On Wed, Dec 5, 2018 at 8:52 AM jimlux <jim...@earthlink.net> wrote: > On 12/5/18 6:32 AM, Bob kb8tq wrote: > > Hi > > > >> On Dec 5, 2018, at 8:45 AM, jimlux <jim...@earthlink.net> wrote: > >> > >> On 12/5/18 5:39 AM, Poul-Henning Kamp wrote: > >>> -------- > >>> In message <4a8ff8d6-70b2-782e-cb79-21c7e9a49...@earthlink.net>, > jimlux writes: > >>>> If I were decoding WWVB to start, I'd break my samples up into 0.1 > >>>> second or 0.5 second chunks and process them to see what the carrier > >>>> phase is. > >>> With stable signals like this, it is a bad idea to chop them up, > >>> in particular if your ADC runs from a good stable frequency. > >> > >> True enough - this was just to get started. > >> > >>> Instead continuously average the square of the signal into a 1 > >>> second long circular buffer. > >>> Then multiply/sum that buffer with a 120kHz sine and cosine to find > >>> the phase angle. > >> > >> yes.. assuming your ADC is running off a sufficiently stable source. I > was thinking about a very low cost implementation where the ADC is running > off a not very wonderful microcontroller clock. >
Are you aware that the KiwiSDR receivers are locked to GPS and time-stamp their samples? Some people are playing with TDoA location of HF emitters using multiple KiwiSDRs out there. > > > A stable clock probably is a pretty good bet on a “Time Nut” grade > design. Indeed one objective might be to ultimately > > read out the phase directly WRT that reference . Some sort of PPS tick > likely would get into all this as well. > Yeah, do more research into the KiwiSDR. > > > > > > I was thinking more about "can you receive it with a SDR implementation > for <$50 and minimal heating of the soldering iron" without worrying too > much about measuring small phase shifts. > > Once you've got to that - then you've got a basis for further improvements. > > I'll try the RTL-SDR with a non-active antenna on Friday and see what I > can see here in Southern California. I know my old style "atomic" clock > does see the signal sometimes, so I can grab some sample when the clock > says it's live. > > > If anyone has a suggestion for an off the shelf active antenna that's > orderable and receivable by Friday, I'd love to hear it. There's 3 or 4 > of them I've seen (Clifford labs, DX Engineering has one, I'm sure MFJ > has one) > I have the PixelSat loop (now sold by DX Engineering) and it works great at 60kHz. I hear WWVB 7x24 in San Antonio. MFJ has a cheaper version that I've heard works OK. I have my loop driving my KiwiSDR. I haven't made it public (yet). I hear WWVB with it just peachy all the time. > Why available by Friday? I'm going to be really busy starting next week > for a month commissioning a satellite launching next week, so this > weekend is my last opportunity to fool with actual technology. > DX Engineering or MFJ. You might find that HRO has one or the other in stock. Don't they have a store in Las Vegas, not too far from you? UPS ground should get to you in a day. -- Brian Lloyd 706 Flightline Spring Branch, TX 78070 br...@lloyd.aero +1.210.802-8FLY (1.210.802-8359) _______________________________________________ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.