Experiments with Software Defined Radio!

Awesome new way to listen to the radio.

Luigi Freitas
2 min readDec 3, 2016
C.H.I.P. and RTL-SDR Dongle.

Hey guys, this summer I will be talking more about my projects here at Medium, cool things are coming soon.

This week I bought a Realtek SDR (R820T2) which is capable of scanning a wide band of radio-frequency (25 MHz-1.7 GHz) and this is awesome! This tiny little USB dongle (blue thing above) have a massive amount of applications which I’ll talk more about here soon.

GQRX Waterfall Graph with a FM Radio Station.

For now I’m using this for receiving ADS-B signals constantly transmited from airplanes transponders, which means that I can receive the exact location, altitude, speed, callsign and the Squawk.

Airplane ADS-B Data from dump1090.

For that I’m using the Dump1090 software for display and decode the data received in real time. To know how to setup this software, you can check out this awesome tutorial.

And more, with four or more dongles at different locations I can track an aircraft even if the transponder isn’t sending the location, which is a common thing here. This process is called Multilateration (MLAT) widely used by online plane trackers such as FlightRadar24.

My ADS-B radar at FlightRadar24.com.

Once you are listening for ADS-B you can share your collected information with the online airplane trackers (FlightRadar24, FlightAware) and get Premium accounts for free. You can also apply for receiving one SDR for free, but then you can’t use it for other things and have to provide 24/7 power and internet.

QFH Antenna (Source: Børre Ludvigsen)

Next up

In the coming weeks I will make a QFH Antenna (Quadrifilar Helix) to improve my reception of 137 MHz radio-waves coming from fast spinning things, guess what 😜.

I did write how I did it here, so make sure you are following me here and on Twitter.

Yeah, satellites.

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Luigi Freitas

Computer Engineering Student. Experienced in Rockets, Satcom, Satellites, Machine Learning, Websites, Apps and Design. https://luigifreitas.me