In this paper, we consider inhomogeneities of reflectivity within V6, as well as embedded large objects, to determine their effects on SAI measurements. Spaced-antenna interferometry is formulated to detect and locate a discrete object, sub-volume inhomogeneities, and to improve radar performance in measuring reflectivity and wind fields. Auto/cross-correlation functions and spectra are derived based on wave scattering by a large discrete object and clusters of randomly distributed precipitation particles. The antenna separation, mean wind, shear and anisotropic turbulence are all taken into account in the formulation. It is shown that incomplete beam-filling leads to an effective smaller beam and the increase in cross-correlation coefficient at zero lag. Hence, an individual object and sub-volume inhomogeneities can be detected and located by weather radar interferometry. This capability further enhances the potential application of phased-array weather radar used as multi-mission system.