[time-nuts] OOPS on my wwv legal post

[Dana Whitlow]

Since propagation issues quickly degrade both frequency stability and time
accuracy, I see little point in worrying about the difference between UTC
and UTC(NIST).

Of greater interest should be the meaningfulness of time transfer obtained
with
 NIST's TMAS service.  It is apparently referred to UTC(NIST).   See:


https://www.nist.gov/programs-projects/time-measurement-and-analysis-service-tmas

It's an interesting service; it has been in use at the Arecibo Observatory
since soon
after its inception (~5 years ago IIRC) to provide information relevant to
decisions
for  tweaking the observatory's H-maser's frequency.  TMAS revolves around
"Common
View GPS measurements".   A major down side (for most time-nuts, anyway) is
the cost
of the service, which is presently  in the neighborhood of $10k per year.

I have made inquiry regarding whether or not TMAS is also on the chopping
block;
nothing heard back so far.

Dana


Dana




On Thu, Aug 30, 2018 at 2:05 AM John Marvin <jm-tnut at themarvins.org> wrote:

> 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                    <sla at 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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