[time-nuts] 53132A Polish UHS Time Base Option Interesting Ovservation

J. L. Trantham jltran at att.net
Mon May 11 21:24:35 EDT 2015


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



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