A review and an investigation of gamma noise studies was conducted at Otaniemi, Finland, including the development of stochastic models, numerical studies, and experience gained from subcritical reactors. Three special and concrete aspects were considered: the use of photon-sensitive detectors for data extraction in reactor noise measurements, the degrading influence of gamma radiation in some types of measurements with gamma-compensated and -uncompensated ionization chambers, and a special gamma suppression technique in linear power measurements.