The FuMO 21 (Funkmess-Ortung, "Radio-direction finder, active ranging") was designed in 1941 as a search radar for Nazi Germany's Kriegsmarine, suitable for ships between light cruiser and large torpedo boats in size. First designated FMG^{[Note 1]} 39G(gL),^[1] it received its final designation when the Kriegsmarine revised its radar nomenclature system around 1943.^[2] It was derived from the earlier Seetakt search radar and had an antenna 2 m × 4 m (6 ft 7 in × 13 ft 1 in) in size.^[1]

FuMO 21

The rectangular antenna of the FuMO 21 of the ex-German torpedo boat T35
Country of origin	Nazi Germany
Introduced	1941
Type	Search radar
Frequency	368 MHz/81.5 cm
PRF	500 per second
Pulsewidth	5 μs
Range	about 10 nmi (19 km; 12 mi)
Precision	±70 m (230 ft)
Power	8 kW