Suppose that I'm working on a system which needs to use a transceiver with an FM signal. If that system moves very fast (i.e. it is a satellite or whatever) in which the maximum doppler effect can be comparable with frequency spacing, do I need an higher spacing than the doppler? Or it is not related at all? Or the usefulness of simply changing the spacing is related only to achieve a better insulation between other frequencies, and/or obtain an higher SNR, and therefore nothing to do with the doppler?
Thank you, and sorry for the dummy question. :)