The device, shown in the following picture, is a DVB-T (Digital Video Broadcasting - Terrestrial) USB stick which you would normally use to enhance your viewing pleasure.
At the same time, though, there is an active SDR (Software Defined Radio) community which is constantly in search of new DIY ways of experimenting. Decoding of various signals & protocols (like AIS) using a cost-effective, easily obtainable DVB-T USB stick has become a popular DIY method!
As you may have guessed, it is possible to set-up an AIS-Receiving Station capable of decoding AIS-transmitted messages using a DVB-T stick instead of a dedicated AIS Receiver. The fact is that you can achieve great results for only a fraction of the cost of a commercial solution. A DVB-T stick would cost about €20 while all the relevant software is available for free. You would only need a relatively powerful PC as the decoding operation is rather CPU-intensive.
Here are some key points:
- The demodulator chip allows for raw I/Q transfer to the host - this means that the PC can handle the decoding (by using special software).
- It is possible to have direct control over the DVB-T tuner directly from the host.
- The span of the tuning frequencies is wide enough to cover the AIS-transmitting frequencies (161.975Mhz & 162.025Mhz).
What's more, you can easily start sharing your AIS data with MarineTraffic and have your own station providing near real-time data to the world!
The whole process of setting-up a DVB-T based AIS-Receiving Station is described in full detail in the following manual: