Apollo Comms Part 1: Opening the S-Band Transponder and Amplifier

[@Steph.98114]

Next video: restoring the Saturn 5

[@RossComputerGuy]

Including the trainer LM and CM?

[@macartm]

Don't forget the first rule of rocket science. Pointy end up.

[@ivanmartinez-arroyo6184]

And after that, restoring the whole MSFN to support one more Apollo mission

[@thiesenf]

@@macartm ...and flamey end down... :-) Don't we all love Tim Dodd... :-)

[@jebediahkerman8245]

If pointy end down, you will not be going to space today.

[@georgewhitehead4916]

I worked in the Apollo Communications Systems group at North American Aviation Space and Information Systems Division, the prime contractor for the Apollo Spacecraft and had principal engineering responsibility for the Apollo PCM Telemetry Equipment. I'd be happy to contribute my personal knowledge and experience with this, the other Apollo communications equipment and the engineers I worked with. George Whitehead

[@CuriousMarc]

Awesome! Can you please contact us via the link in under the video description?

[@ET2carbon]

Hey I'm a retired US navy satcom tech post 9/11 era. Both strategic earth station terminal and shipboard surface tactical SHF EHF X-BAND. i've had questions about this system on apollo that never made total sense looking into past systems that don't translate into the more current stuff i worked on. Just one question to start with if I may have a moment of your time, why was there a floppy parabolic 3foot antenna on the lunar rover buggy. That would really set my suspicions at ease. I just always saw that thing flopping around and never believed it could lock onto a satellite relay tracking beacon. I would appreciate your insights. Much respect and it's an honor to chat. ET2

[@ebrombaugh]

Beautiful stuff. I worked at Motorola GEG (Gov't Electronics Group) in the late 1980s and many of my older colleagues had been involved in development of these radios.

[@Spookieham]

When you consider how much money it must have cost to design, build and test that one system alone you can understand where the utterly mind-boggling cost of Apollo came from. Can't wait for the rest of it!

[@Broken_Yugo]

Some of it was that the whole thing was bleeding edge technology, part of it was it was funded by congress ,and thus inefficiently smeared across the 4th largest country in the world to keep them happy. The infrastructure to move all that stuff around is almost as interesting as the tech itself.

[@AsbestosMuffins]

and yet it really didn't cost that much because they were mostly allowed to build exactly what they needed with exactly the materials they wanted, no reused unsuitable parts dictated by congress like SRBs, overly expensive engines, and an entire payload that has no purpose

[@chargehanger]

60 tech, but it really exactly looks like 90's RF stuff. it was so much ahead.

[@jimb12312]

The entire Apollo program cost only 25% of the 20 year Afghanistan debacle (adjusted for inflation). Imagine having a program 4 times bigger than the Apollo program going since 2001. That's what we missed out on, for absolutely nothing.

[@Reth_Hard]

I just know that once you opened it, you better not drop your coffee inside of it... lol

[@ninetailscosmicfox5585]

The ADC restoration was the best 30 hours I've ever spent on a KZbin playlist. Fangirls like me have a high bar for this series, but only because you are the best person possible to document this.

[@ninetailscosmicfox5585]

@@mjgII Neat. You will never be an expert on the subject.

[@Silversurfer604]

@@ninetailscosmicfox5585 please more popcorn is ready :-)

[@benespection]

Fellow fangirl reporting in... Have been hanging on for this series since it was teased ;) I have always admired the attention to detail and care taken by Marc & co. with previous projects.

[@3ffrige]

This is absolutely a marvel to look at. And to think that the required math needed behind these things were done by slide rule calculators. And to think these primitive systems brought us to the moon and back. They don’t make things like this anymore. Stuff nowadays is designed to be disposable.

[@ninetailscosmicfox5585]

@@benespection Same! :)

[@wm6h]

They built the amplifier here in town (Cedar Rapids). Probably some retirees that designed it still around. Posted link on fb. I think they will enjoy the series.

[@CuriousMarc]

Would love to connect with the people that designed and built this! Some unsung engineering heroes there.

