Dreamcatcher: rfl-fm error

I made a try to install on Dreamcatcher the aprs iGate/direwolf example.
It was evident the steps, but finally, when I start the direwolf prog, a got the error:

rtl_fm: symbol lookup error: rtl_fm: undefined symbol: rtlsdr_set_bias_tee

It seems, the started rtl_fm version hasnot the code dealing with the bias-tee switching. It is only in a newer version of the osmocom rtl-sdr tools.

In my case, first I instelled the “standard” version of the rtl-sdr tools, with the apt-get install command, and this was the “generally accessible”, when I call the rtl_fm.
After, I modified the path to the rtl_fm prgoram, to the extended version, it sarted running whithout error messages.
Maybe the solution of this situation, to remove the “standard” rtl-sdr tools, and make install the version, has link in the outernet doc here:

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I believe the bias-t switching is handled differently on the Dreamcatcher anyway, so you should just be able to use the standard install of the tools for what you need, but I’m not familiar with the iGate requirements in this area. HTH

The Direwolf aprs iGate system dont deal directly with the bias-tee switch, it is true.
But it monitoring the aprs channel with the rtl-sdr, specially in this setup.
So, start it, need two concatenated commands:

  • start the rtl-sdr tool, in this case the rtl_fm program.
  • start the Direwolf with its config file, in this case its name is sdr.conf. The contents of this config file described in the tutorial.
    Here is the start command with the “standard” version of rtl_fm program. You can see how it configure its environments, and the rtl_fm command recognize the rtl-sdr hardware unit, and after immedietly send the error message about missing symbols, procedure entry points. The result is the program abort:

rtl_fm -f 144.80M - | direwolf -c sdr.conf -r 24000 -D 1 -
Dire Wolf version 1.4

Reading config file sdr.conf
Config file: Unrecognized command ‘euro.aprs2.net’ on line 16.
Audio input device for receive: stdin (channel 0)
Audio out device for transmit: null (channel 0)
Channel 0: 1200 baud, AFSK 1200 & 2200 Hz, E+, 24000 sample rate.
Note: PTT not configured for channel 0. (Ignore this if using VOX.)
Use -p command line option to enable KISS pseudo terminal.
Ready to accept AGW client application 0 on port 8000 …
Ready to accept KISS client application on port 8001 …
Found 1 device(s):
_ 0: Generic, RTL2832U, SN: 77771111153705700_

Using device 0: Generic RTL2832U
Found Rafael Micro R820T tuner
Tuner gain set to automatic.
rtl_fm: symbol lookup error: rtl_fm: undefined symbol: rtlsdr_set_bias_tee
End of file on stdin. Exiting.

If I redirected to the newly downloaded and compiled rtl-sdr tool the rtl_fm call, it start normally.
In my case the freshly compiled rtl-sdr is here, in the redirect path of the Direwolf start commands:

/home/janos/rtl-sdr/build/src/rtl_fm -f 144.80M - | direwolf -c sdr.conf -r 24000 -D 1 -

I explained this situation, because, when I first got this error, I made google search on it, but I didnot find any solution to this error.
The consequence is: if you dont experiment with the different versions of the osmocom tools, you dont keep more then one package on your system. Maybe the latest version would be the usefull…


@zoltan Has this running correctly and can answer this question.