Wimax Airspan Air4G WL24 trouble

[mikkhail_]

Often rise alarms: "PLL Lock Lost, SDR PLL lost lock to the SDR VCXO" and "RF Hardware Fault, Low Forward Power, RF is transmitting at very low forward power owing to an RF fault" on BS (using Netspan). Maybe somebody know what mean this alarms? And how to repair those Base Stations?