Although the first operational unit was delivered in May 1943, various bureaucratic problems led to it being delayed in being delivered to the front-line troops. The SCR-584 was first used in combat at Anzio in February 1944, where it played a key role in breaking up the Luftwaffe's concentrated air attacks on the confined beachhead. The SCR-584 was no stranger to the front, where it followed the troops, being used to direct aircraft, locate enemy vehicles (one radar is said to have picked up German vehicles at a distance of 26 kilometers), and track the trajectories of artillery shells, both to adjust the ballistic tables for the 90 millimeter guns, and to pinpoint the location of German batteries for counter-battery fire. After D-Day, the SCR-584 was used in the rapidly shifting very front lines to guide planes to their targets with increased accuracy. For example, the Control Net Systems Group of the 508th Sq of the 404th Fighter Bomber Group, 9th Air Force ran the SCR-584. From 14 Jul 1944 until 27 Oct 1944 they were attached to Sec 1 Co A, 555th Sig Aircraft Warning Battalion and served in fluid, forward positions.