Tag Archives: Apollo 11

Quindar Tones: From the SWLing Post Archives

I’ve been listening to Apollo 11 in real-time, as mentioned in a previous post. Today, I’ve been listening to NASA communications as the Eagle landed on the moon (53 years ago).

Of course, any of those Apollo era comms include loads of Quindar Tones, so this reminded me of the following post from the SWLing Post Archives. I thought I might resurrect it for those who might not have caught it when first published. Enjoy:

Quindar Tones: Those iconic NASA PTT confirmation beeps

Apollo 11 (Photo: NASA)

Yesterday, my family watched the successful launch of the NASA Demo-2 SpaceX Dragon via YouTube.

As astronauts Robert Behnken and Douglas Hurley communicated with Mission Control, we heard PTT confirmation beeps after each transmission.

Those beeps, of course, reminded me of past NASA missions and those iconic confirmation tones we heard in audio from the Mercury, Gemini, and Apollo days all the way into Space Shuttle missions.

Quindar Tones

Source: honeysucklecreek.net

Last year, after spending a couple of days at the US Space and Rocket Center (and attending the Huntsville Hamfest), I heard numerous NASA audio clips and that lead me down the path of researching those PTT confirmation tones.

Turns out, they’re called “Quindar Tones.”

I couldn’t find any information about Quindar Tones at the US Space and Rocket Center–although, admittedly, the place is massive and I could have easily overlooked it–so I did a little research when I returned home.

I found this archived post on the NASA’s Apollo Lunar Surface Journal wesbite:

Re: Apollo beeps

Journal Contributor Mark Burckhard writes:

“I’ve always wondered what purpose the ‘beeps’ served that one heard intermittently during the voice communications with the Command and Lunar Modules during the Apollo missions, as well as other space missions.”

Journal Contributor Mike Dinn provides an MP3 clip ( 123k ) from a network audio check that includes numerous Quindar Tones.

Journal Contributor Markus Mehring replies:

“‘Other space missions’ is quite an accurate observation, since the ‘beeps’, in fact, are still in use today on Shuttle flights, at least on the UHF frequencies.”

“These beeps are called ‘Quindar-Tones’. Their purpose is to trigger the ground station transmitters when there is an outgoing transmission from Earth. The CapCom in the Mission Control Center, who is taking care of communications with the crew, uses his communication gear in a PTT mode exclusively. ‘PTT’ is short for Push-To-Talk, which means that the CapCom presses a button every time and as long as he wants to talk. (The crews back during Apollo – and also today – usually communicate via PTT as well, but they also have the so-called ‘VOX mode’ at their disposal, in which their microphones are voice-triggered by a certain adjustable threshold volume levels. VOX is used when they don’t necessarily have their hands free.)

When the CapCom presses his PTT button to start a transmission, an intro tone (2.525KHz sine wave with a length of 250ms) is generated and triggers the ground station transmitters to send. And when he is finished talking and releases the button again, a slightly lower outro tone (2.475KHz, sine, 250ms) is generated to trigger the ground station transmitters to turn off. So in short, these are remote control trigger tones.

CU! Markus”

I then discovered this article via the Internet Archive Wayback Machine, which gave more detail about the Quindar Tones’ name and some of the idiosyncrasies of the system:

The story behind the “Beep”

Steve Schindler, an engineer with voice systems engineering at NASA’s Kennedy Space Center, offers the following history of [Quindar Tones] origins.

“Quindar tones, named after the manufacturer of the tone generation and detection equipment, are actually used to turn on and off, or “key,” the remote transmitters at the various tracking stations (Merritt Island Launch Area–now Kennedy Space Center, Bermuda, Australia, etc.) that were used to communicate with the Mercury through Apollo spacecraft and, in some cases, are still used with the Space Shuttle.”

[…]”Although it usually worked well, there were a couple of peculiarities with this system. If the transmitter was keyed and the telephone line connection broken, the transmitter would never get the tone to turn off. To prevent this there was a “transmitter on” light at each remote site that would come on when the transmitter was keyed. Someone was supposed to monitor the circuit and if the audio dropped, but the “transmitter on” light was still on, they would have to manually unkey the transmitter. Also, just before communications was handed over to a new tracking station, the key-unkey tone pair was sent 10 times to ensure that everything was functioning correctly. This was done before the audio was patched to the tracking station’s line so it wasn’t heard in the control room or on NASA Select audio.

