This is a dataset with ELF radio spectrum from 80-84Hz, in 60s intervals over a period of several months, recorded in Warsaw / Poland by Jacek Lipkowski SQ5BPF.

The data was used to produce the spectrum visible in the ZEVS 82Hz Grabber on the KLUBNL.PL site. The grabber scripts don't delete the spectrum files, and i thought they might be useful research material.

The data is from 25 August 2021 to 13 June 2022, with a few periods missing. The missing data is because the grabber was offline, or because the antenna was disconnected due to thunderstorms.

The data is avaliable here: https://klubnl.pl/zevs/zevs_dir.tar.gz (warning, this is a big 1.6GB file). The data was produced by vtnspec. The command line was:

extract_60s_of_data | vtfilter -h lp,f=1000,poles=3 -a th=7 | vtblank -v -a40 -d0 -t1 | vtnspec -f 82 -w4 -r16.6666e-3 > file

The filenames are the unix time (number of seconds since January 1st 1970 UTC) when the sample was taken. The columns are frequency, real, imagimary, rms. Example data:

80.00000800 2.080809e-05 -6.614392e-06 1.543902e-05
80.01667460 -9.690319e-07 -1.231563e-05 8.735385e-06
80.03334120 -1.651825e-05 -1.124793e-05 1.413097e-05
80.05000780 3.791154e-05 4.053642e-05 3.924593e-05
80.06667440 -1.471637e-05 5.985279e-06 1.123377e-05
80.08334100 -9.629256e-06 -3.050421e-05 2.261890e-05
80.10000760 2.780673e-05 -5.441355e-05 4.320908e-05
80.11667420 1.100251e-05 -1.696162e-05 1.429601e-05
80.13334080 -9.189010e-06 9.730371e-06 9.463563e-06
80.15000740 -1.405457e-05 1.576747e-05 1.493560e-05
80.16667400 1.738760e-05 -1.409283e-05 1.582618e-05
80.18334060 -1.262028e-05 1.509170e-05 1.391098e-05
80.20000720 8.167513e-06 -4.741268e-06 6.677870e-06

The receiver is an e-field probe installed in a city area (with lots of electromagnetic interference). The signal is sampled by a Creative EMU0204 sound card (24bit @48kHz). This setup is optimised for reception at VLF (3-30 kHz) frequencies, not 82Hz, but the ZEVS signal is clearly readable.

In the future further data might also be published. Please email me at sq5bpf (at) lipkowski.org if you're interested.

You can use this data under the Attribution 4.0 International (CC BY 4.0) License.
Please attribute to: Jacek Lipkowski SQ5BPF sq5bpf (at) lipkowski.org, dataset URL https://klubnl.pl/zevs/ .
Full license text HERE.