[Discuss-gnuradio] cant see any signals with limesdr on osmocom source

Hi there 

I am trying to use limesdr with gnuradio on ubuntu 16.04 When I use osmocom_fft tool from the cli eveything seems ok but when i switch back to gnuradio and connected osmocom source and gui fft sink I cant see any wifi signal. What could be the problem ? You can check from the photos below. 

Thanks