http://www.spacetechexpo.eu/assets/files/2015/Recent-Developments-in-Phase-Stable-Cables.pdf
is a more readily accessible source of data on coax cable delay tempco et. Bruce > > On 04 April 2017 at 00:13 Bruce Griffiths <bruce.griffi...@xtra.co.nz> > wrote: > > Copper jacketed low density PTFE insulated coax cables typically exhibit > a net phase change of over 1000ppm during the PTFE phase transition. See > figure 2 p14 of the Cables and connectors supplement to March 2017 microwave > journal. Solid PTFE insulated cables exhibit an even greater (2 -3x) phase > change. to achieve a phase shift tempco of 10ppm/C either hermetically selaed > silicon dioxide powder insulated coax or "phase tracking" semirigid or better > phase tracking flexible coax is required. > > Bruce > > > > > > On 03 April 2017 at 21:22 Attila Kinali <att...@kinali.ch> wrote: > > > > On Mon, 3 Apr 2017 15:05:55 +1200 (NZST) > > Bruce Griffiths <bruce.griffi...@xtra.co.nz> wrote: > > > > > > > > > > > > > > > > > > For even more fun you could try to detect the PTFE > > > > phase change at around 20C using a cable with PTFE dielectric. > > > > > > > > This will require several 100 meters of cable to be > > > > measureable with > > > > the TICC. Modern cables are all <500ppm/K, good cables > > > > <10ppm/K, phase > > > > stable cables reach even <1ppm/K. Measuring a change of > > > > 10ppm with > > > > a resolution of 60ps means that the delay has to be in > > > > the order of 6µs, > > > > which is close to 1000m of cable. Even if dithering > > > > gives another facor > > > > of 10, this still means 100m of cable. > > > > > > > > > > > > > > > > > > For this level of comparison I would suggest to use a sinusoidal > > signal, > > instead of a pulse, and do phase comparison, which gives a > > resolution > > in the order of 1ps with very little effort, thus reducing the > > required > > cable length to 10-20 meters. > > > > Attila Kinali > > > > [1] "Temperature Stability of Coaxial Cables", Czuba and Sikora, > > 2011 > > http://przyrbwn.icm.edu.pl/APP/PDF/119/a119z4p17.pdf > > > > -- > > It is upon moral qualities that a society is ultimately founded. All > > the prosperity and technological sophistication in the world is of > > no > > use without that foundation. > > -- Miss Matheson, The Diamond Age, Neil Stephenson > > > > _______________________________________________ > > 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.
