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
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
The ADC restoration was the best 30 hours I've ever spent on a TH-cam playlist. Fangirls like me have a high bar for this series, but only because you are the best person possible to document this.
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.
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.
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.
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!
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.
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
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.
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.
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.
"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.
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."
@@vincei4252 Wise words and yet I think the psychological phenomenon is instructive, especially to people who consider themselves well-educated and rational.
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.
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.
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. 😊
@@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.
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.
What an absolute honour getting to witness such fine engineering that defined a milestone in the history of mankind! Many thanks from the bottom of my heart, and greatest respects to everyone who designed this and you folks who are telling these stories through the eyes of the past!
A correction to your narration: The old Collins Radio Company is now Collins Aerospace, a part of Raytheon Technologies. "Rockwell Collins" is no more.
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.
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
@@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
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!
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.
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...
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.
@@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..
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.
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!
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...).
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!
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
The VCO and phase detector were running at only 10-20 MHz. The rest was done by downconverting microwave frequencies and multiplying the VCO frequency.
@@djtransnazgrz Of course, this was top of the line gear. Very, very expensive -- Collins and Motorola were paid approximately 2 billion dollars in today's money for their work on communication equipment for NASA projects. I have not seen the schematics, but the block-diagram shows many frequency multipliers, a couple of which are x96 and x54 -- getting in one jump to 2 GHz. NASA report does not mention it, but these ones are most likely based on a Step Recovery Diode -- which just became commercially available in those years.
@How Does it Really Work: Yep lots of multipliers. Even the transmitter output is not amplified directly. The final RF power amplification is at a few 100's of MHz, and it's passively multiplied to generate the final output (as you said, probably by a step recovery diode). I was also wondering how they did it with solid state at the time, which was incapable of running at 2 GHz.
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!
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.
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
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.
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.
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.
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.
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!
Does anyone know why the flat-pack chips from 1965 (date code 6541) in that guidance computer logic board at 1:36 have the little red dabs of red paint on every chip? I've noticed it on other flat pack ICs from 1965 as well. Some sort of final-approval mark from the chip's backend test process?
I can't speak for the rest of the industry, but in the context of the AGC, those red dots indicate flight qualification. Their presence elevates these chips from the 1006321 part number printed on them to part number 1004301-001 (the flight qualified equivalent). Per drawing 1004301, "Upon completion of all requirements as specified in ND 1002248, the NOR gates which qualify for flight hardware under the provisions of ND 1002248 shall be marked in red as indicated in this document." Unfortunately we don't (yet?) have a copy of ND 1002248, but ND 1002359 can be found on the klabs website -- it appears to be a different version of essentially the same document.
@@mikestewart8928 Ah yes that does make a lot of sense now, thank you! 1965 was right at the crossover from the TO-5 style package into the newer flatpack/dip styles so I guess they were also still formulating how to identify usage standards too. Awesome info Mike!
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
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
@@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.
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.
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.
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.
The innards of the 1960s Tektronix 1L20 spectrum analyzer look like a baby version of the transponder. The color of the coax cable jacket is meaningful, the white ones have a resistance wire as the center conductor to help absorb reflections in the 1L20, I wonder if it's the same here.
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 👏🏻
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.
@@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?
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.
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.
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
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.
@@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
@@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.
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!
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.
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.)
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?
(1) The label isn't wrong about high voltage. Even if the supply isn't very "hot" the signal processing equipment may still contain rather high voltage waveform nodes. (2) FM and PM can be seen as special cases of each other. They aren't radically different between themselves.
How far are you allowed to take then apart ? I would love to see what is hiding inside the modules... BTW it looks like the coax connectors are secured by epoxy, it will not help for dissasembly without damage to the original work :-/
The frequency, 2.1 GHz, is rather close to the WiFi and Bluetooth bands. It would be interesting to compare the contents of that first box with a modern solution that's found in something especially tiny like earbuds. The second box is the power amplifier: 11 W I think you said, and could not use transistors. How big and heavy is a modern microwave amplifier capable of that much power?
So, I don't know if you run into any info on the people who worked on these systems, but I'm 90% sure that my grandfather, who was a USAF Lt. Col. at the time, worked on these systems while he was at Lincoln Labs. Basically, we know he worked on comms for the Apollo project, and he had been heavily involved with USAF research on both communications and radar systems. I don't know if you run into any papers or other documents that might have names attached to them, but if you do, I'd love to email you his name and see if you've run across anything that he published/worked on.
