[time-nuts] My Garmin 18x, Ver 3.50, currently 1 second slow to UTC

[David J Taylor]

> 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
-- 
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