[time-nuts] Timing receivers' observations of leap second

xaos xaos at darksmile.net
Sat Dec 31 20:13:01 EST 2005


My two HP Z3801As are still showing Leap Second pending.
My two Motorola Oncores changed right away.

My Trutime Irig-B GPS synchronized generator did something cool.
It did not switch right away but it showed that it was in special mode
and it made the correction about 10 seconds later.

NTP has finally adjusted.

-George
 James Maynard wrote:

>Here in Salem, Oregon, USA, I observed two timing displays at the moment 
>of the leap second: the display of an Ultralink Model 333 WWVB Decoder 
>and that of some PC software from CNS Systems, Inc. I was also listening 
>   to the audio of the HF time and frequency stations, WWV and WWVH, at 
>that time.
>
>Ultralink Model 333:
>
>My UltraLink model 333 WWVB receiver has not yet recorded the leap 
>second, probably because its antenna is in too noisy a location to 
>receive WWVB's 60 kHz signal at this time of day. The display still 
>indicates that a leap second is pending, and it still indicates an 
>offset from UTC to UT1 of -0.6 s.
>
>Apparently the Model 333 WWVB receiver's software does not apply the 
>leap second to its display at the scheduled time, althouth it does know 
>that a leap second is pending.  It seems that this software does not 
>apply the leap second until it actually receives a signal from WWVB with 
>the newly adjusted UTC timescale.
>
>The SynTac32 software (from CNS Systems, Inc.) that displays the output 
>of my Motorola M12+ timing receiver waited a couple of seconds after the 
>leap second occurred before displaying the correct time, including the 
>leap second adjustment.
>
>My guess is that this display software, like that in the WWVB receiver, 
>does not apply the leap second adjustment at the scheduled time, but 
>waits until it receives messages from the M12+ that reflect the newly 
>adjusted UTC time scale.
>
>The Motorola M12+ itself, however, as indicated in the posting from 
>Christopher Hover <ch at murgatroid.com>, does apply the leap second at the 
>scheduled time.
>
>  
>





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