[time-nuts] WWVB Dephaser Question

[Graham / KE9H]

If you are looking for a serious ferrite rod antenna, then this is a good
(but slow delivery) source
http://stormwise.com/
go to:
     VLF Antennas,
          Antennas for Long Wave and 30 KHz - 530 KHz,
               Low Frequency Antenna 50 KHz - 90 KHz

Their part number  12LF50K90KBC,  50 KHz - 90 KHz antenna
is a "Monster-size 12.3 inch long x 1.02 inch diameter ferrite rod" that
will resonate to 60 kHz with an external 1000 pF capacitor.
A three turn coil around the outside center of the tube will match it to 50
Ohms for using coax such as RG-174 to run it to a standard receiver input.

I have one for receiving WWVB. It works well.
Although I have not run the detailed test, yet, my impression is that,
although the absolute signal level is higher, the signal to noise ratio for
a received WWVB signal is no better than on a five or six inch ferrite rod.

--- Graham



On Sat, Oct 10, 2020 at 8:02 AM Ole Stender Nielsen via time-nuts <
time-nuts at lists.febo.com> wrote:

> A general comment on the use of Schmitt-trigger and counters on a
> conditioned analog signal:
> You will likely run into issues with missing counts or additional counts
> when the receiver experiences fadings or glitches (lightning, etc.)
> If this happens, the 60 kHz signal will jump in phase.
>
> Ole
>
>
> Den 08-10-2020 kl. 20:07 skrev rcbuck at atcelectronics.com:
> > I have read several different articles where the WWVB phase shift is
> > eliminated by doubling the signal to 120 kHz. Several members of the
> > list have built these units.
> >
> > Assume I build a circuit to double the incoming signal and use a schmitt
> > trigger to get a 120 kHz square wave.  If I then divide that signal back
> > down to 60 kHz will that signal be strong enough to swamp out the WWVB
> > signal? I'm guessing it will be since it is at the 5 volt level and
> > somewhere in the +25 dBm or greater range.
> >
> > Ray,
> > AB7HE
> >
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