Near 2 years ago it was found that some USB sticks that were used to view digital television could ran in a debug mode that allowed them to send IQ samples directly to the host computer. After this feature was discovered a large community started to work together to take advantage of this capability.
The USB sticks that allow this feature are based on the RTL2832U chipset and are called RTL-SDR.
Online we can found USB sticks for sale with various different tuners. Each one have unique frequency ranges:
Tuner | Frequency range |
Elonics E4000 | 52 - 2200 MHz with a gap from 1100 MHz to 1250 MHz (varies) |
Rafael Micro R820T | 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) |
Some characteristics of the majority of the RTL-SDR devices:
· Max sample rate: 3.2 MS/s (Typical 2.6 MHz without dropped samples);
· Resolution: 8 bits/sample;
· Noise figure1 : < 4.5 dB.
Matlab 2013 or higher is needed. The toolbox is available in: http://www.mathworks.com/hardware-support/rtl-sdr.html.
No need to install anything, just run “gnuradio-companion” from the live DVD available in: http://gnuradio.org/redmine/news/31.
The block used is the “RTL-SDR Source”. And can be directly connected to a Sink. If you want to have a frequency analysis you can connect it to a “WX GUI FFT SINK”, if you want to save the file into the disk you can connect the source to a “FILE SINK”.
For use of the GNURadio distribution from a USB drive the steps are the following:
1. Download the ISO that you want to install;
2. Download Linux Live USB Creator from: http://www.linuxliveusb.com/;
3. Run it;
4. Insert and select the USB pendrive;
5. Choose the ISO/IMG/ZIP method;
6. Give some persistence space to save your file and definitions when you run the OS;
7. Click on the thunder.
Search in your favorite electronics online stores or Ebay for “rtl-sdr e4000” or “rtl-sdr r820t” according to your preferences.
To connect your rtl-sdr with test equipment that usually uses SMA buy a “TV PAL male to SMA male”, if you want to connect to a antenna buy a “TV PAL male to SMA female” or a simple male to female SMA adaptor.
Some examples: