XM Whales (The Backwards Music Station)

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The Backwards Music Station, also known as Whales, is nothing more than an audio feedback loop. It is caused by a keyed up transmitter and co-located receiving equipment. It is not a spy numbers station. It is not transmitting any sort of a message. It is not that interesting.
The Backwards Music Station, also known as Whales, is nothing more than an audio feedback loop. It is caused by a keyed up transmitter and co-located receiving equipment. It is not a spy numbers station. It is not transmitting any sort of a message. It is not that interesting.
 +
 +
An audio sample illustrating the way many of these circuits work and
 +
why they create audio feedback loops is the following:
 +
 +
[http://signals.taunus.de/PUB/AJE_to_NSY.WAV http://signals.taunus.de/PUB/AJE_to_NSY.WAV]
 +
 +
The recording was made on an ISB circuit from Croughton (AJE) to
 +
Sigonella (NSY).
 +
 +
The circuit sent continuous KG-84 encrypted MIL-STD 188-110B serial tone
 +
data traffic on the upper side band (USB), while the lower side band (LSB) was
 +
used for voice coordination between Croughton and Sigonella. If you listen
 +
closely, you can hear the voice of the operator at Sigonella coming in via the
 +
Croughton audio circuit, despite the fact that Sigonella actually transmits on a
 +
totally different frequency. So what you are hearing is simply audio from the
 +
return circuit being retransmitted by AJE's transmitter that in this
 +
case is constantly keyed up. The same setup is used at Sigonella, hence the audio feedback whenever
 +
NSY starts to transmit).
 +
 +
To illustrate this further, the setup at Croughton was:
 +
 +
Transmitter on frequency A
 +
Receiver on frequency B
 +
 +
The Setup at Sigonella was of course the other way round:
 +
 +
Transmitter on frequency B
 +
Receiver on frequency A
 +
 +
There are similar setups on several HF circuits, hence the large
 +
occurrence of these audio feedback loops. 
 +
 +
One good example of such a constantly keyed up circuit is the Russian Naval
 +
aviation circuit on 11354 USB. You'll hear it keyed up for hours without any
 +
voice traffic being sent - only retransmitting atmospheric noise. Then
 +
suddenly, it will spring to life with analogue voice, mostly accompanied
 +
by fierce audio feedback loops.
 +
 +
[http://signals.taunus.de/PUB/11354_PRIBOJ_FEEDBACK.WAV http://signals.taunus.de/PUB/11354_PRIBOJ_FEEDBACK.WAV]
 +
 +
Another good example are the French Air Force circuits on 6700, 6712, 8992
 +
and 18012 kHz USB. They leave their transmitters keyed up for hours even if
 +
there is no traffic on hand (easily recognized by their constant hum/buzz).
==External links==
==External links==
*[http://www.youtube.com/watch?v=KULe-mWDhwc YouTube Recording]
*[http://www.youtube.com/watch?v=KULe-mWDhwc YouTube Recording]

Revision as of 18:14, 12 September 2010

The Backwards Music Station, also known as Whales, is nothing more than an audio feedback loop. It is caused by a keyed up transmitter and co-located receiving equipment. It is not a spy numbers station. It is not transmitting any sort of a message. It is not that interesting.

An audio sample illustrating the way many of these circuits work and why they create audio feedback loops is the following:

http://signals.taunus.de/PUB/AJE_to_NSY.WAV

The recording was made on an ISB circuit from Croughton (AJE) to Sigonella (NSY).

The circuit sent continuous KG-84 encrypted MIL-STD 188-110B serial tone data traffic on the upper side band (USB), while the lower side band (LSB) was used for voice coordination between Croughton and Sigonella. If you listen closely, you can hear the voice of the operator at Sigonella coming in via the Croughton audio circuit, despite the fact that Sigonella actually transmits on a totally different frequency. So what you are hearing is simply audio from the return circuit being retransmitted by AJE's transmitter that in this case is constantly keyed up. The same setup is used at Sigonella, hence the audio feedback whenever NSY starts to transmit).

To illustrate this further, the setup at Croughton was:

Transmitter on frequency A Receiver on frequency B

The Setup at Sigonella was of course the other way round:

Transmitter on frequency B Receiver on frequency A

There are similar setups on several HF circuits, hence the large occurrence of these audio feedback loops.

One good example of such a constantly keyed up circuit is the Russian Naval aviation circuit on 11354 USB. You'll hear it keyed up for hours without any voice traffic being sent - only retransmitting atmospheric noise. Then suddenly, it will spring to life with analogue voice, mostly accompanied by fierce audio feedback loops.

http://signals.taunus.de/PUB/11354_PRIBOJ_FEEDBACK.WAV

Another good example are the French Air Force circuits on 6700, 6712, 8992 and 18012 kHz USB. They leave their transmitters keyed up for hours even if there is no traffic on hand (easily recognized by their constant hum/buzz).

External links



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