1952 29 July 9/1 Electronic counter-measures (ECM) may have something to do with some of the recent radar sightings.
1986 Sept. 79/2 ECM jams enemy radars by laying down a barrage of noise that swamps their receivers.
2013 E. Sierras xvii. 218 He would brief..strike planners to make detailed mission planning folders including launch order..as well as ordnance loads and electronic countermeasures (ECM).