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
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.
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
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.