WFM (mono/stereo) not working

[teletoby]

I encountered a strange problem today with WFM after upgrading to the latest package versions on the “Gqrx dev” team PPA.

Here my setup:

• quite standard i3 desktop running under Linux Mint Olivia (amd64)
• Ettus N210 via UHD

After updating today to the latest packages in the PPA (based on gnuradio 3.7.2) I ran gqrx and somehow the WFM receiver does not work anymore (mono and stereo). The other receivers seem to work normally, but when I choose WFM the audio fft vanishes and if I tune on a UKW radio channel the speakers remain silent. When I record the audio the file will only contain silence. The waterfall graph and fft of the incoming stream is fine, however. When I choose the Narrow FM receiver and then I hear the station - although distorted as expected.

So I built gnuradio (3.7.3++), osmocom libraries and gqrx on the system (master branches in git) but the issue with WFM remained.

Finally I restored the older packages from the PPA and gqrx worked again as expected. Then I built locally gqrx from the master branch and tested and it also works! So there might be a problem somewhere, maybe between stereo_demod and some newer version of gnuradio, but unfortunately I was not able to pinpoint the problem yet.

[csete]

Any chance you could try this with an rtl-sdr dongle or with your USRP and the latest UHD release?

[teletoby]

It's true that I kept the "old" uhd. Since Narrow FM was working I did not expect a problem in uhd but in some other part like gr-filter. Regarding to what you suggested I can try both, but maybe I should just have a look at the filter taps that are generated.

On Sat, Nov 23, 2013 at 11:36 PM, Alexandru Csete notifications@github.comwrote:

Any chance you could try this with an rtl-sdr dongle or with your USRP and the latest UHD release?

— Reply to this email directly or view it on GitHubhttps://github.com/csete/gqrx/issues/132#issuecomment-29143497 .

[teletoby]

Hi,

rtl-sdr works, USRP with UHD from master branch doesn't, see console output below:

--- CUT ---

toby@bureau ~/Downloads/gqrx/build $ ./gqrx linux; GNU C++ version 4.7.3; Boost_104900; UHD_003.006.000-0-g7788c692

Controlport disabled No user supplied config file. Using "default.conf" gr-osmosdr v0.1.0-44-g0d10f5e9 (0.1.1git) gnuradio 3.7.3git-52-gb6cf12e6 built-in source types: file osmosdr fcd rtl rtl_tcp uhd bladerf netsdr Using Volk machine: sse4_2_64 IQ DCR alpha: 1.04166e-05 Using audio backend: auto New filter offset: 0 Hz Loading configuration from: "default.conf" Configuration file: "/home/toby/.config/gqrx/default.conf" gr-osmosdr v0.1.0-44-g0d10f5e9 (0.1.1git) gnuradio 3.7.3git-52-gb6cf12e6 built-in source types: file osmosdr fcd rtl rtl_tcp uhd bladerf netsdr -- Opening a USRP2/N-Series device... -- Current recv frame size: 1472 bytes -- Current send frame size: 1472 bytes -- Using subdev spec 'A:0'. New antenna selected: "TX/RX"

---

Gain name: "ADC-digital" min: 0 max: 6 step: 0.5 Gain name: "ADC-fine" min: 0 max: 0.5 step: 0.05 Gain name: "PGA0" min: 0 max: 31.5 step: 0.5

---

No change in output device: old: new: IQ DCR samp_rate: 250000 IQ DCR alpha: 3.99998e-06 Changing NBRX quad rate: 96000 -> 250000 Requested sample rate: 250000 Actual sample rate : "250000.000000" Requested bandwidth: 0 Hz Actual bandwidth : 0 Hz setFreqCorr : 0 ppm New LNB LO: 0 Hz "New frequnecy range: 68.75 - 2200 MHz (step is 0.0232831 Hz but we use 1 Hz)." "New frequnecy range: 68.75 - 2200 MHz (step is 0.0232831 Hz but we use 1 Hz)." ../qtgui/dockrxopt.cpp currentMaxdev FIXME Filter preset for mode 3 LO: -5000 HI: 5000 Genrating taps for new filter LO:-5000 HI:5000 TW:1000 Required number of taps: 115 New filter offset: -300 Hz setFftRate to "15 fps" New FFT rate: 15 Hz setFftSize to "2048" Changing baseband FFT size to 2048 New FFT rate: 15 Hz New FFT rate: 15 Hz No audio FFT data. No audio FFT data. Force RX reconf (jerky dongle workarond)... ../qtgui/dockrxopt.cpp currentMaxdev FIXME Filter preset for mode 3 LO: -5000 HI: 5000 Genrating taps for new filter LO:-5000 HI:5000 TW:1000 Required number of taps: 115 New mode: 4 Filter preset for mode 4 LO: -80000 HI: 80000 Genrating taps for new filter LO:-80000 HI:80000 TW:16000 Required number of taps: 37 New mode: 3 ../qtgui/dockrxopt.cpp currentMaxdev FIXME Filter preset for mode 3 LO: -5000 HI: 5000 Genrating taps for new filter LO:-5000 HI:5000 TW:1000 Required number of taps: 115 New mode: 4 Filter preset for mode 4 LO: -80000 HI: 80000 Genrating taps for new filter LO:-80000 HI:80000 TW:16000 Required number of taps: 37 saveSettings *\ FIXME SQL on/off New FFT rate: 15 Hz

On Sun, Nov 24, 2013 at 9:44 PM, Tobias Gresch tobias.gresch@gmail.comwrote:

It's true that I kept the "old" uhd. Since Narrow FM was working I did not expect a problem in uhd but in some other part like gr-filter. Regarding to what you suggested I can try both, but maybe I should just have a look at the filter taps that are generated.

On Sat, Nov 23, 2013 at 11:36 PM, Alexandru Csete < notifications@github.com> wrote:

Any chance you could try this with an rtl-sdr dongle or with your USRP and the latest UHD release?

— Reply to this email directly or view it on GitHubhttps://github.com/csete/gqrx/issues/132#issuecomment-29143497 .

[csete]

Thanks for the test. I will try to reproduce it with my USRP1 when I can get to it (currently it is tied up with telemetry reception).

[courtarro]

Just adding a data point ... I have working WFM with my USRP B210. I'm using the git masters of GR, UHD, and gqrx.

[teletoby]

I must admit I haven't tried since but it is pretty much possible that my installation was "dirty" and there was some contamination with an old library or so.

[teletoby]

Built gnuradio and out of tree modules using pybombs and the issue described is gone.