Abstract: EMI from an operating information handling system is managed by disposing a stirring device in the chassis of the information handling system to mechanically modulate the resonance of predetermined RF signals emitted from processing components within the chassis. For example, a cooling fan disposed in the chassis has a reflective surface formed on its blades so that rotation of the blades mechanically modulates the RF signals. The blades have a depth of at least one-quarter of the wavelength of the RF signal and are coated with a low resistance material, such as steel, aluminum, copper, carbon loaded plastic or a high dielectric ceramic. The fan rotates at the faster of the speed required to provide desired cooling or the speed desired to produce a desired average RF signal amplitude.