Transmitting DVB-T with the BladeRF and Receiving it on a RTL-SDR

The BladeRF is a software defined radio that has transmit and receive capability. Over on his blog, Clayton Smith has recently posted about his experiments which involve using the BladeRF to transmit DVB-T digital TV on one laptop to another laptop running an RTL-SDR in DVB-T mode. This is one of the few applications where the RTL-SDR is used as a DVB-T receiver as it was originally intended. Clayton used GNU Radio, a DVB-T package for GNU Radio and some python scripts to create the BladeRF transmitter.

The newer Linux kernels have DVB-T support for the RTL2832U chip, so the latest version of Ubuntu 13.10 will be able to recognize the RTL-SDR stick as a DVB-T receiver easily. Clayton used VLC in Ubuntu 13.10 to receive the DVB-T signal transmitted by the BladeRF which was tested on the 70cm, 33cm and 23cm bands.

DVB-T Received by the RTL-SDR
Webcam DVB-T TX by a BladeRF and RX by the RTL-SDR
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RTL-SDR Wrapper for Max/MSP

Max/MSP is a graphical programming tool for creating music, sound, video and interactive graphics applications. YouTube user Tom Zicarelli has recently posted a video showing his test of a Max wrapper for rtl_fm, allowing an FM audio stream to be received and controlled in Max. Tom is also working on an RTL-SDR wrapper for PureData, another visual programming language aimed at artists. These wrappers will be useful for artists who wish to utilize RF in their projects.

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Video Tutorial: Hak5 on Decoding RDS with GNU Radio and GR-RDS

Hak5 has recently posted another video continuing their easy to follow series on GNU Radio and the RTL-SDR. In this video they talk about Radio Data System (RDS) and explain how it is a digital signal that is embedded in broadcast FM signals. They then download GR-RDS, a GNU Radio based RDS decoder program and use it to decode a local RDS signal.

Decoding Digital Subcarriers with a $20 SDR, Hak5 1602

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Building an Upconverter from the LNA4HF

Adam the manufacturer of the LNA4HF has recently uploaded a video showing how to easily build an upconverter from the LNA4HF. The LNA4HF is a low noise amplifier intended for use with SDRs like the RTL-SDR. The video shows how to connect up two components, the Mixer and Oscillator which are required to create the upconverter.

HF upconverter built from the LNA4HF

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Antenna Performance Comparison for the RTL-SDR

Akos from the SDR for Mariners blog has put out another post this time comparing various antennas cut for 121 MHz with the RTL-SDR. He tests monopole, dipole, two radial and rubber ducky antennas on their signal to noise ratio performance on an ATIS signal in SDRSharp.

It is important to note that different antennas will have different gain directionality, so your own experimentation may still be required for your own RF environment.

Main Antenna Comparison Results
Main Antenna Comparison Results
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Video Tutorial: Hak5 GNU Radio FM Radio Receiver

The popular YouTube technology show Hak5 has recently been posting videos related to software defined radio and more specifically RTL-SDR. Two of their recent videos are about an easy to follow GNU Radio tutorial for complete beginners. In the first tutorial they show how to add an RTL2832U source in GNU Radio and output it to a FFT Sink. In the second tutorial they go further and show how to build an FM Receiver.

Building Software Radios With A Little Bit Of Python, Hak5 1526

Going Deeper Into GNURadio Companion, Hak5 1601

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Video Tutorial: Recording Audio with SDR# and Audacity

On Eric Williams YouTube channel Eric has posted a video showing how he records audio from his RTL-SDR using SDR# and Audacity. Although SDR# can record audio itself, the advantage to using Audacity is that you can set up Voice Activation (VOX), which will only record audio when someone is speaking or when a digital signal is active. This allows you to listen to a summary of communications at a later time.

RTL-SDR - Voice Activated Recording with Audacity

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Installing SDR# on OSX

SDR# is the most commonly used Software Defined Radio receiver GUI that is used with the RTL-SDR. Natively, it runs on Windows, but since it is written in C#, it can also run on Mac OSX and Linux with Mono. Installing SDR# on OSX using Mono is a little more complicated compared to simply running it on Windows however.

To help with this, Jan Szumiec has written a simple guide on installing SDR# using Mono on OSX. The guide includes the steps of installing Mono, the Xamarin Studio Mono IDE, the rtl-sdr libraries and then compiling the SDR Sharp sources and symlinking the Mono runtime to the native libraries.

Update: This is no longer possible as the SDR# code is not available anymore.

SDR Sharp on OSX
SDR Sharp on OSX
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