DavidEduardo said:
Old radios from the era had a red triangle at 640 and 1240 indicating where to tune in the event of an emergency. Remember, this was the time when you probably had someone in your neighborhood who had or was thinking about building an underground bomb shelter...
It still fascinates me because that era ended just before I was born. I actually have a couple of old radios with the triangles at 640 and 1240; also recall an episode of
The Twilight Zone that featured announcements from CONELRAD (one family had a bomb shelter, the others didn't - trouble ensues). Fantastic opportunity to dx, that's for sure! One can just imagine that, if you got CBK in Cleveland, it must have been audible well south into a place like Oklahoma too.