Let’s Try RTL-SDR! – Part 1

Recently, I received a device that was originally marketed as a USB DAB/DVB/FM receiver, containing a chipset compatible with the utilities from the RTL-SDR project.

It cost £17.50 (roughly €22.42/2159円/US$27.45, according to WolframAlpha) including free shipping from the US.

What’s in the kit?

The receiver that I ordered was supplied with only a remote control, and a stubby antenna with a magnetic base. No CD-ROMs, or user manuals were included.

About the hardware

The eBay listing page claims that it contains an Elonics E4000 tuner IC, and a RealTek RTL2832U DVB-T demodulator IC.

lsusb -v Reports:

	Bus 001 Device 002: ID 0bda:2838 Realtek Semiconductor Corp.
	Device Descriptor:
	bLength 18
	bDescriptorType 1
	bcdUSB 2.00
	bDeviceClass 0 (Defined at Interface level)
	bDeviceSubClass 0
	bDeviceProtocol 0
	bMaxPacketSize0 64
	idVendor 0x0bda Realtek Semiconductor Corp.
	idProduct 0x2838
	bcdDevice 1.00
	iManufacturer 1 Realtek
	iProduct 2 RTL2838UHIDIR
	iSerial 3 00000088
	bNumConfigurations 1
	Configuration Descriptor:
	bLength 9
	bDescriptorType 2
	wTotalLength 34
	bNumInterfaces 2
	bConfigurationValue 1
	iConfiguration 4 USB2.0-Bulk&Iso
	bmAttributes 0x80
	(Bus Powered)
	MaxPower 500mA
	Interface Descriptor:
	bLength 9
	bDescriptorType 4
	bInterfaceNumber 0
	bAlternateSetting 0
	bNumEndpoints 1
	bInterfaceClass 255 Vendor Specific Class
	bInterfaceSubClass 255 Vendor Specific Subclass
	bInterfaceProtocol 255 Vendor Specific Protocol
	iInterface 5 Bulk-In, Interface
	Endpoint Descriptor:
	bLength 7
	bDescriptorType 5
	bEndpointAddress 0x81 EP 1 IN
	bmAttributes 2
	Transfer Type Bulk
	Synch Type None
	Usage Type Data
	wMaxPacketSize 0x0200 1x 512 bytes
	bInterval 0
	Interface Descriptor:
	bLength 9
	bDescriptorType 4
	bInterfaceNumber 1
	bAlternateSetting 0
	bNumEndpoints 0
	bInterfaceClass 255 Vendor Specific Class
	bInterfaceSubClass 255 Vendor Specific Subclass
	bInterfaceProtocol 255 Vendor Specific Protocol
	iInterface 5 Bulk-In, Interface
	Device Qualifier (for other device speed):
	bLength 10
	bDescriptorType 6
	bcdUSB 2.00
	bDeviceClass 0 (Defined at Interface level)
	bDeviceSubClass 0
	bDeviceProtocol 0
	bMaxPacketSize0 64
	bNumConfigurations 2
	Device Status: 0x0000
	(Bus Powered)

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Installing RTL-SDR, and associated utilities

Download and run the build-gnuradio script, as recommended by Andrew Back:

	tysonkey@ubuntu:~/SoftRadio$ wget http://www.sbrac.org/files/build-gnuradio
	–2012-07-19 12:35:19– http://www.sbrac.org/files/build-gnuradio
	Resolving http://www.sbrac.org… 174.142.32.20
	Connecting to http://www.sbrac.org|174.142.32.20|:80… connected.
	HTTP request sent, awaiting response… 200 OK
	Length: 29181 (28K) [text/plain]
	Saving to: `build-gnuradio'
	100%[======================================================================================================================================================>] 29,181 80.8K/s in 0.4s
	2012-07-19 12:35:21 (80.8 KB/s) – `build-gnuradio' saved [29181/29181]
	tysonkey@ubuntu:~/SoftRadio$ chmod +x build-gnuradio
	tysonkey@ubuntu:~/SoftRadio$ ./build-gnuradio
	This script will install Gnu Radio from current GIT sources
	You will require Internet access from the computer on which this
	script runs. You will also require SUDO access. You will require
	approximately 500MB of free disk space to perform the build.
	This script will, as a side-effect, remove any existing Gnu Radio
	installation that was installed from your Linux distribution packages.
	It must do this to prevent problems due to interference between
	a linux-distribution-installed Gnu Radio/UHD and one installed from GIT source.
	The whole process may take up to two hours to complete, depending on the
	capabilities of your system.
	!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
	NOTE: if you run into problems while running this script, you can re-run it with
	the –verbose option to produce lots of diagnostic output to help debug problems.
	This script has been written to anticipate some of the more common problems one might
	encounter building ANY large, complex software package. But it is not pefect, and
	there are certainly some situations it could encounter that it cannot deal with
	gracefully. Altering the system configuration from something reasonably standard,
	removing parts of the filesystem, moving system libraries around arbitrarily, etc,
	it likely cannot cope with. It is just a script. It isn't intuitive or artificially
	intelligent. It tries to make life a little easier for you, but at the end of the day
	if it runs into trouble, a certain amount of knowledge on your part about
	system configuration and idiosyncrasies will inevitably be necessary.
	Proceed?

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At this stage, the script will request elevated privileges, in order to search for prerequisite packages using the system package management utilities.

