  It is shown that instability of homogeneous precession is caused by combined
effect of anisotropy of spin wave velocities and dipole interaction. In the
principal order on the ratio of the Leggett frequency to the Larmor frequency
the increments of growth of spin wave amplitudes are found. The magnitude of
the maximum increment for all deviation angles of spin from its equilibrium
orientation is calculated. The estimation is made of the minimum temperature
down to which the precession is stable.
