[time-nuts] Rb vs.Crystal OCXO

SAIDJACK at aol.com SAIDJACK at aol.com
Mon Apr 28 14:38:50 EDT 2014

Hi Hans,
in order not to chase the tempco and aging algorithm (it will reset the  
values by itself every 10 minutes while locked to GPS as you have noted) you 
may  simply turn tempco and aging compensation off manually during your test  
This can be done by the serv:tas x, yy... command. The first  parameter is 
the mode; 0 being both off, 1 being aging compensation only, and 2  being 
both aging and temperature compensation.
So the commands would be:
to query the current settings, then issuing the command:
   serv: tas 0, xx, xx ...
where xx, xx.. are the same values that were shown with the query  command.
   To re-enable the aging and tempco compensation when you  are done with 
your measurement, simply send the 
serv: tas 2, xx, xx ...
command using the same settings again as the query command had  returned.
Hope that helps,

In a message dated 4/28/2014 05:32:41 Pacific Daylight Time,  
hans.holzach at gmail.com writes:


if i understand correctly, while  in holdover, activated by
sync:hold:init, temperature and  aging compensation are still active
(as it should be).  however, to measure drift, i have to somehow
disable these  compensations, haven't i?

yesterday, i wrote down  the values of temperature and aging
compensation, then set  both to 0. in holdover the software does not
seem to  recalculate the values, at least not during the hour or two
i  had the oscillator unlocked. on uli's Z38XX the EFC curve was
flat, unlike when temperature and aging compensation are active (or
not 0) during holdover. one hour or so after sync:hold:rec:init  i
checked the values again, and they were very close to the  values
before i reset them to 0.

my question is: would this be the correct procedure to have a truely
unlocked oscillator: start holdover and then set tempco and aging  to

thank you,



There is  an easier method that does not jiggle the board mechanically:

The  command:


Disables the  disciplining.


Re-enables  disciplining.

The sync:tint? command can be used to check the drift  while in  holdover..

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