[@chromosundrift]

This is so fantastic. It makes such strange phenomena as moon landing deniers even more perplexing, when all the engineering artefacts, designs and administrative paper trails are so detailed and complete. Faking all this as well as the landing would have been more work! Thanks Marc.

[@vincei4252]

I wouldn't waste a moment thought on those clowns. The same as flat earthers.

[@frankbrockler]

Lack of knowledge gives rise to mythology and conspiracy theories because the ignorant are easily misled. When your knowledge of microwaves is limited to making popcorn, faking the moon landings sounds reasonable.

[@josugambee3701]

"5G is microwaves, and microwaves cook things, therefore 5G cooks people!" - Conspiracy theorists in a nutshell. I work with radio waves as a hobby, and I know for a fact that RF radiation is completely safe, unless you're right next to a very powerful transmitter for some reason. That is why there are warning signs on radio towers, because engineers know that radio waves CAN be harmful under specific circumstances (I.E. being right next to a several-kilowatt transmitter), and have implemented measures to protect you with fences and signs. That is, unless you're a moron who decides to destroy cell towers for no reason, in which case many people may get hurt.

[@daveb3910]

I've only met 2 in my entire life, I. Really think their numbers are way overestimated so people like us can say, "at least we're not stupid clowns like those people."

[@chromosundrift]

@@vincei4252 Wise words and yet I think the psychological phenomenon is instructive, especially to people who consider themselves well-educated and rational.

[@AsbestosMuffins]

always love that Australian dish, it looks like an ordinary windmill with an impossibly large looking dish ontop

[@abelramirez7320]

Writting a report about this for the final project of my technology class. That box is a very fascinating thing.

[@marwinthedja5450]

Unified S-Band, the kind of USB I can actually admire ;)

[@winstonsmith478]

The Danger High Voltage warning is humorous since anyone authorized to even look at let alone touch the innards would know that.

[@MLX1401]

Haha, my first thought was if they did the milling just to make the build look more bad-ass :D

[@maniette-kdlt]

That’s just in case any Martian guy opens the box.

[@stopthephilosophicalzombie9017]

Nanny state is always watching, especially at NASA.

[@Regi62]

the 3 minutes of rocket engine noise really helped tie the whole experience together with headphones. Thanks a lot

[@jamesflorence4394]

I always look forward to these……

[@davidwagner6116]

And this time it's microwave analog electronics! I learn so much from Marc and his friends.

[@davidhardin5546]

A correction to your narration: The old Collins Radio Company is now Collins Aerospace, a part of Raytheon Technologies. "Rockwell Collins" is no more.

[@timballam3675]

Collins Aerospace has just acquired FlightAware so will be a familiar name to many.

[@rogervanbommel1086]

Another correction, transponder means transmitter + responder (13:36)

[@electronash]

@Virtex Alpha lol

[@alpcns]

Gorgeous, brilliant and fantastic engineering. Absolutely stunning, just spectacular what you guys routinely do. Apollo still gives me goosebumps. It must feel like finding and opening the Ark of the Covenant or something similarly ultra-special. Thank you for these priceless videos and enormous efforts.

[@CuriousMarc]

You put it well. It feels exactly like that, Ark of the Covenant opening! Without the negative consequences of course…

[@TheGmr140]

these systems used sub-band modulation. that is many signals at different baseband frequencies combined and then sent to final PM or FM modulator. this was to allow the final RF amps, to be in compression a bit to get max RF power. PM and FM can work when amps in compression, unlike AM and SSB

[@TheGmr140]

@@uploadJ it's not three freq they are combined and feed into fm mod, so one carrier that is fm modulated. trust me i do this all the time for work, fm and pm signals work with amps in compression. info is in the phase of signal, not amplitude. simple idea, most don't get

[@MattVileta]

For transmitter comparison; I can get a 2.4Ghz 1 watt transceiver for an FPV drone for $30, that weighs less than 30 grams and is only 20mm X 20mm. How far we've come!

[@SimonBauer7]

transistors rule!

