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On Feb 10, 11:38*am, Jeff Liebermann wrote:
On Fri, 10 Feb 2012 06:17:03 -0800 (PST), JIMMIE wrote: Jeff, I installed TVRO systems for several years and used a lot of F connectors. Suprisingly the ones I found that worked best were the ultra cheap ones that only took a pair of pliers to fasten *These were the ones with the separate crimp rings. Used with some good quality heat shrink tubing this eliminated most of the problems you mention. I dont know why these connectors went away, my only guess is *that someone wasn't making enough money on them. Jimmie Yech... Please try this test. *Insert such a crimp type F connector and cable into some useless piece of equipment with a type F jack. *Pull on the cable hard. *In my experience, it doesn't take much to make the cable and connector part ways. *Repeat with a screw on connector. *Now, repeat the experiment using a properly assembled compression type F connector and cable. *It takes considerably more brute force to break the connection. *I think the official minimum pull test is 55 lbs, but I'm too lazy to Google for it now. Hiding the workmanship under shrink tube is not very functional. *It will have little effect on the pull test. Most of the cable leakage problems I've seen (and found) were due to crimp type F connectors coming apart or badly crimped. *That includes both the hex shaped crimp, and ones held together with a crimped ring. Bad: http://www.fconnector.org/wp-content/uploads/2011/12/F-Connector2.jpg Worse: http://www.showmecables.com/images/catalog/product/F-connector-RG59.j... Good: http://images.lowes.com/product/converted/783250/783250926510lg.jpg -- Jeff Liebermann * * 150 Felker St #D * *http://www.LearnByDestroying.com Santa Cruz CA 95060http://802.11junk.com Skype: JeffLiebermann * * AE6KS * *831-336-255 Sorry Jeff but I never used my connectors to support my cables. You may be right but completely irrelevant to me. 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. 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. Ive never seen one pull apart except in the shoddiest of installations. 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. Jimmie |
#2
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In message
, JIMMIE writes On Feb 10, 11:38*am, Jeff Liebermann wrote: On Fri, 10 Feb 2012 06:17:03 -0800 (PST), JIMMIE wrote: Jeff, I installed TVRO systems for several years and used a lot of F connectors. Suprisingly the ones I found that worked best were the ultra cheap ones that only took a pair of pliers to fasten *These were the ones with the separate crimp rings. Used with some good quality heat shrink tubing this eliminated most of the problems you mention. I dont know why these connectors went away, my only guess is *that someone wasn't making enough money on them. Jimmie Yech... Please try this test. *Insert such a crimp type F connector and cable into some useless piece of equipment with a type F jack. *Pull on the cable hard. *In my experience, it doesn't take much to make the cable and connector part ways. *Repeat with a screw on connector. *Now, repeat the experiment using a properly assembled compression type F connector and cable. *It takes considerably more brute force to break the connection. *I think the official minimum pull test is 55 lbs, but I'm too lazy to Google for it now. Hiding the workmanship under shrink tube is not very functional. *It will have little effect on the pull test. Most of the cable leakage problems I've seen (and found) were due to crimp type F connectors coming apart or badly crimped. *That includes both the hex shaped crimp, and ones held together with a crimped ring. Bad: http://www.fconnector.org/wp-content/uploads/2011/12/F-Connector2.jpg Worse: http://www.showmecables.com/images/catalog/product/F-connector-RG59.j... Good: http://images.lowes.com/product/converted/783250/783250926510lg.jpg -- Jeff Liebermann * * 150 Felker St #D * *http://www.LearnByDestroying.com Santa Cruz CA 95060http://802.11junk.com Skype: JeffLiebermann * * AE6KS * *831-336-255 Sorry Jeff but I never used my connectors to support my cables. You may be right but completely irrelevant to me. 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. 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. Ive never seen one pull apart except in the shoddiest of installations. 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. There little wrong with good quality F-connectors. They are generally good enough for what they were intended for. Problems are usually down to who installs them, and how. For personal outdoor use, I always give any connectors a squirt of WD40 - both during and after installation. [I guess DeOxit would be similar or better.] After cleaning off most of the WD40, I then seal with self-amalgamating tape. Obviously, heatshrink would be better, but for me, is usually less convenient. Mechanically, even screw-on Fs can be hard to dislodge, provided just the right amount of braid is trapped under the screw thread. However, I suppose that sometimes they might not provide the ultimate in screening. In the UK, in the large CATV networks, crimped connectors are well and truly a thing of the past. Anyone using them (even the good ones) would be liable to be hung, drawn and quartered, and then severely punished. The standard connector is of the 'Snap and Seal' type (and similar). In themselves, these are pretty well watertight, and the screening is excellent. It should be almost impossible to pull one off the cable. However, it is unusual for F-connections to appear naked in the open air. The final RF distribution to the home is invariably from a street cabinet which houses an optical node or an RF distribution / line extender amplifier feeding a bank of taps/splitters. The 'traditional' cascade of in-line taps has not been used for a very long time. Under these relatively benign conditions, the F-connectors probably suffer much less from corrosion than those used on taps hanging on aerial messenger wires, USA-style. Nevertheless, there are various purpose-made short 'chunky' rubber sleeves which can be installed first on the tap ports before the cable connectors are screwed on. These seal the screw threads. Personally, I would have liked to have seen a bit of WD40 used but I never managed to drum up much enthusiasm for this as an approved practice. -- Ian |
#3
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![]() JIMMIE wrote: On Feb 10, 11:38 am, Jeff Liebermann wrote: On Fri, 10 Feb 2012 06:17:03 -0800 (PST), JIMMIE wrote: Jeff, I installed TVRO systems for several years and used a lot of F connectors. Suprisingly the ones I found that worked best were the ultra cheap ones that only took a pair of pliers to fasten These were the ones with the separate crimp rings. Used with some good quality heat shrink tubing this eliminated most of the problems you mention. I dont know why these connectors went away, my only guess is that someone wasn't making enough money on them. Jimmie Yech... Please try this test. Insert such a crimp type F connector and cable into some useless piece of equipment with a type F jack. Pull on the cable hard. In my experience, it doesn't take much to make the cable and connector part ways. Repeat with a screw on connector. Now, repeat the experiment using a properly assembled compression type F connector and cable. It takes considerably more brute force to break the connection. I think the official minimum pull test is 55 lbs, but I'm too lazy to Google for it now. Hiding the workmanship under shrink tube is not very functional. It will have little effect on the pull test. Most of the cable leakage problems I've seen (and found) were due to crimp type F connectors coming apart or badly crimped. That includes both the hex shaped crimp, and ones held together with a crimped ring. Bad: http://www.fconnector.org/wp-content/uploads/2011/12/F-Connector2.jpg Worse: http://www.showmecables.com/images/catalog/product/F-connector-RG59.j... Good: http://images.lowes.com/product/converted/783250/783250926510lg.jpg -- Jeff Liebermann 150 Felker St #D http://www.LearnByDestroying.com Santa Cruz CA 95060http://802.11junk.com Skype: JeffLiebermann AE6KS 831-336-255 Sorry Jeff but I never used my connectors to support my cables. You may be right but completely irrelevant to me. 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. Then you would hate most microwave connectors lit SMA. Now that is Yech. 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. You didn't need heat shrink on good 'F' connectors. Ive never seen one pull apart except in the shoddiest of installations. 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. Not needed, if you use flooded outdoor cable. -- You can't have a sense of humor, if you have no sense. |
#4
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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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