We seek to understand and document all radio transmissions, legal and otherwise, as part of the radio listening hobby. We do not encourage any radio operations contrary to regulations. Always consult with the appropriate authorities if you have questions concerning what is permissable in your locale.

Author Topic: 9024 kHz, DSB, oddity, 03 April, 2020, 0420 UTC  (Read 1836 times)

Offline Token

  • Global Moderator
  • DX Legend
  • *****
  • Posts: 1917
  • Karma: +16/-0
    • View Profile
9024 kHz, DSB, oddity, 03 April, 2020, 0420 UTC
« on: April 04, 2020, 0103 UTC »
This is an oddity on shortwave that I don't think I have seen before.  If it is common then somehow or another I have missed it.

About 0420 UTC, 03 April, 2020, I noticed what appeared to be a DSB transmission on 9024 kHz.  DSB is not a commonly used mode these days, so I looked a bit closer.

The signal did appear to be DSB, it also appeared to be a repeating audio loop.  About every 21.6 seconds (start to start) the loop repeated, with about 1.6 seconds pause between audio segments.  The audio was not understandable, either it was distorted, processed in some way, or encrypted.  Longer observation showed that every 11th repeated segment included a longer pause, about 3.1 seconds.  This made a repeating cycle of 11 segments about every 239.6 seconds.

Every segment transmitted appeared identical.  Just the same 21.6 second segment (time includes the audio pause) over and over, with every 11th including an increased length pause.

I have uploaded a video of this signal to my YouTube channel.  If you watch the video I include spectrograms of the audio loops, and visual comparisons of multiple examples.  I also demodulate the signal using multiple modes, USB, LSB, AM, and NFM, to show the sound in each mode.  And the last minute or so of the video is the signal demodulated with LSB in the left audio channel and USB in the right audio channel, for comparison.

Video here:
https://www.youtube.com/watch?v=axqgrSzFzG8

T!
T!
Mojave Desert, California USA

Offline Josh

  • DX Legend
  • ******
  • Posts: 4064
  • Karma: +9/-0
    • View Profile
Re: 9024 kHz, DSB, oddity, 03 April, 2020, 0420 UTC
« Reply #1 on: April 04, 2020, 2139 UTC »
Sounds to me like Asian male and female voices reading news or something else, recorded and then transmitted as dsb or exalted carrier am for whatever reason. Tdoa? Jammer testing?
We do not encourage any radio operations contrary to regulations.

Offline Strange Beacons

  • Sr. Member
  • ****
  • Posts: 256
  • Karma: +1/-0
  • Naples, Florida USA
    • View Profile
    • Strange Beacons Website
Re: 9024 kHz, DSB, oddity, 03 April, 2020, 0420 UTC
« Reply #2 on: April 05, 2020, 0240 UTC »
Very strange indeed, and what could possibly be the purpose of such a transmission? I shared this one via my Twitter feed in the hope that one of my followers might have a clue as to what language is being spoken.

Offline Token

  • Global Moderator
  • DX Legend
  • *****
  • Posts: 1917
  • Karma: +16/-0
    • View Profile
Re: 9024 kHz, DSB, oddity, 03 April, 2020, 0420 UTC
« Reply #3 on: April 05, 2020, 1308 UTC »
Sounds to me like Asian male and female voices reading news or something else, recorded and then transmitted as dsb or exalted carrier am for whatever reason. Tdoa? Jammer testing?

I tried to TDOA the signal, however too few receivers had it with sufficient quality to get a good result.  Lots of receivers heard it, but for most it was weak enough that Kiwi TDOA was not going to work well and the results I got were all over the place, but mostly within the US, concentrating towards the south west.  I would be very careful with that possible source region though, the plots were not confidence inspiring.  Call the region a "maybe".

T!
T!
Mojave Desert, California USA

Offline Josh

  • DX Legend
  • ******
  • Posts: 4064
  • Karma: +9/-0
    • View Profile
Re: 9024 kHz, DSB, oddity, 03 April, 2020, 0420 UTC
« Reply #4 on: April 05, 2020, 1954 UTC »
When I hear about sigs like this I can't help but to recall the Yosemite Sam on hf episode. Mebbe mil sigint ops training, mebbe some asshat just fooling around giving his finals a life test.

https://www.hfunderground.com/wiki/Yosemite_Sam
https://www.youtube.com/watch?v=tuEmG0Oxa2M
We do not encourage any radio operations contrary to regulations.

