[time-nuts] Clock accuracy

[Jim Harman]

Somewhat tongue in cheek, from another relative beginner:

There are also several seconday effects you will need to consider over the
next 100 years:

-- Do you have a way of changing the battery in the clock without it
stopping?
-- Will the $10 clock's bearings last 100 years?
-- If the 1 pps output from your GPSDO comes directly from the GPS, and not
by dividing down the oscillator, how will you handle holdover events, when
it may skip some pulses?
-- Is the adjustment range of your oscillator sufficient to compensate for
100 years of drift?
-- Will the other components in your GPSDO (esp. electrolytic capacitors)
last 100 years?
-- Will the GPS system still be operating 100 years from now, or will it go
the way of LORAN? You might need a provision for seamlessly switching to a
different 1-pps source if the technology changes.


On Fri, Jul 19, 2019 at 5:10 AM Hal Murray <hmurray at megapathdsl.net> wrote:

>
> > If I live another 100 years [Let`s say I take antioxidants ;-)  ] what
> sort
> > of error should I expect in this clock? [I know that it`s better than 1
> > second per day]
>
> You didn't say anything about skipping leap seconds.
>
> Ignoring that part, and assuming you have a good antenna, and assuming the
> GPS
> operators don't screwup and/or that your GPSDO has good enough holdover,
> it
> will be right on.
>
> Your system is tracking GPS.  So the next question is what do you expect
> your
> clock to be tracking?  If you want to track UTC, then you need to research
> the
> offset between GPS and UTC.  (Hint: It's not very big.)
>
>
> --
> These are my opinions.  I hate spam.
>
>
>
>
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-- 

--Jim Harman