A Homemade Boat Computer with RTL-SDR for Weather Fax, NavTex and more
Over on Hackaday we've seen a post about [mgrouch]'s "boat computer" which consists of a Raspberry Pi 4, HDMI display, and a whole slew of sensors and receivers useful for a marine environment including an RTL-SDR.
The built in equipment includes a GNSS receiver, orientation sensors, AIS receiver, 4G and WiFi, lightning EMI sensor and alarm, optional autopilot integration, rudder angle sensor, connections to boat instruments like wind, depth, speed, temperature, barometric and humidity sensors, an Iridium receiver, and finally an RTL-SDR for receiving weather fax, NavTex, satellite weather, AIS, RTL 433, morse code and more. It really is an "all-in-one" device.
His blog post explains in detail how each of the components work in the system, and in particular for the RTL-SDR he shows how you can use the boat computer to receive FM via GQRX, and NavTex via the Java based Frisnit Navtex decoder. Navtex is a marine radio service that transmits at 518 kHz or 490 kHz. It provides text data regarding weather forecasts, weather warnings, navigational information, and urgent maritime safety messages. For his antenna he writes that he uses a 10 kHz - 30 MHz Mini Whip antenna that he purchased on Aliexpress.
![mgrouch's Boat Computer with RTL-SDR](https://www.rtl-sdr.com/wp-content/uploads/2020/03/boat_computer-1024x384.jpg)
Very interesting and thanks for posting. It is greatly appreciated sadly I’m a bit ham fisted when it comes to things like this or I would love to build my own – at least then I would – perhaps- understand when things go wrong and be able to fix on the fly..
I did all that with a cheap windows tablet and a dongle. Why build all that? I also had inmarsat fleer safety decoder.
it was attached to the boats sensors