Which component is not part of the three components replacing HSD-400?

• A. DF-500
• B. Cobham Aviator 700 Satellite Data Unit (SDU)
• C. Swift Broadband unit
• D. High Power Amplifier

Answer: (A)

When replacing HSD-400, the system is rebuilt with a complete satellite data path in mind: a Satellite Data Unit (SDU) to prepare and format the data for the satellite link, a broadband unit to handle the actual satellite communication link, and an RF stage that provides the required transmit power. The Cobham Aviator 700 SDU, the Swift Broadband unit, and the High Power Amplifier together cover these essential roles, ensuring data is processed, transmitted, and amplified for reliable satellite connectivity.

The DF-500 does not fit into this three-part replacement because it serves a function outside of that primary satellite data path. It isn’t a core component of the uplink/downlink chain (data formatting, broadband link handling, and amplification) and thus is not part of the replacement trio.