[@ahmetmutlu348]

Well Ewen the frequency is sone or similar ... It'll not be that powerful.. if they manage to make this devices work and put that on a drone I'm sure their range will be more then 10s if kilometers in earth surface Ewen with relatively small antennas.

[@kuebbisch]

We are past the vacuum tube age :-) Even home stereo amplifiers are now just cheap boxes with triple digit output powers.

[@Dwarg91]

@@uploadJ the answer is yes.

[@Reth_Hard]

I'd be very curious to know how big this would be now if we had to build it with our current technology, with the same signals in & out. And also how much wattage the new box would be consuming...

[@classicaudioadventures]

As an Apollo program junkie, I love your videos. Nobody out there goes into the nuances and hardware details as you do.

[@Slugg-O]

I am amazed every day by modern technology but I have far greater admiration and respect for old tech like this because it required tremendous brain power and teamwork. Much of today's tech is developed using computers for design and simulation, whereas Apollo era tech was built by hand using blood, sweat, tears, cigarettes and coffee. They couldn't just build a com system that worked, they had to build a system with the highest reliability humanly possible. I would say that next to life support the com system was the most important part of the spacecraft.

[@parttime9070]

The whole program used the slide rule..

[@parttime9070]

@@uploadJ I realize NASA used IBM's, Sorry for the blanket statement.. The engineers and machinists used side rules for the most part , I still have my father's..

[@dalemettee1147]

Marc, this reminds me of when I was a lot younger, I worked for a company who did a lot of work for the DOD and also for NASA. One of the contracts they had was for the L.E.M. (the lunar excursion module) trainer. I worked on the electrical hook up of all the gauges and lights inside. After all was completed, I sat down in the center couch and looked at all of the gauges lit up. Quite impressive. I never forgot seeing all of the EL panels.

[@TheEmeraldMenOfficial]

You had coworkers who helped with the LLRV? Awesome! It’s amazing how many people have a link to this wonder of human ingenuity. Also, I assume you worked at Bell Aircraft (since they’re the ones who built the LLRV): If so, did you work at their helicopter division? I think hearing that one would send me to the moon WITHOUT a rocket, lol!

[@whitechannel2669]

Excellent! This is the kind of contents KZbin should exist for.

[@henrylikesradios]

I'm a radio technician and I'm fascinated by this, how the comms systems worked in the Apollo program. They were very clever engineers to develop the PLL and other systems and all done in the 1960s. State of the art for the time. A close look at the transponder module, I saw a VCO module and the other receiver modules, looks like a dual conversion receiver.

[@CuriousMarc]

Good eyes! It is a dual conversion receiver. Everything is done with PLLs, including the PM and FM demodulators, this is much more advanced than I would have thought.

[@RobatRobot]

I had a quick read down the comments but couldn't see what I wanted to mention. You say they operated three links, for the CSM, LM and S-IVB stage. However, they would not usually power the LM during the trans-lunar stage since it shared the same carrier as the S-IVB booster. This allowed them to perform ranging on the booster stage until it impacted the moon, at which point they could power the LM without interference. However, during the flight of Apollo 13 they had to power down the CSM. At that point the carriers for the LM and S-IVB conflicted and they lost uplink. They were very lucky that the larger ground station was just coming on line and could physically discriminate between the two in terms of their position in the sky. By getting PLL with the one they could then manually steer the frequency away and allow the lock to be acquired with the LM again. I did not fully understand this until you described it so well. Listening to FIDO having a blue fit on the Apollo 13 loops is priceless. As is the calm response from SELECT. It's another piece of overlooked history that deserves to be remembered... thanks Marc. 😊

[@RobatRobot]

@@uploadJ They were shutting down the CSM but powering up the LM.

[@RobatRobot]

@@uploadJ I seem to be having trouble posting a reply to you. But I think we are talking at crossed purposes. The beacons on the lunar module and booster stages both transmitted on the same frequency. That's why there was communication failure, not because they had turned off the CSM beacon. If you Google the UniverseToday article that covers the Apollo 13 S-IVB frequency issue you will find more info. Also, if you go to Apollo In Real Time and choose the Apollo 13 loop for FIDO, scroll to mission time 058:33:00 to hear Bill Stoval or possibly Jay Greene realising just how much of an impact this is going to be. Keep listening for at least 5 or 10 minutes.

