[time-nuts] Re: Has Line-Frequency Timekeeping Become Less Reliable in the U.S.?

[Tim Shoppa]

See those sites track frequency. And the original poster was asking about
long-term phase (timekeeping). They're related but different goals.

We have the same confusion regarding Leo Bednar-descended OCXO units which
(with a few recent exceptions) are actually frequency-locked units, not
phase-locked.

Sometimes I think we ought to call this list "phase-nuts" :-).

Tim N3QE

On Sat, Jul 18, 2026 at 8:16 AM David Cureton via time-nuts <
time-nuts at lists.febo.com> wrote:

> Cool website that tracks grid frequency..
>
> https://fnetgrideye.utk.edu/frequencygauge.html
>
> or
>
> https://kestrelgrid.com/?utm_source=chatgpt.com
>
>
>
> not the one is was thinking of which was someone's DIY project that had
> much greater published observation windows.
>
>
>
> Regards,
>
> David
>
> ----- Original Message -----
> From: "Larry McDavid via time-nuts" <time-nuts at lists.febo.com>
> To: "Discussion of precise time and frequency measurement" <
> time-nuts at lists.febo.com>
> Cc: "Larry McDavid" <lmcdavid at lmceng.com>
> Sent: Thursday, 16 July, 2026 3:02:09 PM
> Subject: [time-nuts] Re: Has Line-Frequency Timekeeping Become Less
> Reliable in the U.S.?
>
> Nope. All appliances I've checked count mains cycles; this includes
> three microwave ovens, a kitchen oven and an air fryer. I've set them
> accurately and watched the minute turn over simultaneously on the
> several kitchen appliances, concurrent with a very old digital,
> single-chip clock that also counts line cycles. They all run slow or
> fast equally. Mains cycle count is no longer maintained. By a lot...
>
> I do have two nightstand clocks that count oscillator cycles; one runs
> slow, one fast.
>
> Only my GPS clocks (and GPSDO) are accurate. WWVB clocks vary a few
> seconds until they reset after midnight. Except for two BPSK WWVB
> clocks; those reset throughout the day due to 100X 60 KHz receiver
> decode sensitivity.
>
> These are solid, empirical data.
>
> Best wishes,
>
> Larry McDavid W6FUB
> Anaheim, California (SE of Los Angeles, near Disneyland)
>
> On 7/15/2026 3:06 PM, Jim Lux via time-nuts wrote:
> >
> >
> >
> >
> >
> > I would think that ovens, appliances, and the like don't count cycles
> any more.  They all have microcontrollers in them, and they'd count
> oscillator cycles.
> > Even my 20 year old bedside clock doesn't use line frequency (because it
> has battery backup, it can't).
> >
> > Yes, my grandmother's old stove with the clock built in, manufactured
> some time pre-1960, certainly is line frequency dependent.
> > A washing machine with a mechanical timer perhaps.  But the old
> microwave oven I have in the garage that has a "turn knob to set cooking
> time" uses a *mechanical* spring wound timer.
> >
> > Is there anything that uses line frequency as a time standard any more
> (other than weird stuff like PDP-11's using line frequency for RTC input)
> >
> > Older timeclocks controlling lighting (the ones with the pegs to turn
> and off) probably use synchronous motors. Same with the household timers
> that one might use for holiday lights.
> >
> > I note that in a new installation for lighting controls, almost
> invariably, for exterior and sign lighting they're required to be
> "astronomical" timers that know when sunrise and sunset are. (CA TItle 24,
> ASHRAE 90.1) (or photodetectors). And for interiors, they're required to be
> able to automatically deal with holidays and daylight saving time. That
> pretty much means the old mechanical timers have limited uses.
> >
> >
> >
> >
> > On Wed, 15 Jul 2026 15:15:10 +0000, "Thomas D. Erb via time-nuts" <
> time-nuts at lists.febo.com> wrote:
> >
> > I recently came across information suggesting that the way the North
> American power grid handles accumulated time error may be changing, and I
> had not realized this was even being discussed.
> >
> > Historically, synchronous clocks-and some electronic appliance clocks
> that count the 60 Hz AC waveform-benefited from long-term grid-frequency
> correction. Although the instantaneous frequency varied slightly,
> accumulated error was corrected so that these clocks remained reasonably
> accurate over time.
> >
> > Does anyone here know the current status of Time Error Correction on the
> different North American interconnections?
> >
> > More specifically, are traditional synchronous clocks now likely to
> accumulate noticeable long-term error? And what about microwave ovens,
> ranges and other digital clocks that may use AC zero crossings rather than
> a crystal or real-time clock for their time base?
> >
> > I initially saw a reference to an April 14, 2026 NERC/FERC action, but
> on looking more closely, that appears to concern retirement of
> BAL-002-WECC-3, a contingency-reserve standard-not BAL-004 time-error
> correction. NERC still lists BAL-004-WECC-4, Automatic Time Error
> Correction, as active in the Western Interconnection.
> >
> > I would be interested to hear from anyone familiar with current utility
> frequency-control practices, particularly in the Eastern Interconnection.
> >
> >
> > Thomas D. Erb
> > o: 508-359-9684
> > p: 508-359-4396 x 1700
> > f: 508-359-4482
> > a: 97 West Street, Medfield, MA 02052 USA
> > e: tde at electrictime.com
> > w: www.electrictime.com
> > Tower & Street Clocks Since 1928
> >
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> >
> >
> >
> >
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