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steve-m, 02/19/2016 10:51 PM


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DVB-T sticks 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.

Specifications

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 so far is 2.8 MS/s. The frequency range is highly dependent of the used tuner, sticks that use the Elonics E4000 offer the best range (64 - 1700 MHz).

Supported Hardware

So far, the following devices are supported:

  • ezcap USB 2.0 DVB-T/DAB/FM stick (Elonics E4000 tuner)
  • Terratec NOXON DAB/DAB+ USB-Stick (Fitipower FC0013 tuner)

Other sticks based on the RTL2832U might be added in the future as well.

Software

rtl-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
}}}

It can also be browsed on http://cgit.osmocom.org/cgit/rtl-sdr/

=== Building the software ===
To build it, simply run 'make' in the src/-directory and make sure you have libusb1.0-0-dev installed.

=== Usage ===

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

{{{
./rtl-sdr /tmp/out.bin -s 1800000 -f 392000000
}}}

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 data

To convert the data to a standard cfile, following GNU Radio Block can be used:
Image(rtl2832-cfile.png)
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 [http://thread.gmane.org/gmane.linux.drivers.video-input-infrastructure/44461/focus=44525 on this thread].

Files (9)
rtl2832-cfile.png View rtl2832-cfile.png 23.8 KB steve-m, 03/17/2012 08:35 PM
ezcap_top.jpg View ezcap_top.jpg 178 KB top view of the ezcap PCB steve-m, 03/17/2012 08:41 PM
rtl2832-cfile.grc rtl2832-cfile.grc 8.56 KB GRC flowgraph for the RTL2832 file format steve-m, 03/17/2012 08:45 PM
rtl-sdr-gmr.png View rtl-sdr-gmr.png 42.4 KB spectrum view of GMR carriers steve-m, 03/17/2012 09:27 PM
EZTV666.JPG View EZTV666.JPG 163 KB Similar but smaller EZTV 666 receiver laforge, 03/26/2012 06:49 PM
rtl-sdr.2.pdf View rtl-sdr.2.pdf 1.78 MB Presentation given at FreedomHEC 2012 Taipei laforge, 06/20/2012 03:08 PM
osmosource.png View osmosource.png 24.5 KB gr-osmosdr sources horiz0n, 07/08/2012 09:00 AM
RelWithDebInfo.zip RelWithDebInfo.zip 416 KB - Hoernchen, 01/24/2014 04:33 PM
Histo_DATA_Packets.png View Histo_DATA_Packets.png 21.8 KB steve-m, 12/08/2019 04:10 PM

Updated by steve-m about 8 years ago · 2 revisions

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