[time-nuts] WWVB Dephaser Question

[paul swed]

The teensy is on order and downloaded the arduino plugin.
In looking at the code I should mention it does not appear to be a I&Q
sampling. Just a single stream I AM sampler. Though at 60 Khz. Its
essentially a diode with AGC and a slicer to determine a 1 or 0. No matter
a good start in the world of SDR. (At least I do not see an I&Q approach)
Regards
Paul

On Tue, Oct 13, 2020 at 2:47 AM John C. Westmoreland, P.E. <
john at westmorelandengineering.com> wrote:

> Paul,
>
> Sure - even on my OpenHPSDR system using my vertical antenna - I am almost
> able to decode WWVB (reliably) using the clock
> program from:
>
> http://f6cte.free.fr/index_anglais.htm
>
> with no changes whatsoever.  If I 'fix' the antenna - I'm sure it'll work
> more reliably.
>
> Teensy is Arduino compatible - pretty sure you can use the tools/libs
> fairly easily from Arduino - I don't have a Teensy (yet) but I will
> probably
> get a kit like what's outlined in Chris's post and also here for the people
> that may not be in the US:
>
> https://github.com/DD4WH/Teensy-DCF77 (referenced by Chris in his post).
>
> that describes the antenna circuit in more detail.
>
> 73's,
> John
> AJ6BC
>
>
>
>
>
>
>
> On Mon, Oct 12, 2020 at 8:20 PM paul swed <paulswedb at gmail.com> wrote:
>
> > John
> > I would simply use any number of receivers and grab 60 KHz out of one or
> > could use the IF at 10 KHz or 1 KHz. But more fun to use 60 KHz. The cost
> > on the teensy components is very reasonable.
> > Regards
> > Paul
> >
> > On Mon, Oct 12, 2020 at 7:44 PM John C. Westmoreland, P.E. <
> > john at westmorelandengineering.com> wrote:
> >
> > > 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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