Geoffrey S. Mendelson schrieb:
A friend was given a clock that syncronizes itself to the 60kHz time
signal broadcasts. I know there are stations in the US (WWV?) and one in
Germany. The clock cannot receive either here in Israel.
60 kHz, that's MSF Rugby in .uk. Not overly strong even here in Germany.
In the US, there's WWVB on this frequency.
Is it a question of we are simply out of range of either of them,
or it needs a better antenna.
Try a good communications receiver known to receive well down there with
a decent antenna. If it can pick up a time signal on 60 kHz halfway
well, it might be worth it.
A sheilded loop and preamp would not
be hard to make, but I don't want to waste my time and possible
damage to his clock if there is nothing to be gained.
When building an antenna, be sure to make it very selective around the
desired frequency.
Any ideas?
You may have better luck receiving DCF77 on 77.5 kHz (Frankfurt,
Germany, nominal range 2000 km but apparently also to be picked up
occcasionally at night in Isreal and yet further locations [1]), but
this would require modifying the clock. Actually, many radio-controlled
clocks seem to be shipped in multiple versions for the various time
signal stations (with the same chip but differently tuned frontends I
suppose, though I have never taken one apart; OK, done that now, looks
like there's a little ferrite antenna with a 6800 pF film cap in
parallel forming a resonant L-C circuit for 77.5 kHz, not much else to
see).
One that came to me is to take the time from a computer synced via NTP
and transmit a signal on 60kHz to the clock. A microwatt or two would
be more than enough, and any antenna at that wavelenth I could build
would be a point source so radiation could be easily limited to a few
feet.
This may also be an option, if you have software to generate a time
signal that is.
Stephan
[1]
http://www.heret.de/funkuhr/reichw.htm
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