Note that partial air core (9913) and foam dielectric is better than
solid polyethylene.
David N1HAC
On 11/21/16 5:39 PM, Mark Spencer wrote:
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 <[email protected]> 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 <[email protected]> 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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