Software-defined radio (SDR) is a technique for turning a computer into a radio. But not just an AM/FM radio - by using the computing power on your desktop you can listen and decode a wide variety of broadcasts. SDR can turn your computer into a weather-band receiver, a police/fire report scanner, a music listening station, and more! Instead of manually tuning inductors, its all done in software by chips fast enough to pick up and decode radio waves on the fly
If you've ever been curious about software defined radio (SDR), this USB
stick is the easiest way possible to have fun with a powerful,
configurable receiver. Packed with the powerful RTL2832U and R820T
tuner, it can tune into signals from 24MHz to 1850MHz. That means you
can use a computer (with Windows, Mac, or Linux) to tune into: FM Radio,
AM signals (but not AM radio), CW (morse code!), unencrypted radio
signals (such as those used by many police and fire departments), POCSAG
pagers, and more.
In this tutorial we'll show how to get your very first listening adventure underway - listening to FM radio and decoding the RDS/RBDS data signal that is sent along with many FM radio stations as well.
Next, we'll set up the software -- if you're using windows, head to the next page -- SDR-Sharp for Windows. On mac os, jump to the page CubicSDR for mac os.
To see some SDR action live, check out this episode of John Park's Workshop:
Download & Install Software
We'll be using the awesome SDR# software for windows, which is really easy to use and very powerful as well! Visit http://sdrsharp.com/
to download - we're using Rev 1243
Save and uncompress the zip file
Double-click on install.bat
This will download the latest build and extract it into the current folder. SDR# does not install into the toolbar or start menu!
Before we continue, we'll have to install the Windows driver for the RTL USB stick and then swap it for a 'low level access' driver. The default driver assumes you'll just be using the RTL-SDR for watching TV or radio but we want to be able to control it to do much more.
Plug in the stick, Windows should automatically install the REALTEK 2832U driver
Now from inside the SDR# directory, run Zadig which will do the driver swapping for us.
Here's a version 2.2 exe if you need it:
From the Options menu, select List All Devices
Then from the devices drop-down, find one that says Bulk-In, Interface (interface 0). If there's more then one, select one at a time, and verify below to get the right one.
Check that you get USB ID 0x0BDA (vid) and 0x2838 (pid) and the RTL2832UUSB driver
Make sure to the right of the green arrow you see WinUSB
Click Replace Driver
Lets start by just listening to every-day FM radio. Open up SDRsharp.exe (you can close Zadig)
Begin by selecting the RTL-USB dongle instead of audio card
Select WFM (wide-band FM radio) under the Radio signal type
Click on Configure
And set the gain about half-way up
You can set your favorite frequency (FM station) by clicking on the large numbers up top
Click Play/Start and set the volume starting from low to high so you don't hurt your ears!
You can 'seek' for radio stations by looking for peaks. Click on them to tune in
With the latest versions of SDR-Sharp it will automatically detect and decode RBDS/RDS data that is sent along with FM radio
Chances are your radio station is also playing Donna Summer!
Most every-day AM/FM radios can't tune into theNOAA Weather Radio (NWR) All Hazards network but with RTL-SDR we can! NWR is the national weather alert system, which broadcasts weather data as well as emergency alerts.
Let's tune into the closest weather station to Adafruit Southern California, which is in Los Angeles. You'll want to tune into whatever station is closest to you.
To begin, visit the NOAA weather station frequencies-by-county index here
The frequency is 162.550 MHz, type that into the SDR# frequency window
You can see a little peak, its much smaller signal than the FM radio stations. It's also much thinner which makes it a narrow-band FM rather than wideband. Since its voice, not stereo music, they use less of the frequency band, so select NFM as the decoding type
The station is marked as degraded, but by amplifying the gain on the RTL-SDR we were able to tune in
You should be able to hear a computer-generated voice speaking out the weather forcast. It's not terribly exciting but it is very thorough, often giving very detailed reports. The signal continuously transmits so you can tune in at any time!
now that you have some basic functionality
working, try tuning into other frequencies, and trying the different
kind of decoding (e.g. CW/AM/NFM) to tune into AM radio!