Comparing Watches to NIST Time

Discussion in 'Watch Repair' started by GeneJockey, Oct 12, 2019.

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  1. GeneJockey

    GeneJockey Registered User
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    Mar 2, 2012
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    On a thread a while back, somebody was asking how do you compare your watch to NIST time, so you know how it's running. Here's a way to do it with a number of watches at the same time. You need a tablet and a phone with a camera.

    On the tablet go to time.gov and leave that on the screen. Arrange your watches to be compared around the tablet, and take a picture.

    IMG_2432.JPG
    NIST time shows 1:10:42

    From the left
    1. 1:10:53 +11s
    2. 1:10:17 -25s
    3. 1:11:12 +30s
    4. 1:10:47 +5s
    5. 1:10:37 -5s
    So, these are all set within +/- 30 seconds from NIST. In a day, or a week - always keeping them wound - I can do the same thing again, and see how far they've changed. This saves you trying to switch your eyes quickly from the watch to the screen and back. You can take the picture, and figure the variance at your leisure.
     
    Gregory Smith, Rob P. and viclip like this.
  2. GeneJockey

    GeneJockey Registered User
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    Sharp eyes will see what seems to be a 3057 case, with a dial that belongs to a 571 movement from a few years before that case was released (second from left) Close! It's actually one of Star's replacement cases that they sold after Elgin stopped selling 571s. I picked it up last month on Ebay with a 572 in it, and used it to house a U-prefix 571 movement. The case itself seems to be NEW. All edges sharp, no scratches, all brushing perfect. But it didn't come with the right crown, so if anyone's got one let me know!
     
  3. watchwldr940

    watchwldr940 Registered User
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    The other thing you can do, as I do, is call the US Naval observatory and put it on speaker. That gives recorded tics every 5 seconds or so and the mechanical voice announces them so it's super simple to use. George
     
    viclip likes this.
  4. glenhead

    glenhead Registered User
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    In the USA, telephone number 303-499-7111 dials into the annunciator for the NIST master clock in Ft. Collins, Colorado. That's the source for the WWV and WWVB time-reference signals. It ticks once a second and gives UCT (GMT) time on the minute. Around the globe a shortwave radio tuned to 2.5, 5, 10, 15, or 20MHz can pull the same signal out of the æther. The frequency will vary depending on the time of day. Hands-free, accurate, always there.

    Glen
     
    Leigh Callaway likes this.
  5. Leigh Callaway

    Leigh Callaway Registered User
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  6. johnbscott

    johnbscott Registered User
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    My suggestion is to get the Emerald Sequoia app on your phone. It reads out satellite time to a fraction of a second and provides audible one second "ticks" so that you don't need to take your eyes off the watch you are timing.

    In the watch factories (in later times) they had electromagnetic sounders beating out seconds, so the approach was the same when the watches were being manufactured.
     
    viclip likes this.

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