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Re: [Amps] Cleaning air-wound coils

To: Dan Zimmerman N3OX <>
Subject: Re: [Amps] Cleaning air-wound coils
From: Larry Benko <>
Date: Wed, 05 May 2010 10:40:59 -0600
List-post: <">>
Thanks for the plug Dan.  I did the tests you mentioned primarily at 
28MHz a couple years ago.  Increasing the wire size 1 gauge is better 
than silver plating assuming you have adequate spacing between the turns 
so that the Q is not impaired by the turns being too close together.  I 
still like painting the coil with high temp barbeque paint which had 
absolutely no Q reduction and looks very cool.

Larry, W0QE

Dan Zimmerman N3OX wrote:
>> Has anyone done any tests on the comparative Q between Silver plated,
>> enamelled and tinned wire coils?  I've always felt that factory
>> enamelled wire stood a much better chance of retaining a good Q for a
>> long time as the surface of the copper should still be pristine under
>> the enamel.  The other question is how long the enamel will last if used
>> at high temperatures.  Carbonised enamel is probably worse than
>> tarnished tin!
> W0QE found that there wasn't a substantial difference between shiny copper
> and terribly corroded copper:
> Metallic platings should be analyzed based on the skin depth of the plating
> at the frequency of operation... if the plating is thin and the conductivity
> is low, more current will just flow in the base metal.
> W8JI had this to say about Miniductor stock, which I think is all tinned,
> right?
> "Miniductor-type coils have a surprising amount of Q for the wire size, and
> maintain Q better as self-resonance is approached than larger coils.  "
> I've heard others on this reflector suggest that silver or other fancy
> plating is good to make the coils look pretty, and I would tend to agree
> with that based on the evidence I've seen.
> 73
> Dan
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