RTL-SDRDVB-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 the V4L/DVB kernel developer Antti Palosaari
SpecificationsThe 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 so far is 2.8 MS/s. The frequency range is highly dependent of the used tuner, dongles that use the Elonics E4000 offer the widest possible range (64 - 1700 MHz).
Supported Hardware 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 | 0x1f4d | 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 | 0x0458 | ? | Genius TVGo DVB-T03 USB dongle (Ver. B) | 0x1b80 | 0xd393 | 0xd393 | 0xd393 | 0x1b80 | 0xd394 | ? | DIKOM USB-DVBT HD | 0x1b80 | 0xd395 | FC0012 | Peak 102569AGPK | 0x1b80 | 0xd39d | FC0012 | SVEON STV20 DVB-T USB & FM |
If you don't know where to buy one or if you are just looking for a trustworthy source, try http://shop.sysmocom.de/products/eztv668-bulk
People over at reddit are collecting a list (v2) of other devices that are compatible. Other dongles based on the RTL2832U might be added in the future as well. This is the PCB of the ezcap-stick:
More pictures can be found here. Softwarertl-sdr is a commandline tool that can initialize the RTL2832, tune to a given frequency, and record the I/Q-samples to a file. The code can be checked out with: git clone git://git.osmocom.org/rtl-sdr.git
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
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:
mkdir build
cd build
cmake ../
make
sudo make install
cd rtl-sdr/ autoreconf -i ./configure make sudo make install
The build executable (rtl_sdr) can be found in rtl-sdr/src/.
The gnuradio source requires the rtl-sdr package and a recent gnuradio (>= v3.5.3) 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.
git clone git://git.osmocom.org/gr-osmosdr cd gr-osmosdr/ mkdir build cd build/ cmake ../ -Wno-dev make sudo make install sudo ldconfig
NOTE: The source block will appear under 'OsmoSDR' category in GRC menu.
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
If the device can't be opened, make sure you have the appropriate rights to access the device (udev-rules, or running it as root).
Known problems- If the samples are written to a harddrive, and not a ramdisk, samples may get dropped. An improved version with proper buffering and asynchronous usage of libusb is in the works.
Using the dataTo convert the data to a standard cfile, following GNU Radio Block can be used:
The GNU Radio Companion flowgraph (rtl2832-cfile.grc) is attached to this page. 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. Tell us your success story with other wireless protocols in ##rtlsdr channel on freenode IRC network.
Multiple GMR-carriers can be seen in a spectrum view with the full 3.2 MHz bandwidth (at 3.2 MS/s).
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