  Kinematic dipole signal originates from the motion of the Sun with respect to
the CMB rest frame. It is a remarkable signal, two orders of magnitude larger
than the observed pattern of CMB anisotropies. Therefore the dipole subtraction
from the main beam is of primary importance. But what happens to the dipole
signal entering the main spillover (i.e. the most relevant far antenna pattern
feature, responsible for the bulk of the straylight effect)? We present here an
analytical and statistical study of this systematic effect for a spinning
space-mission like {\sc Planck}.
