November 14, 2013

ShinySDR: A new SDR software package that supports RTL-SDR

ShinySDR is a new still in development SDR software package which supports the RTL-SDR. It is built on GNU Radio and has a web based user interface and a plugin system.

One of the main differentiating features of ShinySDR is that it has a persistent waterfall display. This means that as you browse through the frequency spectrum and zoom in and out on the waterfall, the displayed history will not be lost like on other SDR programs. Some other features are

Browser-based UI: The receiver can be listened to and remotely controlled over a network or the Internet, as well as from the same machine the actual hardware is connected to. (Required bandwidth: 3 Mb/s to 11 Mb/s, depending on selected spectrum frame rate. This may be improved in future versions by using more compact data formats.)

Modularity: plugin system allows adding support for new modes (types of modulation) and hardware devices.

“Hackability”: All server code is Python, and has no mandatory build or install step. Demodulators prototyped in GNU Radio Companion can be turned into plugins with very little additional code. Control UI can be automatically generated or customized and is based on a generic networking layer.

Frequency database: Jump to favorite stations; catalog signals you hear; import published tables of band, channel, and station info; take notes. (Note: Writing changes to disk is not yet implemented, unfortunately.)

The software also comes with an included VOR demodulator plugin.

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November 12, 2013

Visualizing Broadcast Satellite Signals with the RTL-SDR

Over on Gough’s Tech blog, Lui Gough has posted about his experiences with visualizing broadcast satellite signals with the RTL-SDR. In his post he shows how to receive broadcast satellite signals by using a LNB, or low noise block downconverter, which allows the RTL-SDR to receive satellite frequencies which are typically out of the range of the RTL-SDR.

Later in the post he also shows what several broadcast satellite signals look like on the waterfall, as well as some of their telemetry signals.

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November 12, 2013

True Random Numbers with RTL-Entropy

RTL-Entropy is a Linux based entropy generator which uses the RTL-SDR as the entropy source. It works by using the RTL-SDR to sample atmospheric noise and then using that noise to create randomly generated numbers.

This is useful as computers are only capable of generating pseudo-random numbers, which may look random, but are not truly random. For cryptography and security, it is desirable to use true random numbers, as pseudo-random numbers can possibly be predicted. Combining this RTL-SDR based entropy source with other entropy sources may help improve security.

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November 10, 2013

Transmitting Data with a Raspberry Pi and RTL-SDR

Hackaday brings to attention a simple hack where hacker Marc uses an antenna connected to a general purpose I/O (GPIO) pin on his Raspberry Pi to wirelessly transmit a wav file via AFSK modulation to his RTL-SDR. He uses a program called minimodem to encode the wav on the Raspberry Pi and then on the PC to decode the data received by the RTL-SDR.

Using this method, it is claimed that a signal can be transmitted up to 50m away, even through walls.

Raspberry Pi Transmitter Received with RTL-SDR

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November 10, 2013

ADS-B Active PCB Antenna for the RTL-SDR

This ADS-B antenna by amateur radio hobbyist F5ANN combines a 30dB LNA preamplifier, bandpass filter and antenna tuned for 1090MHz together on a single PCB board. The LNA preamplifier helps boost weak signals, whilst the bandpass filter helps to remove interference from others signals such as GSM. The novel thing about this antenna is that everything is neatly packaged into a single PCB board, which makes this antenna very compact, and yet have high performance.

F5ANN uses his combined antenna together with an RTL-SDR dongle and the RTL 1090 ADS-B decoding software with PlanePlotter, and was able to receive 194 simultaneous aircraft signals with a message rate of 556 messages a second at distances of up to 250 nm.

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November 7, 2013

New RTL-SDR Tuner Chip R828D

A new tuner known as the Rafeal R828D has become officially supported by the main software branch of RTL-SDR. Comments on the initial testing from this thread on the Reddit RTL-SDR forum show that there is no real improvement over the cheaper R820T tuner, and that a hardware mod is required to get acceptable results from the tuner.

On the Reddit thread user metropolis_pt2, the developer of the driver for this tuner writes

Internally it seems to be almost identical with the R820T, the only real difference is that it has 3 inputs instead of only one (Air-In, Cable1, Cable2), of which two are connected on the Astrometa DVB-T2 stick. Air-In is connected to an external (probably LC-)highpass which seems to have a cutoff-frequency around 320 MHz, and Cable1 to a low-pass with a similar cutoff-frequency. The driver I’ve added will switch automatically to Air-In if you tune > 345 MHz. The filters are not sharp at all though (not surprising given their low order, I only see a few capacitors and inductors in the input path), and their added benefit is a bit questionable. You might get a bit less WFM interference at, say, 900 MHz, but that’s about it…

In Antti’s LinuxTV blog, Antti talks about the internals of the device and shows many pictures of the insides.

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November 4, 2013

Receiving and Decoding Tire Pressure Monitor Systems using an RTL-SDR

Tire Pressure Monitoring Systems (TPMS) are comprised of sensors that are designed to measure the tire pressures on a vehicle and then wirelessly transmit the data to a monitoring computer, which will then alert the driver when the tire pressure is incorrectly set.

At the Toorcon conference, Jared Boon has given a talk showing how he used an RTL-SDR and a GNU Radio program that he developed to reverse engineer the TPMS wireless protocol, and read the data that is sent. Jarod also notes that TPMS is potentially a security risk that could be used to track cars. The talk has been uploaded to YouTube and is shown below.

Reversing Tire Pressure Monitors with a Software-Defined Radio

Watch this video on YouTube

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November 4, 2013

HDSDR Updated to Version 2.70. Now with Autocorrelation Feature for Signal Identification

HDSDR, a popular SDR program used with the RTL-SDR dongle has been updated to version 2.70. The new features include

– better CPU utilization
– added Automatic Notch Filter
– added AFC for AM and FM. AFC can be deactivated in ECSS mode
– smoothed S-Meter display
– enhanced parameters for ‘SDR on IF output’
– new keyboard shortcuts for Lo/HiCut and WAV files
– ‘spectrum’ switchable to Autocorrelation/Cepstrum display (Click on ‘Spectrum’ label)
– TX-Button for HRD(DDE) / CAT to HDSDR
– added ‘Double Size’ option in Frequency Input Dialog
– Frequency Manager now provides 5 User Banks

The new autocorrelation feature is particularly useful for signal identification. The authors of HDSDR have created a webpage showing what the autocorrelation feature can be used for, and how to use it.