Yep. I used to worry about eliminating potential error sources such as that from my home lab. On the flip side the Teflon cable I used did have a defined spec vis a vis behaviour in a fire that gave me some comfort when routing it thru my house on the way to the roof mounted antenna. I also had it on hand.
Many items to consider. If I was doing it again I'd probably just use 75 ohm RG6 CATV style cable with an appropriate fire rating for indoor / in home installations. The local electronics store sells nice F female to (apparently 50 ohm) N male adapters that ease the interconnection issues if you can live with the impedance miss match. Sent from my iPhone > On Dec 7, 2015, at 11:23 AM, Bruce Griffiths <bruce.griffi...@xtra.co.nz> > wrote: > >> 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. > _______________________________________________ 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.