The primary reason for silver plate, and that includes connectors, is
that silver oxide is a much better conductor of RF than copper oxide.
Therefore, the silver coating doesn't conduct much of the RF but
prevents the resistive copper oxides from forming. Therefore, polishing
the copper and then silver plating to seal it gives you a long lasting
low resistance tank coil. I suppose that a tin dip would probably be
close to as good as silver at a lot less money.
I don't use the kits. Rather, I take the coils to a local industrial plater.
Mike, W1NR
On 10/04/2010 07:42 AM, LB3HC wrote:
> I am working on some loss estimates for the tank circuit of my GS35B
> amp. design and I am considering if silver plating of the tank circuit
> coil is feasible or not. I intend to use copper tubing intended for
> camping gas installations in the tank coil(s), as it is readily
> available. According to VE1ALQ's tool, the 3 times skin depth for RF
> current on 10 meters wavelength is 36 Microns. Silver plating kits
> that are available on the market** typically states a plating
> thickness of 70 micro inches, which is only 1,7 microns. This is 1/20
> of what is necessary to have silver down to the 3 x skin depth, if my
> calculations are correct.
>
> What are your experiences with silver coated contra non coated tank coils?
>
> Polishing the copper tubing will reduce the RF skin current resistance
> according to some sources. Is this true, and in case it is, what are
> the mechanisms that makes polished copper conduct better (RF) than non
> polished copper?
>
> **
> http://www.cool-amp.com/product%20info/COOL-AMP%20One-page%20Info%20Sheet%20&%20inserts%20%28FINAL%2004.30.09%29.pdf
>
> 73
> LB3HC
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