[time-nuts] Clock accuracy
D. Resor
organlists1 at sonic.net
Fri Jul 19 14:17:46 UTC 2019
For curiosity sake, this sounds like it is a Master Clock > Slave Clock
system.
Are the slave clocks DC Impulse driven or do they have AC synchronous
gearbox motors which then correct on/near the hour every 12 hours?
For instance at 6 O'clock twice a day on let's say the 58th minute?
You want something more accurate than a TCXO module which might plug into a
slot on the backplane of the master clock?
Donald Resor
N6KAW
-----Original Message-----
From: time-nuts <time-nuts-bounces at lists.febo.com> On Behalf Of paul swed
Sent: Friday, July 19, 2019 6:34 AM
To: Discussion of precise time and frequency measurement
<time-nuts at lists.febo.com>
Subject: Re: [time-nuts] Clock accuracy
Jim
Boy did you actually hit the issues.
I have run into all of them. The bearings are a real issue.
I have one clock I need to pull down and lube. Pain in the butt.
Regards
Paul
On Fri, Jul 19, 2019 at 9:20 AM Jim Harman <j99harman at gmail.com> wrote:
> 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
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