection depth data on usual targets like rings, chains and coins etc please Gary?

Regards Jim.

Hi Jim, Unless I had some Specific info on what "rings, coins, etc", that is difficult to say.
They Vary in "Size Shape and Metal Content".

[TH Jim]

Yes, as do gold nuggets

Maybe you could tell us what detection depth you can achieve using your local currency as a target?

Regards, Jim.

[chemelec]

Doing an Air Test on my workbench with my Pi Detector connected to this 6" coil and operating at 1000Hz.

Both a 1967 & 2000 US Quarter were detected at 7.5 Inches.

A 1969 Canadian Quarter (Made of Nickel Metal) was detected at 8.25 Inches.

A 2004 US Dime was detected at 6.75 inches.

A 2002 Canadian Dime (Unknown Metal) was detected at 7 inches.

A 2011 Canadian Penny (Believed to be Copper plated steel Metal as It is MAGNETIC) was detected at 7.5 Inches.

A 1961 Canadian Penny (Solid Copper Metal) also detected at 7.5 Inches.

Hope this Helps.

[TH Jim]

That's great! Thank you Gary. A pretty good coil then, able to detect small targets at a greater distance than it's diameter. I shall be making up one of these coils and trying it on my SurfPI - thanks to your hard work and kindness for sharing your results.

All the best,

Jim.