The Quindar system was actually built from a piece of equipment that was used to put multiple teletype circuits on a single phone line by means of frequency domain multiplexing. Because replacement parts are no longer available, an “out-of-band signaling” system was installed in 1998 for the transmitters located in the U.S. This system uses a continuous tone that is below the normal audio frequency range. When the tone is present, the transmitters are keyed. When the tone is not present, the transmitters are unkeyed. It worked fine, but the Astronaut Office complained about the lack of tones which everyone had become accustomed to as an alert that a transmission was about to start. So, the Quindar tone generator, which was still installed in case it was necessary to key the transmitters at an overseas site, was re-enabled.

Even though you won’t hear the same Quindar tones in present-day space missions, you can listen until your heart is content at the website Apollo In Real Time.

The Internet Archive also has a massive collection of Apollo audio free to stream and download.

Quindar Music

If you’re fascinated with the NASA audio soundscape in general, you might check out the electronic music duo Quindar featuring longtime Wilco member Mikael Jorgensen, and art historian-curator James Merle Thomas.

Quindar: Mikael Jorgensen & James Merle Thomas. Photo by Chad Ress, Spacesuits by Cassandra C. Jones

Science Friday featured an extended interview with the group in 2017. If you love electronic music–especially if you’re a fan of Wilco, it’s well worth a listen:

Check out their latest video, Choco Hilton:

Speaking of Mikael Jorgensen and Wilco, I should note here that their album yankee hotel foxtrot has a deep shortwave motif.

Anyone else fascinated with Quindar Tones and NASA audio? Feel free to comment and share any other resources or projects you’ve found.

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Listen: Apollo 11 Real-Time Mission Experience

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CAPCOM Charles Duke (left), with backup crewmen Jim Lovell and Fred Haise listening in during Apollo 11’s descent (Photo: NASA)

Many thanks to SWLing Post contributor, Wilbur, who writes:

I thought you may be interested in this. A few years back the same group posted Apollo 13 realtime audio. I listened to for days. It was during lockdown for Covid-19 so I had lots of time at home to keep it on.

It really renewed my love of radio.

I missed the Launch, as I just found it here at 2:00 local EST. But I will be monitoring for the next few days.

This the Big one, so it will be interesting to hear.

Click here to check out NASA’s Apollo 11 Real-Time Mission Experience.

Thanks for all that you do!

Wilbur

Thank you for the tip! As I did with Apollo 13, I’ll keep this running in the background for the next few days!

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A shortwave audio archive tribute to Apollo 11 astronaut Michael Collins

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Today we learned that Michael Collins, the American astronaut who flew the Apollo 11 command module Columbia around the moon, has passed away at the age of 90. For those of us who’ve always looked to the sky and dreamed of exploring our amazing universe, Michael Collins was a hero.

As a little shortwave radio tribute, I thought I’d share a few recordings from the Shortwave Radio Audio Archive:

Voice of America (Studio Recording): July 20, 1969

Many thanks to SRAA contributor, Tom Gavaras, for sharing the following recording and notes:

Voice of America studio quality recording of shortwave coverage of Apollo 11. Starts with newscast on the status of Soviet Luna 2 orbiter that was also sent to the moon, Egyptian-Israel conflict at the Suez Canal, Organization of American States call for a cease fire between El Salvador and Honduras, entire cabinet in South Vietnam resigns, American air attacks against the Viet Cong, etc. Followed by latest updates on Apollo 11 (lunar module is on the moon), international reaction to landing on the moon, etc.

