Under Doppler Basics, Solving the Doppler Dilemma, it appears that the Companion PowerPoint presentation contains an error. On page 4 of the presentation, when the wind is 20 m/s the displayed folded wind for the 1200 PRF case should be 12 m/s towards and 4 m/s towards for the 900 PRF... opposite to what the page indicates.
Michel Bisson