What is the best channel?

Hello guys i want to know what is the best setting for my 31Km b11 link ?
and i want to know how to read spectrum analyzer probely
i’m seeking for best way to take bandwidth

If your country uses Licensing for the 11 GHz band then you should follow what your License is for.

If not, then I would stay away from the large noise sources you are seeing on your Spectrum Graph, 10800 and 11500 look alright IMO.