LimeSDR Mini - Transmission starts then abruptly stops?

I’m using gnuradio and LimeSDR (using gr-limesdr)

I’m trying to run the WBFM example to make sure that my LimeSDR Mini is really working. (I’m aware of the self-test)

I also own an RTL-SDR which I use to make sure that the Lime is transmitting properly. I find that the LimeSDR transmits a WBFM signal with nothing on it (no audio) for a few seconds, and then abruptly stops before the audio plays (the signal goes away). I’m using 40db gain, if that mattters.

On the RTL-SDR, I’m able to see the Lime transmit for a few seconds, before the music file starts. Just before the music file starts, it cuts out

In gnuradio, I added a WBFM decoder connected to an audio sink just to make sure the audio file is playing and the issue is not in the encoding or modulation.

Anyone else with this problem? I’m on a Debian machine with USB 3.0 ports. I’ve tried both through a USB 3.0 Hub and directly. I also tried it on my old Debian machine with USB 2.0. I’ve followed calibration instructions as well.

Logs:
    ---------------------------------------------------------------
LimeSuite Sink (TX) info

##################
Connecting to device
##################
LimeSuite version: 19.04.0-gabf82140
gr-limesdr version: 2.1.4
##################
Device list:
Nr.:0 device:LimeSDR Mini, media=USB 3.0, module=FT601, addr=24607:1027, serial=1D4C4445A57EF3
##################
INFO: device_handler::open_device(): no serial number. Using first device in the list.
Use "LimeUtil --find" in terminal to find prefered device serial.
Reference clock 40.00 MHz
Using device: LimeSDR-Mini(1D4C4445A57EF3) GW: 1.30 FW: 6
##################

INFO: device_handler::enable_channels(): SISO CH0 set for device number 0.
INFO: device_handler::set_samp_rate(): set sampling rate: 2.4 MS/s.
INFO: device_handler::set_rf_freq(): Selected TX path: Band 2
RF frequency set [TX]: 100 MHz.
INFO: device_handler::set_analog_filter(): Filter calibrated. Filter order-4th, filter bandwidth set to 5 MHz.Real pole 1st order filter set to 2.5 MHz. Preemphasis filter not active
TX LPF configured
INFO: device_handler::set_digital_filter(): digital filter CH0 [TX]: 2 MHz.
INFO: device_handler::set_gain(): set gain [TX] CH0: 40 dB.
INFO: device_handler::set_antenna(): CH0 antenna set [TX]: BAND1.
INFO: device_handler::calibrate(): Tx calibration finished
INFO: device_handler::set_nco(): NCO [TX] CH0: 0.2 MHz (0 deg.)(UPCONVERT).
gr::log :INFO: audio source - Audio sink arch: alsa
gr::log :INFO: audio_alsa_sink0 - [default]: unable to support sampling rate 2400000
	Card requested 192000 instead.
len(interp_taps) = 668
INFO: sink_impl::init_stream(): sink channel 0 (device nr. 0) stream setup done.

Source of GRC: https://github.com/jakeson21/gr-limesdr-examples

Hi, I’m having the same issue using GRC to transmit a signal on my LimeSDR. The transmission periodically stops and then restarts seemingly at random. Were you or anyone else able to find a solution?

I seem to be having a similar issue with LimeSDR-USB. Were you able to resolve yours?

I created a thread to track the issue I’m facing …

Also on discuss-gnuradio, but no resolution yet.

https://lists.gnu.org/archive/html/discuss-gnuradio/2021-03/msg00081.html