AN/CRT-2 Radio Communications Jammer Note: This exhibit has temporarily been removed from display. The AN/CRT-2 was an air-delivered radio transmitter that jammed radio communications. The AN/CRT-2 was dropped to the ground by parachute near enemy radio receivers in groups of six (each covering a different range of frequencies). The AN/CRT-2 could be set to jam immediately upon release or after a preset period up to 23 hours. Click here to return to the World War II Gallery.