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xealits
Asked: 2015-12-13 16:21:13 +0800 CST

Software defined radio, rtl-sdr, no output from rtl_fm

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I am trying out an rtl-sdr dongle (RTL2832U/R820T) on Ubuntu. Following this guide I run the test command successfully.

$ rtl_test -t
Found 1 device(s):
  0:  Generic RTL2832U OEM

Using device 0: Generic RTL2832U OEM
Found Rafael Micro R820T tuner
Supported gain values (29): 0.0 0.9 1.4 2.7 3.7 7.7 8.7 12.5 14.4 15.7 16.6 19.7 20.7 22.9 25.4 28.0 29.7 32.8 33.8 36.4 37.2 38.6 40.2 42.1 43.4 43.9 44.5 48.0 49.6 
No E4000 tuner found, aborting.

But I cannot get any real output. Running rtl_fm (as in here or in this video-guide):

$ rtl_fm -M wbfm -f 89.1M 
Found 1 device(s):
  0:  Realtek, RTL2838UHIDIR, SN: 00000001

Using device 0: Generic RTL2832U OEM
Found Rafael Micro R820T tuner
Oversampling input by: 42x.
Oversampling output by: 1x.
Buffer size: 8.13ms
Tuned to 89352000 Hz.
Sampling at 1008000 Hz.
Output at 24000 Hz.
Exact sample rate is: 1008000.009613 Hz
Tuner gain set to automatic.
^X^CSignal caught, exiting!

User cancel, exiting...

gives no output.

Also, running rtl_sdr capture.bin -s 1.8e6 -f 392e6 did produce 23Mb file, but I don't know how to open/use it.

Could someone suggest what I could do now to at least be sure the dongle really works?

Also info: I run Ubuntu 14.04, rtl-sdr was installed from Ubuntu repositories, the version is 0.5.2.7.3ab6-1. Also I use the simple antena which came with the dongle. It is the same as in the video-guide. I guess it should be ok for fm frequencies.

gnuradio

1 Answers

  1. Your rtl-sdr dongle and driver seems to be working. You should be getting binary output while running 

    $ rtl_fm -M wbfm -f 89.1M

    Try running command from your link to play FM

    1. Install sox to play audio sudo apt install sox -y
    2. Now play the FM 
      rtl_fm -M wbfm -f 89.1M | play -r 32k -t raw -e s -b 16 -c 1 -V1 -
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