Graf Spee's radar and the limits of target identification

Detection was not identification. Radar could supply useful measurements, but it could not establish whether a return was a friend, a soft target, or a hard target. At the Battle of the River Plate the next day, Langsdorff initially appears to have taken the British force for one cruiser and two destroyers, only recognizing three cruisers after the action began. A working Arado might have identified the force before Graf Spee committed herself and left Langsdorff free to turn away, run, or fight at long range with his heavier guns.