Inside a 20-Watt Traveling Wave Tube Amplifier from Apollo

.hilite {cursor:zoom-in} a:link img.hilite, a:visited img.hilite { color: #fff;} How did the Apollo astronauts communicate on their trip to the Moon, 240,000 miles back to Earth? They used a 32-pound amplifier, built around a special kind of vacuum tube called a traveling-wave tube. In this blog post, I look inside this amplifier and explain how the traveling-wave tube works. The Collins Radio traveling-wave tube amplifier. The label says "Not for flight" so this amplifier was only used on...