Typically have a noise level of 1 S unit or less. Last few days that has jumped to 5. Figured the neighbors had a new toy and was really bummed out. Then, on a hunch, I took out my small KA1103 shortwave radio, dialed it to 27.255 (local CB channel) and walked around the house. Near the kitchen I suddenly began picking up up a buzz in the speaker. Followed it into the kitchen and directly to the culprit where the buzz became LOUD. The source? A Mr. Coffee coffeemaker we had recently set up. It wasn't on, but was plugged in. Unplugged it and BAM! Noise gone! Problem solved. Never would have suspected that was the source. Needless to say, we now leave it unplugged except to make coffee in the mornings.