Subject: Re: Reducing contact resistance for low volt use?
Summary: What do you think of these ping times eh?
Reply-To: You can't see me, and I pass right through planets...
References: <firstname.lastname@example.org> <email@example.com> <firstname.lastname@example.org> <email@example.com> <firstname.lastname@example.org> <email@example.com>
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Date: Tue, 07 Jan 2003 21:44:19 GMT
NNTP-Posting-Date: Tue, 07 Jan 2003 16:44:19 EST
On Tue, 07 Jan 2003 21:23:26 GMT, firstname.lastname@example.org (John Fields) Gave
>On Tue, 07 Jan 2003 04:16:14 GMT, DarkMatter
>>On Mon, 06 Jan 2003 15:20:41 GMT, email@example.com (John Fields) Gave
>>>I don't believe I made any mention of the reason the military uses
>>>it all. However, if you'd like to start a thread on that subject
>>>I'd be glad to join in.
>> For the silver at 24 gauge it is 25.2 ohms per 1000 feet
>That depends on the plating thickness.
*That* was the "nominal" quoted figure. Since plating thickness for
all but solid silver wire is measured in percentage of the whole wire,
and runs only through a three percent range from 1 to 3 percent, I
doubt much change would be noted.
That kind of says that solid silver strands bundled up into a custom
feed line would be the best solution.
>> For copper (bare) at the same gauge, it is 25.67 ohms per 1000 feet.
>> As for the reasons for silver on wire in the military, it was
>>originally used soled in transmitter equipment initially because the
>>cost for silver was a lot higher back then.
>Your argument that it was used originally because it was more
>expensive back then is nonsensical _and_ untrue. Check the Silver
>Institute website for the facts.
Bullshit. If it were not an issue, they would have made transmitter
coils from solid silver, not just plated silver. The corrosion
problems for silver plated copper would be gone as well. They
definitely used it only in radios for that reason. Then it became
apparent that it would benefit power transmission lines as well.
Again, not solid, but plated strands. Were cost not the factor in
that, they would have opted for pure silver as we always use the best
for mil spec. Their "best" was silver plated. Sounds good enough for
>As I recall, silver was/is used to plate the wire used to make coils
>in HF equipment in order to minimize skin effect.
No. It was in fact, to optimize it. Silver is a better conductor.
Plating HF components in it, particularly coils, make them work better
*WITH* the skin effect, not abate it, which is impossible anyway.
> I don't recall
>silver plated chassis wiring or cables on vintage military radio
As I said. Originally, it was only used in the RF sections. It is
STILL used to this day to plate output tube connection rings, etc.
Yet another proof that silver oxides are far more desirable in
contact faces than copper oxide would be.
>>It has since migrated to
>>power cabling for corrosion resistance reasons, mainly.
>> One of the mentions in the mil specs are susceptibility to "rd
>>plague" corrosion, A galvanic response at the copper/silver interface.
>>No electrical stimulus needed. It surround plating thickness and
>>integrity as oxygen seems to be the culprit. I guess that is why they
>>call it "oxidation".
>"Red plague" isn't oxidation, it's a form of galvanic corrosion
>which occurs in the presence of humidity because of the location of
>copper and silver in the electrochemical series.
Yes. Note that I said this above. That galvanic response is due to
the porosity of the plating. It takes form in the way of allowing
oxygen into the area where the two metals interface. Though the
mechanism is galvanic, the product is copper and silver oxides.
> It is exacerbated,
>but not caused by the presence of oxygen, and occurs when the silver
>plating is too thin, allowing moisture to form an electrolyte
>between the two metals, which then become a shorted battery.
No. The sole motivator is the presence of oxygen. That is why
heavier platings do not exhibit the problem... at all.
>> I'm sure there are many other factors. Another good one is that SPC
>>is far more solderable (especially over time and environ)than is TPC
>>or straight copper even. It remains "wettable" longer.
>Since it's the flux in the solder which is responsible for removing
>the chemical contaminants from the surfaces to be soldered, I don't
>think there's a really big difference between tinned copper, copper,
>or silver plated copper.
I guess that you have never tried to wet a TPC HV wire then.
We have spools of it on the shelf where it was improperly purchased.
It hasn't aged, it has a reaction with the teflon. making wetting
nearly impossible. The SPC versions, however, tin right up. A well
known fact in HVPS circles.
Did you take a prozac, Zanex or something? You seem more calm.
Are you bipolar?