[time-nuts] WWVB sync

Charles P. Steinmetz charles_steinmetz at lavabit.com
Thu Mar 21 14:06:01 EDT 2013

Bob wrote:

>Some of these clocks and watches seem to like midnight as the magic 
>time to synchronize. That's certainly what the Casio's do.

Mine (it's a Brookstone, I don't know who manufactured it) will go a 
few days without a successful sync, then it switches to trying every 
two hours until it successfully synchronizes.  I think it will then 
use that time every day until you intervene manually or it has to do 
it again.  It also seems to adjust the local XO when it has daily 
success -- after running awhile with daily sync, it has outstanding 
holdover performance.

I'm in a low-signal area, but even here signal strength does not seem 
to be a problem.  Local interference at 60 kHz, however, is a big problem.

NIST Special Publication 960-14 (2009) gives recommended practices 
for WWVB-disciplined clock manufacturers and consumers.  (It may have 
been updated or replaced since the new modulation scheme was adopted) 

See this page for near-real-time signal monitoring 
status:  <http://tf.nist.gov/tf-cgi/wwvbmonitor_e.cgi>

Best regards,


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