I was under the mistaken impression that WWV/WWVB had some type of
direct line to NIST in Boulder. However, when I toured the facility in
Fort Collins earlier this year, I learned otherwise. The signals and
carriers are derived/synced from "ordinary" HP (possibly some more
recent Symmetricom's) cesium beam atomic clocks. I wish I remembered
the details, but I asked how they synced them with NIST. I believe the
answer was that at one time they had some type of connection to Boulder,
but now just use a GPS based solution.
The WWV and WWVB stations in Fort Collins are old, and run on a fairly
tight budget, with a very small (but dedicated) staff. They are not on
the cutting edge of timekeeping technology. I'm not trying to imply
that WWV/WWVB is "inaccurate", but there is nothing special there. Many
of the participants on this list, if they were determined, could put out
a signal every bit as accurate as WWV or WWVB, they just wouldn't be
able to do it at the power levels (especially WWVB) that WWV and WWVB
signals are transmitted at. The antenna's and transmitter's are some of
the most impressive parts of the WWV / WWVB facilities.
Regards,
John
P.S. I was also impressed with their backup generator, although I now
can't remember if that only provided power for the WWVB station, or for
both WWVB and WWV (they are separate facilities, although in easy
walking distance of each other on the same property).
On 8/29/2018 7:24 PM, Steve Allen wrote:
On Wed 2018-08-29T19:49:59-0400 Bob kb8tq hath writ:
A few more details about “traceability”. USNO is by statute the official source
of time for the US.
I suggest reading Matsakis, Levine, and Lombardi from this year's PTTI meeting.
USNO and NIST are both legal sources for the US.
The USNO site currently has a broken SSL cert, but the paper is also here
https://www.researchgate.net/publication/323600621_Metrological_and_legal_traceability_of_time_signals
--
Steve Allen <s...@ucolick.org> WGS-84 (GPS)
UCO/Lick Observatory--ISB 260 Natural Sciences II, Room 165 Lat +36.99855
1156 High Street Voice: +1 831 459 3046 Lng -122.06015
Santa Cruz, CA 95064 http://www.ucolick.org/~sla/ Hgt +250 m
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