They did a lot more than just D-Day. They could make a company sound like a battalion or brigade by broadcasting the sounds of trucks and tanks moving in the night. They could make the Germans think there were tanks where they were not. One time, the Germans attacked and called the bluff; a very bad day for the good guys, but imagine the Germans surprise to find instead of an opfor, just a few guys with trucks with big-arsed loudspeakers on the beds.
“They did a lot more than just D-Day. They could make a company sound like a battalion or brigade by broadcasting the sounds of trucks and tanks moving in the night. They could make the Germans think there were tanks where they were not...”
Try watching: The Ghost Army
https://www.amazon.com/Ghost-Army-Peter-Coyote/dp/B00D5PA5CA
It’s a documentary explaining the many deceptions that were used in WWII and the brave men who created the illusion(s).
Most excellent!