Re: Discuss-gnuradio Digest, Vol 270, Issue 12

Hi Marcus,

The degradation was 40 dB relative to expected.  My measurements were ballpark.  For an indication of the Minimum Discernible Signal, I looked at when a signal fell below the noise in a QT QUI Sink (FFT 32K, 570K sampling rate).  The same test with an Ettus B200mini showed the minimum discernible signal was better than -120 dBm.  Doing the same test with LimeSuiteGUI (the Lime test/control suite) with the Lime Mini showed a minimum discernible signal better than -120 dBm. 

A published comparative review (that seemed to use a good measurement approach) gave the LimeSDR Mini a Noise Figure of around 10 dB (gitlab.com/librespacefoundation/sdrmakerspace/sdreval).

Today I've found that the deprecated gr-soapy source works fine with the LimeSDR Mini.  I see Rx performance (with GR) at about the same level as with LineSuiteGUI.  I did need to change Ch0: Antenna to LNAH.

From examining the yml for gr-limesdr-source and the generated py code, gr-limesdr-source seems to be missing provision for some parameters including the antenna.  The default is apparently not correct for a LimeSDR Mini.   LNAH for Antenna works for me. 

I expect that editing the generated py file would be OK as a workaround, but it is easier for the moment to use the deprecated block.

I see that there are some variations in the LimeSDR family of devices that might affect writing a generic LimeSDR source block ( wiki.myriadrf.org/Gr-limesdr_Plugin_for_GNURadio). 

Tx is Work In Progress.

Dave

Hi Dave, I'm not an expert on the Lime hardware, but I could see how different filter, gain etc configurations would lead to different performance. Can you explain what exactly you mean with "degraded performance"? Best, Marcus

On 4/10/25 6:59 AM, dave_abel@bigpond.com wrote: > I have a LimeSDR Mini 2.4.When I test Rx performance using the LimeSuiteGUI, I see > performance in line with the device specifications.With GNU Radio 3.10.1.1 under Ubuntu > 22.04.5, the performance is severely degraded.The GR test is a simple flowgraph of a Soapy > LimeSDR Sink into a QT GUI Sink.