LimeSDR-USB transmitting issue

Projects LimeSDR
1

Hi,

I’m experiencing some issues trasmitting with my brand new LimeSDR-USB (v1.4s) and GNURadio.

My setup is:

  1. GNURadio 3.8.2 with gr-limesdr (latest commit from gr-3.8, 47511dd) and LimeSuite (latest commit from master, a45e482)
  2. LimeSDR-USB v1.4s with latest gateware connected through USB3.0
  3. Spectrum analyzer connected to TX1_1 port from LimeSDR-USB

I configure GNURadio to produce a tone at 10kHz, amplitude 0.5, like this:

Screenshot_20210303_101232
Screenshot_20210303_101710

What I obtain in the spectrum analyzer is this:

ScreenImg (8)
ScreenImg (8)880×577 23.2 KB

I have a LimeSDR-Mini as well, so I’ve tried just swaping one Lime for the other, same configuration and flowgraph, and I get this:

ScreenImg (9)
ScreenImg (9)882×582 22.3 KB

Then I’ve tried setting gain for LimeSDR-USB to 0, with the same result, just different scale.
I have several LimeSDR-USB units, and all of them show the same results, so I think it’s a configuration issue.

I gave it another try using the ENABLE_NEW_GAIN_BEHAVIOUR option in LimeSuite and recompiling everything, but was without luck.

Do you have any idea how to fix this?

Thanks in advance.

2

I’m experiencing the same issue with basicTX example from LimeSuite so I guess this is not up to GNURadio or gr-limesdr.