Antenna and filtering are not a problem for me. I use the 10' X 10' square loop and about 800' of wire with a cap to resonate at 60 KHz and then a preamp really to drive 140' of coax. Currently using a modified KD2BD receiver frontend but using a 350 Hz xtal filter. Yes indeed that hamfest find was amazing.
Looks like you have to build a costa loop SDR. Looked at lots of documents. My first question to the group. Can a single incoming sample be converted to I & Q through math. I sort of think so. The original sample might be I and then use math to make Q. That would save an entire analog chain. The teensy has a single chain for mic level input. Though it does feed left and right channels. Granted there are two audio chains at line level. The teensy has a NCO that can create a quadrature output. The alternate would be to use that to drive analog switches as a multiplier to form I & Q samples. Regards Paul WB8TSL On Sat, Oct 24, 2020 at 2:05 PM John C. Westmoreland, P.E. < [email protected]> wrote: > 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. < > [email protected]> 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 <[email protected]> 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. < > >> [email protected]> 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. < > >> > [email protected]> 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 <[email protected]> > >> 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. < > >> > >> [email protected]> 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. < > >> > >> > [email protected]> 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 < > [email protected]> > >> > >> 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 < > [email protected]> > >> > >> 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. < > >> > >> > >> > > [email protected]> 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 < > >> > [email protected]> > >> > >> > >> 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. < > >> > >> > >> > >>> [email protected]> 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 < > >> > >> [email protected]> > >> > >> > >> > >> 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 < > >> > [email protected]> > >> > >> > >> 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. < > >> > >> > >> > >>>>>>>> [email protected]> 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 > >> > >> > >> > >>>>>>>>> > >> > >> > >> > >>>>>>>>> > >> > >> > >> > >>>>>> _______________________________________________ > >> > >> > >> > >>>>>> time-nuts mailing list -- [email protected] > >> > >> > >> > >>>>>> To unsubscribe, go to > >> > >> > >> > >>>>>> > >> > >> > http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com > >> > >> > >> > >>>>>> and follow the instructions there. > >> > >> > >> > >>>>> > >> > >> > >> > >>>>> _______________________________________________ > >> > >> > >> > >>>>> time-nuts mailing list -- [email protected] > >> > >> > >> > >>>>> To unsubscribe, go to > >> > >> > >> > >>>>> > >> > >> http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com > >> > >> > >> > >>>>> and follow the instructions there. > >> > >> > >> > >>>>> > >> > >> > >> > >>>> _______________________________________________ > >> > >> > >> > >>>> time-nuts mailing list -- [email protected] > >> > >> > >> > >>>> To unsubscribe, go to > >> > >> > >> > >>>> > >> > >> http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com > >> > >> > >> > >>>> and follow the instructions there. > >> > >> > >> > >>>> > >> > >> > >> > >>> _______________________________________________ > >> > >> > >> > >>> time-nuts mailing list -- [email protected] > >> > >> > >> > >>> To unsubscribe, go to > >> > >> > >> > >>> > >> > >> http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com > >> > >> > >> > >>> and follow the instructions there. > >> > >> > >> > >>> > >> > >> > >> > >> _______________________________________________ > >> > >> > >> > >> time-nuts mailing list -- [email protected] > >> > >> > >> > >> To unsubscribe, go to > >> > >> > >> > >> > >> > http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com > >> > >> > >> > >> and follow the instructions there. > >> > >> > >> > >> > >> > >> > >> > > _______________________________________________ > >> > >> > >> > > time-nuts mailing list -- [email protected] > >> > >> > >> > > To unsubscribe, go to > >> > >> > >> > > >> http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com > >> > >> > >> > > and follow the instructions there. > >> > >> > >> > > >> > >> > >> > > >> > >> > >> > _______________________________________________ > >> > >> > >> > time-nuts mailing list -- [email protected] > >> > >> > >> > To unsubscribe, go to > >> > >> > >> > > >> http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com > >> > >> > >> > and follow the instructions there. > >> > >> > >> > > >> > >> > >> _______________________________________________ > >> > >> > >> time-nuts mailing list -- [email protected] > >> > >> > >> To unsubscribe, go to > >> > >> > >> > http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com > >> > >> > >> and follow the instructions there. > >> > >> > >> > >> > >> > > > >> > >> > _______________________________________________ > >> > >> > time-nuts mailing list -- [email protected] > >> > >> > To unsubscribe, go to > >> > >> > http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com > >> > >> > and follow the instructions there. > >> > >> > > >> > >> _______________________________________________ > >> > >> time-nuts mailing list -- [email protected] > >> > >> To unsubscribe, go to > >> > >> http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com > >> > >> and follow the instructions there. > >> > >> > >> > > > >> > _______________________________________________ > >> > time-nuts mailing list -- [email protected] > >> > To unsubscribe, go to > >> > http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com > >> > and follow the instructions there. > >> > > >> _______________________________________________ > >> time-nuts mailing list -- [email protected] > >> To unsubscribe, go to > >> http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com > >> and follow the instructions there. > >> > > > _______________________________________________ > time-nuts mailing list -- [email protected] > To unsubscribe, go to > http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com > and follow the instructions there. > _______________________________________________ time-nuts mailing list -- [email protected] To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
