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    Re: Chronometer Suggestions
    From: Fred Hebard
    Date: 2009 Jan 11, 13:01 -0500

    Just in case anybody missed it, I took a picture of Paul's data.
    There's a seasonal periodicity and the watch and clock are in
    opposite phase!
    
    Fred
    
    
    Overlay Plot
    
    
    
    On Jan 11, 2009, at 12:18 PM, Paul Hirose wrote:
    
    >
    > It may be interesting to look at the seasonal variations in daily rate
    > of an ordinary battery powered wall clock. I check this clock monthly,
    > so the values are the average daily rate for the month. All values are
    > positive, i.e., the clock always runs fast.
    >
    >       2006  2007  2008
    > Jan   .40   .38*  .37
    > Feb   .40   .45   .39
    > Mar   .38   .46   .44
    > Apr   .43   .46   .45
    > May   .47   .50   .50
    > Jun   .48   .52   .52*
    > Jul   .40   .48   .50
    > Aug   .48   .48   .49
    > Sep   .47   .50   .52
    > Oct   .44   .47   .49
    > Nov   .41   .41   .46
    > Dec   .35   .38   .41
    >
    > * new battery installed at beginning of this month
    >
    >
    > And here are values for a $25 Timex digital watch I bought in 2000. It
    > still has the original battery. I don't wear this watch a lot;
    > probably
    > less than 5 hours per week.
    >
    >       2006  2007  2008
    > Jan   .43   .41   .42
    > Feb   .40   .42   .42
    > Mar   .41   .43   .45
    > Apr   .41   .41   .43
    > May   .39   .41   .42
    > Jun   .34   .40   .38
    > Jul   .26   .35   .34
    > Aug   .35   .34   .34
    > Sep   .40   .40   .40
    > Oct   .43   .45   .43
    > Nov   .43   .44   .46
    > Dec   .41   .43   .44
    >
    >
    > The time checks are by eye and ear using WWV on a cell phone. By
    > comparing the phone audio to the audio from a shortwave receiver I've
    > found that the phone is consistently 1/4 second late, as well as I can
    > estimate, so this constant is disregarded.
    >
    > My monthly error checks are accurate to perhaps 1/4 second, so the
    > corresponding daily rate is probably accurate to plus or minus .01
    > second.
    >
    > --
    > I block messages that contain attachments or HTML.
    >
    >
    > >
    >
    
    
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