[time-nuts] Frequency standard

Mark Sims holrum at hotmail.com
Sun Jan 27 02:05:54 UTC 2019


Most of the UCCM devices don't store the position.  They do a survey every time they power on.  The Samsung devices also seem to do a survey after extended periods of holdover.  Some of the Trimble (or is it Symmetricom) units will save the survey position in EEPROM.

I recently did a comparison of 17 different models of GPSDOs.  The Samsung UCCM device performed quite well...  it's currently my favorite "set it and forget it" GPSDO.  

Note that my antenna position is rather horrible (antenna 1 m above ground, lots of trees, 2 story house 20 feet west of the antenna) so these comparisons provide a good idea of what is possible in sub-optimal conditions.

http://www.eevblog.com/forum/metrology/comparing-the-performance-of-17-different-gpsdos/msg2025283/#msg2025283

TVB did some more processing of the raw data through Timelab and came up with some very nice plots of the results:

http://leapsecond.com/u/sims/gpsdo17/

------------

>  I recommend the UCCM boxes for you because they 
are pretty well automated; when first connected they do a self survey, 
store the position they find and then start to output very accurate 10 
MHz and 1 pps signals, all with no outside intervention.



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