[time-nuts] Freq cal to 1ppm without GPSDO

WB6BNQ wb6bnq at cox.net
Thu Feb 17 08:36:50 UTC 2011


John,

One other thing I forgot to touch on.  The 1pps signal out of the a GPS receiver
is very jittery.  For your TCXO it will be good enough except for you having to
stare at the scope while comparing the GPS to your TCXO.  Any oscillator of
higher quality will be a problem when just using the GPS in the raw manner you
are suggesting.

73....Bill....WB6BNQ


John Beale wrote:

> Hi Murray,
>
> Thanks to you and the others for your replies. After some more HF reception
> problems here, I have come to the same conclusion as you. I found an Oncore
> M12+ timing GPS is available pretty cheap from Hong Kong, so that's my plan.
>
> best regards,
> John Beale
>
>  > 1. My best advice is to get hold of a cheap GPS module with a 1pps
> (seconds pulse) output. Connect it up, and when you have a fix, use the
> 1pps to trigger your digital oscilloscope. Set the timebase to 1us/div to
> start with, and ultimately 100ns, and observe the 10MHz output of your
> TCXO. You will see the waveform drifting slowly. Counting how long it takes
> to slip one cycle will tell you how far off the TCXO is. If you have a
> counter with Time Interval mode capability, you could use that, using the
> GPS to start and 10MHz to stop, again observing the drift.
>
> _______________________________________________
> time-nuts mailing list -- time-nuts at febo.com
> To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
> and follow the instructions there.




More information about the time-nuts mailing list