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Old September 11th 11, 06:57 PM posted to rec.radio.amateur.antenna
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Default duplexers, antennas, repeaters

In article ,
Jeff Liebermann wrote:

Sorta. I have problems securely attaching connectors to RG-213/u.
Unlike the rigid and semi-rigid cables, crimp type connectors are
problematic. In addition, much of the RG-213/u floating around is NOT
silver plated, but bare copper. That will corrode, and form diodes.


Yeah, you have to make sure you're getting the "good stuff", with
silver-plated copper braid... and then (I think) solder, rather
than crimp.

Interesting. I always hear people bragging about LMR. Are we using the
term "Heliax" generically? Is semi-flex no good too, (It's all aluminum
and brass metallically isn't it?)


A picture is worth 1000 words:
Heliax:
http://www.google.com/search?tbm=isch&q=heliax
LMR type coax:
http://www.google.com/search?tbm=isch&q=LMR+coax

I've never heard of semi-flex. Perhaps you mean semi-rigid coax,
which includes aluminum outer jacket coax as used in the CATV
industry? The coax is fine, but where it transitions to a brass or
silver plated connector, there's a problem. In general, it's a bad
idea for reducing PIM (although I use CATV coax because I'm cheap).


See http://www.isoconnector.com/cableassemblies.html - "semi-rigid"
and "semi-flex" are different constructions.

Cramolin is now DeOxit and has been reformulated.


Well, sorta and sorta not. Cramolin is still made by the original
(German) manufacturer, but isn't easily acquired in the U.S. DeOxIt
is made by Caig, who used to import Cramolin but are now making a
similar product themselves.

It's a total disaster on RF connectors because it contains oleic acid,
which is great for removing oxides from electrical contacts, but
equally good at rotting off the plating from connectors over long time
periods. The reformulated DeOxit allegedly contains a different
anti-oxidant, which allegedly has the same effect.


My recollection is that the instructions which came with Cramolin said
that you should clean the remains of the "red" Cramolin (the oxide
remover) off of the contacts after de-oxidizing.

They made another "blue" product which was intended to provide some
residual anti-re-tarnishing protection... I think it was based on palm
oil.

When I use Cramolin (I still have a bit of the concentrate) or DeOxIt
on contacts, I follow it with a final cleaning using isopropyl or
denatured alcohol (or acetone if I'm feeling really thorough), to
remove the remains of the anti-oxidant.

--
Dave Platt AE6EO
Friends of Jade Warrior home page: http://www.radagast.org/jade-warrior
I do _not_ wish to receive unsolicited commercial email, and I will
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