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    Re: Radio Clock or Internet GMT - which should I believe?
    From: Lu Abel
    Date: 2012 Mar 2, 23:29 -0800
    WWV is indeed the "gold standard" but not always available reliably and cheaply, so alternatives such as time.gov or atomic clocks are reasonable parts of a navigator's arsenal.



    On Mar 2, 2012, at 5:16 PM, Gary LaPook <garylapook---.net> wrote:

    I have always used WWV on short wave. There are other time signals available around the world.

    gl

    --- On Fri, 3/2/12, Lu Abel <luabel{at}ymail.com> wrote:

    From: Lu Abel <luabel{at}ymail.com>
    Subject: [NavList] Re: Radio Clock or Internet GMT - which should I believe?
    To: NavList@fer3.com
    Date: Friday, March 2, 2012, 4:34 PM

    Zvi:

    There's a lot of important information missing in this message.   Are you using time.gov or some other source of "Internet time?"

    time.gov is fairly sophisticated.   It measures the round-trip delay to your computer and adjusts your computer's display to do an electronic version of Watch Error, so the for any reasonable Internet connection it should be accurate to a fraction of a second.

    Radio clocks do not necessarily constantly adjust themselves, so the difference you are seeing may be the clock running without synchronizing back to WWVB.  

    Have you tried getting a "third opinion?"    WWV or CHU?   Although others have given counter-examples in other locations, I find that Verizon Wireless gives very accurate time in the SF Bay area where I'm located.   I just checked and it's dead on with time.gov.  (BTW, your computer's clock is not necessarily an accurate source -- it synchronizes to the "mother ship" very infrequently and may drift significantly in between)


    From: Zvi <zvidoron---.com>
    To: NavList@fer3.com
    Sent: Friday, March 2, 2012 11:00 AM
    Subject: [NavList] Radio Clock or Internet GMT - which should I believe?

    I have been using GMT provided over the Internet (via Wi-Fi) to set my time pieces by for celestial navigation, but when compared to a radio clock (AccTim Galaxias) the two time sources seem to differ, mostly by a second or two but sometimes by up to 5 seconds. Intuitively I would have thought that the radio clock would be the stable and accurate one and that the Internet GMT, delivered to a laptop or to a smartphone via Wi-Fi would suffer short delays and inconsistencies. Any thoughts or experience?


       
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