RF performace of LimeSDR

Dear sir,
We use LimeSDR to measure spectrum of FM band. We find that the Spectrum in the frequency range of 88-108MHz is rather bad. The feature of the FM radio is not obvious. Could give us same example? Is there any solution?

Try with all gains all set to zero to start.
Make slider adjusters with settings from -10 to 10 and set the three gains to the sliders. Then you can see the effect of each one in real time.
There are examples of FM broadcast receivers here somewhere.

+1.

I would also highly recommend watching the Wireless Masterclass video series and in particular the second episode, which looks at the LMS7002M architecture and how best to configure this.