There is a clear indication of influence of strong coherent spurious signal on phase calibration signal at the 8550.99 MHz channel . Amplitude of phase calibration signal had strong variations at the frequency channel 8250.99 MHz . See plot of amplitude versus time for 2212.99 MHz frequancy channel. Residuals phases at S-band don't have zero mean.
Time is in hours from beginning of the session.
These frequencies were dropped in final fringing. Most of the problems of such a sort could arise from not perfect insulation of a cable. The station reported they have changed the cable after this campaign. I didn't succeed in fixing this problem by making manual phase calibration or using the accumulation period by accumulation period phase calibration. Letter from station when they started experiment.