a substantial problem of analog am transmission is that it is subject to poor signal to noise ratio due to radio frequency noise from man made and natural sources, such as fluorescent lamps, motors, switches and lightning. simply adding high frequency information does not produce high fidelity. hd radio signals on am, however, use more bandwidth signal wise and often create "hash" on surrounding frequencies, up to 30 khz from the center frequency. this interference, which is audible mainly on analog radios, was one of the reasons citadel communications pulled night broadcasts of their am hd station's signals. cam-d does not produce interference on any channels 10 khz or more from the center frequency.