[time-nuts] Leap Second quirk, Another hanging bridge

David Forbes dforbes at dakotacom.net
Tue Aug 12 16:22:52 EDT 2008

Hal Murray wrote:
> I've got a couple of GPS units that use the SiRF chips feeding NTP.  I was 
> looking for low cost units for time keeping.  They don't work very well.  The 
> time offset of the NMEA message wanders/jitters by about 100 ms.  I can 
> easily correct for a constant offset, but I can't dance around an offset that 
> won't hold still.  (Oh, well.  I tried.)

I looked into using some US GlobalSat units for my scope clock instead of the 
higher-priced GPS 18 LVC. The one I tried has an RS-232 serial port. The manual 
refers obliquely to a 1PPS capability, but unfortunately they didn't pin out the 
1PPS signal to the board connector. I guess that their market is automotive 
navigation or logging, so they didn't consider it worth their while to add the 
1PPS signal.

I got the impression that the extra $50 you pay for the Garmin receiver is money 
well spent on a well-engineered device.

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