Lee, I appreciate your comments, but I can rebut them easily. I have seen too many clamp-type connectors pull apart, usually because they were over-tightened during assembly. Take a close look at a MIL-spec clamp-type N connector, and you can see that the knife-edge component can slice right through the braid if the nut is over-tightened, allowing the cable and the center conductor to pull right out of the connector. That seldom, if ever, happens with a properly-applied crimp connector. Moreover, how often do you see a technician use a torque wrench to tighten the nut, per instructions? Most cable techs just wrench the nut until it doesn't move any more- and that's exactly where the faulty installation occurs. When the proper crimper is used, that cannot occur with a crimp connector.
One of the first requirements of a jumper or cable installation is that there should not be any tension on the connector or the cable. I daresay that any connector, whether crimp or clamp, that pulls apart did so because of tension. DUH! A proper cable or jumper installation does *not* subject its connectors to tension, so there should be no case of connectors pulling apart! As far as consistent results, I think it's a wash. I recognize that an experienced craftsman can assemble and attach any connector consistently, time after time. But, time is money. I can install a crimp-type male N connector on a given type of cable in perhaps 1/2 or 1/3 the time it takes to install a MIL-spec clamp connector. On a complex job, this disparity may amount to several hours. If the project engineer knows that a high-quality crimp connector is just as reliable as a high-quality clamp connector, he or she will make the right choice. Since the N connector is a constant-impedance design, there should not be any impedance "bump" seen on a VNA, regardless of whether it is attached by crimp or by clamp means. I will admit that a crimp N connector is not waterproof to the degree that a MIL-clamp N connector is, but I don't install crimp N connectors outdoors without a multiple overwrap of bi-seal tape. The final installation is absolutely waterproof and reliable, as evidenced by several decades of performance. I happen to prefer silver/gold connectors made by RF Industries, but equally reliable crimp connectors are made by Amphenol, Delta, Huber+Suhner, and others. 73, Eric Lemmon WB6FLY -----Original Message----- From: Repeater-Builder@yahoogroups.com [mailto:[EMAIL PROTECTED] On Behalf Of Q Sent: Tuesday, January 31, 2006 4:53 AM To: Repeater-Builder@yahoogroups.com Subject: Re: [Repeater-Builder] Re: Loss through adaptors: I have issues with crimp-on connectors. I have seen too many of them pull apart when used as pigtails to tower mounted antennas.I have also seen the braid break right at the crimp. Blame it on improper crimping or the human element or whatever,but I will use the clamp style connectors. I seem to be able to get more consistent results and better mechanical strength. I agree with all the other points and will add proper weatherproofing to outside connections with vapor wrap and Scotch tape topped off with Scotchkote. 28 years with a large RCC taught me what works and what doesnt,lessons learned the hard way are not soon forgotten! 73,Lee,N3APP Eric Lemmon wrote: >This topic interests me, not just because I personally abhor adaptors in any >repeater system, but also because I see that others are equally passionate >about certain cables. > >After spending many years troubleshooting repeater systems cobbled together >by my friends and colleagues, most of which were replete with every >connector series known to Mankind- and which used many adapters to mate >between series- I became aware that the most troublesome repeaters had the >largest number of adapters. > >When I began to design my own repeater systems, I vowed to abide by three >simple rules: >1. Use only Mil-spec RG-400/U or RG-214/U cable for jumpers and >interconnecting cables, and >2. Make up these cables with the correct connectors on each end, using the >specified tools, and >3. Use only crimped connectors with silver-plated brass bodies, gold-plated >contacts, and Teflon dielectric. > >None of my systems have adaptors or "barrel" connectors, since the cables >are made up to fit the job. There are no BNC or UHF connectors; except for >very unusual situations, all connectors are Type N with a few mini-UHF >needed to mate with a particular radio. It would not occur to me to use an >adapter to mate a male N connector to a UHF female connector- I would have a >premium UHF male connector on that end of the cable! Of course, this only >is an issue with older radios and duplexers; the modern counterparts have >female N connectors. > >I guess the bottom line here is that almost all double-shielded and 100% >shielded cable will perform superbly in a repeater system, if properly >installed. I have never heard of any repeater system that was significantly >improved by replacing RG-214/U with 3/8" hardline, Superflex, or any other >trendy cable- unless the original installation was flawed. We should all be >ready to accept that a flawed installation does not condemn a cable brand or >type. In my personal opinion, the use of adapters in place of the exactly >correct connectors leads to a flawed installation. YMMV! > >73, Eric Lemmon WB6FLY > > >-----Original Message----- >From: Repeater-Builder@yahoogroups.com >[mailto:[EMAIL PROTECTED] On Behalf Of Jay Urish >Sent: Monday, January 30, 2006 7:04 PM >To: Repeater-Builder@yahoogroups.com >Subject: Re: [Repeater-Builder] Re: Loss through adaptors: > >Yea, I use the heck out of LMR-400UF.. Please enlighton me! > > >Dave VanHorn wrote: > > >>>For tight spots, consider superflex 1/4 or 3/8 >>>in hard line. I actually use the mini 141 rigid >>>line for modest power levels. >>> >>> >>FSJ1-50 now in every cable except my adaptor mess (soon to be replaced) >>and the 2M duplexer harness. >> >> >> >> >>>Avoid trying to use foam center cables where >>>possible. >>> >>> >>My FJS1-50 is foam, what's the beef with foam? >> >> >> > > > > Yahoo! Groups Links Yahoo! Groups Links <*> To visit your group on the web, go to: http://groups.yahoo.com/group/Repeater-Builder/ <*> To unsubscribe from this group, send an email to: [EMAIL PROTECTED] <*> Your use of Yahoo! Groups is subject to: http://docs.yahoo.com/info/terms/
