[time-nuts] time.gov reply from NIST

Jerry Hancock jerry at hanler.com
Fri May 12 20:45:45 EDT 2017


Sounds like there was a change made to the time.gov code recently that could have caused the error we noticed.  I replied to Andrew that I didn’t remember the time.gov site loading any slower or faster than usual.


Jerry, 

Thanks for writing.  I have had a few reports of incorrect time, but they were from people comparing to cell phones and WWVB clocks.  I have not been able to replicate any errors, but I had our network folks verify that the servers serving the web content are synchronizing with NTPd to NIST servers.  I trust time-nuts implicitly - if you guys say there's a problem, I believe it.

It would be difficult to believe that the server clocks could be on that far, and then corrected, and then off again.  If a refresh fixes it, then I'm confident that it is a network problem. The app corrects for half the round-trip delay, assuming that to be a good estimate for the one way delay from the web server.  However, if there is a network bottleneck or vary slow packet transfer in one direction, then the correction will not be accurate.  Have you happened to notice if it looked like it took several seconds to connect after making the web request?

I might have to take out the correction and just report the delay, how it used to be.  This is also how the widget operates: http://time.gov/widget/widget.html <http://time.gov/widget/widget.html>  So a check of the widget at the time the HTML5 application is showing an error I would expect it to be correct.  

Thanks for the information!  Please keep in touch.

Andrew Novick
NIST
(xxx) xxx - xxxx phone removed by Jerry

On 5/12/2017 11:15 AM, Jerry Hancock wrote:
> Hello,
> 
> I am a member of a group of individuals called time-nuts.  Most of us have atomic clocks or at a minimum, GPS disciplined oscillators that record and display time with a variance below 10 nanoseconds.  Yesterday around 14:00 Pacific Time I noticed while setting a new watch that time.gov <http://time.gov/> was as much as 5 seconds slow.  After reporting this on the time-nuts site, other members found the same discrepancy.  This was corrected later in the day.  At least one member of our group reported that refreshing the site corrected the error.  I found that by running the flash application that also corrected the error.  Since around 18:00 Pacific yesterday the error has been corrected.
> 
> Can you account for the discrepancy?  
> 
> Thank you,
> 
> Jerry Hancock


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