[time-nuts] WWVB Dephaser Question

[paul swed]

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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