TSVCIS performance analysis over bent-pipe relays with automatic gain control

This paper presents a performance analysis of modern voice and FM plaintext voice with squelch over the automatic gain control (AGC) method developed by the U.S. Naval Research Laboratory (NRL) and implemented on the NRL Surrogate TACSAT communications relay payload. The AGC enabled relaying U.S. Military VHF voice and data communications beyond line of sight (BLOS) without exceeding our RF combiners input power limits. It was found to perform as desired with transmitters at a range of 27 miles (43.4523 kilometers) with a tethered balloon borne relay payload at a height of 600 feet (182.88 meters). Additionally, the performance analysis shows that (1) several Tactical Secure Voice Cryptographic Interoperability Specification (TSVCIS) modes found in modern tactical voice will operate without errors through a bent-pipe relay with automatic gain control and (2) pseudo noise (PN) code sequences can be detected as long as the correlation threshold is set low enough to allow for the bit errors that occur during an AGC update.