Whistler mode instability having propagation vector oblique to ambient magnetic field has been studied for pitch angle loss-cone unperturbed distribution function for inhomogeneous ionospheric plasma. Dispersion relation and growth rate have been derived and calculated for ionospheric plasma having in homogeneity in perpendicular AC electric field, loss-cone and temperature anisotropy. The growth rate of electromagnetic circularly polarized VLF wave has been founded to be enhanced by free energy source like temperature anisotropy and loss- cone up to a limited angle of propagation. It is also inferred that perpendicular A C electric field modifies the resonance frequency condition.
