...I wound a 160m monoband PI-NET coil from TWT #10 wire, close spaced over
4"PVC. A pair of 813s and a couple of air capacitors with this home brew low
tech coil puts out 1100 watts into the bird.
I wonder if anyone could hear the difference between the # 10 copper wire or
appropriately silver coated coil stock?
73,
dave
wa3gin
----- Original Message -----
From: "K4SAV" <RadioIR@charter.net>
To: <towertalk@contesting.com>
Sent: Tuesday, November 20, 2007 7:53 PM
Subject: Re: [TowerTalk] Topband: Silver Plated Conductor
> 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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>>
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>>
>
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