Ghost armies and chaff spread the D-Day threat

Small craft transmitted off threatened coasts while Lancaster bombers dropped chaff to simulate a larger radar picture. The notional British Fourth Army suggested an invasion of Norway and forced Germany to consider a threat far from Normandy. Patton's First U.S. Army Group reinforced the expectation of an assault around Calais. An actor impersonating Montgomery, along with other false officer movements, widened the geographic uncertainty. Radio traffic, radar returns, paper formations, and human sightings gave German intelligence several routes to the same false conclusion.