[time-nuts] WWVB

paul swed paulswedb at gmail.com
Sat Feb 23 10:11:51 EST 2013


Now about those dead true-times. I am still looking for 1 or two to test
with as I work on the WWVB d-PSK-r. I have shared one spectrcom solution
with the group. And been working on a more universal costas loop answer.
The loops seems to work nicely and has been operational over a two week
period. Currently building a general purpose TRF front end for the loop.
Johns put up with my emails through the year long process. Thanks.
Regards
Paul

On Sat, Feb 23, 2013 at 9:37 AM, J. Forster <jfor at quikus.com> wrote:

> So, if you use phase-tracking hardware, it's good for three more weeks.
>
> Wonderful...  not.  :((
>
> LORAN-C all over again!
>
> -John
>
> =================
>
>
> > On Fri, Feb 22, 2013 at 06:01:46PM -0500, paul swed wrote:
> >> Donald from what I have been seeing they are consistent.
> >
> >> But there is a 1 hour period up around 1 or 2 pm est that
> >> they go back to the old modulation and that allows time
> >> clocks to lock.
> >
> > Just for information here (from their web page):
> >
> > Since October 29, 2012 at 1500 UTC (9:00 AM MDT), NIST
> > Radio Station WWVB has been broadcasting a phase modulation
> > (PM) time code protocol that has been added to the legacy
> > AM/pulse-width-modulation signal.
> >
> > This enhancement to the broadcast, which has been tested
> > throughout 2012, provides significantly improved performance
> > in new products that are designed to receive it.
> >
> > Existing radio-controlled clocks and watches are not
> > affected by this enhancement, and continue to work as before.
> >
> > Disciplined oscillator products that track and lock to the
> > 60 kHz WWVB carrier and were designed to work as frequency
> > standards, will not work with the PM signal and will now
> > become obsolete.
> >
> > A few radio controlled clocks that used information from the
> > carrier – specifically the Spectracom NetClock and receivers
> > manufactured by True Time during the 1970s and 1980s – will
> > no longer be able to read the time code and will also be
> > obsolete.
> >
> > To allow users of these receivers to migrate to new products,
> > the plan for implementing the new modulation protocol
> > includes a transition period that will extend until at least
> > March 21, 2013.
> >
> > During the transition period, the PM signal will be turned
> > off for 30 minutes twice per day, at noon and midnight
> > Mountain Standard Time (MST), allowing carrier tracking
> > receivers to temporarily acquire the legacy signal.
> >
> > HTC,
> > Herbert
> >
> >> At least thats what the spectracom 8170 does. Then it says
> >> its locked for a very long time even though it isn't.
> >
> >> Regards
> >> Paul
> >> WB8TSL
> >
> >> On Fri, Feb 22, 2013 at 3:35 PM, Donald Henderickx
> >> <wa9ylp at sandprairie.net>wrote:
> >
> >>> Is wwvb consistent in the testing of there modulation scheme?I find
> >>> that
> >>> My Spectracom 8182  will stay in time sync for several days,and then
> >>> loose
> >>> it for five or six hours. Is any one else experiencing this?
> >>> I am thinking of trying my kinemetrics/truetime 60-TF to see if it
> >>> might
> >>> function.
> >>> Don Henderickx
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