Mesospheric gravity-wave (GW) phase velocity spectra and total powers at two Antarctic stations, Davis and Syowa, were derived using OH airglow image data from March to October in 2016. The total powers have similar seasonal variation, that is, maxima in winter at both stations. However, the power at Davis was one standard deviation larger in winter and three times smaller in September than at Syowa. The total power at Davis in winter was mainly attributed to GWs with high eastward ( phase velocity. On the other hand, the higher total power at Syowa in September was attributed to GWs with omnidirectional phase velocity. These differences between Syowa and Davis can not be explained by the wind filtering effect, and other factors are needed. To further explorer the origin of the difference in winter, we focused on an event on August 29, 2016, in which GWs with ~100 ms^-1 southeastward phase velocity appeared at Davis. The raytracing method was applied, and its result indicated that those GWs with high southeastward phase velocity propagated from ~45 km altitude over the southern ocean (~ where GWs with high amplitude and southeastward propagating emitted from the tropospheric jet appeared. These jet GWs were probably saturated in 45-50 km altitudes. Therefore, the GWs with eastward phase velocity were probably secondary gravity waves. This result suggests that the higher power in the eastward high phase velocity domain at Davis was contributed to by secondary GWs.