Greetings, I've been tuning up a new Trimble/Nortel NTGS50AA GPSDO and discovered an interesting phenomenon: Barometric pressure has a larger effect on the device than day-to-day temperature variations. In the attached plot, DAC scaling is 500 uV and TEMP scaling is 5000 milli-degC per division. A plot of local barometric pressure, stretched to match the time frame, was photoshopped over the Lady Heather display. The OXCO is marked 34310-T2. A Trimble/Nortel NTBW50AA (with oscillator "O") running nearby doesn't show any significant sensitivity to temperature or pressure. Regards, Peter