UNID 12371 USB signal: Mystery solved.

The peculiar signal seems to be the result of audio feedback:

http://signals.taunus.de/PUB/Feedback.HTML

The above article resolves most of the similar "mystery" signals like "the whales". However, I can't forget that...

Any sufficiently advanced technology is indistinguishable from noise.

UNID (encrypted voice?) on 12371 kHz using University of Twente web SDR

I had the chance to use the free web SDR service provided by the University of Twente in Netherlands. It covers the entire HF and is an excellent way to monitor the bands from office :-)

As I was scanning the bands, I found a peculiar transmission on 12371 USB at approx. 1237z (14/09). I am not sure if the tuning and mode selected is correct, but here is what I heard (recorded from the soundcard output), and this is a spectrogram image:

 12371USB 14/09/2012 1237z (click for larger)

Any ideas?

73
Manolis

Links to files issue

I think now all the links to audio files works as expected! Sorry for the inconvenience!

Update regarding the UNID station found on 11000 kHz

The message which the UNID station found on 11MHz sent, was:

GR35
NO125
MESSAGE
KLPAS BDMGC SPADM SPILB KADCC SBAPP OCMZO PADZZ SPAIK CISBK
QUVAD APCNS SBAAA NOZII KKQUS CAPAA NBOKF EPFFZ PACCM SBADN
KLPAS NNCOM SIKSF PCPIF MKQZF SQUFB SIMCD SPPGC MSNQU ZOIKF
CEPQU VIIOA FFEKS NZPAC LOPSS

It is a short message for giving trustworthy analysis results. But it doesn't seem too "random". And there are only 19 out of the 26 letters of the Latin alphabet.

The same station reappeared on 10400 kHz, between roughly 1400z - 1600z with the same message, and occasionally classical music . Also, I heard some OM talking (not sure for the language). Unfortunately I don't have any sound samples.

To be honest, I think this is a hoax. But I'll give it a try whenever I have free time, just for the fun of it!

UNID station on 11000 kHz

A UNID transmission began at 1429z on 11000 kHz, USB mode. Moderate signal strength with some QSB. Note the noisy background and the funny sounds near the beginning and the distinct pronunciation of the letter v. It faded out at 1503z.

Sound sample

Test transmission on 9450kHz, along with an E25a message

A long test session occurred on 15 December, at 9450 kHz. It started at 1303z and lasted for a bit more than a half an hour.

The session began with PC sounds, then a prayer, then again, sounds from the Windows game "Spider Solitaire". At 1317z and after a brief 1000 Hz tone, the YL counted 0-9, each number spoken in both variants. The second variant is used when the number is in the end of a numbers group. After a while, at 1323z a tone and the YL counting 0-6 this time was heard. The carrier stayed up with again some Windows sounds. At 1327z, an E25a message (785 2) was sent, and the session ended at 1335z, with some more sounds from "Spider Solitaire".

And here is the sound file of the whole transmission. Enjoy!

Abdel Halim Hafez - Ahwak ("I love you"), transmitted on 6140 kHz

On 15 December, 0837z, 6140 kHz, E25 transmitted this song from Abdel Halim Hafez. The song is called "Ahwak" which means "I love you". Here is a YouTube video featuring the same song,
and some more info regarding the singer can be found in the corresponding Wikipedia article.