A symmetric magneto-optical resonance arising from the single two-quantum RF transition $|{F}_{g}=1,{m}_{{F}_{g}}=\ensuremath{-}1\ensuremath{\rangle}\ensuremath{\leftrightarrows}|{F}_{g}=1,\phantom{\rule{4pt}{0ex}}{m}_{{F}_{g}}=1\ensuremath{\rangle}$ in an optically aligned atomic ensemble is studied in the case when the quadratic Zeeman shift exceeds the width of the resonance. It is shown that the signal-to-noise ratio of the resonance can be significantly increased by applying the phase modulation to the RF field at a frequency close to the value of quadratic Zeeman shift. This theoretical prediction is corroborated by the experimental results with $^{87}\mathrm{Rb}$ atoms. The proposed technique can be used in magnetometers based on atomic alignment or by utilizing multiquantum RF resonances in optically oriented atomic ensembles.