[time-nuts] Recommendations for Mains Power Monitor / Logger

[Tom Van Baak]

> “Back in the day” we used WWV and the kitchen clock for that sort of thing……

Bob,

Yes, not much has changed. I use multiple methods to measure 60 Hz in order to gain confidence in the results. Besides the picPET, I've used a commercial TrueTime TFDM (Time/Frequency Deviation Meter) and also a plain old kitchen clock (synchronous motor, wall clock).

Example: I took photos of the kitchen clock precisely 30 seconds after each quarter hour. Here's the short animated GIF of that run; you can see how the wall clock wanders from 0 to 5 seconds ahead of the UTC reference clock (seen in the background):

http://leapsecond.com/pages/tec/mains-clock-ani.gif

For alert readers: the +/- 1 second jitter in the reference clock is due to drift and latency in the PC scripts used to trigger the photo capture. Also sunrise (Pacific time) can be seen in the background starting about 1300 UTC.

/tvb