  A simple method has been proposed to determine acoustic-gravity wave (AGW)
properties at mesosphere heights from measurements of VLF radio signals. For
relatively short paths (less than $\sim$ 2000 km long), simple relations are
obtained for estimation of AGW neutral density fluctuation from measurements of
amplitudes of radio signals. In the wave-hop approximation, we relate the
fluctuations in radio signal reflection height with AGW-induced vertical
displacement of an elementary volume of atmospheric gas. Using these relations,
we can recover some properties of AGWs at mesosphere heights.
