[time-nuts] Z3801A gps week rollover

Art Sepin art at synergy-gps.com
Thu Sep 8 18:50:51 EDT 2016

Timing product manufacturers used a variety of OEM GPS timing receivers over the years including the Motorola Oncore series. The 1024 Week-Roll-Over dates for Oncore receivers, computed from the firmware version compile date, are listed here:


Synergy is adding 8 channel Motorola binary commands to our u-Blox based SSR-6Tf OEM timing receiver that plugs into an Oncore 8 channel slot - available "soon."

Art Sepin

-----Original Message-----
From: time-nuts [mailto:time-nuts-bounces at febo.com] On Behalf Of Hal Murray
Sent: Thursday, September 08, 2016 2:54 PM
To: Discussion of precise time and frequency measurement <time-nuts at febo.com>
Cc: hmurray at megapathdsl.net
Subject: Re: [time-nuts] Z3801A gps week rollover

petervince1952 at gmail.com said:
> Can I just ask why the Z3801As are  having week roll-over problems now 
> - I didn't think it was 2048 weeks since GPS "zero-hour" until late on 
> the 6th of April 2019?

It's probably 1024 weeks since a date was built into the firmware.

It's like the year 2000 problem.  If you aren't worried about old people and I tell you somebody was born in 03, you can assume that's 2003 rather than 1903.  For GPS, a handy value for the cutoff is the date the firmware was built.  Any date that looks like it is older than the firmware is probably off by a rollover.

These are my opinions.  I hate spam.

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