Dear Ed Troy: (Also, it is not a simple flowgraph, but I heard that there is a test build of GQRX for PlutoSDR (gr-iio based). You should be able to use that to demodulate WBFM signals, if that is all you want..)
Regards, Kyeong Su Shin On Mon, Dec 18, 2017 at 1:34 AM, Kyeong Su Shin <[email protected]> wrote: > Dear Ed Troy: > > Actually, I did re-test this with a PlutoSDR (I do have one unit at home, > although I do not usually carry this with me) and your flowgraph worked on > my PC + PlutoSDR once I reduced the sampling rate from 5MS/s to 2.5MS/s > (and adjusted the decim ratio accordingly). Could you try different FM > stations, different antennas, or different GNU Radio installations (maybe > try running this on different computers)? > > One other thing that I would check is the sampling rate that the audio > card supports. I know 96kS/s is usually an acceptable value (and did work > on my PC), but maybe you should try 48kS/s instead. > > I am also concerned about the two-clock problem between the PC and the > radio, but I still expect to get some audible sounds even in the worst case > scenario... > > Regards, > Kyeong Su Shin > > On Sun, Dec 17, 2017 at 9:08 AM, Ed Troy <[email protected]> wrote: > >> Hi Kyeong, >> First, sorry about the double transmission of my message. I did not >> attach [discuss-gnuradio] to the first one and when I did not see it, I >> figured it got lost and so resent with the correct subject line. >> >> I have checked my board and it does seem to work down to 90 MHz. I need >> to run more detailed tests with a signal generator to get exact sensitivity >> numbers, but it should be good enough. >> >> I tried making the changes to sample rate and other things that you >> suggested, but it still does not demodulate FM broadcast signals. I have to >> admit that the RTL-SDR devices never did a very good job, either, but I >> attributed that to relatively poor sensitivity, although I have some pretty >> good ones, as far as they go. I also tried to lower the gain, but that did >> not seem to work, either. >> >> If anyone has had success getting the Pluto to work with FM broadcast >> signals, perhaps they could publish the grc file? >> Regards, >> Ed >> >> >> >> On 12/15/2017 8:33 PM, Kyeong Su Shin wrote: >> >> Dear Ed Troy: >> >> I don't have the PlutoSDR with me right now, so I cannot test it now, but >> a few things to check: >> >> -Make sure that your Pluto can go down to 90MHz alright; it is only rated >> to operate on 325MHz - 3.8GHz, and not guaranteed to behave well on such >> frequencies (even when you did made the changes). >> -Try lower sampling rate; like 2MS/s. PlutoSDR is known to drop samples >> at relatively high sampling rates (and yes, I do mean that 5MS/s is too >> high). >> -Try lowering gain; FM signals can easily overload the frontend of such >> devices. >> >> If I replace that PlutoSDR source block with an Osmocom source block, >> change the carrier frequency to my local station, and attach a different >> radio, it works. (Can't test on a PlutoSDR now, as I do not have one with >> me now). >> >> Regards, >> Kyeong Su Shin >> >> On Fri, Dec 15, 2017 at 4:12 PM, Ed Troy <[email protected]> wrote: >> >>> Hi, >>> >>> I have been trying to get my Pluto to work with WBFM, but I am not >>> having any luck. I am attaching a grc file that I am pretty sure should >>> work, but it does not. It just generates sporadic noise. I did the changes >>> recommended to get the Pluto to work over a wider frequency range, and the >>> results indicated that the changes worked. And, I have tried using the >>> Pluto at higher frequencies to detect a WBFM signal, and it still does not >>> work properly. So, I know it has to be something with my grc file. >>> >>> What am I doing wrong? >>> >>> Ed >>> >>> >>> >>> _______________________________________________ >>> Discuss-gnuradio mailing list >>> [email protected] >>> https://lists.gnu.org/mailman/listinfo/discuss-gnuradio >>> >>> >> >> -- >> RF, Microwave, Antenna, and Analog Design, >> Development,Simulation, and Research Consultinghttp://aeroconsult.com >> Aerospace Consulting LLC >> P.O. Box 536 >> Buckingham, Pa. 18912(215) 345-7184(215) 345-1309 FAX >> >> >
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