Actually I may be misremembering this. Am not sure if the cable I used was Teflon on not. It did have a defined fire rating though, and I was concerned about it's phase stability vis a vis temperatures.
Sent from my iPhone > On Dec 7, 2015, at 1:58 PM, Mark Spencer <m...@alignedsolutions.com> wrote: > > 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. > _______________________________________________ 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.