[time-nuts] WWVB Dephaser Question

[John C. Westmoreland, P.E.]

Hello Time Nuts,

Chris - maybe you can share that if that's something you can share right
now.

Jim and Paul,

Like Chris pointed out - on that audio board in the design he's worked on -
the Line In has L and R channels - the input resistance is higher than for
the mic input -
but I suppose it's possible to try a BPSK implementation using that as a
starting point.  There's no separate gain stage for the Line In inputs like
for the mic - but
it could work - a small preamp that works with the input impedance of the
Line In circuitry may be necessary to get a good input signal - but that
shouldn't be too hard
to add.  Also - do the internals of that chip - the

https://www.pjrc.com/teensy/SGTL5000.pdf

really allow the L/R Line In channels to be treated independently?  If so,
it should be good to go at least for experimentation.

73's,
John
AJ6BC




On Mon, Oct 12, 2020 at 12:07 PM Chris Howard <chris at elfpen.com> wrote:

>
> I received a good pointer about doing the BPSK implementation
> but have just not gotten it done.
>
> Chris Howard
>
>
>
> On 10/12/20 11:02 AM, jimlux wrote:
> > On 10/12/20 7:40 AM, paul swed wrote:
> >> John really appreciate the pointer. Though it doesn't help wwvb BPSK
> >> its a
> >> really good intro to SDR and DSP super simple. A good way to get your
> >> feet
> >> wet. Hmmm is there a parts order soon? :-)
> >> Regards
> >> Paul
> >> WB8TSL
> >
> >
> > And the teensy has plenty of space and speed to implement a PLL for
> > doing BPSK demodulation.
> >
> >
> >>
> >> On Mon, Oct 12, 2020 at 10:33 AM Bob kb8tq <kb8tq at n1k.org> wrote:
> >>
> >>> Hi
> >>>
> >>> The “ideal” antenna solenoid would be a bit longer ( say 2 X to 5X ).
> >>> The turns should be spaced apart by a few percent of the length.
> >>> ( so turns over 30 or so … not so much …).
> >>>
> >>> How much better is “ideal” compared to “just get it done?”. At least
> >>> from the stories that are told, it is significant. Since all these
> >>> antennas
> >>> are very small (so non-ideal) it’s a bit of a snail race.
> >>>
> >>> Bob
> >>>
> >>>> On Oct 12, 2020, at 3:42 AM, John C. Westmoreland, P.E. <
> >>> john at westmorelandengineering.com> wrote:
> >>>>
> >>>> Paul,
> >>>>
> >>>> Doesn't the post by Chris Howard above appear to be a good/great
> >>>> starting
> >>>> point?
> >>>> Seems like that approach could be extended.
> >>>>
> >>>> https://github.com/chris-elfpen/Teensy4WWVBsdr
> >>>>
> >>>> 73's,
> >>>> John
> >>>> AJ6BC
> >>>>
> >>>>
> >
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