A shield frequency, shield harmonic or shield modulation refers to the frequency settings of the shield emitters on a particular starship or other shielded location.
The Borg use regenerative shields which constantly remodulate their shield frequencies to best resist enemy fire. (TNG episodes: "Q Who?", "The Best of Both Worlds, Part I" et al.)
An unusual hybrid starship encountered by the USS Enterprise-D in 2370 included Borg components and operated with a Borg shield structure; the constant shift in shield frequencies made it hard to gain a proper sensor lock on the vessel to learn anything about it. (TNG - The Space Between comic: "Strategy")
If an attacker is aware of a ship's shield frequency, they can adjust their weapons frequency accordingly to fire through the shields; this tactic was used in 2371 to devastating effect on the USS Enterprise-D. (TNG movie: Star Trek Generations)
In 2376, the USS Equinox successfully engaged the USS Voyager after obtaining her shield frequencies. Although the crew of Voyager remodulated their shields on several occasions, the new frequencies were passed on to the Equinox by their EMH, who had been switched with Voyager's EMH. (VOY episode: "Equinox, Part II")
External link[]
- Shield frequency article at Memory Alpha, the wiki for canon Star Trek.