The North Vietnamese also netted their SA-2 Fan Song fire-control radars with their Bar Lock, Whiff, and Spoon Rest ground control intercept (GCI) radars. The GCI radars could feed the tracking data to Fan Song, which then did not have to be turned on until after missile launch. The Radar Homing and Warning (RHAW) gear carried by the American aircraft provided warning when the aircraft were being tracked by the Fan Song, but could not detect emissions from the GCI radar. Thus pilots had little or no warning of a missile attack.