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As I expected, the BBB SDR road test would lead me down an exciting road to discovery.  I have not been disappointed.  The 1st step was of course to unpack all of

the components of the road test package.  I was impressed by the small size of the SDR USB dongle.  I have had previous experience with the BeagleBone Black,

having purchased one in late 2013.  The LCD display however was entirely new to me.

 

I admit to requiring a moment to figure out exactly how the LCD display mounts on top of the BeagleBone Black, since there wasn't any documentation specifically

explaining which direction it was to be mounted.  Fortunately, on closer inspection you discover that the display can only be mounted successfully in one

orientation.  A quick confirmation on the Internet proved my deduction correct.

 

For your own reference, the LCD display mounts with the left side of the display above the 5 V power connector and ethernet connector of the BeagleBone Black.  The

right side of the LCD display, which contains the 5 pushbuttons for controlling the display, hangs over the right side of the BeagleBone Black above the USB

connector.

 

BBB_LCD.JPG

 

The display is easy to mount into the 2 sets of header sockets on the top of the BeagleBone Black.  There isn't any set up required, just plug it in and reboot

your BBB and voilà you have your LCD display.  With the keyboard plugged in you have a complete self-contained standalone Linux-based computer.

 

Since I had no previous experience with the USB SDR dongle, I felt the best way to proceed was to start by connecting it to my desktop PC.  After doing some

research on the web, I found and downloaded several Windows-based software packages which would interface with the SDR.

 

I have experimented with the following:

 

 

 

While each of these offer slightly different features, the SDR# was the easiest to install and get operational.  I was able to confirm that my USB SDR dongle was

capable of receiving local commercial FM broadcast signals.

 

SDR#.PNG

 

I was intending to use the local WeatherRadio Canada broadcast station close to my location has a known radio source.  The station broadcasts at 162.400 MHz,

continuously 24 hours a day.  My initial experimentation with the SDR dongle showed that I was just barely able to pick out the signal from the background noise

with the SDR antenna mounted on my office desk beside me.  This discovery leads me to believe that if I intend to produce an accurate RF signal map of the local

radio sources in my area I will need to improve the signal-to-noise ratio of incoming signals.  This will probably mean that I will need to replace the magnetic

mount antenna that comes default with the SDR dongle, or at the very least mount the antenna outside in a better receiving position.

 

In the meantime, I've decided to proceed with a proof of concept where I will scan across the commercial FM broadcast band and make an inventory of the stations

I'm able to receive.  The stations are strong enough to be able to be received by the default antenna in a convenient indoor location.  In addition they bring with

them the bonus that I know where to expect to find these stations.  Once I've developed a system capable of scanning across that band and successfully locating and

identifying the frequencies and received signal strengths of those stations then I can concentrate on improving the reception capabilities of the SDR.

 

It is now time to turn my attention to getting the SDR dongle to work on the BeagleBone Black device.  Initially I had envisioned using the GnuRadio software

system as the heart of my frequency scanner.  As I did more research I realized that the processing requirements of that software package might in fact be too

intense for the BeagleBone Black.  I did install this package on a Ubuntu Linux VM running in VMware on my Windows 7 PC.  It certainly lives up to its reputation

as being a very complex piece of software.  I can appreciate the power and flexibility that it seems to provide.  I began to wonder however if it was overkill for

my application.

 

I took a step back and decided to try a minimalist approach.  I followed the procedures described here (http://sdr.osmocom.org/trac/wiki/rtl-sdr) to install the

rtlsdr library and utility programs designed to work with the Realtek RTL2832U based SDR dongle's.

 

The RTLSDR library was fairly straightforward to install.  Make sure that you take note of the requirement to have the development packages for libusb1.0 installed

on your BeagleBone Black before you attempt to install the RTLSDR software.

 

Once I completed the installation of the RTLSDR library, I was able to test the success of the installation by running the following command from the BeagleBone

Black terminal.

root@beagleboneblack:~# rtl_test -t

 

This provided me with the following return information thereby confirming the successful installation and connection to my SDR dongle.

 

Found 1 device(s):

  0:  Realtek, RTL2841UHIDIR, SN: 00000001

 

 

Using device 0: Generic RTL2832U OEM

Found Rafael Micro R820T tuner

Supported gain values (29): 0.0 0.9 1.4 2.7 3.7 7.7 8.7 12.5 14.4 15.7 16.6 19.7 20.7 22.9 25.4 28.0 29.7 32.8 33.8 36.4 37.2 38.6 40.2 42.1 43.4 43.9 44.5 48.0 49.6

Sampling at 2048000 S/s.

No E4000 tuner found, aborting.

root@beaglebone:~#

 

After looking through the documentation available for the RTLSDR library, I discovered that there is a utility called rtl_power, which may do exactly what I need to help me create my local RF source map.  In my next blog installment, I will describe in detail how I plan to use rtl_power for my BeagleBone Black Internet Radio Challenge Road Test.

 

William

Greetings everyone.  Welcome to my first blog post covering my road test of the BeagleBone Black single board computer, and the DVB-T Stick Software Defined Radio.

 

I should probably start by introducing myself.  My name is William, and I'm a senior software engineer for Art & Logic, a custom software development outsourcing company based in California.  I work from my home in Prince Edward Island, on the east coast of Canada.  I've been interested in computers and radio most of my life and have been a licensed amateur radio operator since 1977.

 

I was very pleased to be selected for this road test and am excited to start with my project using the BeagleBone Black (BBB) and the software defined radio (SDR) module.

 

The focus of my road test is to create a local RF source catalog.  This will catalog all stationary RF sources for a given frequency range, within reception of my location.  In addition to the frequency, and received signal strength of each RF source, data on transmission schedule patterns as well as direction to source information would be collected.  From this data, a map will be constructed displaying each radio source based on direction and implied distance from the receiving station based on relative received signal strength.

 

Over the next 4 or 5 weeks, I will be posting regular updates on my progress.  I will attempt to provide you with details on the steps I take along the way.  This should give you the ability to replicate my project on your own, and to perhaps take it in new directions.

 

Much of the effort in this road test will be focused on software to control the SDR, and capture and store the data gathered during the project.

 

I will be starting with the powerful and somewhat daunting GnuRadio software package.  This is probably the most widely used and highly flexible software available for controlling software defined radio systems. It comes with a number of individual source code modules which can be combined to create a vast array of SDR behaviours.  There will be it of a challenge for me, since this modules are written in Python.  While I am fluent in a number of computer languages, C, C++, Java, C#, VB.NET etc, I've only just dabbled a bit in Python, so there will be a bit of a learning curve there.

 

So.. please stay tuned as I'm sure we are in for a fun time experimenting with this combination of components.