This report provides a preliminary analysis of a passive Doppler radar system to remotely sense precipitation and windspeed by observing the scatter of microwave broadcasts from geosynchronous satellites. Completely passive radar systems have begun to appear for aerospace and ionospheric applications (observing terrestrial VHF and UHF transmissions), successfully demonstrating the principle of passive radars. Thus we consider the exploitation of microwave broadcasts at frequencies similar to conventional precipitation radars. This report describes a link budget analysis for a candidate radar system and describes a simpler ``proof of concept'' instrument that could be developed fairly easily before committing to a more elaborate instrument. We conclude that it is unlikely to be able to build a completely passive system with space-time resolution that meets the needs of the weather community with currently available transmitters. Should anticipated more powerful sources become available, the PDPR with lower procurement cost and much lower operation cost, would be very welcome.