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

Hal Murray hmurray at megapathdsl.net
Wed Jan 5 09:32:29 UTC 2011

david-taylor at blueyonder.co.uk said:
> I had an e-mail response from Garmin which suggested turning off the
> position averaging introduced as a new option in 3.50 firmware.  Whilst
> that may have helped a little, I still saw (at 19200 baud) sentences
> starting during the PPS signal, i.e. more than one second delayed.  This
> using a single GPS sentence. 

I think you will have a much better chance of getting Garmin to fix something 
if we can come up with a clear description of what is broken and/or a simple 
recipe for a setup that demonstrates the problem.

What do you mean by "more than one second delayed"?  That sounds like you are 
looking at the wrong PPS signal.

Could you describe your test setup?

I don't see a problem with a delay as long as it's reasonably stable.  ntpd 
has fudge time1 to correct for that.  (Even the old "working" firmware had a 
horrible delay.)  Jitter would be a problem.

What sort of range of delays are you seeing?

Kiwi Geoff reported about 150 ms of jitter.  That's ugly, but I think we can 
live with it.

These are my opinions, not necessarily my employer's.  I hate spam.

More information about the time-nuts mailing list