[ntp:questions] Re: ntp servers reporting leap second erroneously?

David L. Mills mills at udel.edu
Sun Oct 16 04:00:28 UTC 2005


Thank you for using plain ASCII, which is much easier for me to read.

The predictions are amazing.

The DUT1 does take on negative and positive values as the TAI offset 
wanders; however, the broadcast timecodes of WWV/H and WWVB have only 
four bits, one of them the sign. There is no provision for a delete 
second. So, if the UT1 moves north instead of south, more than 0.7 s 
would be lost.


Steve Allen wrote:
> David L. Mills wrote:
>>I have no idea how you arrived at a prediction when multiple steps in
>>one year would be required. With great relief it seems the IERS UT1
>>curve shows that the UTC offset from TAI continues to increase, although
>>slowly. My fear is that it might decrease, eventually causing a delete
>>second event, which is not possible in NIST radio timecode formats.
> My extrapolations of earth rotation are in plots and tables at
> http://www.ucolick.org/~sla/leapsecs/dutc.html
> Despite the best efforts of the earth's core, the values of LOD
> remain longer than 86400 SI seconds of TT, so we are safe so far.
> If I am not mistaken Tom van Baak has pointed out that it is possible
> to infer a negative leap second because of the DUT1 values.

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