Sorry, posted to the wrong reflector.
K4SAV wrote:
>Before you consider silver plating a coil, here is something you should
>know. At 2 MHz the RF skin depth in silver is 0.00178 inches. You need
>about three skin depths of plating, that's about 0.0053 inches. If you
>just walk into a plating shop and say, here silver plate this, you will
>get about 0.00002 inches. "Highly polish-able" grade silver plating is
>0.001 inches and costly. You need 5 times that. It's going to be
>expensive. Most ham coils used at low frequencies are silver plated
>just for appearance purposes.
>
>Jerry, K4SAV
>
>GEORGE WALLNER wrote:
>
>
>
>>Dear Group Member,
>>
>>I have a question regrading the importance of silver
>>plating inductor wire in high power TX circuits in the HF
>>bands.
>>
>>I am just rebuilding my antenna tuner ahead of the 160m
>>ARRL contest. The tuner configuration is a T with two
>>inductors forming the horizontal arms with the variable
>>capacitor in the vertical arm (i.e. between the junction
>>of the two inductors and GND). The inductors use 3 mm
>>diameter bare solid copper wire (good quality copper),
>>with a solenoid diamater of 3" and length of 6". Each
>>inductor is tapped for inductances of between 4uH and 33
>>uH. Conductor spacing is 1:1.
>>
>>Would silver plating the conductors make a practical
>>difference? There is no significant heating of the
>>conductors now with full legal power.
>>
>>I have done some rough math on the difference in
>>resistance, taking into consideration the skin effect at
>>1.8 and 3.5 MHz, but there only seems to be an 8%
>>difference between pure copper and silver plated wire. Am
>>I missing something and should I replace the copper with
>>sliver plated wire?
>>
>>TKS for your thoughts,
>>
>>George
>>AA7JV
>>_______________________________________________
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>>Topband@contesting.com
>>http://lists.contesting.com/mailman/listinfo/topband
>>
>>
>>
>>
>>
>
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