Apollo Comms Part 27: Quindar Tones Microphone Hack

Nothing is more emblematic of the Apollo communications than the Quindar tones, which you hear at the beginning and end of each transmission. In this episode, we hack a cheap commercial microphone to bring it up to NASA standards by adding the tones. After explaining what they do, of course.

Links to doc:

Music Credit: Crinoline Dreams by Kevin MacLeod

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[frankbrockler]

Quindar tones still work to this day. Whenever I hear one, it instantly triggers "7 year old boy sitting on the living room floor 2 feet from the TV watching astronauts on the moon" mode in my brain. Thanks for the trip down memory lane, Marc.

[sethtaylor]

Quindar aka QEI is an Electronic Manufacturing firm in Springfield NJ that manufactured analog DTMF and FSK hardware back in the 70's and 80's. They are still in business.

[greenconscious]

Darn it. Now I want a Quintar tones plugin for Zoom PTT mode

[Yrouel]

Not only the Quindar tones were used for Shuttle but they are still in use today with Crew Dragon

[TimoNoko]

These two tones are already ingrained to our psyche. I have push button which turns a remote device on or off. I wanted immediate feedback what it is doing. So I made these Moon Men Microphone Sounds from a small speaker, without knowing what they are called.

[richardmattocks]

I had no idea these beeps had an official name and also, until you pointed it out I hadn’t spotted that the start and end transmission tones were different, and the reasons for them is so obvious once I thought about it.

Also, I appreciate you using actual electronics to generate the tones. You absolutely nail the tones in every way that any digital version just couldn’t and would have been ever so slightly “off” (it’s a real niggle of mine when I hear recreations of oldschool sounds made via digital generation). It never quite hits the mark IMHO, so total respect to you sir!

Loving your channel. Great work!

[thes]

Always learn something new on this channel. This time: NASA "roger beeps" are called "Quindar Tones" and really are in-channel signalling for the ground station networks PTT. Excellent video Marc & crew!

[TheMman]

Spending my saturday night watching 20 minutes about beeping sounds and im not even sad! This is amazing, thank you for your service for humanity!

[clayp]

If only NASA had saved all this stuff and preserved it all in one place. It would be amazing to go to a museum and see all this stuff working and integrated together.
Also I just wanted to say, what you are doing is amazing.

[AndyFletcherX]

Back in the 1980s I used to design equipment which used a continuous 2970Hz tone to key transmitters. Because the tones were present whenever someone was speaking they had to be filtered out of the audio stream.
There is a problem with Qiundar keyon and keyoff tone system design in that if a tone burst is missed by the transmitter it will stay stuck in whatever mode it was in until the next tone burst comes along. Considering the worldwide routing of the Apollo audio streams I would expect occasional dropouts which could if you were unlucky would lose the Quindar keytones.

[Dudley]

Thanks Marc! All these years I thought the tones were simply audio cues, used in the way you mentioned. I didn’t know about their triggering function. This channel is awesome! 👍👍

[benjaminhanke]

05:20 "Radio teletype transmitter" I'm looking forward to see a video of this.

[rsmrsm]

It was exactly what I expected. Thank you very much for this survey. It had a bonus: simulating the quinder tone in current circuits. You guys are amazing, keeping the magic of man going to the moon alive.

[reneschmitz]

You have to do this with an original Apollo era Headset. Fran Blanche had showed one on her channel. The sonic signature of these makes it sound like Apollo instantly.

[JD_Viddy]

I remember using a XR2206 back in the mid 1970's when I built a controller for a 2m RTTY repeater above Los Angeles. In normal operation it would convert the incoming audio to digital using a common circuit using a couple of toroids. That would then go into a UART to be converted to 5 parallel bits and then back into the UART for regeneration and then on to the XR2206 to go back to audio. For testing you could apply a PL tone and it would just route audio from the receiver to the transmitter. Good times.

[johnk]

haha stir the oxygen tanks that's a good one man.

[Derrick]

I have a faded memory of my grandfather sitting in front of an old black and white console tv watching the landing as I stirred about.

[thomasgrunwald]

Marc.... Kudos to you and your team for all the amazing restoration of this sometimes maddening original Apollo comms equipment!!
The trigger for my comment is the elite 2 Circuit Design Test System that you breadboarded the Quindar circuitry on. I worked on one of them for over 10 years, mocking up the circuit designs that the engineer I worked with came up with. I just finished a 42-year career with the FAA, specializing in Air Traffic Control Radar, then Physical Security. I believe that the Moon Race is what sparked my early-teens interest in electronics, leading to my career.
Again, congratulations to you and your team!!!

[soulrobotics]

Fantastic Marc! (add french pronunciation! lol. clever output with that mosfet!.
so this video make my day! thanks! I am not the only one that wants to visit that basement!!!Man, that is a living museum!

[sarhtaq]

I remember back in the late 1970'ies early 80'ies, the CB community around here simply called them "Apollo beeps" when we used them on our radioes :)