By detecting subspace field fluctuations within the Borg cube, Geordi La Forge was able to determine the cube was regenerating and restoring its power. (TNG: "The Best of Both Worlds" , "The Best of Both Worlds, Part II" ) The sensors of a USS Enterprise-D runabout were unable to get through a subspace field caused by a temporal fragment. (TNG: "Timescape" ) Subspace field emitters were a component of starships. (DS9: "The Homecoming") If a high-energy output was used in the generation of a subspace field, it could be used to jam sensors. (TNG: "The Wounded" )