A method and a satellite gateway for minimizing an impact of a noise floor variation in a spot beam satellite system. A demodulator processes digitized signals from multiple channels. Digitized signals are automatically gain controlled by respective automatic gain control components associated with respective channels. Automatic gain controlled digitized signals are downconverted and provided to a burst processor. The burst processor processes each downconverted signal and provides, with respect to each downconverted signal, an automatic gain control estimate, a code rate, and an inroute number to a processor component. The processor component determines an average automatic gain control value for each inroute, provides automatic gain control references to the respective automatic gain control components, and periodically sends noise map information to satellite terminals served by the satellite gateway. In some embodiments, the automatic gain control values are biased according to corresponding code rates.