Paul/Chris, Also - in addition to the white screen, I get this sometimes after running for a while - have you guys seen this?
https://user-images.githubusercontent.com/2308903/98118247-cd4c7b00-1e5f-11eb-8510-aa1ed0beba52.jpg 73's, John AJ6BC On Wed, Nov 4, 2020 at 1:44 AM John C. Westmoreland, P.E. < [email protected]> wrote: > Paul, > > Thanks for the info. I took some good measurements on the signal coming > in on one of the small ferrite antennas when the signal was fairly OK - I > measured > 4-9 uV. I haven't done this same measurement yet on the antenna I'm > testing on - I didn't think I could be over driving the mic input but > that's a possibility. Also, I haven't done a great job in assembling this > project - I need to neaten things up and maybe encase in a housing > that will reject RFI, etc. > > Thanks for mentioning this. I have ordered one of those nice antennas > from Stormwise but I'm still waiting to receive it. > > 73's, > John > AJ6BC > > > > > On Tue, Nov 3, 2020 at 12:13 PM paul swed <[email protected]> wrote: > >> By the way thats leads. A typo. >> It just hit me I had to cut the signal down so that the signal graph was >> in >> the middle. >> On the large antenna thats a 330K resistor to a 100K pot. >> For the wwvb simulator its simply the 100K pot turned up about 2/3rds of >> the way. The simulator is something like 60 uv out. >> Maybe you have a overdrive issue. >> Regards >> Paul. >> >> On Tue, Nov 3, 2020 at 9:49 AM paul swed <[email protected]> wrote: >> >> > John >> > Yes I have used Chris's code to decode the wwvb AM timecode. I am in >> > Boston so just about as far away as you can get. Though maybe Florida is >> > further. But Boston is in more of a null from wwvb. >> > Granted the antenna is a tuned 10' X 10' 800 ft of wire loop and preamp >> > mentioned numerous times on time-nuts. It reliably during the day >> delivers >> > 100 uv at the end of the coax. >> > I found the teensy wwvb sdr really worked best during the day. With >> > respect to power for the antenna its just a power inserter I built, 8 Mh >> > choke, 100 ohm resistor, .47 uf coupling cap to the teensy. No magic at >> all. >> > One very serious issue with the teensy is that the audio module must be >> > directly stacked on to the cpu. I originally used 3" leeds those little >> > jumpers. It makes a mess of the clock signals. >> > Regards >> > Paul. >> > >> > On Mon, Nov 2, 2020 at 10:55 PM John C. Westmoreland, P.E. < >> > [email protected]> wrote: >> > >> >> Paul, >> >> >> >> Have you successfully decoded WWVB with Chris's code? >> >> >> >> I haven't gotten that to work. >> >> >> >> I'm using the same antenna set up I've used that works with the >> multipsk >> >> Clock program to decode WWVB that will decode fairly reliably as long >> as >> >> atmospheric conditions are favorable. >> >> >> >> Note, if using the Arduino IDE and you're connected to a PC; it will >> >> sometimes set the clock on the TFT to the PC's clock; I'm mentioning >> that >> >> since some that try this could think their set up is synced to WWVB >> when >> >> it >> >> actually grabbed time from the PC. Maybe the loader from Teensy does >> >> that; >> >> I haven't looked close enough yet to know for sure what's setting that. >> >> >> >> Glad you're making progress with your approach. >> >> >> >> 73's, >> >> John >> >> AJ6BC >> >> >> >> >> >> On Mon, Nov 2, 2020, 18:20 paul swed <[email protected]> wrote: >> >> >> >> > John thats exactly what Chris did. Its the teensywwvb.ino. It decodes >> >> the >> >> > AM timecode just as the DCF code does. In fact Chris's code is >> derived >> >> from >> >> > the DCF code with the changes you are asking about and it works. >> >> Download >> >> > his solution and read the comments throughout. The original DCF >> comments >> >> > are in it also. >> >> > >> >> > Its the starting point for the tinkering I am doing towards a BPSK >> SDR. >> >> > Thats a big leap for me. >> >> > What the code gives you is the frontend gain, followed by a bandpass >> >> > filter. Multiplier that mixes the LO and incoming signal to a lowpass >> >> > filter. Then on to AM detection and AGC. >> >> > >> >> > If you don't care to install the arduino IDE with teensy extension >> just >> >> use >> >> > notepad ++ to look at the code. Pretty exciting. >> >> > >> >> > Regards >> >> > Paul >> >> > WB8TSL >> >> > >> >> > On Mon, Nov 2, 2020 at 8:24 PM John C. Westmoreland, P.E. < >> >> > [email protected]> wrote: >> >> > >> >> > > Hello Time Nuts, >> >> > > >> >> > > I have a question - >> >> > > >> >> > > Has anyone been successful getting WWVB to decode using the example >> >> for >> >> > > DCF77 and