The most recent experience I've had is with single hole mount SO-239 connectors, Teflon insulation, purchased the The RF Connection.
I installed six of them in a batch of Norton preamplifiers Friday and when I plugged a UHF-BNC adapter in to connect some test equipment, I noticed the center pin rotated inside the Teflon insulator. The center conductor broke from the windlass effect. The upshot is that Joel, W3RFC, the owner of The RF Connection determined that a significant fraction of this part had a manufacturing defect. These are imports, presumably from China, although I didn't ask. The defective parts I have will be replaced as soon as the compliant parts arrive. However, I can't recover the two hours it took to install the first set of connectors, then remove them, drill the extra holes to substitute flanged connectors and install flanged connectors. (Which are also imports, silver/Teflon but higher quality.) I've lost track of the number of failures with other Chinese adapters. Some that I remember include a couple of BNC F-F connectors where the center insulator fell out. Same thing happened with a BNC "T" connector. I have a BNC-UHF adapter where the UHF shell is unthreaded for half the length. Two of the same type of adapter had the shell separate from the body. All the BNC-F adapters I have are extremely tight fitting on the BNC end. In the past I've purchased a quantity of Chinese BNC connectors for kits I sell. While they work, the dimensions are subtlety off someplace so that they have to be fiddled with to connect to a MILSPEC BNC connector. So far, the inexpensive Chinese SMA connectors seem fine, however. I've since switched to Amphenol BNC parts, which are also made in China but with much better dimensional and quality control. I suspect my experience is not unique. Jack K8ZOA On 11/1/2010 7:06 PM, Mike Harris wrote: > G'day, > > Under what normal operation usage does a coax connector suffer > sufficient stress to mechanically break it? I've seen connections > fail due to incorrect installation but mechanical breakage due to > poor design, never, at least not on the products I have or would > use. To imply that Amphenol is the only maker of a quality > component is nonsense. I accept that if you buy Amphenol, Suhner, > Greenpar, Aircom, Andrew or similar badged products you know it will > most likely be quality. However, it's not rocket science and there > are undoubtedly many competent manufacturers out there perhaps > without the Mil spec or domestic USA labour rate overheads. There > will always be junk, unfortunately some folks just might not > recognise it as such. > > My 6m feeder has US, German and unknown origin fittings in its run, > nothing has failed or deteriorated or shown any signs of overheating > during high power eme operation. My tower is a telescopic/fold over > model so regular maintenance checks are easy and something I'm used > to doing after a career in the rf business, LF to C-band. > > Personally, I find the coax terminations within the K3 unappealing > but I'm not going to die in a ditch over it. > > Regards, > > Mike VP8NO > > > > > ----- Original Message ----- > From: "Jim Brown"<j...@audiosystemsgroup.com> > Cc: "Reflector Elecraft"<elecraft@mailman.qth.net> > Sent: Monday, November 01, 2010 6:59 PM > Subject: Re: [Elecraft] K3 Intermittently loses gain > > >> On 11/1/2010 9:37 AM, Mike Harris wrote: >>> I have not been let down by the items I've bought from "The >>> RF Connection". >> I have bought some really lousy junk connectors from the RF >> Connection, >> and when I tried to get real tech info from them on coax they >> wanted to >> sell to a DXpedition, I got nothing but a salesman's bluster. >> >>> I have paid 2-3 times as much for Amphenol barrels >> Yes, Amphenol is more expensive than cheap junk. How much does it >> cost >> to get someone to climb a tower? How much do you spend to go on a >> DXpedition? How much time do you lose chasing intermittent >> problems? >>> but not found them any better than good quality imports. >> How would you KNOW if they are any good or not? Have you cut one >> open >> to see what it looks like? Have you done any serious power tests? >> Have >> you done serious loss or reflection measurements? Have you put >> stress >> on them to break them mechanically? >> >> I used them in my station and nothing blew up (yet)? That isn't a >> real >> test, it's luck. >> >> 73, Jim K9YC > ______________________________________________________________ > Elecraft mailing list > Home: http://mailman.qth.net/mailman/listinfo/elecraft > Help: http://mailman.qth.net/mmfaq.htm > Post: mailto:Elecraft@mailman.qth.net > > This list hosted by: http://www.qsl.net > Please help support this email list: http://www.qsl.net/donate.html > ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
