. "radio navigation beam" . "''Knickebein''" . "foil" . "Battle of the Beams#Knickebein" . "Y-Ger\u00E4t" . . "radio beam" . . "Battle of the Beams#Y-Ger\u00E4t" . "Knickebein" . "Battle of the Beams#X-Ger\u00E4t" . "''Y-Ger\u00E4t''" . "series of increasingly-sophisticated radio navigation systems" . "equipment devised to interrupt the homing beams" . "radio navigation" . . "jam radio navigation" . . "''X-Ger\u00E4t''" . . "distorted Luftwaffe radio guidance beams" . "counter-measures" . . "Battle_of_the_Beams#Y-Ger\u00E4t" . "Wotan" . "navigational aids" . "jamming German bombers' navigation systems" . "Battle_of_the_Beams#X-Ger.C3.A4t" . "the beams" . "radio beam systems" . "World War II night-navigation and radar systems" . "jamming efforts" . "Battle of the Beams" . . "X-Ger\u00E4t" . . "bearings and cross-bearings" . "Battle of the Beams" . "proving otherwise" .