
Quindar Tones: the beeps heard in recordings of astronauts in space - NaOH
https://jalopnik.com/theres-an-actual-name-and-reason-for-those-beeps-you-he-1841024797
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jcrawfordor
A somewhat similar system used in modern radio systems (well, radio systems
that are now outdated, but still in widespread use) is two-tone sequential
paging or the related QuikCall. These are in-band audio tones used to cause
some receivers to open squelch as a form of selective calling.

The method is predominantly used in public safety radio systems, where tone
paging may be used to cause a fixed receiver in a station to open squelch
(triggering an alarm) or cause a portable paging receiver (like a Motorola
Minitor) to open squelch as a simple form of paging. Rural VFDs often rely on
the latter to call out volunteers.

Anyway, the world of in-band signaling in voice communications is really
pretty interesting, and while digital systems have reduced the need for in-
band there are still a lot of real-world systems that rely on it for
compatibility with legacy equipment. The telephone system has largely moved on
(except for various niche uses of DTMF) but in-band signaling is still pretty
common in radio systems, where upgrading to a digital system is high cost and
comes with its own limitations.

Another example off-hand: most large-area public address systems, the type of
thing the military often calls Giant Voice and might be used for tornado
warning in some areas, use either DTMF or SelCall (five-tone) on the control
radio channel (which in many cases is the same radio system used by public
safety portable radios) to cause the loudspeakers to activate. A particular
oddity of a lot of these systems is that they have different generations of
receivers that use different methods, so sometimes you'll end up hearing the
tones played aloud if a receiver opens squelch in reaction to something
earlier in the sequence.

And a last example, also usually seen in public safety - some radio schemes
like MDC transmit a burst that sounds like a roger beep whenever the PTT is
released, but is actually a short data packet that identifies the transmitting
radio. This allows a specially equipped base station to show e.g. a dispatcher
who was just transmitting. Sometimes the same signaling system is used to
implement other features like 'man down' detection where a radio signals if it
is not upright or has not moved for a period of time (common safety feature in
fire departments), but sometimes these kinds of systems also just use a
sample-based speech synthesizer if there's no digital system already in use.

Oh, I can't resist one more. The "buzz," repeated three times, which proceeds
emergency alert messages in the US is actually a short data packet which gives
certain metadata about the alert and causes hardware in receiving radio
stations (the system operates a bit like a "calling tree") to cut out the
program audio and switch over the received alert. The two-tone beep which
follows is a legacy system for the same purpose, although today no such
receivers should still be in use. It's amusing that many phones use that two-
tone signal as their ringtone for emergency alerts considering how divorced
that is from its original purpose, but it's quite recognizable. Emergency
alert messages should be followed by a three shorter data bursts which inform
receivers that the alert is over. A closely related scheme is used by NOAA
All-Hazards Radio to cause dedicated "weather emergency" receivers in people's
homes to open squelch, these are more common in tornado-prone areas but
generally work throughout the US. As the name suggests, All-Hazards also
retransmits alerts from agencies other than NOAA including emergency alert
system messages.

~~~
EFruit
The NOAA system has a name: SAME, or Specific Area Message Encoding[1]. As the
name implies, those three bursts actually contain a whole packet of
information regarding the incoming message, including areas of effect, hazard
type, duration, source of the alert, etc. There are pieces of software out
there that let you decode the packets, and some let you encode your own, like
minimodem[2]. Do be aware that transmitting valid SAME packets over broadcast
media tends to be very poorly viewed by the FCC because it actually triggers
mechanisms in the broadcast system, as GP noted.

1:
[https://en.wikipedia.org/wiki/Specific_Area_Message_Encoding](https://en.wikipedia.org/wiki/Specific_Area_Message_Encoding)
2: [http://www.whence.com/minimodem/](http://www.whence.com/minimodem/)

~~~
derefr
Would anything interesting happen if a valid SAME packet were dropped into the
FM sub-carrier of a television signal on a CATV or DBS network?

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bilekas
> if NASA wanted to send control signals like transmit on and off, they’d need
> to run a whole parallel set of wires, which would be expensive. So, they
> came up with a solution: use the same lines for control signals as well!

It really seems that in earlier years, when resources were limited, people
really used their ingenuity far better than today.

Maybe I have rose tinted glasses, but the level of creativity and cleverness
seen in old solutions to problems/challenges just blows my mind all the time.

~~~
bmgxyz
I agree that it seems like engineers of the past were more clever than us
today, but I suspect that we feel that way only because a lot of the garbage
systems and code have been lost to time. The good stuff gets immortalized and
passed down, while the bad stuff isn't, much in the same way that nobody will
see my hacky Python scripts in 30 years (with any luck). It's a selection
bias.

See also people who are convinced they were born in the wrong time period.
Much more annoying that you or me, I'd say, but the same principle
nonetheless.

