[time-nuts] wwvb gps d-psk-r details

[Bob Camp]

Hi

Given the (relative) low precision required of the “dummy” timing data, other sources than GPS can be used. NTP 
level precision may be adequate if you have a good NTP source. Of course if GPS catastrophes are the concern, 
accurate NTP probably isn’t going to be a viable thing. 

The more interesting timing source would be a good WWVB clock, possibly upstream of the DPSK removal device.
Once you got things bootstrapped with GPS, switch over to WWVB. 

There are other alternatives. Now that we have a working demodulator, experiments can begin to figure out which
one(s) works. 

Indeed the question of “what’s the target application?” is relevant. In many ways simply having a second reference 
is the desired outcome. That’s what interests me and this gizmo does that quite well. There are always things that
one wonders about in any system. An independent reference chain is sometimes just the thing you need to work
some of them out.

Bob

> On Sep 24, 2015, at 5:11 PM, Charles Steinmetz <csteinmetz at yandex.com> wrote:
> 
> Paul wrote:
> 
>> Here is the detailed document on the wwvb d-psk-r.
> 
> Interesting solution, and a good study in persistence.  Congratulations!  But I thought the main point of having a working WWVB receiver was as a backup if GPS fails (or for use in circumstances where WWVB reception is possible but not GPS reception).  If GPS is working, and you have a GPS rx/GPSDO, what is the point of having a time and/or frequency source that relies on GPS but only has the precision of WWVB?  And what good is the predictive de-psk-r when GPS is not working?
> 
> [Yes, I get that if one runs a museum it's nice to have working exhibits even if they are simulated, and it's no big deal if the exhibits don't work from time to time.  But the curator's solution doesn't seem to solve the time-nuts' real problem.]
> 
> I hasten to add that I don't really care one way or the other about GPS alternatives, particularly alternatives with the relative imprecision of WWVB over time scales shorter than geological.  Personally, I presume that if there is ever a persistent, system-wide GPS failure it will be due to a natural or man-made catastrophe of earthshaking proportions (literally) and there will be many, more urgent concerns than time-nuts' experiments.  But others have expressed concern over having just one time and frequency standard available.  For them, isn't a fully independent solution that does not rely on GPS required?
> 
> Again, congratulations on bringing this idea to fruition.
> 
> Best regards,
> 
> Charles
> 
> 
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