This paper describes the first results of the implementation of frequency domain interferometry (FDI) using the Middle and Upper (MU) atmosphere radar. A new method of using this FDI data is introduced, which is shown to be useful in studying the dynamics of scattering layers in the troposphere and lower stratosphere. Using this method, the effective altitude resolution of the MU radar has been improved. Copyright 1990 by the American Geophysical Union.