Quindar Tones: From the SWLing Post Archives

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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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FM Pirates: FCC Enforcement sends letters to landlords

NYC-Area Landlords Get Pirate Letters (Radio World)

FCC Enforcement Bureau traced FM signals after receiving complaints

Continuing its efforts to fight illegal broadcasts, the Federal Communications Commission has sent notices to five property owners and managers in and around New York City.

The letters from the Enforcement Bureau inform the owners that the FCC, after receiving complaints, traced unlicensed signals to each property in April, May or June. These letters inform the owners that under federal law, anyone who allows pirate radio broadcasting on a property can face significant financial penalties — up to $2.1 million.

The recipients are given 10 business days to show that they are no longer permitting pirate radio on their properties and to identify individuals engaged in pirate radio on the property that they own or manage. [Continue reading…]

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Fun with “The Radio Boys”

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By Jock Elliott, KB2GOM

Back in April of this year (2022), I accidentally discovered The Radio Boys series of books, many of which are available for free if you have an Amazon Kindle.

These books, I believe, are intended for young adults, and, in my mind, they very much resemble The Hardy Boys series of books: a group of high school friends have adventures and discover the wonders of radio together. Think “The Hardy Boys go all-in for radio,” and you have the right idea.

If you are looking for sophisticated plots, deep character development, and a lyrical turn of phrase, you will be disappointed. But if you a looking for a light-hearted adventure with deep enthusiasm for radio, I think you will be pleased.

But what makes these books really cool is that they were written and copyrighted 100 years ago, in the early 1920s. Yes, some of the language and attitudes are somewhat antiquated, but what is fascinating is the window they offer on radio a century ago.

My knowledge of radio history is very limited, but it is my understanding that radio was just beginning to be popular in American culture in the early 1920s, The Radio Boys books reflect this. The first book, The Radio Boys’ First Wireless Or Winning the Ferberton Prize, gives fairly detailed instructions for making your own radio receiver with materials you could get (in the early 1920s) from the local hardware store.

At various points in the books, The Radio Boys extol the virtues of radio: people could hear concerts in the comfort of their own homes or listen to baseball games; if there were radios in cars, travelers could keep track of weather reports; it was a novelty when a minister broadcast the church service; college professors could broadcast their lectures, and so forth. I find the books offer a charming perspective on what we take for granted today.

And, if you have an Amazon Kindle, many of The Radio Boys books are available at no cost.

Click here to check out some of The Radio Boys titles on Amazon.com.

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Radio Waves: DRM Demo in Australia, Decoding the JWST, the ARDC, and EV Makers Dropping AM Radio

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Radio Waves: Stories Making Waves in the World of Radio

Welcome to the SWLing Post’s Radio Waves, a collection of links to interesting stories making waves in the world of radio. Enjoy!

Australia Demonstrates DRM on AM, FM (Radio World)

Since September 2020, ABC Radio has been quietly trialing DRM technology in Victoria

The public-service Australian Broadcasting Corp. and its transmission contractor BAI Communications Transmission Network hosted a public demonstration of Digital Radio Mondiale broadcasts on June 29, 2022. ABC highlighted the use of DRM on both AM and FM in Wagaratta, Victoria.

According to the DRM Consortium, the demonstration was the culmination of almost two years of COVID-impacted work to assess the performance of DRM services in Australia’s VHF and medium-wave bands.

Previously, the Australian Amateur Radio Experimenters Group reported that AREG member Steve Adler (VK5SFA) had been monitoring “a very un-publicized Digital Radio Mondiale (DRM) trial” on 747 kHz from Wangaratta in August 2021.

The Australian Communications and Media Authority provided ABC with a license variation to conduct the DRM 30 trials from September 1, 2020, to August 31, 2022.

At the public demonstration, senior representatives from the public, commercial and community radio sectors, along with regulators and other interested parties, were able to hear and see the capabilities of DRM broadcasting on AM from Dockers Plains and on FM from Mount Baranduda. They were also able to review the transmission equipment at Wagaratta.[Continue reading…]

Also check out the DRM Consortium’s article on this same topic.

Decoding James Webb Space Telescope (Daniel Estévez)

The James Webb Space Telescope probably needs no introduction, since it is perhaps the most important and well-known mission of the last years. It was launched on Christmas day from Kourou, French Guiana, into a direct transfer orbit to the Sun-Earth L2 Lagrange point. JWST uses S-band at 2270.5 MHz to transmit telemetry. The science data will be transmitted in K-band at 25.9 GHz, with a rate of up to 28 Mbps.

After launch, the first groundstation to pick the S-band signal from JWST was the 10 m antenna from the Italian Space Agency in Malindi, Kenya. This groundstation commanded the telemetry rate to increase from 1 kbps to 4 kbps. After this, the spacecraft’s footprint continued moving to the east, and it was tracked for a few hours by the DSN in Canberra. One of the things that Canberra did was to increase the telemetry rate to 40 kbps, which apparently is the maximum to be used in the mission.

As JWST moved away from Earth, its footprint started moving west. After Canberra, the spacecraft was tracked by Madrid. Edgar Kaiser DF2MZ, Iban Cardona EB3FRN and other amateur observers in Europe received the S-band telemetry signal. When Iban started receiving the signal, it was again using 4 kbps, but some time after, Madrid switched it to 40 kbps.

At 00:50 UTC on December 26, the spacecraft made its first correction burn, which lasted an impressive 65 minutes. Edgar caught this manoeuvre in the Doppler track.

