Tarn-X and high-frequency silver-plated RF connectors

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Do you guys think it is OK to clean silver-plated RF connectors with
Tarn-X?
Think:  2 GHz 7/16" DIN connectors used in the cellular & PCS industry
(towers).

Here's the MSDS; I don't recognize the chemicals:
Link:  http://www.hescoinc.com/msds/comtx4.pdf

If OK to use, should one also clean any Tarn-X residue with isopropyl
alcohol afterwards, or is that really necessary?

I'm asking because sometimes these connectors come "new" from the
factory covered in silver tarnish and other crud.   Thanks.

Re: Tarn-X and high-frequency silver-plated RF connectors



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Back when I was in the USAF, we used a lot of silver plated RF
connectors. The rule was simple: never, ever try to clean them, the
'tarnish' is quite conductive and will not affect performance.

Re: Tarn-X and high-frequency silver-plated RF connectors



PeterD wrote:
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   Bullshit.  It has more resistance than the silver alloy, and can
cause incorrect readings, or the connector to overheat.  I guess that
you've never seen a burnt flange on a piece of wave guide?

   We used 91% Isopropyl alcohol and Q-tips to remove as much of the
oxide as we could.


--
Politicians should only get paid if the budget is balanced, and there is
enough left over to pay them.

Re: Tarn-X and high-frequency silver-plated RF connectors


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What about for PIM noise? (Passive Intermodulation).
Does tarnish cause or exacerbate PIM?

Cleaning seems to make a difference, but cleaning a "clean" connector
probably does as well.
Often, just the disassemble/reassemble is enough to improve PIM.  Very
touchy stuff when you're looking for -140 to -150 dBc.

Re: Tarn-X and high-frequency silver-plated RF connectors



mpm wrote:
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   We never used silver plated for low level signals.  Only Nickel or
Gold.

   Silver oxide is a conductor, but it is also a weak semiconductor that
can rectify stray RF.  You know that any resistance in the shield nac
cause all kinds of odd problems.

   The worst offender for me were in the old 'Bird 43' RF watt meters
with a low power slug in the 30 to 76 MHz range.  I used them in QA
testing on the PRC-77 manpack radios.  Every month or so I used a paper
towel to buff away the oxide, rather than call the characters in the
metrology lab.

--
Politicians should only get paid if the budget is balanced, and there is
enough left over to pay them.

Re: Tarn-X and high-frequency silver-plated RF connectors


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It is _NOT_ silver oxide that forms that black tarnish. It is silver
_SULFIDE_ .

---
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Re: Tarn-X and high-frequency silver-plated RF connectors



Sergey Kubushyn wrote:
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   Yes.  That's what happens when I get less than three hours sleep. :(


--
Politicians should only get paid if the budget is balanced, and there is
enough left over to pay them.

Re: Tarn-X and high-frequency silver-plated RF connectors



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Of course. Any time you're troubleshooting, the first step is to reseat
all the connectors. :-)

Cheers!
Rich


Re: Tarn-X and high-frequency silver-plated RF connectors



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Yes I agree they should be kept clean. When you figure all the effort
gone into a matching network any imbalance would cause a loss in signal
strength at minumum.

 An oxidised coax BNC or SMA not sure what their useing up there on the
 drop to my house was the source of intermittent internet connection
 issues for me not to long ago and I think thats only around 900MHz the
 higher the frequency likely the more critical the interconnects.

Mind you I could be wrong just my opinion.I havent touched RF in 5 years
or so. I dont have the cash for VNA's and spectrum anaylizers and
such;-)

Re: Tarn-X and high-frequency silver-plated RF connectors



Hammy wrote:
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   Direct PC, or similar?  I thought they were still using 'F'
connectors?


   I'll give you a 'repairable' Polarad for the cost of shipping.  It's
over 200 pounds, though. ;-)


--
Politicians should only get paid if the budget is balanced, and there is
enough left over to pay them.

Re: Tarn-X and high-frequency silver-plated RF connectors



[snip]
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I'm not sure what they use. He tested my signal strentgth and it was down so he
checked all the interconects  and found the connector at
the drop was oxidised. Once he changed it my signals went back-up and I havent
had an issue yet. Well he was here though I had him
change all the coax from the drop to the splice in the house and change the
splice.;-) Shaws pretty good for stuff like that; no charge
and quick.
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Interesting but considering the shipping rates for 5lbs I dont think I want to
know what they would charge for 200lbs!;-)

At the moment I'm haveing enough fun trying to program a PIC16F887 for
inteligent control of an electronic load. Thats got my hands full
enough for the time being. I have the analog part done the programing part is
always the bitch for me;-)


Re: Tarn-X and high-frequency silver-plated RF connectors


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...

