  This document presents a ray-optics analysis of the response of a two-element
radio interferometer to the presence of a plane gravitational wave. A general
expression for the differential phase observed between the two receiving
stations as a result of an arbitrary gravitational wave is determined, as well
as the specific responses to monochromatic and black hole ring-down waveforms.
Finally, the possibility of gravitational wave detection via this mechanism is
discussed in the context of interferometer noise.
