Natural radio signal recording with electric filed receiver: RS4 with a 1m stilus, T antenna or long wire, using a simply cassette recorder as data support (except for une example). Then frequency range of 100 Hz-12kHz and dynamic range of 40dB or worse. A very basic setup.
The same wistler recorded in two different places at 150 km distance: Cumiana and Pavia. (Thanks to Ezio Mognaschi IW1GOO for the collaboration from Pavia University)
Recorded with T antenna connected to the micro input of SoundBlaster Card (at those time I was a beginner: don't repeat this setup, can be dangerous and damage the PC). Strong static activity. Note the strange silence from 2 and 3 kHz. Same results with a pocket loop of 75 cm.
Tweeks storm: 4 different resonance frequencies are identifiable: 6,6 kHz - 4,9 kHz - 3,3 kHz and 1,6 kHz. Recording from home with RS4 receiver placed outdoor.
"Flying saucer" (the strange W at the bottom of spectrogram), recorded with RS4 receiver with 10m whip antenna. Usually recorded by satellites, very rare at ground level.
This signal (present around 2 kHz) sounds like a frog's croak. Statics and 50 Hz harmonics are also visible in the spectrogram. Recording from my home with RS4 placed at 100m outdoor, with 10m whip.
This signal sound like bees buzzing close to the ear. Recorded on top of a mountain at 2650m over see level, with RS4 receiver and 1m whip.
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