These are the industry-standard and regulated methods for broadcasting radio entertainment. Amplitude-modulated (AM) signals are simple to create / demodulate electronically, which is why AM was an early broadcast format. AM, however, has more inherent noise and a narrower bandwidth than can be obtained with FM. The frequency range that AM operates over is also more suited to amplitude modulation broadcast techniques. Two-channel broadcasting (stereo) is more difficult to implement in AM, while maintaining compatibility with standard mono broadcasts. The frequency response of AM broadcasts is usually limited to about 10 kHz. Frequency modulation (FM) is a more complex process, but since the carrier has much higher frequency and stations are spaced further apart, it can produce better quality sound. It is inherently more immune to the type of noise that plagues AM broadcasting. FM does have problems with multipath distortion, however, in which multiple signals arrive out of phase with one another because of reflections off structures and environmental features. There is sufficient space in the band to handle the two signals in stereo broadcasts: L+R (mono) and L-R (difference). FM broadcasts have a frequency bandwidth of 15 kHz, producing better-quality audio. Your station broadcasts on both bands to reach a wider audience.