868 Mhz Traffic Detective application based on RTL-SDR by Fraunhofer IIS

The Fraunhofer Institute for Integrated Circuits IIS has developed a Java-based Android app that allows you to analyze wireless traffic at 868 MHz using an RTL-SDR dongle. In Europe, many wireless IOT, metering and home automation radio standards operate in the 868 MHz band.

Next to receiving, detection and recognition of the following protocls is possible: ZigBee, M-Bus, KNX RF, EnOcean Radio Protocol and s-net. The beauty is, that all traffic can be inspected at one on different protocols. This can be useful for detection of random access errors and bottle-necks or in which frequency (bands) or how active the communication on those frequencies is (RSSI-based field-strength measurement with dBm). An important application is the frequency and sprectrum planning, especially for new or densed areas like in cities or fully connected production environments. Furthermore  error diagnosis, intrusion detection and interference detection is possible. Continue reading

Double bandwidth monitoring with RTL-SDR in GNU Radio

The maximum usable and stable bandwidth of an RTL-SDR is about 2.4 MHz. In order to get larger bandwidths it is possible to combine two or more dongles, although doing so comes with a big limitation – since the clocks and signal phases between separate dongles would not be synchronised, it would be impossible to decode a wideband signal this way. However, combining dongles for larger bandwidths is still useful for visualizing the spectrum through an FFT plot, or perhaps for decoding various separate narrowband signals. Although creating a wide band FFT plot with multiple dongles is fairly simple, we haven’t seen much software do this before.

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DVB-T with board apps on Linux

I wanted an easy way to watch TV quickly on the go. If you have DVB-T/DAB/FM sticks with the famous RTL-SDR Chip 2838 and a tuner like Elonics 4000 or Rafael Micro R820T / T2 or some Fitipowers you are able to achieve this tutorial here. We use VLC and it’s built-in capabilities to decode DVB-T.

I started with a freshly installed Ubuntu. First get sure to have the latest packages.

sudo apt-get update

sudo apt-get upgrade

After that we are going to install VLC player and the w_scan utils

sudo apt-get install vlc w-scan

Now we can make a program list and start the frequency search. For this purpose we use the command underlying. If you come from another country than Germany search for your 2-letter countrycode or be referred to the w-scan manual / man pages to find out for you (pretty straight forward to find your countrycode – its as usual). The >> in the command sends the found frequencies to a file (conf) in the path given. Feel free to specify another path like / (root) or others like the desktop /home/yourusername/Desktop.

w_scan -ft -c DE >> /etc/vlc/channels.conf

You could also go with another output file (experimental …). Just change .conf to the ending .xspf

Get sure, if you start the w_scan command, that your DVB-T stick is plugged in (type in command line “lsusb” without “”s and look out for your device. Also maybe restart or give free the resource if it may be blocked by another program already / or still. Hardware is a bit dumb. After that the scanning starts and needs some time. Your stations are now saved in the file. If you don’t find any stations. your antenna setuo could be bad. I e.g. had 2 antennas that didn’t work out well and then changed to a Yagi-Uda antenna.Now open VLC and go to the Menu > Media > choose device > select DVB-T stick (usually adapter0, you can proof that by navigating in the file explorer). Enter the command with the file to your conf or xspf file:

vlc /path/toyour/file/channels.conf

Or open in VLC via file open to open .conf or .xspf station lists. Now you should enjoy your stations by selecting them in Programs > station. Another, but unstable way (doesn’t save the stations) is to go to this device window and then press “play”. I was able to find approximately 10 working stations.

If you have trouble and have to mount the stick drivers first, use this command to mount the already implemented linux kernel drivers for the RTL stick:

modprobe dvb_stick_usb_rtl28xxu rtl2830 rtl2832

If you want to eliminate the OS drivers for the DVB-T mode and enter in the I/Q sample mode

sudo rmmod rtl28xxu

Under Debian it’s a bit differnt with an editor (add nano or vim in from of the command). Add the following line “blacklist dvb_usb_rtl28xxu”


Decoding Immarsat geostationary satellite text messages

A nice hack has been published on how to decode satellite-based text messages (STD-C EGC) of an Immarsat geosat. Those messages include information about search and rescue, coast guard, weather and much more. The hack consists of a tutorial on how to build a cheap antenna out of a modified GPS or helix antenna and how to pipe the outputs into SDR# and then to display messages with a program called tdma-demo.exe, which despreads the messages from the time division coding. Continue reading

Pybombs erleichtert das Leben!

Beim Aufsezten meiner Umgebung für das HackRF habe ich zuerst Linux Mint ausprobiert, bin jedoch davon abkommen und jetzt bei Ubuntu 14.04 gelandet.

Ubuntu 14.04 läuft nun auf meinem Thinkpad X230 in einer Dual Boot Umgebung. Die nötigen Tools zum Betrieb des HackRF habe ich mittel Pybombs installiert. Pyboms enthält Rezepte, d.h. Skripte, welche das Kompilieren der Programme um einiges erleichtert. Über Repositories erhält man oft veraltete oder nicht gepflegte Versionen und es kommt häufig zu Fehlern oder bei späterem Bedarf muss man einzelne Komponenten mühsam ersetzen. Pybombs macht das alles “in einem Schritt” und achtet dabei sogar auf die verschiedenen Abhängigkeiten. Pybombs kann nahezu auf jedem System mit allen “Flavours” eingesetzt werden. D.h. ob .deb oder andere Endungen – völlig egal.

Wie geht das ganze?

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