Apollo Comms Part 13: We successfully repair both our NASA transmitter and receiver!

We return our modified NASA transmitter and receiver to their original Apollo specs. For the first time, we are able to get a double locked link to our Apollo S-Band transponder, all with original NASA comms equipment.

Chapters:
0:00 Intro
1:34 Our Apollo equipment was later modified for GEOS-3?
5:27 Inside the Rx VCO
10:01 Rx retuning adventure
19:27 Tx retuning adventure
24:24 Double locked link success!

Links to doc:

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[ratheskin]

I think it's wonderful that with stack upon stack of esoteric TX / RX and test gear, we end up looking a a two inch diameter analogue meter to see if it all works!

[KarlAdamsAudio]

19:55 - yep, it's the age-old truism - amplifiers oscillate, and oscillators don't. Awesome work, everyone - this is an absolute delight.

[cwwhg]

Ooo another Apollo video already, you are spoiling us this week Marc! Thanks for all of the hard work you and the guys are putting into this project, it's wonderful that you are helping to preserve this unique hardware plus we get to watch an excellent series as well, c'est vraiment merveilleux! Merci beaucoup a tous!

[erpi-ksby]

What is amazing to me (aside from these outstanding videos of course) is that the components have lasted and still work almost as if new! I collect and repair antique radios (yes consumer so no comments please) and the difference between a cap for commercial use and a cap/resistor for military/space use is so different. Just wonderful to show what the US could do back when engineering a product was for more than a few weeks or a year or two (and lives on the line too). And let’s give Motorola a hand at this wonderful engineering also. The Galvin brothers started with battery eliminators (for battery operated radios) to car radios etc. in 30 + years they went from what radio was in late 20s to the moon! Just wow.

[BlueSkyScholar]

Something to note... living in FL I have some 44+ RU racks that have seen better days but are painted the same barf color. Well shielded, RF gaskets everywhere in their original form and in the vicinity there were some doors with general electric apollo program asset tags on them. Sadly the doors were outside in the muck and I saved only one asset tag which is somewhere in my collection.

[jlwilliams]

I enjoyed the software-defined radio and Keysight segments and learned a lot from them about current practice, but the real fun of this channel is seeing the vintage tech live again. Super satisfying episode!

[phuzz]

Hooray! The blue cones finally get their moment to shine!

[paulkocyla]

Please record your victory dance, so we can party with you!
Awesome job, I´m dropping a tear here!

[KeritechElectronics]

"Microwave electronics is a joy for ever."
"Any sufficiently high frequency technology is indistinguishable from magic."

I'm not there yet to understand the inner workings of the technology you're resurrecting, but oh hell, it's absolutely amazing!

[BelgianSquirrel]

I work since 2004 with measurements taken by the JPL instrument "Microwave Limb Sounder" aboard NASA satellite Aura. This instrument is the most powerful ever flown to measure the chemistry in the upper atmosphere, and it will not be replaced. The MLS main scientist told me that it was too expensive to replace this instrument due to its complexity. I did not understand but now thanks to this series I get it:
"Microwave electronics, the blackest of black arts in analog electronics..."

[roncarlson]

Simply excellent work, so well done! Now to hear "One small step for..." Thanks to the many contributors' generosity and enthusiasm and NASA.

[nigeljames]

I’m not an RF engineer, but this channel keeps me on the edge of me seat ! I sometimes have problems like this in my line of electronics, but this is just voodoo to me. Congratulations !

[larryscott]

This is what satisfaction looks like.

Using what you know to figure out very complex: electronics and RF physics and stuff. And a happy dance.

[islandhopperstuart]

Fabulous work guys. Truly inspirational and a fabulous tribute to the engineers who, fifty years ago, were on the top of their game, making equipment without compromise and with true quality and reliability at the heart of what they did.

[TheFleetz]

Incredible persistence, amazing knowledge, never phased and what a result! Congratulations to all involved....thank you for sharing this with us! 👍

[carpetbomberz]

Much applause 👏, you found the GEOS Satellite and the S-Band experiments "smoking gun", BRAVO! Now the mystery crystal is a mystery no more. Kudos to you and the whole crew yet again.

[dack]

The posts on the tuning adjustments are designed for special non-conductive adjustment tools. When you use a normal screwdriver, you will sometimes find that the adjustment is affected by touching it with the tool. This can make it difficult to adjust properly.

[mustaphacherkaoui]

très touché par ces inventions merci infiniment à vous 73 de CN8MM

[JensAndree]

Wow!!! RF and this type of analogue electronics are way beyond my electronics capabilities but I do understand almost everything you've done in this mammoth project, and think how all the components and parts were collected and put back into pieces here?! Some were scrap on the floor until someone rescued them... Awesome!
I have my background in telecoms switching and despite beginning rather young I always preferred working with the old and obsolete equipment, both because I knew I was soon going to be in hot demand (and which I also was!) but also because I felt I would learn more by beginning from the beginning ;)
I made a great career maintaining old Ericsson software and hardware (MSC, BSC, HLR, IOG, AXE10) both in office and later in the field around Europe and although it often was a challenge keeping old systems running despite they had their end of life a long time ago, if was really fun and rewarding! Once I raided some hardware in a Ericsson museum in Sweden just to get a pre-paid switch working again! There were only three units left in the world and I was operating two of them, both in need of repairs, so I persuaded the museum to let me swap some of my boards with their museum piece and I got them up and running like they should again! I can't even begin to tell you how nervous I was travelling back through airport security with my unobtanium boards having an argument where I really didn't want to x-ray them, but it all worked out in the end. None of these are in operation today and to be fair they shouldn't have been back then either, but it was a case of if it ain't broken, don't fix it.
At one stage I had every last piece of new old stock MFM hard drives under a desk in my office. If people knew how old some of the hardware was in the mobile networks in the year 2000 nobody would've believed me, but after Y2K we begun replacing everything obsolete and I wish some of the older units were saved, but I doubt it.
I would've loved to be able to join your team rescuing all the obscure and obsolete hardware, but I'm just too far away... Luckily we all can follow along here and I can only thank you so much for making all these videos!!! They're excellent and you all explain so well that even when you hit black magic RF stuff it's still easy to understand everything!
Best Wishes from Sweden!

[SatelliteLily]

I have a theory about why the 24x multiplier on the receiver didn't need to be changed. At the beginning when there was no oscillation at the original crystal frequency, that capacitor Mike adjusted was way out. That and other adjustments were all that must have been needed to retune and compensate for the other crystal without messing with the multiplier. I think you guys are right on about it probably being for the Geos 3 satellite. Great catch on that one.