The broadening of the whistler mode VLE emission band has frequently been observed by the equatorially orbiting S3-A (Explorer 45) satellite outside the midnight sector of the plasmasphere, during periods of geomagnetic disturbance. Prior to the broadening, the band of this emission is narrow with a sharp gap at the half electron gyrofrequency fH/2. The gradual broadening of the emission band on the low-frequency side is associated with the simultaneously observed spreading of the anisotropy of the ring current electrons to higher and wider energy ranges. The observed electron distributions are modeled according to the form E-n sinm(E) &agr; with time dependent parameters m and n, where m depends also on energy E. Using the modeled distribution function, the linear growth rates of the cyclotron instability are calculated numerically. The results suggest the broadening of the VLF emission band near the plasmasphere can be caused by spreading of the ring current electron anisotropy toward higher energies.