In America 80 years ago, a knock on the door, even when you are listening to the radio, meant that a friend had come to call.

But as this RCA ad in the November 22, 1943, issue of Life magazine reminded readers, things weren’t the same in the Axis countries. It could mean the Gestapo and death if they knocked when you were listening to an American or British broadcast.

In America, you could even listen to enemy propaganda without worry, and it was often good for a hearty laugh. For now, American manufacturers such as RCA were supporting the war effort exclusively. But the ad reminds Americans that they would soon be back with fine radios and other electronic products.