Hi,
I have got a similar problem. I raised a thread some time ago about it:
On top of it I have the loopback test that fail. So there is an issue in the RF front head.
See below picture of the signal coming out of the RX sma.
Lime RX connecteed to the CMU. TX has a load with 30dB.
using the FFT tool, 100Mhz.
For info I spent quite a lot of time to develop a 3D case with a radiator.
The 100Mhz spread over 200, 300 … and so.
I tried USB cable 2 and 3, same.
Other SDR works fine.
Pity I was happy with this lime Mini, my joy has felt down.
I contacted crowdfounding with no answer after long time.
I did not spent much time to setup specific register to test the loopback function with LimeSuite GUI.
Any suggestion or action to do will be welcome.