This is the Radar Data Acquisition (RDA) of the NWS Louisville-Ft. Knox (KLVX) WSR-88D Doppler radar. The RDA is located at Ft. Knox, KY. Inside the large white protective covering (radome) is a huge antenna that continuously rotates sending signals to and receiving signals from targets in the atmosphere. These targets are "hydrometeors," ranging from very small, non-precipitating particles (virga) to very large raindrops and hail from thunderstorms. The antenna also can sense movement of particles directed toward and away from the RDA (the "Doppler effect"), which allows calculation and assessment of winds and rotation in the atmosphere, especially within severe thunderstorms.
The antenna is very sensitive and powerful, allowing forecasters to evaluate the structure, evolution, and motion of precipitation systems in great detail. Yet, the antenna transmits only a small fraction of the time, and "listens" for returned power from precipitation targets the rest of the time. The RDA can be controlled by staff members at NWS Louisville. Data received at the RDA is processed and sent to NWS Louisville for further processing before final display of various radar products on AWIPS workstations for observation, forecast, and warning purposes.