~~~
folkhack
> much in the same way that nobody will see my hacky Python scripts in 30
> years (with any luck)

LOTS of us have seen legacy systems long outlast their intended lifespan. I've
seen this in enterprise settings, web development, small business, etc... I've
got multiple custom web solutions (niche industry product catalogs) I
developed in my early 20's that are still going strong 10-15 years later. The
code behind them is dated and god awful, but if/when you talk to the client
it's the "don't fix what's not broken" mentality.

Due to this experience I've learned to document the hell out of my projects
because of really positive feedback from developers who have had to
support/modify my work down-the-road. Docs can be a lifesaver in a less-than-
ideal situation.

Just sharing my anecdotal experience of "holy cow that's STILL LIVE?!" and,
"here's a DB2 mess from the late 80's ... figure it out kid." =)

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shmageggy
When these tones are used in music, it instantly instills a sense of mystery
and wonder. I don't know if it's something intrinsic to the sound, or if it's
because of the recognizable context of exploration and discovery. One song
that comes to mind is Satellite by BT, but I know I've heard it elsewhere too.

~~~
kortex
I think it's the same reason I tear up uncontrollably watching rocket
launches. It's just so _epic_ and bigger than any one human. See also:
overwatch effect.

Here's a collection of songs:

"I'm looking for songs that contain NASA radio transmission snippets, or a
"space" theme conveyed in a creative manner. Examples in text"
[https://www.reddit.com/r/trance/comments/1vl39y/im_looking_f...](https://www.reddit.com/r/trance/comments/1vl39y/im_looking_for_songs_that_contain_nasa_radio/)

~~~
shmageggy
Ah, yes Highroller by Crystal Method is one I've heard

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peterhull90
Does anyone know why they picked frequencies quite close together for the
in/out tones (2525Hz/2475Hz) when the pass band for telephony was much wider?

~~~
lb1lf
-Probably placed at the upper end of the passband so you could use a single high-pass filter in front of the detector to get rid of any noise on the line, easing detection.

Also, if you wanted to remove the tones from the passband for some reason or
other, you could do that with a single notch filter if the tones were
sufficiently close.

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rkagerer
Chatterer is my favorite mod for Kerbal Space Program, and it brings these
tones (and other authentic sounds) to the game:
[https://forum.kerbalspaceprogram.com/index.php?/topic/83290-...](https://forum.kerbalspaceprogram.com/index.php?/topic/83290-18x-chatterer-v0998-moar-
talking-23-oct-2019/)

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NCG_Mike
I know them as "roger beeps" from CB radio terminology.

~~~
werdnapk
The exact tones were generated from Quindar manufactured equipment and would
be specific to that equipment. So CB radio beeps wouldn't be Quindar tones.

~~~
dfox
Also the purpose is different. Quindar tones are intended to control
intermediate equipment, while roger beep is meant as replacement for user
saing "over" at the end of transmission.

~~~
ovi256
"Roger beeps" \- a type of squelch tones - control intermediate equipment too,
like amateur radio repeaters.

See
[https://en.wikipedia.org/wiki/Squelch#Uses](https://en.wikipedia.org/wiki/Squelch#Uses)

~~~
dfox
The article mostly talks about CTCSS/DCS, which really are tones intended to
control equipment, but these are mostly designed to not be audible (both CTCSS
and DCS is sent during the whole transmission on frequencies below the voice
pass band).

Roger beep is a tone that is generated by the transmitting station when user
lets go of the PTT (in similar way to Quindar outro tone). Using this tone to
control anything in CB/HAM context is not really possible because there is
essentially no standardization of how the beep sounds. Also IIRC having roger
beep turned on is mostly frowned upon on ham bands.

~~~
creeble
>Also IIRC having roger beep turned on is mostly frowned upon on ham bands.

Except the Roger beep coming from the repeater, which is semi-important in
that it denotes that the repeater has unlatched and the transmit timer is
reset.

If a repeater user keys up before hearing the Roger beep, the repeater doesn't
restart the transmit timer, so there is a chance that your transmission will
time out.

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oldandcold
I've always enjoyed these beeps...to me, for technical radio comms, they lend
a sense of "tightness" or maybe even "seriousness" that normal comms don't
have. Control purposes aside, I just love them. And until now, I had no idea
they were different frequencies...now that I know this, I can tell.

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asciimo
> ...if NASA wanted to send control signals like transmit on and off, they’d
> need to run a whole parallel set of wires, which would be expensive.

Why not transmit continuously? That seems to be the problem they're solving,
but I'm not sure why that would be a problem.

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ehosca
i thought there were just fancy roger-beeps...

