NIL HEARDRECEPTION LOG

VLF submarine band 17.6-20.0 kHz (RDL, HWU, GBZ chord)

tier A · data

17.3 kHz USB · 2026-10-04 18:21:01Z · 10:00 · received at Hamburg, Drage, 🇩🇪 Germany 🇩🇪

Spectrogram of VLF submarine band 17.6-20.0 kHz (RDL, HWU, GBZ chord), 17.3 kHz USB, 2026-10-04 18:21:01Z, 10:00: data 47% · morse 33% · keyed-tone 13% · mixed 3% · carrier 3% · tone 829 Hz · keying 3.25 Hz depth 0.80
spectrogram 0–6.0 kHz · analysis blocks: keyed-tone morse data carrier mixed
loop [ ] · speed in the player bar · deep link #t=seconds ⤓ FLAC 10.6 MB ⤓ Opus 2587 kB { }
What was heard
data 47% · morse 33% · keyed-tone 13% · mixed 3% · carrier 3% · tone 829 Hz · keying 3.25 Hz depth 0.80 — dominant tone 829 Hz, keyed at 3.25 Hz (depth 0.8). Machine description of the sound by the rig's classifier; it sorts, it does not certify a station.
Receiver
KiwiSDR, Hamburg, Drage, 🇩🇪 Germany 🇩🇪 (JO53dk) · VLF broadband vertical V1.2 08/26 · reported SNR 43 dB — thanks to the operator. Receivers
Provenance
sha256 50b570f1140d9bbd74235a5f767e7fb3eaf568d96ea3a6aae83c1b025cdf3618
source 10:00 WAV, 11999 Hz mono
kiwirecorder.py (jks-prv/kiwiclient v1.11) · rig item 2026-10-04T1821Z-17.3-vlf-17300
Heard in the record
— linked once the record exists.
Licence
CC BY 4.0 — credit NIL HEARD / Reception Log. The recording is ours; the transmission is somebody else's. Descriptions describe sound, never content — why.
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