); SAEximRunCond expanded to false Errors-To: [EMAIL PROTECTED] Tom Van Baak wrote: >> I guess that is why some GPS antenna cables is temperature-stabilized as well >> as the cement-pidestal for the GPS antenna as it stands on solid rock. The >> same >> place have controlled environment for the cesiums and hydrogens, together >> with >> UPS and disel-engine that kicks in for longer runs. >> >> Or I could be wrong... :) >> > > Magnus, > > This is true (temperature stabilization) for sites that do mm > level survey and ps level time transfer, using all the tricks > in the GPS book. > > On the other hand, I think for most of us that play at the > meter and ns levels with cheap OEM receivers and plastic > L1 antennas the coax cable temperature issue is quite > overblown. Or if I'm wrong, show me the data. > > /tvb > > > Tom
Calculations are easy: Cable delay tempco is at worst 100ppm/K. with 100ns of cable delay tempco will be 10ps?K or less. With a 20K temperature change change in delay will be 200ps or less. The group delay tempco of the antenna components (bandpass filters amplifiers etc ) is likely to be much greater. Bruce _______________________________________________ time-nuts mailing list -- [email protected] To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
