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Author Topic: 9024 kHz, DSB, oddity, 03 April, 2020, 0420 UTC  (Read 1838 times)

Offline Token

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Re: 9024 kHz, DSB, oddity, 03 April, 2020, 0420 UTC
« Reply #15 on: April 13, 2020, 1350 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?

DSB has no real transmission advantage over SSB.  I mean it occupies twice the bandwidth for the same amount of usable information, it spreads the same power out over twice the bandwidth, meaning less power available for the same given information.  Unless you send different data on each sideband, in which case it becomes ISB, not DSB, there just really is not an operational reason to prefer DSB over SSB.

As a jammer it is twice as wide, that could be an advantage, but this signal has a significant notch in the middle (where the low frequency components of the speech would be), making it somewhat less than optimal against some kinds of signals.  Also as a jammer it does not waste energy in the carrier, so hammering an SSB signal it works fine, and hammering an AM signal it works fine.  To jam an AM signal you don't need a carrier.

The real advantage of DSB over SSB is that the circuitry can be simpler.  The hardware is cheaper and easier to make.  If you repurpose other hardware and try to send an SSB signal you can end up with DSB.

T!
« Last Edit: April 13, 2020, 1507 UTC by Token »
T!
Mojave Desert, California USA

Offline KM0NAS

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Re: 9024 kHz, DSB, oddity, 03 April, 2020, 0420 UTC
« Reply #16 on: April 13, 2020, 1604 UTC »
Thanks for your thoughts and for finding this signal.

So looking at all the posts it looks like you heard it Monday-Thursday April 6-8
(was it on Friday too and you weren't looking for it or was it actually absent?)
Time appeared to be approx. 0220-0600 each day.

I will be watching/listening tonight!
*KM0NAS*
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Offline Token

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Re: 9024 kHz, DSB, oddity, 03 April, 2020, 0420 UTC
« Reply #17 on: April 13, 2020, 1828 UTC »
Thanks for your thoughts and for finding this signal.

So looking at all the posts it looks like you heard it Monday-Thursday April 6-8
(was it on Friday too and you weren't looking for it or was it actually absent?)
Time appeared to be approx. 0220-0600 each day.

I will be watching/listening tonight!

Those are about the core looking times, but times are variable.

I have looked and recorded spectrum for this signal almost every night since first finding it.  I did look Saturday and Sunday (UTC) and the signal was not present.  So Friday night Pacific time would be Saturday UTC.  It looks like it has been active every weekday (UTC day) at one time or another.  I actually missed it one day myself, forgot to look, but was told by someone else it was on that night.

Keep in mind it has varied the frequencies, it has not always been on 9024 kHz.  And it appears to be active on 2 frequencies at one time.

T!
« Last Edit: April 13, 2020, 1833 UTC by Token »
T!
Mojave Desert, California USA

Offline Josh

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Re: 9024 kHz, DSB, oddity, 03 April, 2020, 0420 UTC
« Reply #18 on: April 13, 2020, 1904 UTC »
Wonder if it's an fup in their patch panel?
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Offline tomasernesto1986

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Re: 9024 kHz, DSB, oddity, 03 April, 2020, 0420 UTC
« Reply #19 on: April 15, 2020, 1210 UTC »
Hi. I think this is a encrypted communication. There is a very famous Netflix's Show called La Casa de Papel (House of Paper from Spain). In season 3 they use a ham radio and they use encryptacion technology in order to avoid the police.

The reason for using an old trasmition technology is that the police can hack all new technology specially internet communication and finds where is located the trasmition but with an old radio is more difficult find it and the authority can't inhibite the signal.

Also if you use a new top technology encriptacion system and send an encrypted message it's impossible to know what are you talking about.

In this vidio minute 1:01 you can hear it actually it sounds quite the same that the oddity frequency

https://youtu.be/HrZfMcp-cKM

I also hear this transition 5/9  in San Cristobal, Venezuela.

Offline KM0NAS

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Re: 9024 kHz, DSB, oddity, 03 April, 2020, 0420 UTC
« Reply #20 on: April 15, 2020, 1430 UTC »
I tuned into the Khabarovsk SDR last night as I had to be up late doing some work. I checked in numerous times over the course of several hours starting around 0220 UTC but there did not appear to be any sign of the signal.
*KM0NAS*
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Offline Pigmeat

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Re: 9024 kHz, DSB, oddity, 03 April, 2020, 0420 UTC
« Reply #21 on: April 16, 2020, 0339 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

"Imma gonna blast you, ya consarnd Rabbit!" LOL!

