[time-nuts] Plug and play GPSDOs was:(no subject)

Mark Sims holrum at hotmail.com
Tue Jun 30 17:44:05 EDT 2009


The main reason for manually doing the self-survey and saving the results is so that the unit won't spend hours doing it every time it powers up.  It's a one time thing and well worth the trouble.

Every foot of position error can introduce a nanosecond of offset in the timing results.   Probably not an issue for most people.  However,  it can also introduce some offsets in the frequency output (which is what most people buy these things for).  

The frequency offsets tend to average out over a day,  but these units are capable of producing cesium-beam quality output for a zillionth the price (and over extended periods of time they will beat a cesium oscillator).  You might was well give them as good a quality head start as you can...




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Yes, it's helpful on the way to perfection. Is it a requirement for the
OPs level of ambition? I think not.

I wonder if the long self-survey procedure is an artifact from the bad old
SA-days, when there was a genuine need to filter out the quarter of an
hour wiggle introduced to the GPS signals.


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