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

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

UNID signal on 9344 kHz

A whistle-like signal is currently present on 9344 kHz, USB mode 1051z:

Spectrogram image

Signal strength is low but clear.

Sound sample.

Any ideas?

Very odd "sinusoidal" sweep on 6990 kHz

Well, HF is a garden of endless sound varieties.

Now, what's this? Something out of order?

Recorded on 6990 USB, wide filter setinng, at approx. 2109 UTC, S5-S7 signal strength.

13320 kHz not numbers related

The mysterious 13320 kHz station logged again ~1351z. It is not a numbers transmission but a live QSO between two stations. Here is the sound clip!

A better sample from 13320 kHz

Here is another sample from 13320 kHz! A bit better reception this morning!

"...LF! LTU, LF! OK? LTU, LF! LTU, LF! Roger? ??? ??? ??? Roger? Roger? ??? Roger? Roger-roger? ??? ???"

The letters are "Lima", "Tango", "Uniform". I can't understand the rest (question marks).

And here is another short one! "OUF, UW! YRC, ZN! WUL, UP!"

UNID station on 13320 kHz

After Poacher's post in Enigma2000 group, I logged 13320 kHz USB, 1222-1241z! Very weak! Here is a short clip! It is heavily processed to improve SNR. Noise reduction introduced some artifacts but you can hear the voice much easier that way!

This station was misidentified as V21.

UNID signal plus XM

A known frequency for the weird whale-song-sounding or "backwards music" station XM (Attention! Not XW, W for Whale! XW is different, "Workshop", check your Enigma Control List!) is 8707 kHz +/-. Here is a sample from today's song, 0814z.

A UNID signal noted by some Enigma2000 members appeared again on 10683 USB, 0809z. I can describe it as a Jet plus a looping banging sound. But today an XM signal appeared there too!!! Listen! The XM interrupted the UNID transmission. I was lucky to catch this since the station QRT at 0817z. Very weird stuff. Any ideas?

UNID HF-Fax station: Must be Tashkent!

I did a search to some old HF-Fax images, received back in 2001-2002 where the Sun was more kind to us offering more sunspots! I found some similar images, of better quality, which resemble the ones I've posted earlier. The service's logo is visible, and I think it reads "UZHYMET". So it must be Uzbekistan. I'll show you my older images later, and ask you if I'm right. Here is a link to the Weather Service web page. Still I haven't found more info about fax transmissions...

First, I believe a transmission was on air commencing earlier than ~1359z, but it was under heavy QRN. A series of images followed, with slightly different timing than the previous days.

4067 kHz, 01/02/2007 1422z

4067 kHz, 01/02/2007 1448z

4067 kHz, 01/02/2007 1601z

4067 kHz, 01/02/2007 1631z

4067 kHz, 01/02/2007 1701z

4067 kHz, 01/02/2007 1731z

There was also a transmission at 1801z, but I was listening to G11 of course!

Here are the old pictures. Definitely then the conditions were better, despite being received in a more noisy location and with Sangean's 7 meter random wire antenna!

15/09/2001 1440z

04/10/2001 1439z

15/09/2001 1501z

22/12/2001 1519z

I have uploaded them full-sized so you can read the labels more easily! Unfortunately no frequency details available. I was novice then and underestimated the value of a good logbook! But it is obvious that the conditions were much better back in 2001.

UNID HF-Fax station: Tashkent?

Yesterday I decided to look again for that UNID Fax station on 4067 kHz, and got 4 complete transmissions and a partial one. Again the problem is the spacing: 1000 Hz instead of 800 Hz, and also some faults during the beginning of the broadcast.

4067 kHz, 30/01/2007 1451z Partial image.

This one probably started at 1430z. Well it still seems Russian to me :-)

4067 kHz, 30/01/2007 1601z

4067 kHz, 30/01/2007 1709z

You see, my environment is not QRN-free! That zig-zag lines are caused by QRN.

4067 kHz, 30/01/2007 1801z

Use the times given as a guide to hunt for this one! Unfortunately the images are not clear and I can't read the boxes. If anyone is familiar with Tashkent fax service, is kindly requested to post a comment saying so.

UNID HF-Fax station

Unidentified HF-Fax station logged on 4067 kHz today on 1631z, 1701z, 1731z, 1801z:

It seems Russian to me :-)