In article ,
"Bob Eager" writes:
On Fri, 17 Oct 2003 14:15:11 UTC, "Mark" wrote:

How do these Radio controlled clocks supposed to work?

The Rugby transmitter sends a continuous time signal. It takes exactly
one minute to send the time *once*.

The signal is transmitted at 1 bit per second, represented by
a 100ms or 200ms break in the carrier IIRC. I built a rugby
clock receiver about 12 years ago, together with a driver for
Interactive UNIX for it to keep the system clock in sync.
If you arrange for the breaks in the carrier to cause an
audiable tone, it's quite easy to decode it by ear. I sat up
on a few occasions to listen to it handling the daylight savings
shift (not sure I should admit things like this;-).

For some years (certainly when I built my receiver 12 years ago),
there was also a fastcode transmission in the last second of
each minute which encoded much (maybe all) of the data again
within that second. I vaguely recall hearing they have since
dropped the fastcode transmission.

--
Andrew Gabriel