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.
