[time-nuts] WWVB Dephaser Question

[paul swed]

The teensy arrived and was easily installed in the arduino IDE. Worked
right off the bat.
The wiring of the A/D and the TFT display is a bit less clear. I have all
of the details but need to go over them carefully. The teensy 4.0 is
slightly different in the pins used as compared to the various
documentation on the wwvb receiver. I will guess this is going to have an
effect in the actual program.
Regards
Paul
WB8TSL

On Sat, Oct 17, 2020 at 12:06 PM John C. Westmoreland, P.E. <
john at westmorelandengineering.com> wrote:

> Hello Time Nuts,
>
> Maybe this should be added to this thread - this page is actually pretty
> good:
>
> https://en.wikipedia.org/wiki/WWVB
>
> 73's,
> John
> AJ6BC
>
>
> On Tue, Oct 13, 2020 at 12:50 PM John C. Westmoreland, P.E. <
> john at westmorelandengineering.com> wrote:
>
> > Hello Time Nuts,
> >
> > Paul, I haven't gone over in fine detail of how the multipsk software is
> > working - so I'd like to answer with that caveat if that's OK.
> >
> > I thought it was more interesting that I got anything working as far as
> > 60kHz with my existing OpenHPSDR rig AND my default antenna.
> > The system wasn't really designed for that - and it worked.
> >
> > I'll dig into some of the details and report back - since the time
> > information is all that is needed for clock synchronization - I think the
> > easiest method available is more than likely what was done.
> >
> > It agrees with the GPS feed from Themis - so, that's a good check.  Also,
> > Themis is driving the reference clock for the HPSDR rig.
> >
> > 73's,
> > John
> > AJ6BC
> >
> >
> >
> >
> >
> >
> > On Tue, Oct 13, 2020 at 12:20 PM paul swed <paulswedb at gmail.com> wrote:
> >
> >> John I looked at what you sent. I assume its decoding the am time signal
> >> is
> >> that correct?
> >>
> >> On Tue, Oct 13, 2020 at 1:19 PM Chris Howard <chris at elfpen.com> wrote:
> >>
> >> >
> >> > That's a fair assessment.  I'm really not very far into SDR
> programming,
> >> > would like to learn more.
> >> >
> >> > I was working with someone who gave me a way forward toward
> >> > using the same hardware to do the BPSK demodulation, but I want
> >> > to get his OK before I spread his stuff into this group or other
> places.
> >> > And I have not yet done anything with it yet myself.
> >> >
> >> >
> >> > Chris
> >> >
> >> >
> >> > On 10/13/20 9:06 AM, paul swed wrote:
> >> > > 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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