Abstract:Frequency Agile Radar(FAR) is recognized as the most promising radar，which is divided into incoherent and coherent types. Focusing on the varied phenomena of the remote sensing curves for Local Oscillator(LO) power in a certain FAR，this paper analyses the reasons of their variation during test basing on the Frequency Agile techniques, LO system, telemetry readings etc. The working condition of this LO system is proved to be in normal at last, which removes the long-standing worry about the key capability of this type of equipment from judge department，and exerts great engineering benefits.