Abstract: An adaptive radar system is presented which is capable of identifying interference frequencies and changing the system operating frequencies to permit radar operation in portions of the frequency spectrum that are free of interference. A time-integrating optical receiver or electronic FFT is employed to detect those frequencies where interference occurs thereby cueing the radar system to noise-free portions of the frequency spectrum. A digital computer processes the information from the optical or electronic FFT receiver to control system operation at those frequencies where interference has not been detected.