Category: Applications

Beaglebone Black FM/Internet Radio Combo Receiver using an RTL-SDR

Last year we missed this interesting project by Frederick Vandenbosch where he created a FM/internet radio combination receiver using a BeagleBone Black mini embedded PC and an RTL-SDR dongle.

The idea is that the system will receive FM radio through the RTL-SDR normally, but when reception is poor or unavailable you can switch to internet radio which is received through WiFi. The radio is controlled through an LCD screen attached to the BeagleBone Black.

Frederick used Linux on the BeagleBone and created a custom GUI that allows for easy tuning using rtl_fm as the RTL-SDR back end, setting channel presets and for switching between internet and live FM radio.

BeagleBone Blade FM/Internet Radio Combo Receiver
BeagleBone Blade FM/Internet Radio Combo Receiver
Beaglebone Black Digital Radio with RTL-SDR and Wifi

Monitoring a Trunked P25 LSM Simulcast System with OP25 and an RTL SDR

Over on YouTube user jdlucas78 has uploaded a video showing a P25 LSM modulated digital voice signal being decoded by the Osmocom OP25 software for Linux. Although DSD and DSD+ can decode P25 voice, it seems that the Osmocom OP25 software is better at decoding P25 signals as it implements better error correction algorithms.

Over on the RadioReference forums there is a thread discussing the use of the OP25 decoding software which can be found here. There is a post in the thread that shows an easy Linux install procedure for the OP25 software.

Monitoring a Trunked P25 LSM Simulcast System w/ OP25 and RTL SDR Dongle

Take 2: Monitoring a Trunked P25 LSM Simulcast System w/ OP25 and RTL SDR Dongle

New SDR# Plugin: PAL / SECAM TV

The SDR# plugins programmer over at rtl-sdr.ru has recently released a new plugin which allows the decoding of PAL / SECAM TV images from within SDR# (note link in Russian, use Google translate or see the download link at the bottom of the page). The author also writes that if you are using a newer software defined radio like an Airspy, you can also receive the audio channel using the SDR# multiple VFO plugin.

We note that there is also the TVSharp software by the same author which is a standalone program that can decode PAL and NTSC.

PAL / SECAM TV SDR# Plugin
PAL / SECAM TV SDR# Plugin

RTL-SDR with GQRX Running on an Odroid C1 at 1 MSPS and Max FFT

Over on YouTube user neutron2025 has uploaded some videos showing GQRX running on an Odroid C1. The Odroid C1 is a low cost ($35 USD) mini computer with an Arm Cortex A5 quad core CPU and 1 GB RAM which runs Ubuntu 14.04 or Android KitKat. It is a much more powerful competitor to the Raspberry Pi which also goes for around the same price.

Despite its low cost, the video by neutron2025 shows that the Odroid C1 has enough processing power to run the relatively CPU intensive GQRX SDR software with the RTL-SDR at a 1 MSPS sampling rate and maximum FFT resolution.

To install GQRX, GNU Radio also needs to be installed. Installation of GNU Radio is a lengthy process containing many writes to the file system. The amount of writes that occur could destroy a SDCard. To get around this neutron2025 connected an external hard drive and used that as a swap file while installing GNU Radio. His installation notes can be found on pastebin. He writes that installation took around 8 hours.


RTL-SDR / Odroid C1 / GQRX / 2msps / Max FFT

Chaos Communications Congress Talks – Iridium Pager Hacking

A few days ago the Chaos Communications Congress (a technology and hacking focused conference) commenced. Among the talks there was one about reverse engineering the Iridium satellite paging system using software defined radio. Iridium satellites provide global communications via special satellite phones, pagers and other transceivers.

In the talk the speaker shows how they used a USRP radio together with a cheap active iridium antenna, a bandpass filter and an LNA to receive the Iridium satellite signals. They also mention that an E4000 RTL-SDR together with an LNA and appropriate home made antenna for frequencies in the ~1.6 GHz region can also be sufficient. Once they were able to receive signals they were then able to reverse engineer the signal and create several pieces of software to decode the pager messages. The code is available on their GitHub at https://github.com/muccc/iridium-toolkit.

Sec, schneider: Iridium Pager Hacking

Freqwatch – RTL-SDR Frequency Scanner and Recorder

Freqwatch is a new Linux based software program that has recently been released by programmer Joshua Davis. Freqwatch makes use of rtl_power to scan a wide swath of RF spectrum and then automatically records and stores in a database sound files of active signals by using rtl_fm.

The software is capable of making use of multiple RTL-SDR dongles in order to efficiently monitor larger bandwidths. After running the software for a while and generating a large database, you can then use a database analyzer like Splunk to find trends in the data or find out when something changes.

The software can be downloaded from its GitHub at https://github.com/covertcodes/freqwatch. Previously we featured some other software called ScanEyes which has a similar logging feature but focused on trunking radio channels and we also featured RTL Airband which monitors multiple airband frequencies simultaneously for logging and streaming.

Freqwatch Database Logs
Freqwatch Database Logs

Digital Ding Dong Ditch – Hacking wireless doorbells with Arduino and RTL-SDR

Over on YouTube user Samy Kamkar has uploaded a video showing how he was able to use an RTL-SDR to copy his friends wireless doorbell signal and prank him by replaying it using an Arduino and 433 MHz transmitter. His video goes through the entire reverse engineering process he used from recording the wireless doorbell signal with the RTL-SDR, to analyzing and understanding the signal and finally to programming the Arduino with the code to replicate the doorbell signal. If you don’t like video explanations, Samy has also done a write up of the same material on his website. 

Digital Ding Dong Ditch Prank - hacking wireless doorbells w/Arduino and RTL-SDR

SDR on TV: Using SDR to Break into Homes with Wireless Alarms

Earlier this year the American TV show Good Morning America featured a segment on software defined radios being used to break into houses with wireless alarm sensors. The story is based on a Defcon 2014 paper “Home Insecurity: No Alarms, False Alarms, and SIGINT” by Logan Lamb. In the TV segment Logan shows how he uses a USRP software defined radio to send a false alarm signal, jam a wireless sensor and finally to record sensor activation data from the alarm system.

Although Logan used a USRP, the same attack could be done with the cheaper HackRF.

SDR HackRf: Home Insecurity: No Alarms, False Alarms, and SIGINT