Moving bump around 3kHz caused by switching power supply of rack 39?, today we opened the back of crate 39 and blowed hot air onto the switching power supply (used one "heating gun") between 8:26 UTC and 8:41 UTC. This produced no evident drift in frequency of the line at 2930Hz (Figure 1) and its companion at 3290Hz (Figure 2) which also is in dark fringe. The test is not conclusive: the power supply could be the source but being no sensitive to heating.
