We take a closer look at the S-Band power amplifier from the Apollo command module, and learn how traveling wave tubes brought us voice, TV and data back from the Moon. The amplifier was manufactured by Collins, who was the prime contractor for the entire Apollo telecommunication system. 00:00 Recap of previous episodes 01:53 Physical location of the amp in the CM 02:35 Identifying the main functional elements 08:02 RF switches and emergency modes 11:14 Actual audio of Apollo 13 using the emergency mode 12:46 Making sense of the coax maze 16:03 Taking the amp apart 17:45 Broken connector scare and repair 20:08 Identification and history of the TWT tube 22:28 TWT explanation 25:33 Outro and future work Full Playlist: https://www.youtube.com/watch?v=v49ucdZcx9s Ken Shirriff’s article on this TWT amplifier: https://www.righto.com/2021/07/inside-20-watt-traveling-wave-tube.html Links to doc: https://www.curiousmarc.com/space/apollo-s-band-communications https://virtualagc.github.io/virtualagc/QuestForInfo.html https://www.ibiblio.org/apollo/ Music credits: Crinoline dreams by Kevin Macleod. Thanks to our sponsors - PCBs: https://www.pcbway.com/ - Test instruments: https://www.keysight.com/ - Connectors: https://www.samtec.com/ Support the team on Patreon: https://www.patreon.com/curiousmarc Buy shirts on Teespring: https://teespring.com/stores/curiousmarcs-store Learn more on the companion site: https://www.curiousmarc.com/ Contact info: null