Date of recording: 7/20/1969

Starting time: 1730 UTC

BBC World Service (20th Anniversary of Apollo 11): July 20, 1989

Many thanks to SRAA contributor, Tom Laskoski, who shares the following recording and notes:

I thought this might be an appropriate file to upload considering we are about to mark the 50th anniversary of Apollo 11. I recorded this program thirty years ago on July 20, 1989, the 20th anniversary of the Apollo 11 moon landing. Omnibus takes a look back at the historic Apollo mission and how and why it happened. Another SWRAA program on Apollo 11 from VOA can be found at https://shortwavearchive.com/archive/voice-of-america-july-20-1979?rq=apollo

Starting time: about 0400 UTC

Frequency: 5.975 MHz

Location: South Bend, IN

Receiver: Sony ICF-2001

Voice of America: July 20, 1979

Many thanks to SRAA contributor, Tom Laskowski, who shares this recording of the Voice of America from July 20, 1979 at 0500 UTC on the 31 meter band. Tom notes:

The first 4:30 is from a VOA newscast that aired before the main part of the program. The main recording was presented on the 10th anniversary of the Apollo 11 moon landing. I enjoy listening to this every year on the landing anniversary.

“About the flight itself, the thing I remember most is the view of planet Earth … bright, beautiful, serene, and fragile.”

—Michael Collins

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Apollo 11 ham radio special event stations

From the Shortwave Radio Audio Archive: VOA and BBC on the anniversary of moon landing

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Eagle in lunar orbit photographed from Columbia. (Image: NASA)

There are a hundreds of fascinating off-air radio recordings in our Shortwave Radio Audio Archive.

One of our frequent contributors, Tom Laskowski, has digitally converted numerous magnetic tape recordings from his personal collection to share with the archive. Tom made the following recording of the Voice of America on July 20, 1979 at 0500 UTC on the 31 meter band.

Tom notes:

The first 4:30 is from a VOA newscast that aired before the main part of the program.

The main recording was presented on the 10th anniversary of the Apollo 11 moon landing. I enjoy listening to this every year on the landing anniversary.

I’ve enjoyed listening to this 10th anniversary presentation as we, today, celebrate the 50th anniversary of the moon landing::

Click here to download this recording.

[Update:] Tom also shares another recording that marks this anniversary:

I thought this might be [another] appropriate file to upload considering we are marking the 50th anniversary of Apollo 11. I recorded this program thirty years ago on July 20, 1989 [5.975 MHz at 0400 UTC] the 20th anniversary of the Apollo 11 moon landing. Omnibus takes a look back at the historic Apollo mission and how and why it happened:

Click here to download the recording.

Thank you so much for sharing this, Tom!

Readers: Note that you can subscribe to the Shortwave Radio Audio Archive as a podcast via iTunes or by using the following RSS feed: http://shortwavearchive.com/archive?format=rss You can also listen via TuneIn.

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Apollo 11 at 50 years: Those who made landing on the moon a reality

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I’ve always said that the key to success is to surround yourself with amazing people.

I’ve been incredibly fortunate in this life to do that very thing–and certainly one of those amazing people is my friend, George Knudsen (W4GCK).

You see, besides being a ham, devoted radio enthusiast, and all around good guy, fifty years ago George was an integral part of putting Apollo 11 on the moon. George’s team was responsible for Apollo 11’s second stage.

The S-II second stage is moved into position for mating with the S-IC first stage. (Source: NASA)

Our local ABC affiliate, WLOS, featured George today:

Click here to view the video on WLOS.

Every time I’m around George, I pick his brain about the Apollo 11 days–his inside stories fascinate me. One thing that always sticks in my mind is the Esprit De Corps his team and everyone–literally everyone from the astronauts to the maintenance crew–on the mission experienced.

They had an outrageous goal and an outrageous timeline, yet they still managed to make it happen.

If you’d like to learn more about George, I’d highly recommend listening to his in-depth interview on the excellent omega tau podcast.

Here’s a description:

George Knudsen started working in 1958 on the Redstone missile, and moved on to working on the Atlas ICBM. Later he worked on the Saturn 5 launch vehicle, where he was responsible for the fuel tanks. He was on the launch team at Cape Canaveral for various Apollo missions. In this episode [we] talk with George about his work in this fascinating period of science and engineering history.

Click here to listen via the omega tau site.

omega tau, hosted by Markus Völter, covers a wide variety of topics from engineering and science. It’s one of my favorite podcasts, so I would encourage you to not only listen to this episode, but subscribe to the podcast.

Please comment with your Apollo 11 stories!

Apollo 11 and all of the missions leading up to and following it involved thousands upon thousands of skilled workers and stakeholders. Please comment if you or someone in your life played a role in any of these missions.

Do you remember Apollo 11? What was it like for you that amazing day?

Please comment!