Jerry & All,
Silver plating Pi Network coils in amps is pure marketing because it
sells!!! The efficiency is of silver plating is maybe 1% better when all is
said and done.
When I was in Aerospace, common military requirements were 100 microinches.
And I don't know why that was and if anyone wants to chime in, we can take
it off line.
Bottom line is keep your connections between components very clean and
don't worry about the plating.
73 Hardy N7RT
At 06:41 PM 11/20/2007 -0600, 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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>>
>>
>>
>
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