Communication - Specifications (page 10 of 11)
Doppler:
Earth rotates CCW while Venus rotates CW. This means that the orbital speed of Earth and its rotational speed tend cancel out the smaller component; in this case, Earth’s rotation. Venus, and thus the satellite, orbit CW which means that the two components tend to be additive. The worst case scenario involves adding the magnitudes of Venus and the satellite and only considering the Earth’s velocity without subtracting anything! At 8.419 GHz the wavelength is .0356 meters.
Thus, the range of possible received frequencies at DSN is: [8.417 GHz, 8.421 GHz].