A large concrete ring at Orford Ness National Nature Reserve on the Suffolk coast has been identified as a remnant of a Cold War-era radar installation. The 165-foot-wide structure, which has intrigued visitors and staff since the National Trust assumed responsibility for the 2,000-acre former military testing site in 1993, was part of a long-range radar system built in the 1960s.

The installation, known as the R-system, was constructed by the United States Air Force to detect missile launches and nuclear explosions from great distances. At the center of the concrete ring was a steerable helical transmitter and receivers designed to monitor activity thousands of miles away. However, the system’s operational use was relatively brief, as advances in satellite technology rendered it obsolete by the end of the decade.

In 2018, researchers Olaf Kirchner and Steve Clifton visited Orford Ness, drawn by the site's Cold War history. The pair joined the International Research Group Orford Ness and traveled to Muirkirk, Maryland, one of eight locations where similar R-systems were installed. There, they met Edwin Lyon, the 94-year-old chief designer of the radar system.

After obtaining security clearance, Lyon shared archival footage and personal accounts detailing the intelligence-gathering operations conducted during the Cold War. Kirchner described the experience as “listening in awe” for over two hours to firsthand stories about the site’s role in monitoring potential nuclear threats.

The researchers are now collaborating with the National Trust to preserve and communicate the history of Orford Ness and its significance during a tense period of international relations. Visitors interested in exploring the site can find access information through the National Trust’s official resources.