[time-nuts] WWVB Dephaser Question

Sat Oct 24 03:34:00 UTC 2020

Hello Time Nuts and Paul,

Glad to hear you're making progress - of course, as Chris Howard mentioned
earlier - it's all based on this as a starting point:

https://github.com/DD4WH/Teensy-DCF77

and Chris' work is here:

https://github.com/chris-elfpen/Teensy4WWVBsdr

Those sites are good to look at and review as well.

I still think some work will be needed to get a good signal in on the Line
In channel.

73's,
John
AJ6BC

On Fri, Oct 23, 2020 at 6:45 PM paul swed <paulswedb at gmail.com> wrote:

> John I was looking for a lot of things around BPSK and SDR and more.
> Had not hit this repository yet. But it has the piles of functions that
> would be useful. I noted it had a I & Q oscillator. So maybe the way this
> all works is you grab these functions and line them up. In looking at the
> wwvb SDR for AM mentioned here by Chris thats what I had started to
> understand.
> Really slowly getting the barest grasp on what a project might look like.
> With respect to the wwvb AM SDR receiver it does not look like any of the
> code would be used for solving the BPSK problem. That is not throwing
> stones by the way. It did nicely prove that a signal could come in and be
> processed through numbers of steps. It does work.
> My next step is to keep learning and then start to tinker with some of the
> modules in this library or even simpler the audio library for the pjrc
> shield. Audio in digitise and then back out. Much like the super simple
> arduino blinky program you have to start someplace.
> Regards
> Paul
> WB8TSL
>
> On Fri, Oct 23, 2020 at 7:55 PM John C. Westmoreland, P.E. <
> john at westmorelandengineering.com> wrote:
>
> > Hello Time Nuts,
> >
> > The code that has been previously discussed in this thread is posted
> here,
> > in case some of you didn't know and could be wondering about it:
> >
> > https://github.com/chipaudette/OpenAudio_ArduinoLibrary
> >
> > It's for the Teensy boards and WWV(B/H) SDR.
> >
> > 73's,
> > John
> > AJ6BC
> >
> > On Sun, Oct 18, 2020 at 12:27 AM John C. Westmoreland, P.E. <
> > john at westmorelandengineering.com> wrote:
> >
> > > Hello Time Nuts,
> > >
> > > FYI:  Teensy NTP server found here:
> > > https://github.com/ddrown/teensy-ntp
> > >
> > > 73's,
> > > John
> > > AJ6BC
> > >
> > >
> > > On Sat, Oct 17, 2020 at 1:16 PM paul swed <paulswedb at gmail.com> wrote:
> > >
> > >> 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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