The WU-650 Receiver Transmitter Antenna (RTA) is an integrated unit which incorporates transmitter, receiver, and antenna into a single unit. The WU-650 accepts either a 10 inch or 12 inch flat-plate radiator with transmitter and receiver components mounted on the rear of the antenna. The remainder of the circuitry is contained in the electronics package which forms the RTA base. The WU-650 is designed for cantilever mounting on the front bulkhead of the aircraft with line-of-sight stabilization employed. The WU-650 incorporates all the circuits required for transmission, reception, signal processing, scan conversion, serial data and control interface. The WU-650 also interfaces with the electronic flight instrument system (EFIS) and with the multifunction flight display (MFD). The WU-650 generates and receives X-band high energy to detect weather and to map ground features. The 9345 MHz transmitted signal from the magnetron is routed to the antenna through the circulator. The selected range of the WU-650 is determined by the pulse width (PW) and pulse repetition frequency (PRF). The size of the radiator (flat-plate antenna) determines the maximum range with a 12 inch radiator the range is 325 nautical miles and with a 10 inch radiator the range is 280 nautical miles.

The WU-650 is used in the Primus 650 Color Radar System. This systems makes up a lightweight, two-box, X-band alphanumeric digital radar with display designed for weather location and analysis, and for ground mapping. The display for the system can be either a dedicated radar indicator or the radar system can be operated in conjunction with EFIS and MFD equipment. This system detects storms along the flight path of the aircraft and gives the pilot a colored visual indication of storm intensity. In weather detection mode, target returns are displayed at one of five video levels. In ground mapping mode, video levels of increasing reflectivity are displayed as black, cyan, yellow, and magenta.