[time-nuts] WWVB Dephaser Question

Sat Oct 24 05:38:59 UTC 2020

Hello Time Nuts and Paul Again,

Paul - Have you thought about adding a 2nd audio board for the orthogonal
antenna?:

https://www.pjrc.com/store/teensy3_audio.html

I think adding a 2nd audio board could work for this possibly - of course
with the correct antenna set up.

Note the setup they have further down that page for 4-channel audio
(Quad).  I think something similar could
work for BPSK.

73's,
John
AJ6BC

On Fri, Oct 23, 2020 at 8:34 PM John C. Westmoreland, P.E. <
john at westmorelandengineering.com> wrote:

> 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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>