LimeSDR Mini V2 IQ output grabbing

Projects LimeSDR
1

Hi, after running satellite obeservations in 402, 437 and 2250 MHz band for some years on HackRF and PlutoSDR I decided to go for a (12 bit) device which can run / grab up to 30 MHz bandwidth over USB 3.0

I have been running the cbass strf tools, with rffft to save the .bin files to SSD with rtlsdr, hackrf, pluto and airspy and now I am trying to get this working with help of rx_sdr tool.

Ubuntu 22.04, LimeSDR Mini is running, I can view 22 MHz wide of signals in either 435 MHz or in S-band without problems.

The script I am trying to use to grab the IQ output and create bin files with also works, meaning, it gives no errors and creates bin files, but if I open those files in rfplot the output does no way look like what I expect to. Start and stop frequency match, continuous carriers show in the plot, but when zooming in I get very low detail / resolution for some reason.

The two lines generating the output:

Start channelizer

nice -20 rffft -i $FIFO -p $WORKINGDIR/data2 -f $FREQ -s $RATE -c 25 -F int -t 10 &

Start rx_samples_to_file

nice -20 rx_sdr -s $RATE -g ‘TIA=0,PGA=0,LNA=30’ -a ‘LNAH’ -d ‘driver=lime’ -F CS16 -f $FREQ $FIFO -p 0 &

Is there another tool know to feed my FIFO with the data from the LimeSDR Mini 2.0 which I can try ?

As example the UHF band in my rffft output zoomed in but totally showing no detail on for example ISM band

image
image800×504 57 KB

and a screenshot of S-band with rffft from a Pluto SDR

image
image1372×816 188 KB

thanks,
Ben

2

Tagging @ricardas

3

For 435 MHz you should use “LNAW” antenna path.

LimeSuiteNG provides command line interface tools for configuring (limeConfig), and streaming data (limeTRX).
You can try use limeTRX to record samples to binary file, and check if that’s what you would expect to see. If everything is good, limeTRX could easily be extended to direct that data stream into a fifo instead of a file.