The Army Communications Electronics Command (CECOM) Space and Terrestrial Communications Directorate (S&TCD) is conducting a multi-year airborne communications range extension program, primarily in support of the Battlefield Information Transmission System (BITS) initiative. As part of this program the Jet Propulsion Laboratory (JPL) is currently under contract to CECOM to design and develop a payload as an unmanned aerial vehicle (UAV) based communications relay package to operate with the US Army's high capacity trunk radios (HCTRs) for test, evaluation and demonstrations. The basic function of this payload is to simultaneously relay full-duplex communication links to and from ground-based HCTRs. The maximum data rate that will be supported across these full-duplex links is 45 Mbps over a range up to 100 miles. Multiple full-duplex communication links can be supported by this UAV payload at the penalty of reduced communication range and/or reduced data rate throughput for each link. In addition to this full-duplex communications capability, a broadcast communication adjunct (at data rates up to Tl) will also be provided. This secondary capability will utilize the identical uplink subsystem as the full-duplex payload but will use an S-band downlink package for broadcast to a small, hand-held omni-directional antenna based receiver.