distance information of a fixed, reliable target on the radar screen. Radar controls Marine radar has performance adjustment controls for brightness and contrast, also manual or automatic adjustment of gain, tuning, sea clutter and rain clutter suppression, and interference reduction. Other common controls consist of range scale, bearing cursor, fix/variable range marker (VRM) or bearing/distance cursor (EBL). References External links Calculatoredge.com Radartutorial.eu Earth.esa.int Alphalpha.org Macuait.com Radar in the 21st Century Sea radars Navigational aids