December 4, 2015

An online Software Defined Radio training course

We’ve recently found what looks to be a new online video based course that uses the RTL-SDR to teach basic software defined radio topics. The course is not free, it is priced at $29.99, but the first three videos are free. Judging from the first three videos the content appears to be quite basic, but is presented in a very clear way that may be useful for beginners. Currently the lessons include:

Course Overview
Welcome to the exciting world of Software Defined Radio. In this video, we’ll discuss what SDR is, and why it’s such a hot button topic right now.
Setting up the environment
In this module, we’ll setup our environment for development. If you’re already very comfortable with Ubuntu, you might want to just follow the guide below.
Browsing the spectrum

In this module, we’ll cut our teeth on GRQX, and learn a little about the radio spectrum.
Signals Intelligence
In this module, we’ll learn how to find transmissions in the frequency domain, and capture them to disk for offline analysis.
Modulations
In this module, we’ll learn how to identify two types of basic digital transmissions, and talk a little about the history of radio.
Demodulation – Part 1
In this module, we’ll practice capturing signals in the wild, identifying the modulation, and demodulating the signal with GNU Radio.
Demodulation – Part 2
In this module, we’ll learn about clock recovery. And we’ll pull out packets from the garage door remote.

It also appears that they plan to have some live classes in the future.

We note that there are also alternative SDR training courses available such as Micheal Ossmanns lessons at greatscottgadgets.com/sdr.

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December 3, 2015

rtl_power_fftw: An improved version of rtl_power designed for radio astronomy

As the RTL-SDR’s maximum usable bandwidth is about 2.8 MHz, programs like rtl_power were written to scan over wider bandwidths by quickly hopping between different swaths of the frequency spectrum and then stitching the data together.

Now a new improved version of rtl_power called rtl_power_fftw has recently been developed and released. This version is designed for radio astronomy use, but also overcomes several issues general users may encounter with rtl_power. One of the authors, Klemen wrote in to us with this information:

I would like to tell you about a program we have been developing at Astronomical Society Vega – Ljubljana, namely one for measuring power spectrum with rtl dongles.

It addresses several shortcomings of the rtl_power program shipped with librtlsdr. The most notable is that it uses a much faster FFT algorithm (from the fftw3 library) and separate threads for acquiring data and FFT processing. This means that even the lowly raspberry pi is capable of processing spectra of sizes up to ~1024 bins in real-time (no slower than data acquisition). This enables the user to sample spectrum continuously and more efficiently.

The other benefit is the output format: data is presented in a gnuplot-friendly way, so plotting is simple, and no data is mangled to make an illusion that spectral hopping is not needed: FFT of each frequency hop is output separately, and user can make and informed decision on how to process data – the program stays out of this, to preserve the accuracy of the gathered data.

The program was developed for use in radio astronomy where all these things matter. Code is available on Github:

https://github.com/AD-Vega/rtl-power-fftw

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December 3, 2015

New Mini RTL-SDR Dongle Available from Nooelec

The Nooelec store have recently come out with a new small RTL-SDR model called the Nano 2, which appears to an improved version of the old tiny square dongles. These new ones are sized at 24mm x 21mm x 8mm and come in a new plastic case with vent holes to prevent overheating. They also come with the newer R820T2 tuner chip. This appears to be a good improvement over the older models which were reported to have overheating and thermal frequency drift issues.

These small dongles look to be great for embedded or mobile phone applications that have space restrictions.

The new dongle is currently selling for $24.95 USD + $1.99 shipping.

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November 26, 2015

Hak5: Reverse Engineering Radio Protocols with SDR and the Yardstick One

Over on YouTube the popular security and hacking themed channel Hak5 have created two videos together with Mike Ossmann (creator of the HackRF and Yardstick One) that give a good introduction and overview on reverse engineering unknown radio protocols. In the video they show how to use a SDR like the RTL-SDR or HackRF to initially capture the radio signal, and then how to use the Yardstick One to reverse engineer and recreate the signal. Using this process they reverse engineer the radio protocol for a wireless liquor cabinet lock.

The Yardstick One is a computer controlled wireless transceiver (but it is not an SDR). The Yardstick One understands many radio protocols by default and can be programmed in Python, lowering the learning barrier for reverse engineering signals.