I'm not sure any of three or four Commander Bunny's at that time knew who or what the Hell that was? The guy who started calling me back after a non WBNY show w/the code the made me call it quits. Whoever it was, they were running a boatload of power. Only one govt. agency at a time,thank you

Offline Token

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Re: 9024 kHz, DSB, oddity, 03 April, 2020, 0420 UTC
« Reply #22 on: April 16, 2020, 1700 UTC »
Hi. I think this is a encrypted communication.

<<<snip>>>


Initially I thought it might be encryption of some kind, it kind of sounds a bit like old voice inversion encryption.  So I ran the signal through a voice inversion decoder, and I still ended up with junk.

Of course, that does not mean it is not some other kind of encryption, or some combination of encryption techniques.

However, the data is the same every cycle.  That means if it is encrypted communications of some kind it is the same ~20 second loop, over and over for hours, with no changes.

Encrypted source or not, it still seems like a junk transmission.  The other day a different waveform showed up, it looked like Gaussian noise or possibly PSK of some kind, on the same two frequencies (9008 and 9024 kHz).  It was never really strong enough for me to do much with it, conditions were poor.  But the 2 signals started at the same time and ended at the same time, so possibly connected.  And while this possible signal was up the normal DSB was not seen.

T!
T!
Mojave Desert, California USA

Offline Rizla

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Re: 9024 kHz, DSB, oddity, 03 April, 2020, 0420 UTC
« Reply #23 on: April 17, 2020, 0350 UTC »
On 9024 kHz tonight again, via Khabarovsk SDR, 10+ over s9...
QTH: Sonoran Desert, AZ. Kenwood TS-820S, FT-891, Tecsun 880, neophyte in a forest of antenna wire.

Offline KM0NAS

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Re: 9024 kHz, DSB, oddity, 03 April, 2020, 0420 UTC
« Reply #24 on: April 17, 2020, 1411 UTC »
Shoot. I must have missed it. I checked into the Khabarovsk SDR, probably around 3:10 UTC and it wasn't there. Must have come on just after I logged off.
*KM0NAS*
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Offline Josh

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Re: 9024 kHz, DSB, oddity, 03 April, 2020, 0420 UTC
« Reply #25 on: April 17, 2020, 2208 UTC »
They're testing something.
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Offline Rizla

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Re: 9024 kHz, DSB, oddity, 03 April, 2020, 0420 UTC
« Reply #26 on: April 20, 2020, 0448 UTC »
"They're testing something."

I think that idea has a lot of merit.

On again tonight, like clockwork, as I write this.

Kiwi in Khabarovsk:
http://khv.proxy.kiwisdr.com:8073/
QTH: Sonoran Desert, AZ. Kenwood TS-820S, FT-891, Tecsun 880, neophyte in a forest of antenna wire.

Offline Rizla

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Re: 9024 kHz, DSB, oddity, 03 April, 2020, 0420 UTC
« Reply #27 on: April 20, 2020, 0502 UTC »
Whew, tonight's experiment gone, just like that QRT 20 seconds ago... and the beat goes on.
QTH: Sonoran Desert, AZ. Kenwood TS-820S, FT-891, Tecsun 880, neophyte in a forest of antenna wire.

Offline Token

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Re: 9024 kHz, DSB, oddity, 03 April, 2020, 0420 UTC
« Reply #28 on: April 20, 2020, 0526 UTC »
Yes, on Monday, 20 April, 2020 it was on a bit before 0200 UTC and off at 0501:23 UTC.

So I have still never seen it on a Saturday or Sunday (Asiatic Russian day), but I have seen it on every other day of the week.  There have been one or two days when it did not transmit, and at least one day when I think they substituted a different waveform.  And some days it is on 2 frequencies, other days I never find another freq.

T!
T!
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Offline KM0NAS

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Re: 9024 kHz, DSB, oddity, 03 April, 2020, 0420 UTC
« Reply #29 on: April 21, 2020, 0208 UTC »
I'm starting to suspect they have a tap on my computer and purposefully don't transmit on days that I am available to listen. I should be sure to post my listening plans here to save you all the trouble of knowing which days to not bother trying.  :)

Okay I take it back. I am listening and signal is on now.

« Last Edit: April 21, 2020, 0317 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