[time-nuts] My Garmin 18x, Ver 3.50, currently 1 second slow to UTC
David J Taylor
david-taylor at blueyonder.co.uk
Wed Dec 29 09:32:22 UTC 2010
> The reason it caught me out, is that I had changed to version 3.30
> (where it also delays NMEA) on the 27th Sep 2010, and it took a couple
> of months to manifest as a problem. It was the "rising of the sap" in
> my trees combined with windy weather - which pushed the NMEA into the
> next second for my application.
I also noticed a gradual deterioration, but that was going into Winter
with fewer branches!
> Luckily I kept all the 18x firmware versions David, so I could simply
> reload the firmware that completed the NMEA sentences well before the
> next PPS.
But which would you trust?
> Yes, that is why it got tricky for me David, because sometimes the GPS
> gave the correct UTC time, and sometimes the UTC time was one second
> slow - depending on how much the NMEA sentences were delayed from the
> PPS.
>
> Regards, Kiwi Geoff (NZ).
With NTP which is my use of the puck, I could fix it so that /only/ the
PPS signal is used, and the coarse "nearest second" is derived elsewhere,
and that's how I'm running right now.
Cheers,
David
--
SatSignal software - quality software written to your requirements
Web: http://www.satsignal.eu
Email: david-taylor at blueyonder.co.uk
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