DVB-T dongles based on the Realtek RTL2832U can be used as a cheap SDR, since the chip allows transferring the raw I/Q samples to the host, which is officially used for DAB/DAB+/FM demodulation. The possibility of this has been discovered by Eric Fry (History and Discovery of RTLSDR). Antti Palosaari has not been involved in development of rtl-sdr.

The RTL2832U outputs 8-bit I/Q-samples, and the highest theoretically possible sample-rate is 3.2 MS/s, however, the highest sample-rate without lost samples that has been tested wit regular USB controllers so far is 2.4 MS/s. A stable sample-rate of 3.2 MS/s without lost samples is only possible with the Etron EJ168/EJ188/EJ198 series of host controllers due to their specific maximum latency. The frequency range is highly dependent of the used tuner, dongles that use the Elonics E4000 offer the widest possible range (see table below).

Tuner Frequency range Elonics E4000 52 - 2200 MHz with a gap from 1100 MHz to 1250 MHz (varies) Rafael Micro R820T 24 - 1766 MHz Rafael Micro R828D 24 - 1766 MHz Fitipower FC0013 22 - 1100 MHz (FC0013B/C, FC0013G has a separate L-band input, which is unconnected on most sticks) Fitipower FC0012 22 - 948.6 MHz FCI FC2580 146 - 308 MHz and 438 - 924 MHz (gap in between)

Supported Hardware¶

Note: Many devices with EEPROM have 0x2838 as PID and RTL2838 as product name, but in fact all of them have an RTL2832U inside.br

Realtek never released a chip marked as RTL2838 so far.

The following devices are known to work fine with RTLSDR software:

VID PID tuner device name 0x0bda 0x2832 all of them Generic RTL2832U (e.g. hama nano) 0x0bda 0x2838 E4000 ezcap USB 2.0 DVB-T/DAB/FM dongle 0x0ccd 0x00a9 FC0012 Terratec Cinergy T Stick Black (rev 1) 0x0ccd 0x00b3 FC0013 Terratec NOXON DAB/DAB+ USB dongle (rev 1) 0x0ccd 0x00d3 E4000 Terratec Cinergy T Stick RC (Rev.3) 0x0ccd 0x00e0 E4000 Terratec NOXON DAB/DAB+ USB dongle (rev 2) 0x185b 0x0620 E4000 Compro Videomate U620F 0x185b 0x0650 E4000 Compro Videomate U650F 0x1f4d 0xb803 FC0012 GTek T803 0x1f4d 0xc803 FC0012 Lifeview LV5TDeluxe 0x1b80 0xd3a4 FC0013 Twintech UT-40 0x1d19 0x1101 FC2580 Dexatek DK DVB-T Dongle (Logilink VG0002A) 0x1d19 0x1102 ? Dexatek DK DVB-T Dongle (MSI DigiVox mini II V3.0) 0x1d19 0x1103 FC2580 Dexatek Technology Ltd. DK 5217 DVB-T Dongle 0x0458 0x707f ? Genius TVGo DVB-T03 USB dongle (Ver. B) 0x1b80 0xd393 FC0012 GIGABYTE GT-U7300 0x1b80 0xd394 ? DIKOM USB-DVBT HD 0x1b80 0xd395 FC0012 Peak 102569AGPK 0x1b80 0xd39d FC0012 SVEON STV20 DVB-T USB & FM

People over at reddit are collecting a list of other devices that are compatible.

If you find a device that is not yet in the device list but should be supported, please send the VID/PID and additional info (used tuner, device name) to our mailing list.

This is the PCB of the ezcap-stick:



More pictures can be found here.

Much software is available for the RTL2832. Most of the user-level packages rely on the librtlsdr library which comes as part of the rtl-sdr codebase. This codebase contains both the library itself and also a number of command line tools such as rtl_test, rtl_sdr, rtl_tcp, and rtl_fm. These command line tools use the library to test for the existence of RTL2832 devices and to perform basic data transfer functions to and from the device.

Because most of the RTL2832 devices are connected using USB, the librtlsdr library depends on the libusb library to communicate with the device.

At the user level, there are several options for interacting with the hardware. The rtl-sdr codebase contains a basic FM receiver program that operates from the command line. The rtl_fm program is a command line tool that can initialize the RTL2832, tune to a given frequency, and output the received audio to a file or pipe the output to command line audio players such as the alsa aplay or the sox play commands. There is also the rtl_sdr program that will output the raw I-Q data to a file for more basic analysis.

