This is a sources sought synopsis for system sustainment support services for the Digital Receivers (DDRx) used in the Relocatable Over-the-Horizon Radar (ROTHR) System, with performance locations in Texas, Virginia, and Puerto Rico. The requirement focuses on repair and engineering support for the DDRx at the Texas location, with an anticipated period of performance from 26 June 2026 to 25 January 2028, including three one-month option periods. The digital receiver technology is proprietary to BAE Australia, and Memorandums of Understanding between the U.S. and Australian governments restrict transfer or disclosure to third parties, limiting potential contractors. Interested vendors must submit a capability response, including an executive summary of no more than two pages, by 10:00 AM local time on 5 June 2026. No budget amount is specified in the description.