I found the below uhd_two_tone_loopback example (which is one of the gnuradio provided examples) and I am trying to run it, it runs but I can't receive signal.
I mean when I run the program I cannot hear the audio tone at all. If I connect an audio sink to the TX side I hear the audio. But when the audio sink is connected to the output port of the USRP source I can't hear the audio tone.
So, I have the b200 mini usrp and I am connecting the TX to the RX using an FW-10+ 10 dB attenuator.
What could be the problem that I can't get the loop working? Thanks.