dramaturg
commented
9 years ago They can be very useful receiving information when offshore.
- Satellite weather pictures come to mind
- Using a frequency transverter HF can be received opening up a whole lot of useful information for any sailor: weatherfax/rtty, NAVTEX, synop ...
Very interesting for better reception. Learned about it only on this years' 31c3: http://www.rtl-sdr.com/lna4all-low-noise-amplifier-review/
Speaking about HF - a ship computer could also provide one or more audio input for use with old-school SSB receivers. they have to be tuned of course but there are also cheap SDR boards for this. I got the Elektor SDR which covers 150 kHz – 30 MHz.
Software and hardware exists but are a hassle to use. Having a guideline about suitable antennas and ancillary hardware would be a good start. Then it needs to be wrapped up in a nice package so that the latest information is always available in your navigation corner without having to fiddle around on a time schedule to catch some broadcast. the box will then take care to catch as many data with the hardware provided as possible and then have it easily accessible on some screen or even a printer. Think of a NAVTEX receiver on steroids.
Radar is a nice thought but I expect it to be complicated to do right. I also consider it an essential piece of navigation equipment and as such needs to be absolutely rock solid and must just work when shit hits the fan.
On a side note I got decent results with a small active antenna with a frequency splitter for HF and VHF bands. They can be found on ebay for ~70 €. But that hasn't gone offshore yet and I haven't used it with an RTL-SDR yet.
And with a second dongle/antenna pair, you get coherent high dynamic range radios that can pick up a lot more by using it as passive radar.
I could even imagine using one of the Transmitters onboard (VHF, Wifi, 3G) as Echo source by listening in with both SDRs on the same frequency to achieve the probably cheapest possible active radar. In terms of both power consumption and price.