USNO Clock Fast? - NTP

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Thread: USNO Clock Fast?

  1. USNO Clock Fast?

    Why does USNO show several seconds faster than time.gov (and other
    references)?


  2. Re: USNO Clock Fast?

    On Nov 6, 1:08 pm, "Daniel Norton" wrote:
    > Why does USNO show several seconds faster than time.gov (and other
    > references)?


    I meant to include these links:

    http://tycho.usno.navy.mil/cstclock.html

    http://www.time.gov/timezone.cgi?Central/d/-6/java


  3. Re: USNO Clock Fast?

    Daniel Norton wrote:

    > Why does USNO show several seconds faster than time.gov (and other
    > references)?
    >


    It is not, now, off by "several seconds". I'm inclined to doubt that it
    ever was! I think you are misinterpreting something. Perhaps you are
    reading milliseconds as seconds?

    From here, tick.usno.navy.mil is within 898 microseconds of my own
    stratum 1 (GPS reference clock) server which is amazingly good. Usually
    internet servers are off by anywhere from two to ten milliseconds! Note
    that the servers themselves are within a few microseconds or even a few
    nanoseconds of the correct time but asymmetric network delays usually
    introduce an offset of several milliseconds.

    FWIW, the "offset" in the ntpq -p banner is in milliseconds!

  4. Re: USNO Clock Fast?

    On Nov 6, 2:56 pm, "Richard B. Gilbert" wrote:
    > From here, tick.usno.navy.mil is within 898 microseconds of my own
    > stratum 1 (GPS reference clock) server which is amazingly good....


    Maybe their NTP server is right, but their web pages are definitely 5-6
    secs fast:

    http://tycho.usno.navy.mil/cstclock.html

    http://tycho.usno.navy.mil/cgi-bin/timer.pl

    --
    Daniel


  5. Re: USNO Clock Fast?


    "Richard B. Gilbert" wrote in message
    news:rPGdnSzleqQbPNLYnZ2dnUVZ_ridnZ2d@comcast.com. ..
    > Daniel Norton wrote:
    >
    > > Why does USNO show several seconds faster than time.gov (and other
    > > references)?
    > >

    >
    > It is not, now, off by "several seconds". I'm inclined to doubt that it
    > ever was! I think you are misinterpreting something. Perhaps you are
    > reading milliseconds as seconds?
    >

    He's not misinterpreting anything. The animated clocks and the static
    display have indeed been several seconds fast lately as compared to
    time.gov, WWV, etc. (I haven't checked lately; they may have fixed it by
    now.)
    I just assumed this was due to their having deprecated these older Web-based
    services in favor of the time.gov site, which is a joint project with NIST.

    > From here, tick.usno.navy.mil is within 898 microseconds of my own
    > stratum 1 (GPS reference clock) server which is amazingly good. Usually
    > internet servers are off by anywhere from two to ten milliseconds! Note
    > that the servers themselves are within a few microseconds or even a few
    > nanoseconds of the correct time but asymmetric network delays usually
    > introduce an offset of several milliseconds.
    >
    > FWIW, the "offset" in the ntpq -p banner is in milliseconds!


    I've no doubt that USNO is spot-on to at least ten decimal places
    internally, but once their internet-based time transmissions leave
    Washington they're subject to getting stuck in traffic, running out of gas
    and carjacking just like the rest of us.


    Brian Garrett



  6. Re: USNO Clock Fast?

    Daniel Norton wrote:
    []
    > http://tycho.usno.navy.mil/cstclock.html


    The image link here does not display.


    > http://tycho.usno.navy.mil/cgi-bin/timer.pl


    This is 6 seconds fast.


    David



  7. Re: USNO Clock Fast?


    "David J Taylor"
    wrote in message news:zZV3h.48331$r61.1373@text.news.blueyonder.co. uk...
    > Daniel Norton wrote:
    > []
    > > http://tycho.usno.navy.mil/cstclock.html

    >
    > The image link here does not display.
    >

    It only works with Netscape or Mozilla/Firefox. Explorer users are SOL.

