Sprectrum analyzer feature

Do you know if is (or will be) possible to convert or to enable some spectrum analyzer feature on the Stellar-AP like on the Aruba AP ?

yes, this is feasible with GUI access of the AP and Under RF environment. Please find the screenshot attached. Please do refer to the user guide of the AP for more details. I would recommend using the Latest AP software version available .(4.0.0.x)