[@jmssun]

3:52 The USB link.. how prophetic

[@bobl78]

what a great piece of technolgy and history.. incredible this thing worked ;).. and none of the hand made systems with tubes, and soldered wires in the AGC and billion other strange components ever failed in the missions

[@michaelhaardt5988]

The state of the art used in Apollo is absolutely amazing. WOW! I am really looking forward to the next episodes.

[@Pedro8k]

Amazing technology and engineering of the time they should be in a museum

[@daveb3910]

There is one, in Louisiana I think and one in Dayton Ohio near wpafb, and I think another in DC somewhere, but DC is a pain to get to. The Ohio one is pretty incredible, got a Saturn v on the lawn

[@rwj1313]

I was born and raised in Huntsville, Alabama home of Marshal Space Flight Center. My father was an Electrical Engineer working directly for NASA. My next-door neighbor was one of the engineers working for Boeing that developed and built the Lunar Rover.

[@bassybossy]

Always a joy to see Mike, even if it's brief. His enthusiasm and knowledge is simply astounding. The perfect guy to have by your side when prospecting for Apollo gold!

[@Christian-zv2em]

Ken: Opens a nitrogene filled S - band transmitter Steve MRE: "Nice hiss!"

[@coppens77]

Alright cool….let’s get this on a tray….nice!

[@waveinversion]

Now this is my jam right now. (I'm a RF system eng. in my day job.) The modules on the transponder looks kind of like the modules from the Old Motorola star point Microwave systems.

[@1971merlin]

Next video: unexpected.visit from the FCC.

[@repatch43]

You are 'mad scientist' levels of insane! Getting that hardware working? So amazing! :) Can't wait for the next ep!

[@joe08867]

It's amazing what they pulled off with such a small amount of power and tubes! It truly was a giant leap for Mankind. Thank you for sharing this with the world.

[@cwdoby]

They didn't pull it off.

[@jonnyj.]

@@cwdoby Open your eyes, use those 2 braincells, and re watch the video. Nah... you wouldnt understand anything anyways ;)

[@ojkolsrud1]

Remember to fill them back up with nitrogen after closing, guys!

[@RemcoStoutjesdijk]

they're 79% full of nitrogen already

[@ojkolsrud1]

@@RemcoStoutjesdijk Yeah, but it's those other things that are concerning;)

[@CuriousMarc]

Absolutely, we plan on refilling them once we are done.

[@VintageTechFan]

@@CuriousMarc How is that done, I suppose you have to flush them many times to get all the normal atmosphere out?

[@ojkolsrud1]

@@CuriousMarc I feel I shouldn't really have needed to point it out=) I can't wait for the next episodes. Do you have a way to send and receive to emulate a ground station?

[@marvintpandroid2213]

Ground control to major Tom.

[@borisvladimir7151]

you should invite Chris Hadfield for your next video and ask if he would like to play this song while you make the transponder and amplifier work.

[@aerohk]

I worked on SLS data handling. Wow these things were huge compared to today's design! Very interesting video, thanks.

[@robertmiles9942]

I've had people complain that the Apollo transmission power is too low, so they couldn't have gone to the moon! Well, yes: The way you handle that is you build a really big antenna on the receiving end, on the ground. That way you can gather more of that signal energy. Essentially, a really big "ear" to hear a whisper. They had to use much more energy transmitting "up" to Apollo because the spacecraft didn't have the luxury of having a really big antenna, it could only carry small ones. So you have to shout very loud so the smaller, relatively deaf "ear" could hear you.

[@standard_output]

I would have expected a 5 episode series on the recovery of the audio from your video camera

[@repatch43]

Oh, that's surely coming! :)

[@edgeeffect]

The loss of audio took me to a reminiscence of Gus Grissom's “How are we going to get to the Moon if we can't talk between two or three buildings?”

