Quote:
Originally Posted by ottavio
Forgive my ignorance, but.. what's the problem? Electric clocks are not meant to be accurate. I've never had an electric clock that didn't need to be adjusted at least once a month.
The only accurate clocks I know are either mechanical clocks or Internet connected ones.
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Your electric clock that needed monthly adjustment was either not a mains synchronous one or was faulty. Typically, the instantaneous time discrepancy should not be more than 30 seconds. Medium term error over a few days should be zero. The whole electric clock industry from the 30s to the 60s was built around this fact, notably the huge range of Smiths 'Sectric' clocks. ISTR that among the multitude of instruments in a power station control room was always a mains synchronous clock to provide confirmation of long-term grid frequency.
The most accurate readily available clocks nowadays are radio-controlled. I have two sitting in front of me here: one receiving MSF 'Rugby' 60kHz (now at Anthorn) and the other its German equivalent DCF77, 77.5 kHz, near Frankfurt. Unsurprisingly, both read exactly the same time to the second. The Smiths synchronous clock on the wall on the other hand currently lags by approx 1 min 30 seconds, whereas it was pretty well correct in January.
Something has deteriorated in the long-term grid frequency stability system and it would be interesting to get the facts.
Martin