[time-nuts] Strange GPS behaviour

David davidwhess at gmail.com
Sat Dec 29 21:01:44 UTC 2012

On Sat, 29 Dec 2012 12:18:56 -0800, Said Jackson <saidjack at aol.com>

>Happens in all the GPS receivers we have tested here. The difference between receivers is how fast they can recognize this error and how fast they can re-aquire once they shut off the 1PPS output due to tcxo instability.
>There was a recent thread here about effects of adding a fan to a Z380x and the behavior you have seen is one of the reasons why that is a bad idea.
>Some receivers like Rockwell, Trimble etc allow for external 10MHz input from an ocxo or atomic clock, and some GPSDOs make use of that feature. Having a very stable and accurate 10MHz reference for the GPS is also supposed to reduce time to second fix.

I am going to have to add that feature to my shopping list of what to
look for when I upgrade from my Garmin GPS18-5.

One feature I found interesting in the GPS18-5 is that the adjustable
dead reckoning time can be set to disable the timing pulse output when
there is no current navigation solution.

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