Since the disclaimer warns that the process may take a long time, I’d recommend obtaining one’s favourite beverage; ensuring that the PC used has a sufficient amount of free disk space, and is well-ventilated (if using a laptop), to prevent it from potentially overheating, and unexpectedly shutting down; and searching for something else to do in the meantime…

For some reason, the Checking for package python-gtk2 step seems to take an unusually long time on my laptop; and temporarily stopping the script yielded:

	^CFailed to find just-installed command 'guile' after pre-requisite installation.
	This very likely indicates that the pre-requisite installation failed
	to install one or more critical pre-requisites for Gnu Radio/UHD

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It seems that despite my best efforts to prepare things in advance, I ran out of disk space at that stage:

	Checking for library libusb …Found library libusb
	Checking for library libboost …Found library libboost
	Checking for library libcppunit …Found library libcppunit
	Checking for library libguile …Found library libguile
	Checking for library libfftw …Found library libfftw
	Checking for library libgsl …Found library libgsl
	Done
	Fetching Gnu Radio via GIT…Could not find gnuradio/gnuradio-core after GIT checkout
	GIT checkout of Gnu Radio failed!

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Eventually, I resorted to running apt-get clean && apt-get autoclean, and moving some large files to an external disk, in order to free 1.5GB of 9.4GB; and re-ran the script, with more successful results:

	Starting function uhd_build at: Thu Jul 19 13:43:39 BST 2012
	Building UHD…
	Done building/installing UHD
	Done function uhd_build at: Thu Jul 19 14:00:07 BST 2012
	Starting function firmware at: Thu Jul 19 14:00:07 BST 2012
	Downloading images from: http://files.ettus.com/binaries/master_images/archive/uhd-images_003.004.001-109-g6ca39ad9.zip
	6.94 MB/6.94 MB (100.00%)
	Images successfully installed to: /usr/local/share/uhd/images
	Done downloading firmware to /usr/local/share/uhd/images
	Done function firmware at: Thu Jul 19 14:00:19 BST 2012
	Starting function gnuradio_build at: Thu Jul 19 14:00:19 BST 2012
	/usr/local/lib already in ld.so.conf.d
	Doing ldconfig…
	Building Gnu Radio…
	…Doing cmake
	…Cmaking
	…Building
	Application asked to unregister timer 0x45000016 which is not registered in this thread. Fix application.
	…Installing
	Done building and installing Gnu Radio
	GRC freedesktop icons install …Done
	Done function gnuradio_build at: Thu Jul 19 14:41:05 BST 2012
	Starting function rtl_build at: Thu Jul 19 14:41:05 BST 2012
	Building rtl-sdr…
	Done building/installing rtl-sdr/gr-osmosdr
	Done function rtl_build at: Thu Jul 19 14:42:46 BST 2012
	Starting function extras at: Thu Jul 19 14:42:46 BST 2012
	Doing GIT checkout for extra module gr-baz
	Building extra module gr-baz
	Doing GIT checkout for extra module grextras
	Building extra module grextras
	Done function extras at: Thu Jul 19 14:51:02 BST 2012
	Starting function mod_groups at: Thu Jul 19 14:51:02 BST 2012
	********************************************************************************
	This script has just modified /etc/group to place your userid '('$USER')' into group 'usrp'
	In order for this change to take effect, you will need to log-out and log back
	in again. You will not be able to access your USRP1 device until you do this.
	If you wish to allow others on your system to use the USRP1 device, you will need to use:
	sudo usermod -a -G usrp userid
	For each userid you wish to allow access to the usrp
	********************************************************************************
	Further
	Done function mod_groups at: Thu Jul 19 14:51:03 BST 2012
	Starting function mod_udev at: Thu Jul 19 14:51:03 BST 2012
	Done function mod_udev at: Thu Jul 19 14:51:03 BST 2012
	Starting function mod_sysctl at: Thu Jul 19 14:51:03 BST 2012
	Applying updates to /etc/sysctl.conf
	Group 'usrp' now has real-time scheduling privileges
	You will need to log-out and back in again for this to
	take effect
	Done function mod_sysctl at: Thu Jul 19 14:51:03 BST 2012
	Starting function pythonpath at: Thu Jul 19 14:51:03 BST 2012
	************************************************************
	You should probably set your PYTHONPATH to:
	/usr/local/lib/python2.7/dist-packages
	Using:
	export PYTHONPATH=/usr/local/lib/python2.7/dist-packages
	in your .bashrc or equivalent file prior to attempting to run
	any Gnu Radio applications or Gnu Radio Companion.
	*************************************************************
	Done function pythonpath at: Thu Jul 19 14:51:04 BST 2012
	Done all functions at: Thu Jul 19 14:51:04 BST 2012
	All Done

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It seems that on a 64-bit Ubuntu installation, a full instance of the script’s working directory (containing all source code, and binaries) is about 520MB in size.

Notes on AirProbe installation

For readers wishing to install AirProbe using the instructions on the project’s Website, I recommend running sudo ln -s /usr/local/include/gruel/swig/gruel_common.i /usr/local/include/gnuradio/swig/ && ldconfig, after installing GNURadio, in order to avoid some frustrating bugs in various build scripts related to missing “Gruel”, and “SWIG”-related files.

Testing the result

Since this post is becoming rather long, and I’m unsatisfied with the content that I planned for this section, I’ll follow up with a second post related to testing the software post-installation, soon.

Explore posts in the same categories: Everything

Tags: DAB, DVB, GSM, Hardware, Linux, Open Source, Radio, RTL-SDR, SDR, Software, Tinkering

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