Tagged “Ilma”

A more sensitive receiver brings in more unreadable Navtex messages. Deciding which to hide turned out to be the easy half.

2,000 nautical miles of Navtex logging: brackish Baltic water, a 4.7 dB gap in the receiver, and a Bias-T that never worked.

Decoding at 48, 8 and 4 kHz from the same raw IQ. Quality, compute saving, and disk saving measured.

Ilma is a NAVTEX, RTTY, and WEFAX decoder for sailors written in Python running on the Raspberry Pi.

Turning noise at 518 kHz into navigational warnings: FSK demodulation, matched filters and SITOR-B forward error correction, on a Raspberry Pi that listens unattended at sea.