Description

pyrtlsdr is a simple Python interface to devices supported by the RTL-SDR project, which turns certain USB DVB-T dongles employing the Realtek RTL2832U chipset into low-cost, general purpose software-defined radio receivers. It wraps all the functions in the librtlsdr library (including asynchronous read support), and also provides a more Pythonic API.

Usage

All functions in librtlsdr are accessible via librtlsdr.py and a Pythonic interface is available in rtlsdr.py (recommended). Some documentation can be found in docstrings in the latter file.

Examples

Simple way to read and print some samples:

from rtlsdr import RtlSdr

sdr = RtlSdr()

# configure device
sdr.sample_rate = 2.048e6
sdr.center_freq = 70e6
sdr.gain = 'auto'

print sdr.read_samples(512)

Plotting the PSD with matplotlib:

from pylab import *
from rtlsdr import *

sdr = RtlSdr()

# configure device
sdr.sample_rate = 2.4e6
sdr.center_freq = 95e6
sdr.gain = 4

samples = sdr.read_samples(256*1024)

# use matplotlib to estimate and plot the PSD
psd(samples, NFFT=1024, Fs=sdr.sample_rate/1e6, Fc=sdr.center_freq/1e6)
xlabel('Frequency (MHz)')
ylabel('Relative power (dB)')

show()

Resulting plot here.

See the files 'demo_waterfall.py' and 'test.py' for more examples.

Dependencies

• Windows/Linux/OSX
• Python 2.7.x
• librtlsdr (builds dated after 5/5/12)
• Optional: distribute (a fork of the Setuptools project) for using setup script
• Optional: NumPy (wraps samples in a more convenient form)

matplotlib is also useful for plotting data. The librtlsdr binaries (rtlsdr.dll in Windows and librtlsdr.so in Linux) should be in the pyrtlsdr directory, or a system path. Note that these binaries may have additional dependencies.

Troubleshooting

• Some operating systems (Linux, OS X) seem to result in libusb buffer issues when performing small reads. Try reading 1024 (or higher powers of two) samples at a time if you have problems.
• If you're having librtlsdr import errors in Windows, make sure all the DLL files are in your system path, or the same folder as this README file. Also make sure you have all of their dependencies (e.g. the Visual Studio runtime files). If rtl_sdr.exe works, then you should be okay.
• In Windows, you can't mix the 64 bit version of Python with 32 bit builds of librtlsdr.

Credit

Credit to dbasden for his earlier wrapper python-librtlsdr.

-- Roger