On 6/19/2012 1:03 PM, rick darwicki wrote: > Hearing strange tone with peak about 50.457 mhz and birdies every 30.5 khz ±. Sure. You're hearing harmonics of a digital clock, either for digital equipment, or a switching power supply. VERY common. The typical home has at least a couple dozen of them. 73, Jim K9YC