[time-nuts] New wrist watch

D W watsondaniel3 at gmail.com
Tue Jul 7 21:24:15 EDT 2015


Last night I put it by a window with 12 o'clock facing out as suggested in the manual. It says that it synced this morning at 12:04, so I can only assume it started at midnight and took four minutes. Spot checking it against the NIST website throughout the day, I can't visually see any difference in the edge of the second. Very happy with it so far.

But I probably will do a no sync test some time. Leaving it in a metal box away from a window at night sounds quite reasonable and easy to set up. I'll do it for a week and see what happens.

Dan

> On Jul 7, 2015, at 6:19 AM, Dave Martindale <dave.martindale at gmail.com> wrote:
> 
> Two data points for one watch:
> When I bought a Casio PAW-1300, it was about 20 seconds fast.  It said that
> it had last synced on September 24, but that information does not include
> the year.  It was now June 10, so it had been running without a radio sync
> for at least 9 months (though it could have been 9 months plus 1 year, or
> plus 2 years...).  If we assume the delay is only 9 months for 20 seconds
> of error, that's a error of about 2.8 seconds/month or about 1 PPM.
> 
> A year later, the same watch got stored in a drawer where there was no
> light and poor radio reception.  After 26 days without a successful radio
> sync, it had gained 2 seconds.
> 
> (On the other hand, the watch does *not* handle a leap second when the leap
> second actually occurs.  It simply keeps counting, so it ended up being 1
> second fast after the recent June 30 leap second.  It was correct the next
> morning, after its usual overnight sync to Colorado.)
> 
> I normally leave the watch on the window ledge of a window approximately
> facing Colorado (I'm near Toronto).  It gets lots of light to keep the
> battery charged, and reliably syncs every night.  It has become my "master"
> time source that I sync all my other watches to when adjusting them.
> (Someday I need to build a time display for one of my GPS receivers, but
> the Casio works well enough).
> 
> - Dave
> 
>> On Mon, Jul 6, 2015 at 6:45 PM, D W <watsondaniel3 at gmail.com> wrote:
>> 
>> With my new found interest in time nuttiness I thought I should upgrade to
>> a decently accurate watch. I had some features I was looking for and
>> settled on a Casio Wave Ceptor. My second choice was an Eco Drive, but the
>> Casio had the right mix of features at a good price.
>> 
>> As I was sitting outside reading the manual after buying it, I laid it
>> flat on the table and started a manual sync to WWVB. The UI is pretty
>> intuitive for having so few buttons and indicators. It quickly told me that
>> it had found a stable signal, and about six minutes later it was synced.
>> Pretty cool.
>> 
>> Anyone know what the drift is like in this watch if it can't find the
>> signal for several days/weeks? I would hope that actual performance is a
>> little better than the +/- 15 sec per month stated in the manual. I should
>> trap it in a faraday bag for a while to test it...
>> 
>> Dan
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