Best practices question

Eric S. Raymond esr at
Wed Jun 26 08:53:29 UTC 2019

Patrick <201905-ntpsec at>:
> What about Radio? I.e. WWVB, JYY, DCF77, etc.?

I've been tracking this and to my knowledge there are no makers of
high-precision WWVB receivers left, following the modulation change in
2012. You can get "atomic clocks" that do the AM part of the signal,
but they have only 1-second resolution. They don't unpack the
subsecond PM information.

Different story in Europe. DCF77 receivers clearly still do exist.  I
can't find any evidence of JJY rexceivers, but that could just be because
I'm not searching in Japanese.

I think this is down to geography.  Getting WWVB signal was always
difficult in the corners of the U.S, including the northeastern
coastal region that is the most densely populated part.  After the
modulation change it appears that WWVB users moved to GPS-based time
and never looked back.
		<a href="">Eric S. Raymond</a>

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