[@kurtnowak8895]

It was like watching silent home movies from the 1960’s narrated by my uncle! You could have added a “vintage effect” to make it seem even more “60’s” ! Haha. I was waiting so long for your next episode. This did not disappoint! Thanks Marc!

[@danielwalker5682]

Outstanding films!

[@alansmithee183]

Marc, love your videos on all this classic stuff! Keep pumping them out!

[@darrinpearce9780]

Yet another freaking awesome geek out. Thanks and can't wait for the remainder on this amazing bit of kit.

[@thecasualengineer99]

The parks dish is still in use after all this time. The movie "The dish", describes the Parks Radio Overvatory as an antenna in a sheep paddock

[@50shadesofbeige88]

I'm soo jealous. I love old Telecom equipment. This is right up my alley.

[@thejackofeverything7961]

Good to see they authorized the hot snot!

[@marioenc04]

Engineering at it’s finest. I keep wondering how those equipments performance were measured in the past, like THD, Noise..without a frequency analyzers, vector analyzers and all the digital modern stuff. Nothing but amazing 👏🏻

[@georgegonzalez2476]

They had those tools, they were already needed for radar development. The tools were also large and expensive. I used to have a Polarad spectrum analyzer the size of a large doghouse and weighing nearly 100 pounds. The microwave test equipment used a lot of Klystron tubes and microwave diode mixers and cavities. No transistors at all as these 1960 equipments could only rely on like 4Mc/s germanium transistors.

[@TunioMir]

I was so sleepy and tired until I saw this new video in my feed! You're the best curiousmarc!

[@MrGeoffHilton]

This is important stuff that needs documentation, subbed so that I can keep in touch.

[@ricod9451]

Remember this is technology from the 60’s. THE 60’s!! Almost as jaw-dropping gorgeous as the AGC. Can’t wait for you magicians to test it transmitting original Apollo footage.

[@gammaleader96]

These are the most beautiful Apollo parts so far, at least in my opinion. The construction of the Transponder is surprsingly similar to some old HP testgear, which is pretty cool.

[@BassistInATutu]

It's awesome taking on a project like this. Nut's maybe, but definitely awesome! Love it.

[@silverhawk3324]

I remember a Collins Radio ad - way back 'in the day' deservedly boasting, "Every voice you heard from outer space came on a Collins radio . . ."

[@willarddevoe5893]

In 1970, the crudest avionics you could buy was an ARC RT 328A. Today, it's a collector's item.

[@KitsuneAlex]

Such absolute beautiful engineering work, amazing video too ofc

[@martinsiegbahn3720]

The wonderful AGC restoration project used an oscilloscope. Now it is time for a spectrum analyzer!

[@syntaxerorr]

Another really interesting video. Thanks.

[@michelsrc4023]

Thank's Mr.CuriousMarc, it's very interesting

[@PRRGG1]

I just started this series. I now suspect I have several S-band transponder modules in a box in my basement. Can't wait to see more of this series to learn more.

[@elanman608]

It's amazing that you can get your hands on this kit. As a retired satellite news gathering engineer I really want to see these boxes working. Looks like another fascinating series. It's a bit of a stretch to say Apollo kick started Microwave communications. All of the techniques used in the Apollo comms system were in use for telecommunications SHF links carrying voice data and TV from the 1950's onwards. The novel component of the system is the ranging overlaid on top.

[@XMarkxyz]

Honestly i like a lot the french accent voiceover but I'm still sad for the loss of Ken's commentary

[@repatch43]

Biggest hit was not being able to hear the hiss as they opened the cases

[@CuriousMarc]

I was so bummed out when I realized the mic had gone dead! But not to worry, Ken will be back with their real voice in the next episodes.

[@MarcelHuguenin]

Thank you gang for finding another fascinating project from that wonderful era to educate us and entertains us with. Looking forward to the next episode.

[@kterstal]

Yes! Yet another series! Although I love the old equipment, can you include a short comparison with modern transmitters and transponders?

[@keithglaysher9201]

Excellent as usual Marc, don't forget Goonhilly downs Earth station as well was very important in the program.

