"Night of the Bees"

"Radio listeners across America are trying to hide from a monster, but
there is no shelter. After spending its adolescence in technical
trials during daytime hours, IBOC has now come out at night... For
example, in New York City, WOR broadcasts on 710 kilohertz. When it
turns on its IBOC equipment, the digital noise it produces can be
heard on 690, 700, 720 and 730 kilohertz with a reduced fidelity
analog audio signal remaining on 710..."

http://karlzuk.blogspot.com/2007/09/night-of-bees.html