Category: Applications

New DSD Block Available for GNU Radio

The popular digital speech decoder (DSD) software has now been wrapped into a GNU Radio Companion block. Previously, DSD required use of virtual audio cables to get decoding to work with GNU Radio, but now the signal audio can be passed directly into this block.

Luke Berndt from the HackRF-dev forums has posted his work to make the functionality of DSD available to GNU Radio users in the form of a GRC block. “I have been playing around a bit and found an easy way to receive and playback digital LMR. More and more of the radio systems are going from narrow band FM to Digital. This makes it tough to listen to them on GQRX. DSD is a great program which can decoded the audio you get when you tune in a system in GQRX, but you either have to run it on another machine with a audio cable in between or figure out how to do a virtual audio cable on your machine.

Luckily, someone wrapped the DSD libraries so they can be accessed as GRC blocks. I have put together a GRC file and a Python program that make it a little easier to use the block.

If you have a chance, give them a try and let me know if they work. There is a good chance I have messed up the values in the filters or else where, but I have gotten clean audio out of it.”

Download the files from GitHub.

DSD is a Linux and Windows software program capable of decoding popular digital speech codecs such as APCO P25 and MOTOTRBO/DMR.

Via DangerousPrototypes

ViewRF – RTL-SDR Spectrum Analyzer Software for the BeagleBone Black Released

Last month we showed a video of a spectrum analyzer project by Stephen Ong. He used a BeagleBone Black (mini embedded Linux capable computer similar to a Raspberry Pi), a touch capable LCD screen, and an RTL-SDR dongle to create a portable spectrum analyzer.

Now Stephen has released ‘ViewRF’, which is the software that powers his spectrum analyzer. It is released under the GPL licence. Also on his post are the download and install instructions.

Spectrum Analyzer using Beaglebone Black and RTL-SDR

Software Defined Radio for Mariners: AIS Antenna Design Review

On a new blog called ‘Software Defined Radio for Mariners‘ aimed at mariners wanting to get into cheap software defined radio with the RTL-SDR, the author has posted an article for beginners on choosing a type of AIS antenna to build.

He reviews the performance of multiple homemade AIS antennas with his RTL-SDR, and finds that a Monopole antenna with two radials gave the best value/performance trade off.

He has also written a hardware guide article, explaining some of the most common antennas adapters and cable ends that might be found.

AIS Monopole Antenna

Exploring Unintentional Radio Emissions with the RTL-SDR

Melissa Elliot (0xABAD1DEA), an infosec security researcher has uploaded slides on the topic of investigating unintentional radio emissions from various electronic devices, and the security issues these emissions can cause. She used the RTL-SDR as the radio receiver to show that sophisticated equipment isn’t needed. One interesting experiment she performed was trying to recover a checkerboard image displayed on an LCD screen entirely via its unintentional radio emissions received with the RTL-SDR. She got close, as you can sort of make out the checkerboard pattern on the recovered image below. Update: Tomsguide have written an article on Melissa’s talk.

LCD Recover from Unintentional Radio Emissions

RTL-SDR Panadapter using RANVerter and Cheap Ham Radio

YouTube user ranickel and creator of the RANVerter HF upconverter for software defined radios has posted a video showing how to use an RTL-SDR dongle and RANVerter to create a panadapter for an old and cheap Heathkit HR-10 “beginners receiver” ham radio.

He connects the mixer stage of the HR-10 via a capacitor to his RANVerter which then connects to a RTL-SDR dongle.

RANVerter Panadapter

Cheap and Easy SDR Panadaptor for Older Receivers

Portable Homemade Spectrum Analyzer using a Beaglebone Black and the RTL-SDR

On YouTube, Stephen Ong has posted a video (and written a short post on his blog) of a portable home made spectrum analyzer he made using the RTL-SDR, a Beaglebone Black and an LCD touchscreen. The Beaglebone Black is a small Linux capable PC that fits in a hand, similar to the Raspberry Pi but with slightly more processing power.

Earlier in the year we posted about another Beaglebone based spectrum analyzer, but this new one by Stephen seems to be much improved with touchscreen capabilities and an improved user interface.

Spectrum Analyzer using Beaglebone Black and RTL-SDR

New (Work In Progress) WebRadio Software for the RTL-SDR Released

Mike Stirling has just released a still in-development version of his Linux based WebRadio software, which supports the RTL-SDR. WebRadio allows someone to connect to a remote RTL-SDR device via a web interface over the internet, much like WebSDR.

There is an installation guide here.

WebRadio

I was able to compile, install and run the software, but there were a few issues that required resolving.

Continue reading →

AIS Decoding Video Tutorial with OpenCPN, AISMon and RTL-SDR

YouTube user Drvarnick has posted a good video tutorial on getting AIS decoding set up with the RTL-SDR using the free OpenCPN, AISMon, SDRSharp and VBCable Windows software programs.

We also have an AIS decoding tutorial blog post posted earlier in the year that shows similar steps at this link.

RTL-SDR AIS Reception-Decoding