[@Aengus42]

I heard "AOS Goonhilly" at about T+12 for SpaceX's Inspiration launch yesterday. Still at the forefront of space tx/rx.

[@pulesjet]

Flipping AMAZING STUFF. As a 11 year old kid a person my father knew shown me how to bounce a 1 watt HF radio signal off the moon.

[@brettatton]

Microwave guy here....nerding out big time! I started out my tech career testing TWTs back in 1978 at Varian Associates in Georgetown Ontario. I was hoping to find out more about the NASA USB system at some point. Thank you for these two videos!

[@jeremiefaucher-goulet3365]

This is very exciting. Very much looking forward to the next episodes :) Thanks Mark for gracing us with this!!

[@jlwilliams]

1960s technology wasn't cheap, and it wasn't always safe, but it was amazingly powerful. Looking forward to seeing where all those coaxes go! (And I hope they refill the nitrogen when they're done.)

[@campbellmorrison8540]

Im definitely admiring these modules but I have to say I also admire the new hex keys being used in the disassembly, you guys do a fantastic professional job

[@msylvain59]

Whenever you tinker with avionics or space stuff, you need to be very serious about an extensive collection of hard to find hex keys, far away from the regular sets you get in hardware stores. And when you think you are done sourcing rare tools, you find out you also need a whole set of the totally unobtainium "Bristol spline" keys :-p

[@campbellmorrison8540]

@@msylvain59 Ha yes Im a tool collector, I know what you are saying. Oh and yes I have a set of bristol keys, they used to be used in IBM printers and were standard IBM issue back in the day.

[@nanieas]

Brilliant! I look forward to more in depth study of the technology of the Apollo space program. The race to the moon created the progenitor to all the technology we are so familiar with, including the device I'm using to watch and comment on this video.

[@I967]

I'm at the third minute and I give this content a quadruple thumbs up for using normal measuring units.

[@Skandalos]

Fascinating look back into a time where science was still valued and faced little obstruction.

[@nesagljivic]

The three of you look like kids in the wonderland!

[@StringerNews1]

I remember watching the broadcasts from the moon as a child. Around the same time, I had a pair of walkie-talkies that were limited to 100 mW of power under Part 95 rules. Amazing to think that was the TV exciter for the CSM! IIRC a regular TV transponder used in communication satellites had a bandwidth of 70 MHz FM to send a 6 MHz AM (more precisely VSB) TV channel, trading bandwidth for SNR. And thanks to space deniers and their expressions of personal incredulity, we've had plenty of opportunity to revisit how it all worked once again. Back on the 20th anniversary, I got to learn more than I ever did as a child. No surprise that the boxes were heavy, as a vacuum tube PSU needs lots of copper and iron to get all those DC voltages!

[@XMarkxyz]

There is an interesting fact about the Parkes antenna (04:50) as in the moment of Armstrong's first walk on the Moon it was the last one who had contact with Apollo 11 and as thw Moon was very low on the horizon the dish was kept at its lowest declination nearly toucing the ground and in that exact time the wind rised first at 50 kn and then at 100 kn, at windspeeds higheer than 30kn in order to preserve the instrument the dish should be pointed at the zenith, but the tecnicians of Parkes bravely decided to keep it pointed towards Apollo 11 risking their onw life in case of a collapse of the building

[@frankbrockler]

More steely-eyed missile men.

[@liquidsonly]

"The Dish" is one of my favourite moves and there still are sheep in the paddock.

[@CuriousMarc]

The ground antennas alone are worth a full episode! Unfortunately very little of this Parkes galore is true and the Dish movie is both historically and technically completely wrong, I hated it. Except for the beautiful views of the dish itself! The Goldstone 210 ft antenna did the Apollo 11 descent (and basically saved the day allowing to maintain LM comms on the omnis). Goldstone 210 also did the TV at the beginning of the moonwalk. They had great signal but they had their scan converter setup completely wrong. You can see it at the beginning, image upside down, way too much contrast, then even inverted contrast while the operator is panicking while trying to correct the mess. So they quickly switch to the 80ft at Honeysuckle (Australia), and the picture gets much better. So Honeysuckle did the beginning of the moonwalk including the first steps on the moon. Soon after that (8m30s into the moonwalk), the Moon came into view of the Parkes 210ft which is further east. Although it was earmarked as backup, it had a 10 dB advantage and therefore a better picture. They stuck with Parkes for the rest of the EVA.

