[TowerTalk] solid THHN vs jacketed copperweld

[Steve Maki]

Thanks Jim.

I know this is a scenario of diminishing returns...how many skin depths 
does one shoot for?

On 9/27/2022 5:31 PM, Lux, Jim wrote:
> On 9/27/22 2:22 PM, Steve Maki wrote:
>> I seem to recall ordering Copperweld wire, but it was a long time ago.
>>
>> Just a quick note that after replacing the (insulated) #12 THHN with 
>> the same length insulated #12 "copper clad steel tracer wire", we 
>> could see no change in resonant frequency, so there seems to be enough 
>> copper cladding for my purpose at 3.5 MHZ.
>>
>> There will only be an inch or so of wire exposed to the air at the 
>> center insulators, so that will be easy to monitor for corrosion over 
>> time (such as it is :-) Or I may coat the exposed wire with liquid tape.
>>
>> 73, Steve K8LX
> 
> 
> Skin depth in copper at 4 MHz is 1.3 mils, 32 microns.
> 
> 
> Copperweld
> 
> https://www.copperweld.com/application/files/4915/3833/2604/Welded_Copper-covered_Steel_CCS_21.pdf 
> 
> 
> 
> 21% CCS AWG 12 has 0.0808" diamter (2.05mm) with a nominal thickness of 
> 0.0616 mm ( so about 2 skin depths at 4 MHz)
> 
> 
> https://www.copperweld.com/application/files/7115/3833/2604/Welded_Copper-covered_Steel_CCS_40.pdf 
> 
> 
> 40% CCS  has copper that is 0.2052 mm thick ( 6 skin depths)
> 
> 
> 
>>
>>
>>
>> On 9/21/2022 2:07 PM, Donald Chester wrote:
>>> Steve Maki lists at oakcom.org Tue Sep 20 15:19:37 EDT 2022 wrote:
>>>
>>>> I had sworn off copperweld many years ago after noting that the copper
>>>> plating did not last forever.
>>>
>>> Was that real copperweld, or was it copper-plated steel with only a 
>>> minuscule layer of copper deposited on the surface, like the stuff 
>>> used for electric fence wire?
>>>
>>> Real copperweld has a thick copper jacket that is practically 
>>> indestructible.  I use #10, salvaged from an abandoned railway 
>>> telegraph line of yesteryear, scored free for the taking many decades 
>>> ago.  You can beat it with a hammer or leave it buried in the soil 
>>> (as ground radials) for years and the jacket won't come off unless 
>>> it's deliberately removed with a file or grinding wheel.
>>>
>>> That copper-plated junk begins to rust through in only a couple of 
>>> years.  The copper is so thin that it probably has negligible 
>>> benefit  from the skin effect; you are effectively using plain old 
>>> steel wire.
>>>
>>> Don k4kyv
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