I've been working on the performance of my portable GPSDO (very similar to G3RUH design) and have got down to a reasonable level. Testing against an HP3815A, it will remain within better than 1x10^-10 for periods of 10-15 mins.
However, there are times when it seems to get a "hit" and it will then move up to ± 5x10^-10 before settling down again. The movement seems to follow the time constant of the PLL loop filter, possibly indicating that it's coming from the Jupiter GPS? Reading the Jupiter doco (Zodiac GPS Receiver Family Designer's Guide), there seem to be several Zodiac Binary messages that can be used to alter the GPS's performance (e.g. Satellite Elevation Mask Control). I already have a processor talking to the GPS card and displaying position, time, gridsquare, status etc. It would be a simple matter to have it tweak the parameters as required. Does anyone have any experience with this? Regards, David Smith _______________________________________________ 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.
