we have a Sony dream machine with the atomic clock function . it have no battery backup and occasionally somehow `` lose '' the signal for the clock and end up with the incorrect time . this atomic clock radio do catch the signal and do have the battery backup function . it be not a $ 50 or $ 100 radio , but do the job well . the only drawback have be the small switch which turn the alarm on and off . for the price , I would buy it again .