> http://www.leapsecond.com/pages/mains/
Fun read. Thanks. > Is a wall clock accurate to 5 seconds a day? a week? a month? The > power industry has standards for all this, I'm sure ... An old tale. Palo Alto runs its own local electrical distribution system. A friend of a friend called them up to find out how good it was as a time source. When he finally got through to somebody who knew what he was talking about, the answer was simple. "We're not tariffed for that." --------- I occasionally day-dream of setting up something so I can monitor the line voltage, frequency, current, whatever... but I've never gotten off the ground. Of course, then I'd have to get a UPS so I could save the data for the interesting events. Plan 0 is to use the audio input hardware that comes with a PC, say off a wall wart with a few resistors to adjust the full scale. Plan 1 is to get a multichannel A/D board. Anybody know of one that has a Linux driver? (Or just a good one with clean specs so I could write the driver.) As long as I'm dreaming... I need to replace my main electrical service entrance. Is there some affordable setup to measure current? I'm thinking of a UL approved current transformer, but my alarms go off when I think of low level signals getting near power wiring, especially big wires. One thing I haven't figured out is how much data to save. 16 bits at 8K HZ (telephone number) is 1.4 GB per day, so it's not a big deal to save a day or week of raw data. Probably the right thing to do is to buffer the raw data for a week and post process the raw data to automatically save something like the phase difference relative to a good local PPS source with the expectation that I'll grab the raw data by hand before it gets overwritten if something interesting happens. While I'm at it, I might just as well watch a geophone. :) And temperature... -- The suespammers.org mail server is located in California. So are all my other mailboxes. Please do not send unsolicited bulk e-mail or unsolicited commercial e-mail to my suespammers.org address or any of my other addresses. These are my opinions, not necessarily my employer's. I hate spam. _______________________________________________ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts