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Re: [TowerTalk] Topband: Silver Plated Conductor

To: towertalk@contesting.com
Subject: Re: [TowerTalk] Topband: Silver Plated Conductor
From: K4SAV <RadioIR@charter.net>
Date: Tue, 20 Nov 2007 18:41:03 -0600
List-post: <mailto:towertalk@contesting.com>
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
>_______________________________________________
>Topband mailing list
>Topband@contesting.com
>http://lists.contesting.com/mailman/listinfo/topband
>
>  
>

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