For example, the following command will do reception of commercial wide-band FM signals:

rtl_fm -f 96.3e6 -M wbfm -s 200000 -r 48000 - | aplay -r 48k -f S16_LE

On a Mac, a similar command that works is as follows. This assumes that the sox package is installed, 'port install sox':

rtl_fm -f 90100000 -M wbfm -s 200000 -r 48000 - | play -r 48000 -t s16 -L -c 1 -

If you want to do more advanced experiments, the GNU Radio collection of tools can be used to build custom radio devices. GNU Radio can be used both from a GUI perspective in which you can drag-and-drop radio components to build a radio and also programmatically where software programs written in C or Python are created that directly reference the internal GNU Radio functions.

The use of GNU Radio is attractive because of the large number of pre-built functions that can easily be connected together. However, be aware that this is a large body of software with dependencies on many libraries. Thankfully there is a simple script that will perform the installation but still, the time required can be on the order of hours. When starting out, it might be good to try the command line programs that come with the rtl-sdr package first and then install the GNU Radio system later.

Binary Builds¶

While Osmocom in general is a very much Linux-centric development community, we are now finally publishing automatic weekly Windows binary builds for the most widely used Osmocom SDR related projects: rtl-sdr and osmo-fl2k.

You can find the binaries atThe actual builds are done by roox who is building them using MinGW on OBS, see

The status of the osmocom binary publish job, executed once per week from now on, can be found at https://jenkins.osmocom.org/jenkins/view/All%20no%20Gerrit/job/Osmocom-OBS_MinGW_weekly_publish/

Source Code¶

The rtl-sdr code can be checked out with:



git clone git://git.osmocom.org/rtl-sdr.git

It can also be browsed via cgit, and there's an official mirror on github that also provides packaged releases.

If you are going to "fork it on github" and enhance it, please contribute back and submit your patches to: osmocom-sdr at lists.osmocom.org

A gr-osmosdr GNU Radio source block for OsmoSDR and rtl-sdr is available. Please install a recent gnuradio (>= v3.6.4) in order to be able to use it.

Building the software¶

rtlsdr library & capture tool¶

You have to install development packages for libusb1.0 and can either use cmake or autotools to build the software.

Please note: prior pulling a new version from git and compiling it, please do a "make uninstall" first to properly remove the previous version.

Building with cmake:



cd rtl-sdr/ mkdir build cd build cmake ../ make sudo make install sudo ldconfig

In order to be able to use the dongle as a non-root user, you may install the appropriate udev rules file by calling cmake with -DINSTALL_UDEV_RULES=ON argument in the above build steps.



cmake ../ -DINSTALL_UDEV_RULES=ON

Building with autotools:



cd rtl-sdr/ autoreconf -i ./configure make sudo make install sudo ldconfig

The built executables (rtl_sdr, rtl_tcp and rtl_test) can be found in rtl-sdr/src/.

In order to be able to use the dongle as a non-root user, you may install the appropriate udev rules file by calling



sudo make install-udev-rules

[RelWithDebInfo.zip pre-built Windows version":http://lists.osmocom.org/mailman/listinfo/osmocom-sdr]

Gnuradio Source¶

The Gnu Radio source requires a recent gnuradio (>= v3.7 if building master branch or 3.6.5 when building gr3.6 branch) to be installed.

The source supports direct device operation as well as a tcp client mode when using the rtl_tcp utility as a spectrum server.

Please note: prior pulling a new version from git and compiling it, please do a "make uninstall" first to properly remove the previous version.

Please note: you always should build & install the latest version of the dependencies (librtlsdr in this case) before trying to build the gr source. The build system of gr-osmosdr will recognize them and enable specific source/sink components thereafter.

Building with cmake (as described in the gr-osmosdr wiki page):

git clone git://git.osmocom.org/gr-osmosdr cd gr-osmosdr/

If you are building for gnuradio 3.6 series, you have to switch to the gr3.6 branch as follows



git checkout gr3.6

then continue with

mkdir build cd build/ cmake ../

Now cmake should print out a summary of enabled/disabled components. You may disable certain components by following guidelines shown by cmake. Make sure the device of your interest is listed here. Check your dependencies and retry otherwise.



