Mission Control Beep?
Eric Scharff
old spacecraft, you often hear a high-pitch "beep", presumably that indicates
the end of transmission.
Does anyone know offhand the history of this, or its true function? Anyone
know the frequency that is typically used to represent this beep?
Sorry if this is wildly off-topic, but this has been bugging me for some time.
TIA,
-Eric
(Genuine email replies to scharffe at-sign cs dot colorado dot edu)
Matt Garrett
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RSabast
download section.
They make great Windows event sounds.
Ben Hallert
>
> If you listen to the communication between mission control and many of the
> old spacecraft, you often hear a high-pitch "beep", presumably that indicates
> the end of transmission.
I don't know the history or frequency of it, but back when I played with CB
radios, there was a modification available for many radios that added the same
functionality, and they called it a 'roger beep'. The primary purpose was, as
you surmised, to signal that the transmission was over.
--
/Ben Hallert/ChairBoy-Tension, apprehension and | http://come.to/thevisitors\
\Bandit 1200 - DoD#2081 - dissension have begun | chai...@vipmail.com /
om
wrote:
>Eric Scharff wrote:
>>
>> If you listen to the communication between mission control and many of the
>> old spacecraft, you often hear a high-pitch "beep", presumably that indicates
>> the end of transmission.
>
>I don't know the history or frequency of it, but back when I played with CB
>radios, there was a modification available for many radios that added the same
>functionality, and they called it a 'roger beep'. The primary purpose was, as
>you surmised, to signal that the transmission was over.
...A big 10-4 there, good buddy. That was Browning's trademark "ping"
method of key initiation that everyone was trying to emulate. Bad
thing about it was that outside of Browning's rigs, having such noises
transmitted over the mike was illegal according to the FCC. Good thing
they were so neutered by the Ford and Clinton administrations that
they couldn't bust their own mothers for failing to use a callsign
much less enforce anything within the covers of Part 95.
OM
apollo18
the Apollo/manned mission Wav files as I can't seem to find it anywhere.
Thanx alot.......Adam
Matt Garrett
who aren't signed up with America Online.
ExLunaScientia
apollo18 <adamNO...@bootle32.freeserve.co.uk.invalid> wrote in message
news:000b8d9b...@usw-ex0102-009.remarq.com...
> Please will someone post a link to the page on AOL where you can get
> the Apollo/manned mission Wav files as I can't seem to find it anywhere.
>
> Thanx alot.......Adam
Try my site.. www.wingdriver.com.au/~richard/apollo.html
Various Apollo wavs and au's.
Roger Balettie
> If you listen to the communication between mission control and many of the
> old spacecraft, you often hear a high-pitch "beep", presumably that
indicates
> the end of transmission.
>
Anyone
> know the frequency that is typically used to represent this beep?
Hi Eric,
The tone is referred to as the "Quindar tone"... I *believe* it is named
that way for one of the original equipment manufacturers, but I could be
wrong.
At any rate... the Quindar is on the MCC side of the house, not on the
spacecraft side, and is still used today. Its purpose is to alert the crew
*onboard the spacecraft* that communication from the ground is starting and
ending.
The tone is sounded when the CAPCOM keys and releases his headset control
for communication. It's a much simpler way of saying "Heads up! We're
calling you!" and "Okay, we're done talking now!".
Roger
==============================
Roger Balettie
former Flight Dynamics Officer
Space Shuttle Mission Control
http://members.aol.com/ramjetfdo/
jat...@ecn.ab.ca
<snip>
: At any rate... the Quindar is on the MCC side of the house, not on the
: spacecraft side, and is still used today. Its purpose is to alert the crew
: *onboard the spacecraft* that communication from the ground is starting and
: ending.
: The tone is sounded when the CAPCOM keys and releases his headset control
: for communication. It's a much simpler way of saying "Heads up! We're
: calling you!" and "Okay, we're done talking now!".
After listening to some of the recordings on my copy of the Apollo Lunar
Surface Journal CD-ROM's, I was surprised at the amount of static and
interference in many of the voice transmissions.
A simple tone could possibly be heard much easier through all that noise.
--
**********************************
* Bernhard Michael Jatzeck *
* *
* jat...@freenet.edmonton.ab.ca *
**********************************
Tom
>
> If you listen to the communication between mission control and many of the
> old spacecraft, you often hear a high-pitch "beep", presumably that indicates
> the end of transmission.