Sadly we don’t have much doc on this as this was all from Collins. That said many of the underlying principles were developed in the 1950s by Lincoln Labs, in particular the Phase Locked Loop coherent receiver scheme and the very low noise cryogenic receivers on the ground.
@@CuriousMarc fair enough! Part of the challenge with researching Apollo (and also what my grandfather worked on) is that so much of it is the foundation for modern communication that a ton of it is still classified. If I, in my own research on what he was working on, find anything more general, I'll be sure to pass it on.
Considering all the trouble that FranLab had with her comms equipment during her recent vomit comet ride, it's understandable that NASA needed something of such sophistication to be absolutely bullet proof, or more aptly, subatomic particle radiation hardened. 1960's cutting edge designs really did lead the way for today's everyday hardware. Thanks for sharing!
Next video: restoring the Saturn 5
Including the trainer LM and CM?
Don't forget the first rule of rocket science.
Pointy end up.
And after that, restoring the whole MSFN to support one more Apollo mission
@@macartm ...and flamey end down... :-)
Don't we all love Tim Dodd... :-)
If pointy end down, you will not be going to space today.
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
Awesome! Can you please contact us via the link in under the video description?
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
The ADC restoration was the best 30 hours I've ever spent on a TH-cam playlist. Fangirls like me have a high bar for this series, but only because you are the best person possible to document this.
@@mjgII Neat. You will never be an expert on the subject.
@@ninetailscosmicfox5585 please more popcorn is ready :-)
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.
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.
@@benespection Same! :)
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.
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!
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.
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
60 tech, but it really exactly looks like 90's RF stuff. it was so much ahead.
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.
I just know that once you opened it, you better not drop your coffee inside of it... lol
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.
I wouldn't waste a moment thought on those clowns. The same as flat earthers.
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.
"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.
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."
@@vincei4252 Wise words and yet I think the psychological phenomenon is instructive, especially to people who consider themselves well-educated and rational.
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.
the 3 minutes of rocket engine noise really helped tie the whole experience together with headphones. Thanks a lot
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.
Would love to connect with the people that designed and built this! Some unsung engineering heroes there.
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. 😊
@@uploadJ They were shutting down the CSM but powering up the LM.
@@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.
As an Apollo program junkie, I love your videos. Nobody out there goes into the nuances and hardware details as you do.
Unified S-Band, the kind of USB I can actually admire ;)
always love that Australian dish, it looks like an ordinary windmill with an impossibly large looking dish ontop
Writting a report about this for the final project of my technology class. That box is a very fascinating thing.
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.
You put it well. It feels exactly like that, Ark of the Covenant opening! Without the negative consequences of course…
What an absolute honour getting to witness such fine engineering that defined a milestone in the history of mankind! Many thanks from the bottom of my heart, and greatest respects to everyone who designed this and you folks who are telling these stories through the eyes of the past!
I always look forward to these……
And this time it's microwave analog electronics! I learn so much from Marc and his friends.
A correction to your narration: The old Collins Radio Company is now Collins Aerospace, a part of Raytheon Technologies. "Rockwell Collins" is no more.
Collins Aerospace has just acquired FlightAware so will be a familiar name to many.
Another correction, transponder means transmitter + responder (13:36)
@Virtex Alpha lol
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.
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
@@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
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!
transistors rule!
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.
We are past the vacuum tube age :-) Even home stereo amplifiers are now just cheap boxes with triple digit output powers.
@@uploadJ the answer is yes.
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...
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.
The whole program used the slide rule..
@@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..
Excellent! This is the kind of contents TH-cam should exist for.
You are 'mad scientist' levels of insane! Getting that hardware working? So amazing! :) Can't wait for the next ep!
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.
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!
The state of the art used in Apollo is absolutely amazing. WOW! I am really looking forward to the next episodes.
The Danger High Voltage warning is humorous since anyone authorized to even look at let alone touch the innards would know that.
Haha, my first thought was if they did the milling just to make the build look more bad-ass :D
That’s just in case any Martian guy opens the box.
Nanny state is always watching, especially at NASA.
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...).
