xusmarine1979,
I had the same problem with my BC250D. I kept getting this pulsating buzz on alot of frequencies. I first went to the basement and killed the main disconnect, to pin point that it was coming from in the house. After searching high and low I could not find the source. I tried everything I could think of that was electronic, no luck. One day I was trying to run a lamp cord behind our bed an heard a faint buzz, buzz, buzz. It turned out to be the electric blanket my wife used on our bed in the winter, I unpluged it and pulsating was gone. At that time I noticed a FCC statement on the bottom of the control unit. Everything has been great................except winter is coming and so will that PITA blanket.