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 <pmo...@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 > > _______________________________________________ > time-nuts mailing list -- firstname.lastname@example.org > To unsubscribe, go to > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > _______________________________________________ time-nuts mailing list -- email@example.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.