-- ###################################################### -- # gr-osmosdr enabled components -- ###################################################### -- * Python support -- * Osmocom IQ Imbalance Correction -- * sysmocom [[OsmoSDR]] -- * [[FunCube]] Dongle -- * IQ File Source -- * Osmocom RTLSDR -- * RTLSDR TCP Client -- * Ettus USRP Devices -- * Osmocom [[MiriSDR]] -- * [[HackRF]] Jawbreaker -- -- ###################################################### -- # gr-osmosdr disabled components -- ###################################################### -- -- Building for version: 4c101ea4 / 0.0.1git -- Using install prefix: /usr/local

Now build & install



make sudo make install sudo ldconfig

NOTE: The osmocom source block (osmocom/RTL-SDR Source) will appear under 'Sources' category in GRC menu.

For initial tests we recommend the multimode receiver gnuradio companion flowgraph (see "Known Apps" table below).

You may find more detailed installation instructions in this recent tutorial.

Automated installation¶

Marcus D. Leech has kindly integrated the forementioned build steps into his gnuradio installation script at "This is the most user-friendly option so far.

h2. Mailing List

We discuss both OsmoSDR as well as rtl-sdr on the following mailing list: [mailto:osmocom-sdr@lists.osmocom.org].

You can subscribe and/or unsubscribe via the following link: https://lists.osmocom.org/mailman/listinfo/osmocom-sdr

Please make sure to read the MailingListRules before posting.

Example: To tune to 392.0 MHz, and set the sample-rate to 1.8 MS/s, use:

./rtl_sdr /tmp/capture.bin -s 1.8e6 -f 392e6

to record samples to a file or to forward the data to a fifo.

If the device can't be opened, make sure you have the appropriate rights to access the device (install udev-rules from the repository, or run it as root).

Example:

rtl_tcp -a 10.0.0.2 [-p listen port (default: 1234)":http://www.sbrac.org/files/build-gnuradio]. Found 1 device(s). Found Elonics E4000 tuner Using Generic RTL2832U (e.g. hama nano) Tuned to 100000000 Hz. listening... Use the device argument 'rtl_tcp=10.0.0.2:1234' in [[OsmoSDR]] (gr-osmosdr) source to receive samples in GRC and control rtl_tcp parameters (frequency, gain, ...).

use the rtl_tcp=... device argument in gr-osmosdr source to receive the samples in GRC and control the rtl settings remotely.

This application has been successfully crosscompiled for ARM and MIPS devices and is providing IQ data in a networked ADS-B setup at a rate of 2.4MSps. The gr-osmosdr source is being used together with an optimized gr-air-modes version (see Known Apps below).

It is also available as a package in OpenWRT.

A use case is described here.

To check the possible tuning range (may heavily vary by some MHz depending on device and temperature), call



rtl_test -t

To check the maximum samplerate possible on your machine, type (change the rate down until no sample loss occurs):



rtl_test -s 3.2e6

Using the data¶

A samplerate of 2.4e6 is known to work even over tcp connections (see rtl_tcp above). A sample rate of 2.88e6 may work without lost samples but this may depend on your PC/Laptop's host interface.

To convert the data to a standard cfile, following GNU Radio Block can be used:br



The GNU Radio Companion flowgraph is available as rtl2832-cfile.grc. It is based on the FM demodulation flowgraph posted by Alistair Buxton on this thread.

Please note: for realtime operation you may use fifos (mkfifo) to forward the iq data from the capture utility to the GRC flowgraph.

You may use any of the the following gnuradio sources (they are equivalent):

What has been successfully tested so far is the reception of Broadcast FM and air traffic AM radio, TETRA, GMR, GSM, ADS-B and POCSAG.

Tell us your success story with other wireless protocols in ##rtlsdr channel on freenode IRC network.

Known Apps¶

The following 3rd party applications and libraries are successfully using either librtlsdr directly or the corresponding gnuradio source (gr-osmosdr):

Also take a look at the applications which use rtl-sdr through gr-osmosdr.

Using our lib? Tell us! Don't? Tell us why! :)



Multiple GMR-carriers can be seen in a spectrum view with the full 3.2 MHz bandwidth (at 3.2 MS/s).

rtl-sdr is developed by Steve Markgraf, Dimitri Stolnikov, and Hoernchen, with contributions by Kyle Keen, Christian Vogel and Harald Welte.