Early in my engineering career, I worked for an oscilloscope company in the high performance product line. The last project I worked on was defining the features and requirements of a 33GHz (that’s giga-, not mega-) scope. This experience gave me a strong appreciation for processing digitized signals, especially those in the RF range. So when I picked up my first Software Defined Radio (SDR), you can imagine how much fun it was to use… with the help of some open source hardware.

On and off, I’ve listened to or watched the Hak5 Podcast with Daren Kitchen and Shannon Morris. There are two long-running topics they are covering: drones (quadcopters) and software defined radios.

The team at Hak5 are offering up a Realtek based Software Defined Radio. Basically, its a wide-band data acquisition unit that uses software to do bandpass filtering. In other words: it’s an A/D with an antenna and some fancy digital signal processing (DSP) software.

Within minutes I listening to local radio stations and aircraft approach the nearby airport and all I had to do was install Gqrx.  It is based on GNU Radio with a QT-gui, so it should work on most platforms.  Of course, I’m using it on OSX.

Software Defined Radio Example

Within seconds I found the Lite FM channel in Fort Lauderdale. (Which happens to be a rock station in Austin).

It’s fun to play with the various modulations, just to see how it alters the sounds.

Gqrx Demodulation Options

Since the decoding of the analog signal is all done in software, in theory, you could add a number of different modulations with just a bit of coding.  For 20 bucks, the Hak5 kit makes for a fun toy to play or a serious option if you want a FM radio in your lab.

Have you played with a SDR?  If so, what have you done with it?  If not, do you have questions about what they can do?  Leave a comment below.


Fan of making things beep, blink and fly. Created AddOhms. Stream on Twitch. Video Host on element14 Presents and writing for Hackster.IO. Call sign KN6FGY.

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