[time-nuts] accurate 60 hz reference chips/ckts

Jeremy Nichols jn6wfo at gmail.com
Fri Dec 15 12:14:16 EST 2017


I'm surprised Vlad is seeing as much as six seconds differential but maybe
I don't understand the experiment. I've done measurements of the line
frequency here in California and never seen much variation.

Jeremy


On Fri, Dec 15, 2017 at 9:02 AM Vlad <time at patoka.org> wrote:

>
>
> I have one of my project boxes, which monitor the main freq. Here is
> graph which reflect the time difference between of RTC (based on number
> of pulses from OCXO) and the "MAIN TIME" which is based on number of
> zero-cross events.
> The observation period is 486 hours.
>
>
>
>
> On 2017-12-14 23:13, Jim Harman wrote:
> > On Thu, Dec 14, 2017 at 10:53 PM, Bob kb8tq <kb8tq at n1k.org> wrote:
> >
> >>
> >>
> >> Of course this *assumes* an electronic approach. Given that it’s
> >> moving
> >> pretty slow and you
> >> only are looking at fractions of a millisecond, one *could* do an
> >> electro
> >> mechanical design …...
> >>
> >> Bob
> >>
> >> There is interesting background on power grid frequency/time
> >> adjustment
> > procedures here
> >
> https://en.wikipedia.org/wiki/Utility_frequency#Time_error_correction_(TEC)
> >
> > and here
> > https://en.wikipedia.org/wiki/Electric_clock#Accuracy
>
> --
> WBW,
>
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