Mike Ossmann has also been slowly releasing very detailed video tutorials about DSP and radio related topics. If you are interested in reverse engineering radio signals it is a very helpful series to watch.

Radio Hacking: Reverse Engineering Protocols Part 1 - Hak5 1913

Watch this video on YouTube

Radio Hacking: Reverse Engineering Protocols Part 2 - Hak5 1914

Watch this video on YouTube

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November 20, 2015

Using the RTL-SDR as a Panadapter for a Kenwood TS-570D

Over on YouTube user SA6 HAM has uploaded a video showing how to modify a Kenwood TS-570D so that an RTL-SDR dongle can be connected to its first IF stage in order to create a low cost panadapter. A panadapter is a device that allows you to visually view RF signals with an FFT or waterfall display on a regular analogue hardware radio. Some radios have IF output ports on the case, but older radios tend to need internal modification to expose the IF as a port.

In the video SA6 HAM opens up his Kenwood TS-570D radio and shows exactly where to connect the RTL-SDR dongle’s antenna connector on the inside.

Kenwood TS-570D Panadapter modification with an 820T2 RTL SDR dongle

Watch this video on YouTube

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November 20, 2015

ARM Radio: A Cheap SDR built out of an ARM Processor and not much more

A software defined radio can theoretically be made out of little more than a microprocessor with an onboard ADC and some DSP code. This is exactly what Alberto di Bene (I2PHD) achieved by connecting an antenna directly to the on board 12-bit ADC on a STM32F429 Discovery board.

To make it actually work as an SDR he also wrote some code to utilize the development board’s ARM processor which processes the ADC input into a radio signal, demodulates it and then turns it into audio via the boards DAC and speaker. The radio can tune from 8 kHz up to about 900 kHz.

The only real extra hardware in Alberto’s system is a low pass filter for anti-aliasing and impedance transformation, and a reconstruction filter to get sound to the speakers from the DAC. He also used the boards LCD screen to implement a full GUI tuning system.

A PDF document detailing his work can be downloaded here.

The ARM Radio with the low pass filter and reconstruction filter shown.

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November 18, 2015

Raspberry Pi Docker Images for ADS-B and ACARS with the RTL-SDR

Docker is a Linux based platform which allows you to build and deploy complex applications into a self contained “container” package that contains all the needed applications and dependencies. The container is completely preconfigured to just work as soon as you install the application without the need for any extra configuration.

Over on his blog SysRun has been developing an ADS-B ready docker image for use with the RTL-SDR on a Raspberry Pi embedded computer. His post shows how he prepared and built the docker image on the Pi and how to run the docker image.

In addition he has also uploaded another post showing how to prepare, build and run an ACARS decoding based docker image on the Raspberry Pi.

In the future SysRun also hopes to upload an AIS Docker tutorial.

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November 18, 2015

SDR Presentations Requested for FOSDEM

The Free and Open Source Developers Meeting (FOSDEM) is looking for SDR presentations to give at this years conference in Brussels, Belgium which will be held on January the 80th & 31st of January.

Software Radio has become an important tool to allow anyone access the EM spectrum. Using free software radio libraries and applications and cheap hardware, anyone can now start hacking on wireless communications, remote sensing, radar or other applications. At FOSDEM, we hope to network all these projects and improve collaboration, bring new ideas forward and get more people involved.

The track’s web site resides at: http://gnuradio.org/redmine/projects/gnuradio/wiki/FOSDEM

Here, we will publish updates and announcements. The final schedule will be available through Pentabarf and the official FOSDEM website.

To suggest a talk, go to https://penta.fosdem.org/submission/FOSDEM16 and follow the instructions (you need an account, but can use your account from last year if you have one). You need to create an ‘Event’; make sure it’s in the Software Defined Radio track! Lengths aren’t fixed, but give a realistic estimate and please don’t exceed 30 minutes unless you have something special planned (in that case, contact one of us). Also, don’t forget to include time for Q&A. Typical slot lengths would be 30 Minutes including QA.

You aren’t limited to slide presentations, of course. Be creative. However, FOSDEM is an open source conference, therefore we ask you to stay clear of marketing presentations. Of course, we like nitty-gritty technical stuff.

We will reserve time for interactiveness, it won’t all be talks.

If you are qualified and interested in giving a talk the submission deadline is December 4th 2015.

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