Apollo Comms Part 29: Downvoice @CuriousMarc
Apollo Comms Part 29: Downvoice  @CuriousMarc
Uploaded December 2023 | Updated September 2026, 1 week ago
We back out the last remaining modification from our NASA receiver and return it to its original Apollo voice channel. If we are successful, we'll get to hear the voice from the astronauts the exact same way it was transmitted during the missions. And I hopelessly butchered the name of our hero engineer that left the helpful notes on the equipment, it's Frank Landspurg, not David Landsman! Bravo Mr. Landspurg. His obituary says that he was working for Motorola and supporting the Apollo missions, and passed away in 2014.

Apollo Comms Playlist: youtube.com/watch?v=v49ucdZcx9s&list=PL-_93BVApb58SXL-BCv4rVHL-8GuC2WGb

Links to doc:
curiousmarc.com/space/apollo-s-band-communications
virtualagc.github.io/virtualagc/QuestForInfo.html
ibiblio.org/apollo
ibiblio.org/apollo/Documents/HSI-481260.pdf

Elevator Music Credit: Crinoline Dreams by Kevin MacLeod

Our sponsors
- PCBWay: fast turn PCBs, pcbway.com
- ElectroRent: electrorent.com
- Keysight: test instruments: keysight.com
- Samtec: connectors: samtec.com
- R&D Microwaves: rdmicrowaves.com

Support the team on Patreon: patreon.com/curiousmarc
Buy shirts on Teespring: teespring.com/stores/curiousmarcs-store
Learn more on the companion site: curiousmarc.com
Contact info: youtube.com/curiousmarc/about

00:00 Our Apollo receiver has been modified
05:20 Reverting the modification
07:41 Retuning the filter assembly
11:40 First receiver tests
13:38 How to extract downvoice with a ham radio
15:45 First voice trials, not working!
16:49 Tracking the fault in the spacecraft transmitter
20:35 Receiving downvoice!

Correction: 03:26 Frank Landspurg (not Landsman)
Correction: 05:09 Frank Landspurg (not Dave Landsman)
Apollo Comms Part 29: DownvoiceMy 1956 STW-10 Friden CalculatorApollo Core Rope Memory (Apollo Guidance Computer Part 30)HP 10638A Degausser: checking vintage HP equipment with more vintage HP equipment!Polaroid magic with monster HP 197A and 198A Oscilloscope CamerasThe gooey-est vintage electronics everUSS Hornet and the forgotten Apollo AS-202 missionApollo Comms Part 18: Solving the mystery of NASAs Updata Link box missing partsTMG-303 Test Message Generator RepairF8 Fly-By-Wire System (Apollo Guidance Computer Part 31)Come see us at Open Sauce 2026, July 17-19 #opensauce #vintageelectronics #restorations  #apolloHP 5061A Atomic Clock Repair
CuriousMarc |

Apollo Comms Part 29: Downvoice

SHARE TO X SHARE TO REDDIT SHARE TO FACEBOOK WALLPAPER