); SAEximRunCond expanded to false Errors-To: [EMAIL PROTECTED] I was referring to the crimp connectors like the SMAs where the cable is press-fit in the connector. These work well at t=0 and in low stress equipment, but are not too good in high vibration or thermal cycling environments.
Also, I believe the deformation of the outer conductor where the 1/4" semi-rigid cable is squeezed introduces impedance changes and reflections. Since most of these cables have Teflon insulation, cold flow and thermal expansion create additional problems. These problems are not eliminated by using solder type connectors though, as I have seen a number of soldered SMAs with cracked solder joint. They are very easy to apply though, considerably easier than the solder types, and you are less likely to let a badly crimped connector go through inspection than a badly soldered one. Problems tend to be obvious. A cold solder joint, or too much heat applied to the cable (melting the insulation) while soldering are much harder to spot. I have occasionally used crimp BNC connectors and they were as you describe for the most part. Other than that, my personal experience is mostly with solder-type coax connectors. The cheap but not inexpensive screw-on BNC connectors you can find at Radio Shack do not have an inner sleeve either, if I recall correctly. Not that I would recommend using those for ANYTHING (well, I had to try them, so I did....) Didier KO4BB -----Original Message----- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Chuck Harris Sent: Saturday, July 28, 2007 9:27 AM To: Discussion of precise time and frequency measurement Subject: Re: [time-nuts] HP 5370B low frequency modulation Didier Juges wrote: > ); SAEximRunCond expanded to false > Errors-To: [EMAIL PROTECTED] > > Of course, any method is only as good as it is implemented. Crimping gets > rid of a number of chemistry problems, and creates few problems in return. > > One problem with crimping coax cables is that crimping the braid is usually > done against the plastic (term used generically) insulation between the > center conductor and the braid. Not in my experience! The coax is stripped in a 1/2,1/4,1/8 pattern like this: ==== ------------ ---------------- CCCCCCCCCCCCCCCCCCCC ---------------- ------------ ==== The center conductor is crimped only to the "CCCC" bare center wire. There is an inner metal sleeve that slips between the shield and the center insulation. There is a metal crimp sleeve that slips over the outer insulation and the shield braid. The half of the crimp sleeve that is away from the connector restrains the outer insulation and acts as a strain relief The half of the crimp sleeve that is close to the connector crimps the bare shield against the inner metal sleeve forming the ground connection. -Chuck _______________________________________________ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. _______________________________________________ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.