8992 anomaly

[UtilitySeattle]

Weird noise heard all day on 8992 USB Sounds like a small prop plane buzzing around. Pretty sure it's not local interference. AnyWUN else hearing it?

https://voca.ro/1eeJFuQrmMC4

[Token]

This thing has been present on 8992 in one form or another (it changes over time) since at least Dec 2021.  There is a pretty extensive thread concerning it on UDXF.

No one knows what it is, but the general consensus right now is that it is probably not a site in the HF-GCS network.  It is not data.  It is probably a failing transmitter.  It has been possibly geolocated (via TDOA) to Dakar.

Oh, and it is annoying.

T!

[N9QIW]

I am hearing it as I type this on 8992 USB.   

[paranoidandy]

I hear that here in Utah. Every so often you will here a coded message. "This is Evolution" then a string of characters in phonetics then "Evolution out". Found info on Wikipedia; HFGCS (HF Global Com. System) voice frequencies are 4724.0 kHz, 8992.0 kHz, 11175.0 kHz, and 15016.0 kHz. Been real curious of the motor sound as well.

[~SIGINT~]

I concur with Token with regards to it not being a HFGCS site. I am one of the individuals working the case on the UDXF. I am also convinced that the frequency is 8991.0 kHz and over 4 kHz wide, hence why you hear it interfere with 8992.0 kHz.

As for the location, the speculations currently favour Dakar but I am not so certain about this. I have now run over 30 TDoA each having different results. I cannot get a consistent fix on the signal. Earlier today I did get a few hits around Dakar but right now I am getting fixes around Brest ... in the middle of the water.

Failing transmitter, no, probably not. I have an 18+ minute continuous recording of this from 00:40 UTC 2022-03-05. An "angry" modem, perhaps. For now we are calling it the "Buzz Saw".

[Token]

As for the location, the speculations currently favour Dakar but I am not so certain about this. I have now run over 30 TDoA each having different results. I cannot get a consistent fix on the signal. Earlier today I did get a few hits around Dakar but right now I am getting fixes around Brest ... in the middle of the water.

My TDOA results have also been inconclusive, at best.  I would say that Dakar is a possibility, but far from certain.  In fact, I have never gotten a plot that said, on the money, Dakar, but I respect the work of mco and linkz (they both are extremely experienced), and I believe they both have gotten Dakar plots.

Failing transmitter, no, probably not. I have an 18+ minute continuous recording of this from 00:40 UTC 2022-03-05. An "angry" modem, perhaps. For now we are calling it the "Buzz Saw".

It may not be a failing transmitter, but it is almost certainly something that is functioning in an undesired way.  The transmission is not data in any normal format, and I have strong doubts that it is data at all.

The evolution of the signal has been interesting.  4+ months ago it was a short transmission of a few pulses happening at just under 3 minute intervals, starting at a rate that allowed you to clearly see the individual pulses.  Over time it has slowly sped up and lengthened, so that it now starts at a rate near where it used to end, and sometimes goes on for minutes at a time.  I grabbed a continuous 10 minute recording of it the other night, and I stopped the recording before the signal ended.

T!

[nycrich425]

I was under the impression this was jamming. I hear it only on 8992 and not the other GF-GCS frequencies. I noticed ground units transmitting and airborne units do complain about interference.

[Token]

I was under the impression this was jamming. I hear it only on 8992 and not the other GF-GCS frequencies. I noticed ground units transmitting and airborne units do complain about interference.

Originally the signal was a few seconds every ~3 minutes or so, regular as clock work and really not intrusive at all.  Annoying, but no real hindrance.  Gradually, over the past few weeks, the signal has become longer and longer.  It is only hitting 8992, and none of the other HF-GCS freqs.  It appears to be Europe / North Africa, or that general region, sourced and during daylight hours that is the only region that can hear it.

It is just not a good candidate for an intentional jammer.

T!

[Token]

This signal seems stuck on now.  It has been on, one-stop for the past 45 minutes.  Earlier in the evening it did come on and go off a few times, but each on period got longer and longer.

(edit) It finally turned off after more than an hour and a half of non-stop operation.

T!

[Traveling Wave]

2255 UTC - Anomaly is S7 in WNY, with a steady signal.
2200 UTC - I checked the University of Twente, Netherlands, WebSDR and the signal is a steady S7.

[~SIGINT~]

The signal has been stuck on now for well over the past 15 hours. The level is so strong to my location that believe it or not, it is an S4 from my mini-whip antenna which is not even powered on. It is literally just leaking through the mini-whip.

05:10 UTC 07 MAR 2022 - I just noticed that the Buzz Saw had ceased continuous transmission for now and that by 05:13 UTC had started up again with its shorter on / off duty cycles.

[Erik Mattson]

0142 - Is that jamming?! Or a part of some weird (to me) digital mode?
0147 - Stopped.


Started up again like a slow-to-start gas powered leaf blower. As it started I recognized the sound heard occasionally between the regular EAM messages.
Don't think it's any kind of jamming now that I've heard that. Still, pretty strange the way it winds up like that.

Short clip of it in progress: https://archive.org/download/hfgcs-20220312-204331-8992000-hz/HFGCS_20220312_204331_8992000HZ.mp3

[~SIGINT~]

Hello Erik,

Have a look at this post, 8992 anomaly.
https://www.hfunderground.com/board/index.php/topic,93928.msg299591.html#msg299591

The signal is still UNID at this time and I have been referring to it as the "Buzz Saw". Under normal conditions you will hear an 18 to 26 second or so long emission every 2 minutes 45 seconds.

I still believe the actual frequency to be 8991.0 kHz and 5 kHz wide. I can see some product in the waveform all the way up to 4.8 kHz.

[Erik Mattson]

Hello Erik,

Have a look at this post, 8992 anomaly.
https://www.hfunderground.com/board/index.php/topic,93928.msg299591.html#msg299591

The signal is still UNID at this time and I have been referring to it as the "Buzz Saw". Under normal conditions you will hear an 18 to 26 second or so long emission ever 2 minutes 45 seconds.

I still believe the actual frequency to be 8991.0 kHz and 5 kHz wide. I can see some product in the waveform all the way up to 4.8 kHz.

For a while now (month or so), when catching EAMs on 8992, I've heard it start up but stop after just a second or two, at randoms times in the space between messages. When I caught full-on buzzing last night, I didn't immediately connect the two. Then, right after posting about it, I heard it from its start, and it winds up like an old airplane engine, slowly building up to the full BUZZZZZ.

[aurora]

I started noticing the transmission in January. It started out occurring every 15 minutes but only lasted 1 second in length. It progressively got worse over time and occurred more often. I agree that it seems to be on 8991.

It is so strong that I can hear it on my Tecsun portables with a simple whip antenna.