[@XMarkxyz]

​@@CuriousMarc Thanks Marc, always on point, but now I'm disappointed: they can't put so much false informations in a movie that pretends to be historical; at least the part of the telescope operating above the limits for which was built is true, whoever designed it made a great job

[@liquidsonly]

@@CuriousMarc Getting science from a movie was kinda the purpose of my comment, ie don't. I liked the movie because it was amusing and had a pretty girl in it. So happy though that it prompted your reply. Thank you.

[@das250250]

Pretty amazing that's capable of transmitting from the moon. I always wondered about this segment of the mission. Just 12 watts !

[@TobyAsE120]

Wow, this is seriously beautiful! Can't wait for the microwave black magic!

[@crusaderanimation6967]

3:20 American using KG, i'm moved you are my hero.

[@Kae6502]

Yes!!!! SO looking forward to this! Thank you all.

[@fredlassiter2385]

As a high school physics teacher, I really enjoyed this... particularly the part about how the transponder and antenna angles were used to track the spacecraft. (Yea vectors!). I showed this part in class and my students were awed by the amount of calculation that is required to compensate for Earth position, rotation, etc. I found a great document describing all the ground stations and some info on how the data was moved back to Houston, but nothing on how the calculations were actually done. Did someone have to punch cards and feed them to an IBM mainframe for every observation?

[@devrim-oguz]

Ground computers probably had an input for these kind of systems, only the program is entered by the punch cards.

[@shiratikkas6780]

génial de voir des français faire un aussi bon travail :) merci pour ta vidéo !

[@LMacNeill]

That is mind-bogglingly complex! 1960s does not equal primitive, that's for sure! What an ingenious way to combine all the data and voice signals they needed into a single comm system! Wow!

[@bhempstead]

Parkes didn't receive the first five minutes of communications from Tranquility Base, Neil and Buz where to eager to get out and explore the moon, the the honor of receiving the first steps on the moon went to Honey Suckle Creek in Canberra as it was properly aligned to take the signal and Goldstone had an upside down image, as Honey Suckle drop out of alignment, obviously due to the rotation of the earth , then Parkes took up the signal for the next 2hrs. Parkes was not going to be the primary point of the fist communication but it received the honor because of a circuit breaker fire at Tidbinbilla Tracking Station two weeks prior to the landing. Tidbinbilla Engineers where sent to Parkes to set it up to received the signal. Thanks for explaining wait S-Band was, now I know why my fathers skills were needed at the tracking stations Cooby Creek and Canarvon as he studied on microwave technology.

[@CuriousMarc]

That’s such a bizarre and misleading comment. I never claimed that Parkes received the first minutes of communication from Tranquility Base. The LM was communicating via the Goldstone’s 250 ft antenna (with Madrid as the backup) when it landed. Which was a lucky break: since they had to use the omnis on several occasions, that would have resulted in a mission abort if they had relied only on the smaller primary dishes. Later on, Goldstone, Honeysuckle and Parkes all had reception of the FM downlink signal during the entire EVA. Goldstone had a very good signal and was selected for the first few seconds of EVA TV, but unfortunately, they had their slow-scan converter setup wrong, resulting in the infamous upside down image and bad contrast. NASA realized that within a few seconds and switched to the smaller Honeysuckle antenna for the first few minutes of the EVA. Then at about 8 min into the EVA, the Moon got high enough for Parkes to receive it on the main on-axis receiver (they apparently had it before, but off-axis). They had of course a similar signal to Goldstone due to size. So naturally NASA switched to the Parkes video, which they kept for the rest of the EVA. However they kept Goldstone for the PM uplink transmission throughout the entire EVA. So upvoice (capcom) was from Goldstone the entire time. So all 3 dishes (Goldstone, Parkes, Honeysuckle) received the spacecraft FM data, TV and downvoice throughout the entire EVA. They all got it. It’s just that the TV picture and voice sent out to the broadcasters could only come from one of these sources at a time.

