Apollo Comms Part 8: Which Crystal?

Can we just swap the crystal to revert our test receiver to its original Apollo frequency? Maybe it's not that simple. And we get unexpected help from yet another generous collector.

Links to doc:

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00:00 Our NASA receiver had been modified
01:51 Receiver modules
02:59 Closer look at the VCO
03:58 Receiver principle of operation
05:56 New crystal frequency calculation
06:47 Two types of crystals, which is it?
07:50 Original manual says serial crystal
09:53 Measuring the original crystal
11:29 It's a parallel resonant crystal
12:40 It's a third overtone crystal
14:17 Shout out to Laptech Precision

[ZaphodHarkonnen]

You know when you’ve found a good supplier when they come back asking “You sure that’s what you want? It makes no sense unless it’s actually this other thing you want.”

[rkirke]

There isn't another YouTube channel, TV show or series that has *ever* had me as keenly anticipating the next episode! Huge thank you to Marc and all the supporters and collaborators for making this channel possible!

[TheOddVideoChannel]

"If it keeps going on like that we might soon have to power up the complete space ship" ... now that's a great idea!

[reneschmitz]

The oscillator circuit with the tuned circuit (L + Varactors) in series with the crystal is a clue of it being run on an overtone. The tuned circuit peaks on the overtone, and prevents oscillations on the fundamental.

[senilyDeluxe]

Episode 14: We're transmitting data, voice and video from the fake moon landing set we built in our backyard.
Episode 42: We're transmitting from the real moon, don't ask how we got there

[chewierama]

Astonishing as always .. how stuff finds the way in your lab. This clearly shows that there are collectors that would like to see their treasures up and running again, not collecting dust ! this is by any means the way it should be. Overall I am blown away by the massive detail on your videos and how easy you communicate the intrinsic black art of retro HF engineering. As always an inspiration. Hopefully you and your team will get many more opportunities to revive old Apollo tech, as it always surprises with almost working out of the box.. Not bad compared to some modern equipment that hardly works until the warranty expires !
thx and all the best
Hannes

[flugschulerfluglehrer]

A shout out to the generous collector: Thank you!

[overkillaudioinc]

at 1:20 you can see a little leaf of metal fall out from the crystal hood and fall down inside. a second one falls out and they pick it up, but one fell down inside the unit. hope they get that back out!

[twilliamson]

I love that the community around this preservation is constantly surprising us with "lost" articles of documentation and fixtures!

[Lunchpacked]

In 2028: Rebuilding the entire apollo spaceprogram part 1 - Saturn V delivery and other goodies

[rpavlik]

Seems wild to me that this stuff is in the hands of private collectors (and in this case, with the device and manual in different hands) but I suppose museums only have so much space and these nuggets are interesting to a narrower audience. Thanks for sharing them with us!

[vincei]

Great companies that help to make these endeavors a reality totally deserve called out in these videos. Thanks LapTech!

[evilborg]

My dad was one of the engineers working on the Apollo

[amykathleen]

My dad, who graduated with an engineering degree in 1985, has the same calculator Marc is using at 6:00. It brought back so many memories - throughout my entire childhood, every time I wanted to use a calculator, his (very good) excuse to keep me from using his was “you wouldn’t know how to use it!” (He was right and I still don’t know how it works, haha.) When I first got my TI-84 at age 14, I took great pleasure in telling my dad he couldn’t borrow my calculator because he wouldn’t know how to use it.

[carpetbomberz]

That Motorola manual find was a master stroke. I'm so happy people contact you and share what they have.

[Regular]

Wow dude, everything about this resto is mind blowing. Love the detail you are going into and the work you are putting in. Thank you so much!

[stevensheldon]

This is truly amazing. It is amazing that you were able to do it, but it is also historically important as it is capturing "lost" information. You guys are actually "Electro-archeologists"!

[ajjr]

Really enjoying this series, thanks Marc!

LapTech, what a discovery! I thought there were no custom crystal manufacturers left in North America. I am sure their custom-cut crystals are not cheap, but how expensive? Is it still considered reasonable for amateur radio applications? Thanks!

[soulrobotics]

Everything is so vintage that they calculate in a HP with polish system....
I love this series.
Hey one day, all of you can show up with white shirts, no sleeves, pocket plenty of pencils,
and a tie... or cravate si vous préférez l'appeler ainsi....
and with a smoking machine you can simulate cigarette smoke!