[time-nuts] How phase stable is rg59 or alternate coax

Mark Spencer mark at alignedsolutions.com
Mon Nov 21 17:39:26 EST 2016


At one point I contemplated running Andrews "Heliax" for my GPS antenna.   Part of the rationale was due to the data presented in page 2 of the following paper.

http://ivs.nict.go.jp/mirror/meetings/v2c_wm1/phase_stability.pdf

I subsequently decided to stay with my existing run of plenum rated RG58.  The bulk of my cable run is indoors where the temperature is fairly stable.

Regards
Mark Spencer



> On Nov 21, 2016, at 12:59 PM, Scott Stobbe <scott.j.stobbe at gmail.com> wrote:
> 
> When I first took a look at some of the coax datasheets I couldn't find
> anything. I was able to find the following paper "phase stability of
> typical navy radio frequency coaxial cables"
> http://www.dtic.mil/dtic/tr/fulltext/u2/628682.pdf I attached the table
> from the last page. They estimate RG59 to have a tempCo of -330 PPM/degC
> for electrical length. They also estimated RG-58 at -480 PPM/degC.
> 
>> On Mon, Nov 21, 2016 at 2:44 PM, John Ackermann N8UR <jra at febo.com> wrote:
>> 
>> I can't find the data right now, but will keep digging.  There's also a
>> short paper from the early 2000s from Haystack on their measurement of
>> LMR400 in an environmental chamber.  They came to the same conclusion, but
>> I can't find that paper either. :-
> 
> 
> John, many thanks for the Haystack tip! That is a wonderful paper, I
> believe the one you are quoting is "Dispersion and temperature effects in
> coax cables" http://www.haystack.mit.edu/tech/vlbi/mark5/mark5_memos/067.pdf
> <PhaseTempCo_Coax.png>
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