Hi Joe... Just to show off that I've learned a thing or two in the 6-8 years I've been subscribed to this list, I will venture to say that the culprit is the direction of the gravity vector through the oscillator. I recall a couple of guys talking about the frequency change of their Morion's when flipped 180 degrees.
But, it could be an interference issue as well, like hum pickup from lights or the like, but I don’t know what the magnitude of that effect would be. Tom Holmes, N8ZM -----Original Message----- From: time-nuts [mailto:time-nuts-boun...@febo.com] On Behalf Of J. L. Trantham Sent: Monday, May 11, 2015 9:25 PM To: Discussion of precise time and frequency measurement Subject: [time-nuts] 53132A Polish UHS Time Base Option Interesting Ovservation 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 -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. _______________________________________________ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
