AN/FPS-95 “Cobra Mist”

The AN/FPS-95 “Cobra Mist,” also known by its British designator System 441A, was an experimental Over-The-Horizon (OTH) early warning radar operating in the High Frequency (HF) band (6–40 MHz). Located in Suffolk, England, it operated from the late 1960s until 1973. Its antenna array comprised 18 log-periodic antennas, radially arranged like spokes from a central feed point, covering a bearing range of 19.5° to 110.5°. These antennas, supported by masts 13 to 59 meters high, featured 620-meter-long strings with cross-mounted active dipole elements for both horizontal and vertical polarization, achieving a gain of 25 dB. Despite its advanced design, including a large mesh screen for improved ground wave conductivity, the radar never achieved full operational status due to persistent, unidentified environmental noise, leading to the project's cancellation in 1973.

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