my recent reads..

LEAP#351 SDR with cheap R820T2/RTL2832U dongles

Cheap SDR dongles? Apparently it all started when a bunch of folks (Antti Palosaari, Eric Fry and Osmocom) found that the signal I/Q data could be accessed directly from the Realtek RTL2832U digital TV tuner chip, allowing it to be turned into a wideband software defined radio receiver with just a little extra hardware and softare.

Combined with a tuner front-end (commonly the Rafael Micro R820T2) in a USB dongle package with dinky antenna, these now show up in droves online for under $20.

I picked a random RTL2832U+R820T2 USB2.0 device from a seller on aliexpress. Like most, it is marketed primarily as a DAB/HDTV receiver, but first thing I did was throw away the Windows-only software provided, as I was more interested in the device as a broad-spectrum SDR receiver.

I’ve tried two MacOSX-compatible open source packages - Gqrx SDR and CubicSDR. Success with both! I’m liking CubicSDR in particular.

The other thing I learned is that the dinky 5” aerial provided with the dongle (and where I put it) is on the one hand surprisingly capable, while also having very little chance of picking out weaker signals!


As always, all notes, schematics and code are in the Little Electronics & Arduino Projects repo on GitHub