Static-Free: Armstrong Unveils FM Radio

On November 6, 1935, 91 years ago, inventor Edwin Armstrong showed a room of radio engineers in New York a new kind of radio: FM. Old AM radio sends sound by making waves taller and shorter, so lightning and static crackle right through. FM keeps the waves the same height and changes how close together they are, so the static drops away. RCA, the company that once backed him, told him to pack up his FM tests and help with television instead. Armstrong kept going, and today FM carries music around the world. A good idea will eventually win, even if people don't get it right away.

Colors: 1 Red · 2 Peach · 3 Gold · 4 Cream · 5 Dark cream · 6 Gray · 7 Light green · 8 Green · 9 Light blue · 10 Blue · 11 Light brown · 12 Brown