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"Dual crimp" coax connectors?
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 |
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