Wikipedia:Today's featured article/May 30, 2025
Radar, Gun Laying, Mark I, or GL Mk. I for short, was an early World War II radar system developed by the British Army to provide information for anti-aircraft artillery. There were two upgrades, GL/EF (elevation finder) and GL Mk. II (pictured), both improving the ability to determine a target's bearing and elevation. GL refers to the radar's ability to direct the guns onto a target, known as gun laying. The first GL sets were developed in 1936 using separate transmitters and receivers mounted on gun carriages. Several were captured in 1940, leading the Germans to believe falsely that British radar was much less advanced than theirs. The GL/EF attachment provided bearing and elevation measurements accurate to about a degree: this caused the number of rounds needed to destroy an aircraft to fall to 4,100, a tenfold improvement over early-war results. The Mk. II, which was able to directly guide the guns, lowered the rounds-per-kill to 2,750. About 410 Mk. Is and 1,679 Mk. IIs were produced. (Full article...)