[time-nuts] Is possible precise 1pps?

David davidwhess at gmail.com
Wed Mar 13 21:05:23 EDT 2013

On Wed, 13 Mar 2013 10:17:30 -0700, Chris Albertson
<albertson.chris at gmail.com> wrote:

>On Wed, Mar 13, 2013 at 6:03 AM,  <hutta.j at seznam.cz> wrote:
>> I have GPS without  "position hold", I wonder how precise 1PPS, which I want
>> to use for disciplined OCXO.
>THere is more difference between brands and models of GPS receivers.
>Accuracy of the pPS can vary over a factor of 1000.    But the good
>news is that you can buy a good one for under $20 on eBay so there is
>not much reason to "make do" and one that does not work well.
>Chris Albertson
>Redondo Beach, California

This brings up something that I have wondered about for a while.

The Garmin GPS18x (and many other receivers) specify the PPS output as
within 1uS but does that mean it wanders around over say 12 or 24
hours within 1uS of GPS Time or does it mean something else?  I can
easily see the granularity of the PPS output but that is obviously not
what the specification refers to.

I guess I need to pickup a real timing receiver or good oscillator to
run a comparison with to see what is going on.

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