NIL HEARDRECEPTION LOG

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

tier A · mixed

17.3 kHz USB · 2026-10-06 09:45:02Z · 02:16 · received at Brettnach F57320

Spectrogram of VLF submarine band 17.6-20.0 kHz (RDL, HWU, GBZ chord), 17.3 kHz USB, 2026-10-06 09:45:02Z, 02:16: mixed 43% · carrier 29% · morse 14% · data 14% · tone 1635 Hz · keying 10.21 Hz depth 0.79
spectrogram 0–6.0 kHz · analysis blocks: morse data carrier mixed
loop [ ] · speed in the player bar · deep link #t=seconds ⤓ FLAC 2.4 MB ⤓ Opus 563 kB { }
What was heard
mixed 43% · carrier 29% · morse 14% · data 14% · tone 1635 Hz · keying 10.21 Hz depth 0.79 — dominant tone 1635 Hz, keyed at 10.21 Hz (depth 0.79). Machine description of the sound by the rig's classifier; it sorts, it does not certify a station.
Receiver
KiwiSDR, Brettnach F57320 (JN39GG) · vertical · reported SNR 27 dB — thanks to the operator. Receivers
Provenance
sha256 e41030e6b78ef564eb32a68d812b1d70ebb5d69ea1987c2cf40b8adb626bbdff
source 02:16 WAV, 11999 Hz mono
kiwirecorder.py (jks-prv/kiwiclient v1.11) · rig item 2026-10-06T0945Z-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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