[@JxH]

12:18 "...today Rockwell Collins..." Not since 2018. Collins was sold by Rockwell to UTC in 2018, and Collins Aerospace was tucked under the Raytheon umbrella (which may not have been a brilliant idea, since Collins has forgotten more about Radio comms than Raytheon has ever known; not even close...).

[@grahamwallis6568]

I learn so much from your videos, thank you

[@tomschmidt381]

Great deep dive. I agree the Apollo communications system was pushing the state of the art in the 1960s. Can't wait for next video.

[@72polara]

A RF project! This will be fun!!!!

[@RobertoViti]

Can we highlight a bit the amazing voice over/actor skills by Marc in this video? 😅 Chapeau

[@Thisandthat8908]

The Power amplifier (i think) that was shut down on Apollo 13 to save power, giving us the noisiest Apollo audio recordings ever. I know the term from the recordings but had no idea what it actually was or looked like.

[@wacholder5690]

Hi there ! Uffa. Most people go mentally overboard in just understanding WiFi-LAN ... and you are going to but back the Apollo S-band back to work. Hmm. Okay. You need a goal in life ... :-) Waiting for the next episode.

[@aserta]

In parallel with this, man, i would love to see the tech behind the Lunokhods. I mean, considering it landed on November 17th, 1970 months after... you just have to wonder. I think the transmission number for TV images is pegged somewhere at 20k + other things like panoramas. But i bet getting your hands on the transmission modules is like trying to find gold in ether.

[@XMarkxyz]

Completely agree, I think that Luna 16 too would be very interesting (20/9/'70) as it was completely automated and took a smple back to Earth

[@jlwilliams]

CuriousMarc already has demonstrated his respect for Russian technology in his Soyuz-clock videos. Would anyone like to ask Mr. Putin if he would be interested in sending a ground-test article and a set of schematics over to the lab?

[@VintageTechFan]

@@jlwilliams I have a huge respect for Russian technology. They may have had often quite subpar materials and had to cut corners, but they DEFINITELY weren't incompetent, NOT AT ALL. Whatever you look at, they absolutely knew what they were doing and made stuff possible with basically junk components nobody would ever have believed to be possible here.

[@cogoid]

One clever device that Soviets developed then, and are still using in their spacecraft today is a gamma-ray altimeter. It shines a beam of gamma-rays down, and measures how much radiation is scattered back from the ground. The beauty of this is that the reflection happens from the dense material only, and the signal is not significantly affected by the dust, snow, grass, etc -- the stuff that you should ignore when landing. Soviet moon probes and Soyuz landing capsule all use such altimeters.

[@CuriousMarc]

Me and Ken were thinking the exact same thing - it would be interesting to see how the Russians did it. Putting a remote controlled rover on the Moon in the 1960's is no small feat.

[@givemeakawasaki]

Awesome, thanks guys!

[@zebop917]

With boxes made of magnesium, it’s not hard to imagine why the Apollo 1 fire was so severe. Looking forward to more of this series though.

[@CuriousMarc]

I believe the hermetic magnesium enclosures were Block II only. They were not present on Block I. At least this is true fir the AGC.

[@tekvax01]

Very impressive as always Marc!

[@VintageTechFan]

I was hoping to see some tube stuff in there. And I'm kinda surprised to see SMA in there, didn't know it was already around back then.

[@CuriousMarc]

SMA and N-connectors. I was surprised too to find out how old they are! But they also have the older SMC and you'll see in future episodes I had to spend a fortune on General Radio 900 connectors.

[@jdmbeats]

Looks like the inside of my dad's Kenwood Stereo amplifier from the 70's.

[@ET2carbon]

I'm very interested in learning what you have in this series. This is what i questioned most about the program. Mainly I'm interested in the antenna 📡

[@k7iq]

Beautiful stuff !

[@jtveg]

Fascinating hardware. Thanks so much for sharing.