A Comparison of 2 Coils.

[chemelec]

I made a Scramble wound 8 inch coil and one of my Flat wound Radial Coils.
Than Tested both of these.

It Was interesting to see the Big Difference in "Free Air Resonance" and "Inter-Wire Capacitance" Values.

[chemelec]

Another Coil for Comparison.

All Similar Size and Inductance values.

Surprized me, Has Higher Inter-wire Capacitance and Lower Free Air Resonance, Compared to the Flat wound Coil.
Possibly because of the Fiberglass material?

But it was the Only suitable, Rigid material I have.

[baum7154]

Another Coil for Comparison.

All Similar Size and Inductance values.

Surprized me, Has Higher Inter-wire Capacitance and Lower Free Air Resonance, Compared to the Flat wound Coil.
Possibly because of the Fiberglass material?

But it was the Only suitable, Rigid material I have.

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It would be interesting to see what the SRF and capacitance would be if you wound the same spider coil on your fiberglass form with 600 volt PTFE insulated wire. In my experience it makes a significant difference. I don't use magnet wire any more because the extremely thin enamel insulation does not give the best conductor separation and dielectric performance of the 600 volt PTFE (Teflon) insul.

Thanks,

Dan

[Koala]

Wounder how repeatable these results are ?

A small variation in the wire or how tight they are wound does it make much difference. I know the induction does not change much.

[Daren]

This is very informative. Any idea how flat spiral multilayer coil would perform? Lets say 3 or 4 layers separated by spacers?
I think its hard to beat single flat spiral coil; its geometric configuration and naturally low inter winding voltage difference.