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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 18:53:13 -0600
List-post: <mailto:towertalk@contesting.com>
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
>>_______________________________________________
>>Topband mailing list
>>Topband@contesting.com
>>http://lists.contesting.com/mailman/listinfo/topband
>>
>> 
>>
>>    
>>
>
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