klubnl.pl

SAQ “50-th Anniversary of the UNESCO World Heritage Convention” transmission on 20221116

A video of the SAQ transmission on 20221116 16:00 UTC, commemorating the 50-th Anniversary of the UNESCO World Heritage Convention.

Received at SQ5BPF QTH Warsaw/Poland KO02md.

E-field active antenna, vlfrx-tools and Spectrum Lab receiver

The transmitted message is:

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Analyzing ZEVS part 2 – 82.0Hz

In previous articles i’ve shown some typical ZEVS messages , and an analysis of the amount of messages per day .

This repository has all of the scripts used during the analysis: https://github.com/sq5bpf/zevs-analysis

So what more could we get out of the opublished ZEVS dataset ?

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An analysis of ZEVS messages during the russian invasion in Ukraine in 2022

In the last article i’ve written about a method of automatically finding ZEVS trasmissions, and an analysis of it’s messages: Analysis of ZEVS messages

Luckiny i have data from 25 August 2021 until now. Using it i can check if anything has changed during the Russian invasion of Ukraine in 2022.

These are encrypted military messages. So there is no reason to analyze them, right? 🙂

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Analysis of ZEVS messages

Russia uses radiocommunications in the ELF band to send messages to it’s nuclear submarine fleet. This transmitter it called ZEVS, the frequency is 82Hz (yes: hertz, not kilohertz, not megahertz). For more info see here: http://www.vlf.it/zevs/zevs.htm

I’ve installed a grabber on the KLUBNL.PL page showing the spectrum around 82Hz. It is available here: https://klubnl.pl/wpr/index.php/klubnl-pl-grabbers/grabber-zevs-82hz/

This grabber calculates the spectrum in 80-84Hz every 60 seconds, and makes spectrograms out of it. The files with the spectrum information are not deleted, so out out of coincidence i have a history of data from 25 August 2021 until now (around 10 June 2022).

And since i have this data, it would be nice to do an analysis how the messages to the submarine fleet look like, and how often are they transmitted.

Example ZEVS transmission — The spectrum of an example ZEVS transmisson. The signal around 83.3-83.5Hz is some local interference.

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Data from ELF 82-84Hz observations over a few months has been published

We have published data from observations of the ELF spectrum 80-84Hz (ZEVS) over a period of a few months.

The data is avaliable here: https://klubnl.pl/zevs/

SAQ Christmas 2021 transmission on 17.2 kHz

Christmas transmission from SAQ on 17.2kHz, 24 December 2021 8:00 UTC

Received at SQ5BPF QTH Warsaw/Poland KO02md.

E-field active antenna, vlfrx-tools and Spectrum Lab receiver.

On the recording one can see a weak carrier between the symbols. This is because the keying circuit leaks a weak carrier. The leakage is about 2kW.

QTH Jacek / SQ5BPF Warsaw KO02md

The message was:

THIS IS GRIMETON RADIO STATION/SAQ IN A TRANSMISSION USING THE ALEXANDERSON 200KW ALTERNATOR ON 17.2KHZ. = WE WISH YOU ALL A MERRY CHRISTMAS AND A HAPPY NEW YEAR. = SIGNED WORLD HERITAGE GRIMETON RADIO STATION AND THE ALEXANDER GRIMETON FRIENDSHIP ASSOCIATION.= FOR QSL INFO PLEASE READ OUR WEBSITE ALEXANDER.N.SE. DE SAQ SAQ SK

RSDN stations are active again

After a long period of inactivity the RSDN stations are active again. Right now (12 october 2021) three frequencies are active: 11.9kHz, 12.65kHz, 14.88kHz.

This is a hyperbolic navigation system, which broadcasts a periodic carrier. More information is avaliable here: http://www.vlf.it/alphatrond/alpha.htm

For people interested in VLF this is a great test signal, whch can be used to check receiving equipment.

RSDN 2021

VLF grabbers reactivation at Warsaw / SQ5BPF

In 2019 i’ve written that the SQ5BPF grabbers will be temporarily offline and should return in winter 2019. Unfortunately this “moment” got extended to august 2021.

Now, finally, I’m trying to reactivate them, The VLF antenna has been installed again. For now I’ve activated the ZEVS 82Hz and VLF 8270Hz grabbers. Because of changes in vlfrx-tools noiseblanker from versions 0.6 to 0.9, i will be trying to find the parameters for best reception, so please stay tuned, the grabbers might not be operating at their best right now.

The rest of the grabbers will be activated shortly.

As before, i’m recording the while 0-24kHz bandwidth, and keeping the recordings for a few days. They can be provided to interested parties upon request (for scientific reasons etc).