Offline Token

  • Global Moderator
  • DX Legend
  • *****
  • Posts: 1917
  • Karma: +16/-0
    • View Profile
Re: 9024 kHz, DSB, oddity, 03 April, 2020, 0420 UTC
« Reply #5 on: April 06, 2020, 0229 UTC »
This signal is up again right now, 06 April, 2020, 0220 UTC.  It appears to be identical to what it was in the video I posted.

T!
T!
Mojave Desert, California USA

Offline Josh

  • DX Legend
  • ******
  • Posts: 4064
  • Karma: +9/-0
    • View Profile
Re: 9024 kHz, DSB, oddity, 03 April, 2020, 0420 UTC
« Reply #6 on: April 07, 2020, 0230 UTC »
Just remembered this freq is on or very near a NORAD or STRATCOM freq, one of the ZULU series mebbe, if it turns out to be soviet jammer testing or sending us a "message" it'd not surprise me. The soviets used to employ a hf jammer (one of many) created by distorting the audio of one of their home services (Радио Маяк?) or summin and blasting it all over hf.
We do not encourage any radio operations contrary to regulations.

Offline Token

  • Global Moderator
  • DX Legend
  • *****
  • Posts: 1917
  • Karma: +16/-0
    • View Profile
Re: 9024 kHz, DSB, oddity, 03 April, 2020, 0420 UTC
« Reply #7 on: April 07, 2020, 0248 UTC »
And today, 07 April, 2020, the signal cam online sometime around 0220 UTC or so, but on a different frequency.  The format, timing, apparent content is the same, however the frequency tonight is 9007 kHz.

T!
T!
Mojave Desert, California USA

Offline Josh

  • DX Legend
  • ******
  • Posts: 4064
  • Karma: +9/-0
    • View Profile
Re: 9024 kHz, DSB, oddity, 03 April, 2020, 0420 UTC
« Reply #8 on: April 07, 2020, 1847 UTC »
Guess who owns 9007? CANFORCE. Day pri is 11232, secondary 9007, wich becomes nite pri as I recall. If I was a soviet jammer dude, I'd def be thinkin bout using online sdrs graciously provided by the enemy country near the target area (primary rx sites) to see how effective my efforts were before open hostilities commence.





https://www.youtube.com/watch?v=1FZMCVp5wEw
We do not encourage any radio operations contrary to regulations.

Offline Token

  • Global Moderator
  • DX Legend
  • *****
  • Posts: 1917
  • Karma: +16/-0
    • View Profile
Re: 9024 kHz, DSB, oddity, 03 April, 2020, 0420 UTC
« Reply #9 on: April 08, 2020, 0238 UTC »
Yeah, I realized who regularly occupies it, and I also checked 11232 kHz.  However, no sign of anything there.

Also, while I can buy what you are saying about testing and using remotes, why tip your hand by hitting the frequencies of interest?  Any frequency near there would tell you what you want to know, no need to hammer the exact frequency and cause the target forces to look into what and why.  And in your scenario the targets (US and Can) have the ability to know, in seconds, the approximate area of the source.  Kiwi TDOA may be iffy on the signal location, professional HF TDOA would not.

T!
T!
Mojave Desert, California USA

Offline Josh

  • DX Legend
  • ******
  • Posts: 4064
  • Karma: +9/-0
    • View Profile
Re: 9024 kHz, DSB, oddity, 03 April, 2020, 0420 UTC
« Reply #10 on: April 08, 2020, 0318 UTC »
Also its not like our forces don't have a cheat sheet of extra channels to use when the soviets get feisty. On why tip their hand, they have these things up and running right now with little to do, so why not play with them?
We do not encourage any radio operations contrary to regulations.

Offline Token

  • Global Moderator
  • DX Legend
  • *****
  • Posts: 1917
  • Karma: +16/-0
    • View Profile
Re: 9024 kHz, DSB, oddity, 03 April, 2020, 0420 UTC
« Reply #11 on: April 08, 2020, 1207 UTC »
Play with the equipment I get, play with them on the target frequencies?  I don't get that, and that is the part that makes me skeptical.  It is kind of like peace time and war time modes.  For the types of signals you are talking about, and pretty much anything that emits other than standard comms (and even a little bit there), you have modes you show the enemy all the time and modes you don't show the enemy.  And various reasons, depending on what the ability is, for not showing those abilities.  One of those reasons is telling the enemy you are getting ready.

