[time-nuts] Looking for WWVB digital wall clock with digital 24 hour UTC display

Clint Turner turner at ussc.com
Thu Feb 20 13:17:13 EST 2014


Other than WWVB-based frequency references/clocks that lock onto the 60 
kHz carrier itself, I'm not aware of any WWVB-based clocks that were the 
slightest-bit affected by format change (e.g. the addition of the 
low-rate BPSK):  Please point me to any references to the contrary if 
you find them.

Co-incident with the WWVB format change there were a number of WWVB 
clocks that quit working - namely, a few of the older "SkyScan" models, 
but this had nothing at all to do with the format change, but rather an 
error in the silicon that caused them to fail to automatically set 
themselves (after initially doing so when first powered-up).  For WWVB, 
the timing of the manifestation of this bug was most unfortunate and 
there is/was quite a bit of information on the net that continues to 
propel this myth.

Being a bit of a nerd and Time Nut I went out of my way to determine the 
actual cause of this problem.

There is this:

http://ka7oei.blogspot.com/2013/02/did-nist-break-bunch-of-radio.html

In this, I determined that at least with this receiver, its detection 
bandwidth was far too wide to be adversely affected by the phase 
reversal which - in theory - could skew the timing of the recovered 
amplitude waveform of the time code modulation.  From this I concluded 
that the TRF receivers used by these inexpensive clocks weren't likely 
to be affected in the least by the BPSK.

And secondly, there is this:

http://ka7oei.blogspot.com/2013/03/yes-nist-did-break-bunch-of-radio.html

In short, I created my own, local WWVB signal and demonstrated to my 
satisfaction that the real problem with these particular clocks was that 
they couldn't tolerate dates beyond a certain range.  A shame, too, 
since these same clocks will happily display UTC with no DST - although 
they would sync at "Midnight" and early morning for their set time zone 
which means that they would sync during daylight hours:  Not a problem 
here in Utah where we have mV/m signal levels, but it could be 
disastrous for stations farther east where usable signals are available 
only in the wee hours of the morning!  (These clocks also had a bug that 
would cause them to delay a day during the spring change onto DST -  
disconcerting on the morning of the time change if it was set to local 
time with DST!)

73,

Clint
KA7OEI


> Wouldn't that be nice!
>
> They implement a new format which destroys much of the installed
> infrastructure, then don't actually produce the 'better replacement'.
>
> How very LORAN!
>
> -John




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