Having converted myself to crimped connectors but still a neophyte with the
method, I have come to almost the same set of conclusions that you put
forward. However, I don't understand what you are saying " I now have gone
back to stripping with 40lb monofilament fishing line" I am using a tube
cutter to prepare the center conductor and an DX Engineering coax tool for
just the outer covering. Using the (modified for LMR-400) tool for the
center conductor was just not to my standards for coax with a foam center
insulation like LMR-400.
I, like you, believe that trimming excess braid after crimping is a key
factor to having a good crimp. Plus it is much neater, doesn't require
precise measurement and better insures a uniform distribution of braid for
the outer crimp.
What I really want to ask is, do you do anything to foil shield prior to the
crimping operation? My only concern with coax like LMR-400, is the
proximity of the foil to the center conductor. Even the tube cutter
compresses the foam inner insulation which brings the remaining foil closer
to the center conductor. The best I can seem to do is just peck at the foil
with my fingernails until I am satisfied that the foil has not shorted over
to the center conductor. The only way I've been able to provide some
separation distance between the foil and the center conductor is to use a
grinder on the foil which wasn't a good plan in my estimation (just too
destructive even being very careful). I can see no way to remove the foil
without doing damage to the inner insulation.
On the center conductor, I wonder if a solid center conductor like LMR-400
as compared to a stranded center conductor like RG-213U doesn't also force
the issue of soldering the center conductor. I was considering going to a
fully crimped connector but if I need electricity at the connector for the
heat shrink tubing then using a soldering iron is no more of an impact.
Soldering the outer braid has always kept me up at night wondering about the
condition of the inner insulation even when using all of the good
suggestions others have mentioned (tinning the outer braid, liberal use of
flux, cooling the connector ASAP after soldering, etc.) Soldering the
center conductor leaves me with warm fuzzes.
73 Ken K5RG
Message: 4
Date: Thu, 20 Jan 2011 18:03:41 -0800
From: "Jon Casamajor" <k6el@comcast.net>
Subject: [TowerTalk] Crimp connectors
To: <towertalk@contesting.com>
Message-ID: <019501cbb90f$6d4cf880$47e6e980$@net>
Content-Type: text/plain; charset="us-ascii"
I started using Crimp connectors a few years ago and now that I have figured
out how to properly prepare and crimp them, I think they are good. I'm
responding to the compression connectors thread which I assume is the same
as crimp connector.
Be careful about trusting those slick little cable prep tools sold by many
cable/connector companies. They caused me a lot of problems and cost me lots
of $$ and problems on the tower.
Rather than pick on a particular vendor here is what I found as I waded into
the crimp connector cut over here at K6EL station.
. Even with quality connectors you must verify that the center and
shield exposed will properly crimp to the connector.I know, "DUH" but it was
easy to get lulled into the belief that the $40 slick little stripper solved
that problem.
o I now have gone back to stripping with 40lb monofilament fishing line
and carefully measuring the cuts.
. My bad experiences have led me to solder the center
conductor.PERIOD. It's too simple and easy to validate.
. I expose enough braid to spill out of the crimp collar and then
trim it before I apply the compression/crimp. ALL of my problems can be
traced to an inadequate amount of shield under the crimp collar.
. If you solder the center conductor it's pretty easy to adjust the
length.just pay close attention to the ratio of the lengths of the two as
it's easy, at least for me to get that wrong and waste a connector.
As for WX proofing.I treat Crimps exactly like I treat conventional N or
UHF. I assume none of them are water proof so I make them so that they are
in my relatively dry climate. I really have grown to like the Silicone self
bonding type tape because it is so easy to open up when I need to inspect,
service or modify the connection.
Crimps are great time savers and IMHO, they are as good as the old school
solder types but you need to develop a system that works for you and not
violate the rules trying to shave some time off your connector
installations. Of course, YMMV but this is what I've paid the price to learn
about them. I LOVE them.now.
73, Jon
K6EL
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