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!
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
They built a 2 GHz PLL with 1960s technology? Thats amazing, really inteested in seeing the rest of it.
Yeaaaaa, I'm *really* looking forward to this series!
The VCO and phase detector were running at only 10-20 MHz. The rest was done by downconverting microwave frequencies and multiplying the VCO frequency.
@@cogoid Still very impressive, especially that they multiplied it an order of magnitude higher. I can't wait to see the insides.
@@djtransnazgrz Of course, this was top of the line gear. Very, very expensive -- Collins and Motorola were paid approximately 2 billion dollars in today's money for their work on communication equipment for NASA projects.
I have not seen the schematics, but the block-diagram shows many frequency multipliers, a couple of which are x96 and x54 -- getting in one jump to 2 GHz. NASA report does not mention it, but these ones are most likely based on a Step Recovery Diode -- which just became commercially available in those years.
@How Does it Really Work: Yep lots of multipliers. Even the transmitter output is not amplified directly. The final RF power amplification is at a few 100's of MHz, and it's passively multiplied to generate the final output (as you said, probably by a step recovery diode). I was also wondering how they did it with solid state at the time, which was incapable of running at 2 GHz.
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!
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.
I worked on SLS data handling. Wow these things were huge compared to today's design! Very interesting video, thanks.
Amazing technology and engineering of the time they should be in a museum
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
Yet another freaking awesome geek out. Thanks and can't wait for the remainder on this amazing bit of kit.
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.
They didn't pull it off.
@@cwdoby Open your eyes, use those 2 braincells, and re watch the video. Nah... you wouldnt understand anything anyways ;)
Marc, love your videos on all this classic stuff! Keep pumping them out!
I was so sleepy and tired until I saw this new video in my feed! You're the best curiousmarc!
Engineering marvels from 60s never stop to amaze me.
Outstanding films!
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.
It's awesome taking on a project like this. Nut's maybe, but definitely awesome! Love it.
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.
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.
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!
Does anyone know why the flat-pack chips from 1965 (date code 6541) in that guidance computer logic board at 1:36 have the little red dabs of red paint on every chip? I've noticed it on other flat pack ICs from 1965 as well. Some sort of final-approval mark from the chip's backend test process?
I can't speak for the rest of the industry, but in the context of the AGC, those red dots indicate flight qualification. Their presence elevates these chips from the 1006321 part number printed on them to part number 1004301-001 (the flight qualified equivalent). Per drawing 1004301, "Upon completion of all requirements as specified in ND 1002248, the NOR gates which qualify for flight hardware under the provisions of ND 1002248 shall be marked in red as indicated in this document." Unfortunately we don't (yet?) have a copy of ND 1002248, but ND 1002359 can be found on the klabs website -- it appears to be a different version of essentially the same document.
@@mikestewart8928 Ah yes that does make a lot of sense now, thank you! 1965 was right at the crossover from the TO-5 style package into the newer flatpack/dip styles so I guess they were also still formulating how to identify usage standards too. Awesome info Mike!
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.
Such absolute beautiful engineering work, amazing video too ofc
Good to see they authorized the hot snot!
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
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
@@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.
3:52
The USB link.. how prophetic
I'm soo jealous. I love old Telecom equipment. This is right up my alley.
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.
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.
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.
The innards of the 1960s Tektronix 1L20 spectrum analyzer look like a baby version of the transponder. The color of the coax cable jacket is meaningful, the white ones have a resistance wire as the center conductor to help absorb reflections in the 1L20, I wonder if it's the same here.
Ground control to major Tom.
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.
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 👏🏻
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.
Excellent as usual Marc, don't forget Goonhilly downs Earth station as well was very important in the program.
I heard "AOS Goonhilly" at about T+12 for SpaceX's Inspiration launch yesterday. Still at the forefront of space tx/rx.
6:49 That's... that's the precursor to GNSS:es, isn't it??
I'm at the third minute and I give this content a quadruple thumbs up for using normal measuring units.
Yes! Yet another series! Although I love the old equipment, can you include a short comparison with modern transmitters and transponders?
Next video: unexpected.visit from the FCC.
This is very exciting. Very much looking forward to the next episodes :) Thanks Mark for gracing us with this!!
Ken: Opens a nitrogene filled S - band transmitter
Steve MRE: "Nice hiss!"