>
> Does anyone know offhand the history of this, or its true function? Anyone
> know the frequency that is typically used to represent this beep?
This is kind-of an off-the-wall guess, but it may be related to a
requirement that said if you recorded a phone conversation, you were
required to supply a beep every fifteen seconds or so that indicated you
were recording. Since the signal from the tracking station to Houston
was routed over AT&T lines (I know this - my dad set them up), it's
possible that this tariff was applied to the Apollo conversations.
Roger Balettie
> This is kind-of an off-the-wall guess, but it may be related to a
> requirement that said if you recorded a phone conversation, you were
> required to supply a beep every fifteen seconds or so that indicated you
> were recording. Since the signal from the tracking station to Houston
> was routed over AT&T lines (I know this - my dad set them up), it's
> possible that this tariff was applied to the Apollo conversations.
No... this is incorrect.
As I stated in my previous answer, the "Quindar tone" is sent by the keying
and releasing of the CAPCOM's microphone from Mission Control. It is still
done today during Shuttle flights.
It's a compact and efficient way of saying "We're getting ready to call you"
and "We're done speaking".
Anonymous
Roger, you're correct that the Quindar is the manufacturer of the tone
generation and detection equipment; however, the Quindar tone was
never intended as a signal to humans.
The Quindar tones are actually used to turn on and off, or "key," the
remote transmitters at the various tracking stations (MILA, Bermuda,
Australia, etc.) that were used to communicate with Apollo and, in
some cases, are still used with Shuttle. A one-half second tone burst
is generated when someone in a control room depresses the push-to-talk
(PTT) button of their headset. The decoder at the remote transmitter
site detects this tone and keys the transmitter. When the PTT button
is released a different frequency tone burst is generated. When the
decoder detects this second tone, it unkeys the transmitter. Because
the telephone lines between the control rooms and the remote
transmitters were designed to carry only voice frequencies, the tones
had to be in the voice frequency range ("in-band signaling") and thus
were audible to humans. The tone signaling could have been done on a
separate phone line, but to keep costs down signaling and audio were
done on the same line.
Although it usually worked well, there were a couple of peculiarities
with this system. If the transmitter was keyed and the telephone line
connection was 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 comm has 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 the NASA Select audio.
The Quindar system was actually built from a piece of equipment that
was used to put multiple teletype (mechanical printers for those of
you too young to remember TTYs) circuits on a single phone line by
means of frequency domain multiplexing. Because replacement parts for
are no longer available, an "out-of-band signaling" system was
installed several years ago 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, as Roger mentioned, everyone had become accustom 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.
Steve Schindler
NASA Voice Systems Engineering
Kennedy Space Center
On Mon, 4 Oct 1999 09:26:16 -0500, "Roger Balettie"
<bale...@arlut.utexas.edu> wrote:
>Eric Scharff <scharff...@cs.coloado.edu> wrote:
>> If you listen to the communication between mission control and many of the
>> old spacecraft, you often hear a high-pitch "beep", presumably that
>indicates
>> the end of transmission.
>>
>> Does anyone know offhand the history of this, or its true function?
>Anyone
>> know the frequency that is typically used to represent this beep?
>
>Hi Eric,
>
>The tone is referred to as the "Quindar tone"... I *believe* it is named
>that way for one of the original equipment manufacturers, but I could be
>wrong.
>
>At any rate... the Quindar is on the MCC side of the house, not on the
>spacecraft side, and is still used today. Its purpose is to alert the crew
>*onboard the spacecraft* that communication from the ground is starting and
>ending.
>
>The tone is sounded when the CAPCOM keys and releases his headset control
>for communication. It's a much simpler way of saying "Heads up! We're
>calling you!" and "Okay, we're done talking now!".
>
>Roger
>==============================
>Roger Balettie
>former Flight Dynamics Officer
>Space Shuttle Mission Control
>http://members.aol.com/ramjetfdo/
>
>
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RSabast <rsa...@aol.com> wrote in message
news:19991002181228...@ng-cg1.aol.com...
Roger Balettie
>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.
*Excellent* history post, Steve... thanks for the lesson! :)