Raw gain from radiometer 27M throughout 4 year mission. P_id is a counter for pointings of the spin axis, which had an average duration of about 45 min Planck Collaboration I (2014). The increase of noise corresponding to the periods of “minimum dipole” (see text) are clearly visible for each of the eight surveys. Survey 2 (P_id range approximately 5200−10 000) and Survey 4 (P_id approximately 15 700−20 600) exhibit a significantly higher noise, as expected from the unfavourable alignment of the spacecraft spin axis with the Solar dipole in those two surveys.