  Based on the free precession model of the isolated pulsar PSR B1828-11, Link
& Epstein 2001) showed that the observed pulse durations require the radio beam
to have a non-standard shape: the beam duration is larger for beam sweeps
farthest from the dipole axis. In their analysis they assumed that the actual
precession period is ~ 500 d. Recent theoretical studies suggested that the
actual precession period might be ~ 1000 d as seen in observations (Rezania
2002, Wasserman 2002). In this paper, in a good agreement with the observed
data (Stairs et al. 2000), we model the changes of the pulse shape in a
precession cycle with period ~ 1000 d and find that the variation of the pulse
duration follows from a {\it standard} beam pattern in each cycle.
