Hi All OCXO’s are sensitive to acceleration. Gravity is one form of acceleration. A sensitivity in the 0.5 to 2 ppb / G is not uncommon.
Bob > On May 11, 2015, at 9:24 PM, J. L. Trantham <[email protected]> wrote: > > I recently obtained a 53132A and added the HP Opt 010 High Stability Time > Base option with a 10811 variant OCXO. > > > > I left it on for over a week and it, ultimately, seemed to slow down in its > drift, with the displayed frequency, as it 'read' my GPSDO, slowly > decreasing, suggesting that the Time Base was, slowly, increasing in > frequency. > > > > I then removed the HP option and installed a Polish UHS Time Base option > with a Morion DOCXO. After about 72 hours, it seemed to stabilize. I then > 'calibrated' the 53132A by connecting my GPSDO to Channel 1. The displayed > frequency was +/- 1 to 2 mHz of 10.000 000 000 MHz for the past week or so, > with no drift noticeable. > > > > I had 'calibrated' the 53132A with it sitting at about +30 degrees, propped > up on its 'handle' in a 'vertical' position. I then had occasion to move > the 'handle' under the unit whereby the unit was 'flat', at which point the > displayed frequency dropped to 9.999 999 997 MHz, +/- 1 to 2 mHz. The > displayed frequency was the same this evening when I came home. When I > again 'elevated' the unit by moving the handle to its more 'vertical' > position, the displayed frequency moved to 10.000 000 000 MHz +/- 1 to 2 > mHz. > > > > I'm not sure what this means. > > > > It is a 'repeatable' observation. It displayed the lower frequency all day > and when I 'elevated' the 53132A this evening, the frequency again went to > 10.000 000 000 Mhz. Is this a 'gravity' effect? Is this an issue with the > DOCXO? Is this an issue with the 53132A? If I am correct in my > calculations, the displayed frequency is +/- 1 to 2 parts in 10E-10 of 10 > MHz, assuming my GPSDO is accurate and stable. Otherwise, the GPSDO and > 53132A 'drift' is exactly the same. > > > > I would appreciate anyone's thoughts regarding this analysis and observation > and how to go about 'quantifying' it in a more scientific method, assuming > it's worth pursuing. > > > > Thanks in advance. > > > > Joe > > _______________________________________________ > 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. _______________________________________________ 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.