making the changes for WWVB? >> >> > > >> >> > > Chris has his own approach - it's interesting - but on my setup at >> >> least >> >> > I >> >> > > haven't been successful with it - maybe it's my antenna - not sure >> >> just >> >> > > yet. >> >> > > Also - my screen eventually 'whites-out' after running that for a >> >> while - >> >> > > meaning - the screen goes completely white and I don't know what's >> >> doing >> >> > > that yet - I suppose it's a bug of some sort. >> >> > > >> >> > > But, with the DCF77 approach - it appears to identify bits OK - >> with >> >> the >> >> > > code having only minimal changes - so I'd like to go down that >> path. >> >> > > >> >> > > Note - I have a fork here - but it's debug - and not sure it's >> worth >> >> > > anything other than looking at some of the data that's being >> dumped. >> >> > > https://github.com/jwestmoreland/Teensy-DCF77 >> >> > > >> >> > > For DC7FF - the AM is just 0.2ms (1) and 0.1ms (0) with no AM at >> the >> >> > minute >> >> > > marker, but WWVB is a little more complicated - >> >> > > 0.2ms (0), 0.5ms (1), and 0.8 ms (Marker) - 2 consecutive markers >> mark >> >> > the >> >> > > end of current minute/beginning of next minute. >> >> > > >> >> > > The DCF77 code seems to take some advantage of the signal >> level/timing >> >> > and >> >> > > the dimensions of the TFT display for >> >> > > displaying the signaling - at least that's what it appears to me >> right >> >> > now >> >> > > unless I'm looking at this wrong - I guess that isn't >> >> > > a big deal until you try to deal with the marker timing for WWVB - >> of >> >> > > course I could be looking at this wrong right now too. >> >> > > >> >> > > Maybe trying something like the Goertzel algorithm like KE9NS has >> >> done in >> >> > > his work with WWV is worth taking a look at too with >> >> > > this setup. >> >> > > >> >> > > 73's, >> >> > > John >> >> > > AJ6BC >> >> > > >> >> > > >> >> > > >> >> > > >> >> > > >> >> > > On Sun, Nov 1, 2020 at 10:50 AM Mike Feher <[email protected]> >> wrote: >> >> > > >> >> > > > Too bad I am an old retired hardware engineer and know nothing >> about >> >> > > these >> >> > > > new SW controlled devices. Have Fun - Regards - Mike >> >> > > > >> >> > > > Mike B. Feher, N4FS >> >> > > > 89 Arnold Blvd. >> >> > > > Howell NJ 07731 >> >> > > > 848-245-9115 >> >> > > > >> >> > > > -----Original Message----- >> >> > > > From: time-nuts <[email protected]> On Behalf Of >> >> paul >> >> > > swed >> >> > > > Sent: Sunday, November 1, 2020 12:48 PM >> >> > > > To: Discussion of precise time and frequency measurement < >> >> > > > [email protected]> >> >> > > > Subject: Re: [time-nuts] WWVB teensy BPSK early experiments >> >> > > > >> >> > > > John sent the link on the teensy wwvb AM receiver. It can easily >> be >> >> > > > shifted to other frequencies. Using the work Frank dcf77 and then >> >> Chris >> >> > > > wwvb did with the PJRC audio design tool gives quite a bit of >> >> insight >> >> > to >> >> > > > the work that was done. >> >> > > > The system assumes a sample rate of 192Khz. That limits the >> receive >> >> > range >> >> > > > to about 98KHz. >> >> > > > I have not been able to confirm the rate I am using is 192Khz and >> >> when >> >> > > the >> >> > > > set command is used its not recognized. So somethings up. >> >> > > > The design Chris has essentially is a microphone input with some >> 38 >> >> db >> >> > of >> >> > > > gain feeding a bandpass filter around 60 KHz to a multiplier (RF >> >> mixer) >> >> > > > then a low pass filter. Chris and Franks design is much more than >> >> these >> >> > > few >> >> > > > words with spectrum display, signal level, and AGC. >> >> > > > So without any effort the frontend solution is sitting in the >> teensy >> >> > that >> >> > > > cuts out a bunch of typical wiring. Granted its not as tight as >> >> > discrete >> >> > > > components can be. But its a chunk of software code. No digi key >> >> orders >> >> > > for >> >> > > > L & Cs... :-) The output of the chain is 600 Hz audio that does >> >> contain >> >> > > the >> >> > > > phase changes. >> >> > > > >> >> > > > But the trick is creating the true I & Q channels. Not an issue >> to >> >> add >> >> > a >> >> > > > second multiplier and chain did that last night. But at >> someplace a >> >> 90 >> >> > > > degree phase change or delay needs to occur. >> >> > > > Or as suggested a hilbert transform. >> >> > > > Regards >> >> > > > Paul >> >> > > > WB8TSL >> >> > > > >> >> > > > >> >> > > > >> >> > > > >> >> > > > _______________________________________________ >> >> > > > 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.
