Re: [LEAPSECS] Diagram of CHU Leap-Second Recording and "Atomic" Clock

From: Poul-Henning Kamp <>
Date: Wed, 04 Jan 2006 23:27:29 +0100

In message <003201c61171$43b12fa0$9515f204_at_computer>, "Tom Van Baak" writes:
>> The majority of such clocks only run the receiver for some part of
>> the day to save power.
>> One particular kind I examined ran the receiver until it had sync,
>> then powered the receiver down for 23 hours and repeated the cycle.
>Yes, but the LS bit stays lit for the entire month (at
>least for WWVB) so the RC clock has plenty of notice
>to insert a leap second at the end of the month if it
>wanted to, regardless of reception quality the day
>of the leap second.
>Unfortunately, this is not the case with the DST bits.
>Users routinely complain that WWVB RC clocks do
>not handle DST correctly. This is because there is
>less than one day advance notice of a DST change.

DCF77 lights the bit for only one hour prior to the leap-second :-(

Poul-Henning Kamp       | UNIX since Zilog Zeus 3.20
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Received on Wed Jan 04 2006 - 14:38:00 PST

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