    Brian



  8. Re: USNO Clock Fast?

    Brian Garrett wrote:
    > "David J Taylor"
    > wrote in
    > message news:zZV3h.48331$r61.1373@text.news.blueyonder.co. uk...
    >> Daniel Norton wrote:
    >> []
    >>> http://tycho.usno.navy.mil/cstclock.html

    >>
    >> The image link here does not display.
    >>

    > It only works with Netscape or Mozilla/Firefox. Explorer users are
    > SOL.
    >
    > Brian


    It would be helpful to half the Web browsers if they would fix it.

    What is the problem? If I enter the URL below I get the GIF data as text
    on the screen, rather than it being displayed as graphics. Is it the
    version of GIF (87a) which they are using? Content type not correctly
    sent?

    http://tycho.usno.navy.mil//cgi-bin/...e=CST;ticks=11

    Are they being deliberately obscure in their coding?

    David



  9. Re: USNO Clock Fast?

    Dqniel,

    Which of the dozen or so USNO servers do you have in mind? The
    tick.usno.navy.mil and tock.usno.navy.mil show here within several
    microseconds relative to their GPS sources and within 50 microseconds of
    each other.

    Dave

    Daniel Norton wrote:
    > Why does USNO show several seconds faster than time.gov (and other
    > references)?
    >


  10. Re: USNO Clock Fast?

    David L. Mills wrote:
    > Dqniel,
    >
    > Which of the dozen or so USNO servers do you have in mind? The
    > tick.usno.navy.mil and tock.usno.navy.mil show here within several
    > microseconds relative to their GPS sources and within 50 microseconds of
    > each other.
    >
    > Dave
    >
    > Daniel Norton wrote:



    He's not talking about the NTP servers! He's talking about the USNO web
    site's display which is, indeed, a few seconds fast.

  11. Re: USNO Clock Fast?

    On Nov 7, 11:59 am, "Richard B. Gilbert"
    wrote:
    > David L. Mills wrote:
    > He's not talking about the NTP servers! He's talking about the USNO web
    > site's display which is, indeed, a few seconds fast.


    They're back within a second now, but absent some sort of statement of
    acknowledgement and/or stated policy of keeping it more accurate,
    they're completly bogus. USNO should remove the web pages from their
    site entirely. It's like hick-town banks with public clocks that are
    consistently wrong. Why bother?

    --
    Daniel


  12. Re: USNO Clock Fast?


    "Daniel Norton" wrote in message
    news:1162935616.371737.268370@m7g2000cwm.googlegro ups.com...
    > On Nov 7, 11:59 am, "Richard B. Gilbert"
    > wrote:
    > > David L. Mills wrote:
    > > He's not talking about the NTP servers! He's talking about the USNO web
    > > site's display which is, indeed, a few seconds fast.

    >
    > They're back within a second now, but absent some sort of statement of
    > acknowledgement and/or stated policy of keeping it more accurate,
    > they're completly bogus. USNO should remove the web pages from their
    > site entirely. It's like hick-town banks with public clocks that are
    > consistently wrong. Why bother?
    >
    > --
    > Daniel
    >


    They do give pointers to the www.time.gov site, and even that site has a
    disclaimer indicating that it is not exact enough (due to the asymmetric
    delays mentioned in previous posts) to be used for precision-timing
    purposes. But yes, if time.gov is the preferred site, one wonders why they
    bother with the older web clocks--not to mention the long-broken audio link.

    Brian
    who, if being off-topic were a crime, would now be on death row



  13. Re: USNO Clock Fast?

    On Nov 7, 5:55 pm, "Brian Garrett" wrote:
    > They do give pointers to thewww.time.govsite, and even that site has a
    > disclaimer indicating that it is not exact enough (due to the asymmetric
    > delays mentioned in previous posts) to be used for precision-timing
    > purposes.


    Asymmetric delays are one thing, six seconds fast is something else
    entirely.

    They seem to have disabled the web links, perhaps in response to my
    E-mail to their webmaster, pointing to this thread.

    > But yes, if time.gov is the preferred site, one wonders why they
    > bother with the older web clocks--not to mention the long-broken audio link.
    >
    > Brian
    > who, if being off-topic were a crime, would now be on death row


    --
    Daniel


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