As part of a broader FAA program to improve supportability, the Terminal Doppler Weather Radar (TDWR) radar data acquisition (RDA) subsystem is being replaced. For this purpose we developed an engineering prototype RDA with a scalable, open-systems hardware platform. This paper describes the design and characteristics of this new system. The dramatically increased computing power and more flexible transmitter control also enables modern signal processing algorithms to be implemented to improve the quality of the base data. Results highlighting the improved range-overlay protection provided by the new algorithms are presented.