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 <et...@aeroconsult.com> 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 <et...@aeroconsult.com> 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 >> Discuss-gnuradio@gnu.org >> 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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