What is the accuracy of the Flex 6700's GPSDO?

Roy Laufer · December 2014

I have been looking at the documentation for the improved accuracy with the Flex 6700's GSDO. In places I have seen "<5.0 x 10^-12, but in other places I have seen the accuracy estimated as "0.005 ppm" (which would be 5x10^-9 NOT 10^-12). Am I losing my ability to do simple math, or are one of these published specs a typo??

At these accuracies it's almost just academic, but I'm still curious!

73,
Roy, AC2GS

Martin AA6E · December 2014

The current FRS spec says the stability of the GPSDO is 5 x 10**-12 over 24 hours. They do not specify any level of accuracy, which can be quite a different thing. To my mind, the stability spec means that the frequency (averaged over some short time period) will not vary by more than the given number over a 24 hour period. There will be a constant offset from the nominal frequency -- that's the accuracy. You can take that out by entering the offset in SSDR -- if you can measure it!

Characterizing high performance oscillators is not simple, and I wish FRS gave more information. In my astronomical work, we commonly used the Allan Variance, which tells you what frequency / phase performance you can expect over a wide range of time intervals. See www.rohde-schwarz.de/file/1EF69_E3.pdf, for example.

73 Martin AA6E

NA0B · January 24

Martin,

Did you ever get more information about the GPSDO accuracy in the FLEX-6600?

Do you know if Flex has a specs document for the GPSDO in Flex-6000 transceivers? I found specs for the FLEX-8600 GPSDO, but not the FLEX-6000. The Allen Deviation fo the FLEX-8600 GPSDO is listed as 10Ks < 2E-012.

We (the University of Pittsburgh Amateur Radio Club, W3YJ) are trying to build an S-band receiver to track the Artemis II mission. We need a very accurate oscillator. Any suggestions would be welcome.

73 de Juan, NA0B

What is the accuracy of the Flex 6700's GPSDO?

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