Three consecutive 20 min LBA observations of PSR B1133+16 taken on 2010 Nov. 5. In between these observations, the station calibration was alternately turned off and then back on. The profiles are all scaled to have the same peak height and as can be seen, the S/N of the cumulative pulse profile decreases by roughly a factor of 3 when the static calibration table is not applied. Five Dutch stations were combined incoherently in these observations, and as such the S/N difference is the average calibration gain for all these stations.