Later on, between 7:30 and 11:30 UTC, I have been receiving the signal with one of the 6.1 metre dishes at Allen Telescope Array. The telemetry rate was 40 kbps and the spacecraft was presumably in lock with Goldstone, though it didn’t appear in DSN now. I will publish the recording in Zenodo as usual, but since the files are rather large I will probably reduce the sample rate, so publishing the files will take some time.

In the rest of this post I give a description of the telemetry of JWST and do a first look at the telemetry data. [Continue reading…]

Helping Secure Amateur Radio’s Digital Future (Hackaday)

The average person’s perception of a ham radio operator, assuming they even know what that means, is more than likely some graybeard huddled over the knobs of a war-surplus transmitter in the wee small hours of the morning. It’s a mental image that, admittedly, isn’t entirely off the mark in some cases. But it’s also a gross over-simplification, and a generalization that isn’t doing the hobby any favors when it comes to bringing in new blood.

In reality, a modern ham’s toolkit includes a wide array of technologies that are about as far away from your grandfather’s kit-built rig as could be — and there’s exciting new protocols and tools on the horizon. To ensure a bright future for amateur radio, these technologies need to be nurtured the word needs to be spread about what they can do. Along the way, we’ll also need to push back against stereotypes that can hinder younger operators from signing on.

On the forefront of these efforts is Amateur Radio Digital Communications (ARDC), a private foundation dedicated to supporting amateur radio and digital communication by providing grants to scholarships, educational programs, and promising open source technical projects. For this week’s Hack Chat, ARDC Executive Director Rosy Schechter (KJ7RYV) and Staff Lead John Hays (K7VE) dropped by to talk about the future of radio and digital communications. [Continue reading…]

Interference causes EV makers to drop AM radio (Radio World via the Southgate ARC)

Radio World reports the Electromagnetic Interference generated by Electric Vehicles is causing some EV automakers to drop AM (medium wave) radio

The article says:

Some EV automakers are dropping AM altogether due to audio quality concerns, but that’s just one piece of the puzzle as radio continues to fight for space on the dash.

“As carmakers increase electric vehicle offerings throughout their lineups, the availability of AM radio to consumers is declining,” said Pooja Nair, communications systems engineer with Xperi Corp., in a Radio World guest commentary. “This is because the effects of electromagnetic interference are more pronounced in EVs than in vehicles with internal-combustion engines.”

In other words, electromagnetic frequencies generated by EV motors occupy the same wavelength as AM radio signals. The competing signals clash, effectively cancelling each other out. As EV motors grow more powerful, AM static tends to increase.

Read the full story at
https://www.radioworld.com/news-and-business/headlines/why-are-some-automakers-ditching-am-radio

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Your support makes articles like this one possible. Thank you!

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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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CIDX Special Event Stations and QSL information!

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Many thanks to SWLing Post contributor, Sheldon Harvey, who shares the following announcement from the CIDX:

CIDX AMATEUR RADIO CLUB STATIONS ON THE AIR JULY 17, 2022

CIDX has two amateur radio club stations that are activated from time to time on the ham bands, usually to mark special events, club anniversaries, etc.

VE2AQP is our eastern Canada amateur club station callsign, located at CIDX eastern Canadian headquarters in Saint-Lambert, Quebec

VE6SWL is our western Canada amateur club station callsign, located at CIDX western Canadian headquarters in Sherwood Park, Alberta

CIDX is planning to activate the stations in July to mark the 60th anniversary of the Canadian International DX Club.

VE2AQP will be active from Montreal, Quebec, operated by CIDX World of Utilities editor Gilles Letourneau, VE2ZZI, on July 17th from 1800 UTC to 2200 UTC around 14240 kHz USB, plus or minus, depending on activity and the conditions on the band,

VE6SWL will be active from Lamont, Alberta, operated by CIDX Vice-President & Verie Interesting editor Mickey Delmage, VE6IDX, also July 17th from 1800 UTC to 2200 UTC around 14265 kHz USB, plus or minus, depending on activity and the conditions on the band.

VE2AQP will be active again on July 31st at 2200 UTC to August 1 at 0200 UTC on 40 meters around 7150 kHz LSB, plus or minus, depending on activity and the conditions on the band.

CIDX will be issuing special e-QSLs for contacts with either or both CIDX club stations. SWLs are also welcome to submit reports should you log either or both stations. For those receiving e-QSLs who are not CIDX members, a free sample copy of “Messenger” together with club information will accompany the e-QSL.

CIDX will activate the two CIDX amateur club stations at various times throughout the balance of 2022 to mark CIDX’s 60th anniversary. Notices of future operations will be posted on the CIDX Facebook group and the CIDX IO Group.

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What is it about SWLing that keeps you coming back? A reader participation post.

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By Jock Elliott, KB2GOM

After trying to copy Shortwave Australia on 4835 this AM, the curiosity bug has bitten me. What, I wonder, is it about SWLing that keeps my fellow readers of SWLing.com coming back?

For me, it’s three things. First, I think Treasure Island ruined me as a kid. Ever since I read it, shiver me timbers matey, the search for The Hidden Thing – whether treasure in the ground or a signal on the airwaves – has been a lifelong fascination for me.

Second, I enjoy trying to tease a faint signal out of the ether. That’s why I got a kick out of trying to hear the Armed Forces Crossband Test.

Finally, I enjoy the physical act of operating a radio, turning the dial, adjusting the controls, tuning the preselector, and so forth.

So now, it’s your turn – what keeps you coming back and tuning the airwaves?

Please comment!

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