CuriousMarc | Apollo Comms Part 2: Inside the Traveling Wave Amplifier @CuriousMarc | Uploaded 3 years ago | Updated 2 days ago
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: youtube.com/watch?v=v49ucdZcx9s&list=PL-_93BVApb58SXL-BCv4rVHL-8GuC2WGb

Ken Shirriff’s article on this TWT amplifier:
righto.com/2021/07/inside-20-watt-traveling-wave-tube.html

Links to doc:
curiousmarc.com/space/apollo-s-band-communications
virtualagc.github.io/virtualagc/QuestForInfo.html
ibiblio.org/apollo

Music credits: Crinoline dreams by Kevin Macleod.

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- PCBs: pcbway.com
- Test instruments: keysight.com
- Connectors: samtec.com

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