Alright cool….let’s get this on a tray….nice!
Remember to fill them back up with nitrogen after closing, guys!
they're 79% full of nitrogen already
@@RemcoStoutjesdijk Yeah, but it's those other things that are concerning;)
Absolutely, we plan on refilling them once we are done.
@@CuriousMarc How is that done, I suppose you have to flush them many times to get all the normal atmosphere out?
@@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?
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
The wonderful AGC restoration project used an oscilloscope. Now it is time for a spectrum analyzer!
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.
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.
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
More steely-eyed missile men.
"The Dish" is one of my favourite moves and there still are sheep in the paddock.
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.
@@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
@@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.
hi @CuriousMarc do you mind to publish the links to the "previous videos" you are talking about? THANKS!
Oops I forgot. This one: th-cam.com/video/z-50pSc_wg8/w-d-xo.html . I'll add to the video description too.
I would have expected a 5 episode series on the recovery of the audio from your video camera
Oh, that's surely coming! :)
How does one tighten or loosen the larger coax connectors (BNC?) in the amplifier since they are packed so close to each other?!?
Fascinating look back into a time where science was still valued and faced little obstruction.
What about the antena in Fresnedillas, Spain??
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?”
Wow, this is seriously beautiful! Can't wait for the microwave black magic!
This is important stuff that needs documentation, subbed so that I can keep in touch.
Yes!!!! SO looking forward to this! Thank you all.
génial de voir des français faire un aussi bon travail :) merci pour ta vidéo !
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!
Inline cable connector at 19:31 disconnected. Looks connected at 10:32. Looking forward to finding out why!
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.
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.
The three of you look like kids in the wonderland!
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.)
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?
Ground computers probably had an input for these kind of systems, only the program is entered by the punch cards.
Almost unbelievable that the original nitrogen was still in there. Amazing
(1) The label isn't wrong about high voltage. Even if the supply isn't very "hot" the signal processing equipment may still contain rather high voltage waveform nodes.
(2) FM and PM can be seen as special cases of each other. They aren't radically different between themselves.
How far are you allowed to take then apart ? I would love to see what is hiding inside the modules... BTW it looks like the coax connectors are secured by epoxy, it will not help for dissasembly without damage to the original work :-/
Pretty amazing that's capable of transmitting from the moon. I always wondered about this segment of the mission. Just 12 watts !
The frequency, 2.1 GHz, is rather close to the WiFi and Bluetooth bands. It would be interesting to compare the contents of that first box with a modern solution that's found in something especially tiny like earbuds.
The second box is the power amplifier: 11 W I think you said, and could not use transistors. How big and heavy is a modern microwave amplifier capable of that much power?
Honestly i like a lot the french accent voiceover but I'm still sad for the loss of Ken's commentary
Biggest hit was not being able to hear the hiss as they opened the cases
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.
Very impressive as always Marc!
I learn so much from your videos, thank you
So, I don't know if you run into any info on the people who worked on these systems, but I'm 90% sure that my grandfather, who was a USAF Lt. Col. at the time, worked on these systems while he was at Lincoln Labs. Basically, we know he worked on comms for the Apollo project, and he had been heavily involved with USAF research on both communications and radar systems. I don't know if you run into any papers or other documents that might have names attached to them, but if you do, I'd love to email you his name and see if you've run across anything that he published/worked on.
Sadly we don’t have much doc on this as this was all from Collins. That said many of the underlying principles were developed in the 1950s by Lincoln Labs, in particular the Phase Locked Loop coherent receiver scheme and the very low noise cryogenic receivers on the ground.
@@CuriousMarc fair enough! Part of the challenge with researching Apollo (and also what my grandfather worked on) is that so much of it is the foundation for modern communication that a ton of it is still classified. If I, in my own research on what he was working on, find anything more general, I'll be sure to pass it on.
@@MrKeserian That would be great!
Considering all the trouble that FranLab had with her comms equipment during her recent vomit comet ride, it's understandable that NASA needed something of such sophistication to be absolutely bullet proof, or more aptly, subatomic particle radiation hardened. 1960's cutting edge designs really did lead the way for today's everyday hardware. Thanks for sharing!
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 📡
Fascinating of course, but what is the background music starting at about 11:30?