Since alternating current is another wave, just like radio, why not add a time code? Following a power outage, or at regular intervals, every mains-powered clock in the country would reset to the correct time. Time code could also change in the middle of the night at the beginning and end of summer time.
This is not at all witty, and in fact pretty dull for half bakery, but I have been thinking about it for years and now have the chance to get it off my chest.
08.11.07 17.10 This has been up for a couple of hours and I have had seven comments. Point taken about the duplication of ideas, now get back to work!-- harperolocito, Nov 08 2007 Power-line clock setting Mains_20clock_20signalAnother very very similar idea [vincevincevince, Nov 08 2007] This might be of interest http://en.wikipedia..._line_communicationPower line communication [Ling, Nov 08 2007] AC time AC_20timeSeems to be already halfbaked. [phoenix, Nov 08 2007] I am all for this unless fiddling with the wave makes my telly flicker.-- theNakedApiarist, Nov 08 2007 [vincevincevine] - Your link point to this same idea.
The "AC time" idea (see link) seems to have already halfbaked the idea.
Welcome to the halfbakery [harperolocito].-- phoenix, Nov 08 2007 random, halfbakery