Doppler should be slightly positive in the beginning of the passes starting from 27/10 00:00 UTC (due to Earth rotation and very low radial speed wrt Earth Center before the flyby). The lowest Doppler occurs after the flyby since 4M will then regain speed and radial speed will be negative. Maximum Doppler is -400Hz. The highest Doppler will occur just before flyby and should reach +50Hz and should occur between 1200 and 2200 UTC on 27 Oct.
