On Sunday, December 06, 2015 10:02:43 AM Mark Spencer wrote: > I've seen data re delay vs temperature for high end 50 ohm cables. I've > never seen it for 75 ohm CATV style cable. > > Back when I was into time nuts pursuits this was one of the main reasons I > was contemplating switching my GPS antenna feed line to hardline. I never > made the change but still have the hardline. > > To this day I still use Teflon RG58 style cable (purchased surplus from > Boeing decades ago) for my GPS antenna fee line to the splitter. I doubt > I will ever change it out. > > Sent from my iPhone > > > On Dec 6, 2015, at 4:21 AM, Attila Kinali <att...@kinali.ch> wrote: > > > > On Sat, 5 Dec 2015 17:06:03 -0800 > > > > Mark Spencer <m...@alignedsolutions.com> wrote: > >> Over the years I've used a number of CATV style 75 ohm patch cords > >> with F connectors, F female to female couplers and F to other connector > >> adaptors to distribute gps signals from my GPS splitter to various > >> receivers. I've never been able to notice any difference in reported > >> signal strength vs using "brand name" 50 ohm coax with N connectors. > > > > Well, putting the numbers into a calculator gives: > > VSWR: 1.5 > > Load Return loss: -14dB > > Load Mismatch Attenuation: -0.2dB > > > > I'd say that for a receiver, this is quite negligible. Heck, even 1dB > > loss wouldn't hurt too much. I would suggest, that for all practical > > purposes, the use of (good) satellite coax cable would be more than > > good enough for most of us. The only thing i'm not sure about is how > > the delay through the cable behaves over time (aging, temperature, > > humidity). If anyone has some data on that, for different types of > > cables, I > > would appreciate getting a copy :-) > > > > Attila Kinali > > _______________________________________________ > 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. Teflon has a phase transition around 20C or so. Consequently its phase stability isnt stellar near the transition. Polyethylene insulated cables are superior in this regard.
Bruce _______________________________________________ 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.