On Wed, 10 Dec 2008 01:44:29 -0800, SparkyGuy
wrote:
One nick in a
solid center conductor and the center pin connection falls apart
inside the connector.
Can you say more about this? Or point to some web discussions / photos?
Thanks.
There's not much to say or show. The usual example is the common
RG-6/u cable TV coax, that uses the solid center wire as the center
pin of the F connector. By necessity, the center wire is rather
stiff. There's also no way to immobilize the center wire as there
would be no room for the mating jack. If the rotary razor blade wire
stripper or half asleep tech with the wire cutters manages to nick the
center wire, chances are good that moving the cable around will
eventually break the center wire at the nick.
Crimp type BNC plugs are also susceptible in the same area. The
difference is that the center pin is either crimped or soldered. The
center pin is also supported by the Teflon insulator. However, if the
coax is moved constantly, as is common with test cables, any nicks in
the center wire will eventually turn into a break. This one is
particularly insidious because it occurs inside the connector, where
both ends of the break are supported in place, resulting in an
intermittent, rather than a clean break.
Big fat center wires are not immune. They just have a different
problem. When one of the heavy stranded center wires from RG-8/u
style coax breaks at a nick, it's usually perfectly positioned to
short to ground. In the common PL-259 UHF connector, the coax end of
the break is not supported, resulting in a difficult to find, and
impossible to see, intermittent.
In my limited experience, the tools that cause the most problems are
the ones with the built in razor blades:
http://www.mytoolstore.com/ideal/ide08-07.html
http://www.mytoolstore.com/ideal/ide08-06.html#coax
http://www.mytoolstore.com/ideal/ide08-08.html
http://www.fab-corp.com/product.php?productid=1665&cat=281&page=1
http://www.hyperlinktech.com/item.aspx?id=879
(Note the huge variation in pricing)
As long as the blades are sharp they work just fine. However, when
the blades get dull, the user tends to bend the cable to assist in the
cutting, which sometimes results in a nicked center wire. Cleaning up
the stripping job with a pair of diagonal cutters also causes
problems. Stripping is also difficult with Teflon insulated wire and
non-wicking insulation (marine coax), where the dielectric materials
are bonded to the conductors. The best way to strip these materials
and to be sure not to nick the wires is with a thermal wire stripper.
http://www.teledyneinterconnect.com/products/wire_strippers/wirestrip.asp
I got lucky and ended up with pile of these from some aerospace
surplus outlet. Very handy. Just take care not to breath the fumes.
However, if you're working with LMR-400, LMR-600, or larger, the
blades of the thermal stripper cannot expand wide enough to fit the
coax cable. Therefore, I suggest getting the correct Times Microwave
EZ-Strip coax stripper for these cables:
http://www.hyperlinktech.com/item.aspx?id=881
http://www.hyperlinktech.com/item.aspx?id=882
--
Jeff Liebermann
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060
http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558