The Collins RTA-842 Receiver/Transmitter/Antenna combines the receiver, transmitter, and antenna into a single unit. The RTA-842 is a part of the WXR-840 Advanced Weather Radar System which provides the flight crew with a display of X-band radar detectable wet precipitation within 60 degrees of the flight path. The WXR-840 system consist of two separate units, the RTA-842 and the WXP-840A/B Weather Radar Panel.

The forward portion of the RTA-842 is the flat-plate antenna, which is available in either 12, 14, or 18 inch versions. The RTA-842 has a 12 inch antenna plate, the RTA-844 has a 14 inch antenna plate and the RTA-848 has the 18 inch antenna plate.