[time-nuts] WWVB phase plots

[paul swed]

Jeeze the answers simple DCF is metric and wwvb in english.
They never work correctly together. ;-)
Regards
Paul
WB8TSL

On Tue, Mar 20, 2012 at 6:18 AM, Peter Monta <pmonta at gmail.com> wrote:

> > The transitions (where the phase change!) are what you correlate,
> > the more, the better S/N you get.
>
> Yes---it's too bad that the proposed WWVB changes don't increase the
> number of transitions at all.  Could they not do the
> low-modulation-index DCF77-like signal on top of the BPSK?  That is,
> put some small, fast phase wiggles on top of the slow 180-degree
> transitions (or 120-degree transitions if NIST can be convinced to
> change to that)?
>
> But maybe some Loran-like tricks could be tried with an ordinary WWVB
> signal and a receiver with a few kHz bandwidth.  The first part of the
> exponential decay of the carrier amplitude (at the on-second marks)
> might be relatively uncorrupted by sky wave, just as with Loran.
> Considerable averaging would be needed I guess.  If the
> characteristics of the transmitting antenna are known, a model of the
> pulse decay could be used to estimate the transmit time.
>
> The phase transitions happen during the low-power intervals (-17 dB),
> so they would seem to be less useful than the amplitude transitions:
> an 11 dB penalty, counting the gain from the antipodal signaling.
>
> What is the inherent bandwidth of the DCF77 system, by the way?
>
> John, if you're reading this, would your receiver be capable of
> recording with wider RF bandwidth?  Your recordings made during the
> test period have a bandwidth of about 30 Hz; can it go any wider?  I
> think your web page says you're using an active whip antenna, which is
> good because the resonant loops would impose their own bandwidth
> limit.  If you could eliminate the narrowband receiver and record the
> antenna signal directly with the 192 ksa/s ADC, that would be ideal.
> (I should really cobble up a system of my own, but I'm a fair distance
> from Colorado.)
>
> Cheers,
> Peter
>
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