[Amps] Cleaning air-wound coils

[Carl]

Silver plating ads no benefit at frequencies below around 250 mHz. I have 
1500W amps on 144 and 222 using copper lines and the efficiency measures 
over 60% on both. Getting the tuning and loading optimized was the most 
important part IMO. Some say silver does nothing on 432 either but I did go 
with a plated cavity anyway.

Carl
KM1H

----- Original Message ----- 
From: "Larry Benko" <xxw0qe at comcast.net>
To: "Dan Zimmerman N3OX" <n3ox at n3ox.net>
Cc: "amps" <amps at contesting.com>
Sent: Wednesday, May 05, 2010 12:40 PM
Subject: Re: [Amps] Cleaning air-wound coils


> Thanks for the plug Dan.  I did the tests you mentioned primarily at
> 28MHz a couple years ago.  Increasing the wire size 1 gauge is better
> than silver plating assuming you have adequate spacing between the turns
> so that the Q is not impaired by the turns being too close together.  I
> still like painting the coil with high temp barbeque paint which had
> absolutely no Q reduction and looks very cool.
>
> 73,
> Larry, W0QE
>
> Dan Zimmerman N3OX wrote:
>>> Has anyone done any tests on the comparative Q between Silver plated,
>>> enamelled and tinned wire coils?  I've always felt that factory
>>> enamelled wire stood a much better chance of retaining a good Q for a
>>> long time as the surface of the copper should still be pristine under
>>> the enamel.  The other question is how long the enamel will last if used
>>> at high temperatures.  Carbonised enamel is probably worse than
>>> tarnished tin!
>>>
>>
>>
>> W0QE found that there wasn't a substantial difference between shiny 
>> copper
>> and terribly corroded copper:
>>
>> http://www.bnk.com/w0qe/inductor_Q_tests.html
>>
>> Metallic platings should be analyzed based on the skin depth of the 
>> plating
>> at the frequency of operation... if the plating is thin and the 
>> conductivity
>> is low, more current will just flow in the base metal.
>>
>> W8JI had this to say about Miniductor stock, which I think is all tinned,
>> right?
>>
>> "Miniductor-type coils have a surprising amount of Q for the wire size, 
>> and
>> maintain Q better as self-resonance is approached than larger coils.  "
>>
>> I've heard others on this reflector suggest that silver or other fancy
>> plating is good to make the coils look pretty, and I would tend to agree
>> with that based on the evidence I've seen.
>>
>> 73
>> Dan
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