Peace time modes are the modes (frequencies, techniques, power levels, diversity capability, antenna capability, etc) that you use all the time, for testing, alignment, training, etc.  During normal testing and training you break out these modes, they typically test the system to some specific high level and they allow operator training, all without starting a war, giving the enemy (who absolutely is watching you and analyzing your actions) too much information, or tipping the enemies hand that you might be ramping up for some action.

Wartime modes are modes you break out when things go hot.  Frequency, power, antenna modes, technique, etc, these are capabilities that you have not shown the enemy you can do.  On some Russian systems some of these capabilities are activated by switches that are physically under a wired cover, so that you have to really intend to use them, and other people know, after the fact, if you have done so.

Obviously, hitting active potential enemy frequencies is not giving away too much information on technical capability.  Assuming this was / is some kind of comm jam equipment a profile / assessment of that specific equipment probably exist, including probable or known frequency range.  So the technical capability to hit these freqs would not be revealing.  However, actually hitting potential target freqs, when this is not your normal habit, is revealing.

I guess the basics of what I am saying is, you don't typically train, or test, actually hitting your real enemy targets.  And if you uncharacteristically start doing so in preparation for planned upcoming actions you alert the enemy that the punch is coming.

Not saying that your reasoning is impossible, only that I find it less likely than someone is just playing with the system.

By the way, tonight (Tuesday night local time, Wednesday morning, 08 April, UTC) the signal was up again, and back on 9024 kHz.  It ran from 0300 to 0603 UTC.  I did have a chance to grab a remote receiver in Kharbarovsk, Russia, and the signal was 10 over S9 there with little QSB.  This matches well with the more repeating TDOA plots I managed to grab Monday when the system was on.

T!
T!
Mojave Desert, California USA

Offline Josh

  • DX Legend
  • ******
  • Posts: 4064
  • Karma: +9/-0
    • View Profile
Re: 9024 kHz, DSB, oddity, 03 April, 2020, 0420 UTC
« Reply #12 on: April 08, 2020, 1807 UTC »
If it is soviets getting frisky, this is may be what the systems look like;
https://planesandstuff.wordpress.com/2019/09/09/murmansk-bn-hf-ew-complex/
We do not encourage any radio operations contrary to regulations.

Offline Token

  • Global Moderator
  • DX Legend
  • *****
  • Posts: 1917
  • Karma: +16/-0
    • View Profile
Re: 9024 kHz, DSB, oddity, 03 April, 2020, 0420 UTC
« Reply #13 on: April 13, 2020, 0542 UTC »
So it turns out this signal has, apparently, typically been up on at least 2 frequencies at one time.  The other day it was on 9024 kHz and 5708 kHz at the same time, simulcast.  Tonight (13 April, 2020 UTC date), right now at 0530 UTC, it is on 9008 kHz and 9022 kHz.  The signals on 9008 and 9022 kHz are in sync, simulcast, and started at the same time.

Further, it exhibited a potentially interesting habit tonight.

The Russian operated, Asiatic sourced, numbers station V07 and M12 are both believed to be transmitted from the Kharbarovsk, Russia, area.  And TDOA cuts of this DSB signal puts it, possibly, from the same general area.  So why talk about V07 and M12?  Both of those stations have a habit, as in they do it almost every time they are on the air, of coming up 20 to 40 minutes before the first scheduled time and tuning the transmitter.  The audio they use to tune the transmitter is often the audio form a local radio station in Kharbarovsk, that was one of the ways the source location was initially suspected.

Tonight this DSB signal did exactly the same thing.  20 minutes before it came on the air on 9008 kHz a transmitter tuned up on that frequency.  The tuning signal seemed to be audio from a broadcast station.

Possibly: Strongly probable it is the same region, possibly the same location, and the operators appear to have the same operational habits.

T!
T!
Mojave Desert, California USA

Offline KM0NAS

  • Jr. Member
  • **
  • Posts: 33
  • Karma: +0/-0
  • Minnesota
    • View Profile
Re: 9024 kHz, DSB, oddity, 03 April, 2020, 0420 UTC
« Reply #14 on: April 13, 2020, 1333 UTC »
That's some great information Token and good deductive reasoning. The big questions that remain in my mind are of course, why these odd transmissions and why this particular mode?

Are there any advantages to a DSB signal other than not taking as much power as AM?


« Last Edit: April 13, 2020, 1604 UTC by KM0NAS »
*KM0NAS*
Kenwood TS-570D
Soft66RTL2
40 meter dipole @ 40' height
20 meter dipole @ 40' height
10 meter vertical @ 16' height
Beacon MN on 13562.8