A 2D full-wave simulation of ordinary mode propagation has been developed in an effort to model effects seen in reflectometry experiments but not properly explained by 1D analysis. The geometric fall-off of the fields, together with the effects of both refraction and diffraction, considerably modify the results obtained. The now commonly seen experimental observations of large amplitude and phase variations of the echo signal and occasional ramping of the phase can be explained by these 2D effects in the presence of fluctuations.