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On Sat, 11 Feb 2012 08:02:37 -0800 (PST), JIMMIE
wrote: Sorry Jeff but I never used my connectors to support my cables. You may be right but completely irrelevant to me. Umm... you've never tripped over a cable, had the equipment fall off the table with the cables attached, run RG6a/u up a pole to where it has to support its own weight, moved furniture with cables still attached, flexed the connector when used as a test lead, pulled cable through the wall or conduit with connectors attached, etc? These are all very common situations which will stress the connector to cable connection. While it might not be a problem for a fixed (stapled in place) installation, it certainly will be a problem for the average home user. http://802.11junk.com/jeffl/pics/drivel/slides/mess01.html I find it odd that outdoor CATV uses quad shielded cable to prevent RF leakage and ingress, and having the cable swept to perfection, while you recommend using inferior F connectors. To me F connector and good connection shouldn't even be used in the same sentence. They are what that are, cheap connectors at best that uses the center conductor of the cable for a contact. Now that is Yech. I do have some issues with RG6a/u that uses copper plated steel core center wire. Mostly, it's a corrosion problem for outdoor connections where the home owner does their own wiring, and uses F connectors without the necessary rubber o-ring needed for waterproofing. I've swept F connectors on the bench and find them quite good and often superior to the rare 75 ohm TNC and BNC connectors near the top end (2GHz for satellite). Incidentally, most of the antennas (that survived a recent storm) on my roof use RG6a/u coax. The mismatch loss between 50 and 75 ohms is minimal. Some use F connectors, but most use BNC's made for RG6a/u. Heat shrink has nothing to do with the pull test or hiding poor workmanship but it does help keep corrosion down which is the biggest problem with F connectors. Ahem. I worked for a marine radio company during the 1970's. I learned a few things about waterproofing and corrosion. Heat shrink doesn't work. Capillary action along the heat shrink to connector boundary will suck the water into the connector. What I use (when needed) is a layer of 1" PTFE tape (or 1/2" if that's all I can find) over the connector. Once in place, a layer of Scotch 66 or other electrical tape to hold it in place. The PTFE will cold flow into the irregularities on the connector surface, and there will be zero capillary action. If I want UV resistance, I spray the tape with clear Krlyon (acrylic) spray. While we're on the topic, I've experimented with various allegedly waterproof enclosures and packages. The only ones I consider genuinely waterproof are sealed and pressurized with dry air. Anything less will eventually leak. Ive never seen one pull apart except in the shoddiest of installations. I have and all too often. I was at the neighbors trying to troubleshoot their Comcast cable tv and modem mess. They had some friend of theirs do the wiring. All the F connectors were crimp ring type and were falling apart. The coax was mostly RG-59 with maybe 80% coverage. I replaced the most disgusting and will finish the job when I have time. One of the best things I have found to insure you maintain a good connection is to apply something like DeOxit to the connectors when you assemble them. Best done while all the parts are new. DeOxit and Cramolin contain oleic acid, which will slightly corrode copper. It's good for CLEANING connectors by removing the oxides, but should not be left on the connector. If you want to make sure that you can take the connector apart after the threads rot in place due to galvanic action between the aluminum receptacle, and the nickel plated crimp type F connector, some silicon or lithium grease would probably be better. Some notes on the contents: http://www.antiqueradios.com/forums/viewtopic.php?t=82058&start=40&sid=71ca160c8f60768 6916a0f355e9ecc34 Jimmie As for special tools, I love them. My various cable preparation tools for various coax cable have saved me countless hours of fumbling with a pocket knife and diagonal cutters. Using the various compression tools on F connectors almost guarantee a good connection, unless I did something dumb. Same with crimp lugs, various LMR-xxx coax cables, and Anderson Power Pole connectors. The days of using a hammer or vice grips to crimp a connector are over. The cost can be substantial, but is well worth it if you work with connectors regularly. http://802.11junk.com/jeffl/antennas/Misc/slides/crimpers.html About $35/ea. -- 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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