jfor at quikus.com
Sat Feb 23 09:37:43 EST 2013
So, if you use phase-tracking hardware, it's good for three more weeks.
Wonderful... not. :((
LORAN-C all over again!
> 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 â specifically the Spectracom NetClock and receivers
> manufactured by True Time during the 1970s and 1980s â will
> no longer be able to read the time code and will also be
> 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.
>> At least thats what the spectracom 8170 does. Then it says
>> its locked for a very long time even though it isn't.
>> 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
>>> My Spectracom 8182 will stay in time sync for several days,and then
>>> 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
>>> Don Henderickx
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