I was in the USAF too, and I think that rule was to keep the grunts
(of which I was one) from using sandpaper or wire brushes or scouring
powder.

When I was in Okinawa, ca. 1970's-ish, I had a buddy down the hall who
was a ham. They (the commander) had let him install an antenna tower and
20M quad antenna on the roof of the dorm!

Anyway, back then in Okinawa, the amount of surplus electronics available
for a song was mind-bogging. I watched this guy build a 1KW linear from
parts he got entirely from surplus WWII schtuff, except for the 4-400A
and its socket, which I stole for him out of bench stock.

One of the surplus Xmtrs had a beautiful tank coil, about 2.5" dia, by
about 6" long, of about 3/16" silver-plated (or maybe solid silver!)
tube that was almost all black on the outside.

As has been noted, not only is the tarnish almost as conductive as
silver itself, but it's really easy to shine up chemically, with
Tarn-X or even Brasso.

This idiot SANDPAPERED it! "What? You're a ham, and you've never
heard of the skin effect?"

Well, the thing _did_ work - it was grounded-grid, so what could go
wrong? ;-P

Cheers!
Rich



Re: Tarn-X and high-frequency silver-plated RF connectors


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*Cough*,

If the tarnish is nonconductive, it isn't carrying any current.
Therefore, the metal underneath is carrying the current.  Since there's
still plating under the tarnish, nothing funny happens.

If the tarnish is conductive, it has fairly high resistivity.  Therefore,
the skin depth is large, and little current flows in it.  Almost all the
current flows in the metal surface.

Tim

--
Deep Friar: a very philosophical monk.
Website: http://webpages.charter.net/dawill/tmoranwms



Re: Tarn-X and high-frequency silver-plated RF connectors



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I believe silver oxide is resistive.

I'd like to add that if you use Tarn-X,you rinse with WATER,then you can
use 90%IPA to dry it off.
I used Tarn-X all the time at TEK to clean off silver plated switches in
500 series scopes.Followed by a spray bath in the wash rack and 3 days in a
drying oven.

--
Jim Yanik
jyanik
at
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Re: Tarn-X and high-frequency silver-plated RF connectors



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Silver tarnish is silver sulfide, which IIRC is conductive.
 
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Re: Tarn-X and high-frequency silver-plated RF connectors


On Sep 19, 1:32A0%pm, " snipped-for-privacy@att.bizzzzzzzzzzzz"
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My question is not so much about the conductivity of the silver
tarnish.
I'm concerned about all those little semiconductor discontinuities
that "probably" generate excessive passive intermodulation (PIM).  No
matter how conductive the tarnish might be, it's not silver-on-silver
mating surfaces.  And through experimentation, we do find that
excessive tarnish (which could include other crud) does cause PIM
failures.

The client wants -150 dBc (150 dB below a 20-watt carrier).
-140 is achievable with some effort.   But to get -150 reliably, we
generally only see that on mating surfaces that are squeaky clean!

Thus, my question about Tarn-X.  As a labor saver.
Not whether tarnish is conductive.  But I think I have a book in the
library that might provide this number.  If I can find it, I'll post
it.

Re: Tarn-X and high-frequency silver-plated RF connectors


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I would be interested to see the real numbers on Ag2O and Ag2S.  I'd also
be very curious to know if it varies much with doping (like most compounds
in this area of the periodic table, they should be semiconductors of some
capacity).

Tim

--
Deep Friar: a very philosophical monk.
Website: http://webpages.charter.net/dawill/tmoranwms



Re: Tarn-X and high-frequency silver-plated RF connectors


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  Silver Oxide is conductive.  No need to remove it, and a fine patina
of
it is always a good thing., when it isn't pristine, which they rarely
are after
a short period.

  No need to fuss with it at all.


Re: Tarn-X and high-frequency silver-plated RF connectors


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I'm thinking, no.  The Tarn-X is intended to reduce AgS (sulphide
is the black 'tarnish'), but not to enhance conductivity.  Mechanical
cleaning to remove loose material (or even just reseating the
connector) suffices.  If there's any residue from the 'cleaner'
on the insulators, that's BAD; for anything critical, use
a low-residue cleaner (alcohol good, Freon TF better).

Re: Tarn-X and high-frequency silver-plated RF connectors



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Absolutely yes; I've seen it in action. The tarnish just disappears,
and the silver is "none the worse for wear." :-)

I'd be interested in your experience if you simply dip them, rather
than use a rag or Q-tip or whatever.

Cheers!
Rich


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