Subspace amplifier
A subspace amplifier or subspace buoy was a communication array designed to extend the range of subspace communications.

A series of subspace amplifiers were deployed by the Earth starship  during its initial exploratory mission. The amplifiers were deployed to allow better communication with Earth and United Earth Starfleet Command. The amplifiers were designated by letter-number combinations. The first such device, Echo 1, was deployed in August of 2151, with Echo 2 being deployed one month later. ()

In September of 2151, an unknown alien vessel destroyed both Echo 1 and 2 during a sustained attack on Enterprise. Following the successful elimination of the alien threat, a third amplifier was dropped, to replace the lost two. ()

To distract the automated repair station after it made repairs to Enterprise, Commander  claimed that the subspace amplifiers aboard Enterprise only picked up distortion on all the high-band frequencies following the repair work. ()

Starfleet Command Council held contact via subspace buoys with Enterprise while the ship was on its mission in the Delphic Expanse. ()

In 2259, the  deployed subspace buoys to maintain contact with Starfleet as they ventured beyond the border of Federation space to search for a trio of stranded colonial ships. ()

de:Subraumverstärker
sv:Underrymdsförstärkare
amplifier
Communications technology