This page is a guide aimed at helping anyone set up a cheap radio scanner based on the RTL-SDR software defined radio as fast as possible on a Windows system.
To get the most enjoyment out of RTL-SDR you will need a decent antenna. The stock antenna that is shipped with the dongle is okay for testing and will pick up a number of signals, but is generally considered as poor for any serious radio scanning. For beginners, a bunny ears antenna like those you get for TVs should already work much better than the stock antenna. The most recommended antenna for general scanning is a scantenna or discone due to their wide band receiving properties.
Set Up Guide (Tested on Windows Vista/7 + XP)
- Purchase an RTL-SDR dongle. The cheapest and best for most applications is the R820T dongle, which can be purchased here from Nooelec.
- SDRSharp is the easiest and most commonly used software defined radio software receiver for the RTL-SDR. Go to sdrsharp.com and head to the downloads page. Note that you must have the Microsoft .NET redistributable installed to use SDRSharp. Most modern Windows PCs should already have this installed by default, but older PCs running XP may need this to be installed.
- Ignore the downloads on the top of the page. Scroll down to where it says “Important note for RTL-SDR users”. Download sdr_install.zip from that link.
- Extract sdr_install.zip to a folder.
- Double click on install.bat from within the extracted folder. This will start a command prompt that will download SDRSharp and all the files required to make SDRSharp work with RTL-SDR. Everything will be placed into a new folder within the sdr-install folder called “sdrsharp”. The command prompt will automatically close when it is done.
- Plug in your dongle and do not install any of the software that it came with, but ensure you let plug and play finish trying to install it. If you’ve already installed the software drivers it came with previously, uninstall them first.
- Open the newly created sdrsharp folder. Find the file zadig.exe. Right click this file and select “Run as administrator” if using Windows Vista/7/8. If you are using Windows XP, download the XP version from this page.
- In Zadig, go to Options->List All Devices and make sure this option is checked.
- Select “Bulk-In, Interface (Interface 0)” from the drop down list. Ensure that WinUSB is selected in the box next to where it says Driver. (Note on some PCs you may see something like RTL2832UHIDIR instead of the bulk in interface. This is also a valid selection).
- Click Install Driver. You might get a warning that the publisher cannot be verified, but just accept it by clicking on Install this driver software anyway. This will install the drivers necessary to run the dongle as a software defined radio. Note that you may need to run zadig.exe again if you move the dongle to another USB port, or want to use two or more dongles together.
- Open SDRSharp.exe. Set the drop down box at the top next to the Play button to ’RTLSDR / USB’. Press Play. Your rtl-sdr software radio should now be set up and ready to use! If everything has worked you should be able to start tuning to frequencies. Be sure to also adjust the gain settings by pressing the Configure button up the top near the Play button.
- Zadig takes a long time to install the driver, then fails
You have probably not run zadig in administrator mode. Make sure to right click zadig, and select “Run as Administrator”
- I don’t see Bulk-In, Interface (Interface 0)
Ensure Options->List All Devices is checked. Some people report seeing something else other than the bulk in interface. It may also show up as the brand of your dongle or something prefixed with “rtl”. This option should work too.
- I don’t see RTL-SDR/USB in SDRSharp
You may have downloaded a version without rtl-sdr support. Check that you followed the instructions in step 3 and downloaded the version under the heading “Important note for RTL-SDR users”.
- Zadig gives “System policy has been modified to reject unsigned drivers“ error in Windows 8
Windows 8 can cause signed driver issues with zadig. Some users report getting the error “System policy has been modified to reject unsigned drivers”. A possible solution has been posted here in the SDRSharp Yahoo Group.
How to set the Gain
When tuning the RF gain you are trying to get the signal as strong as possible, whilst keeping the noise floor as low as possible. Start with a low gain setting, and slowly increase the gain slider. Watch in the frequency spectrum as the signal strength increases, but stop just before the point at which the noise floor starts to rise.
The noise floor is the part of the frequency spectrum where there are no signals.
A list of SDRSharp plugins can be found here.
A good guide to learning how to use SDRSharp and what all the options do can be found here.
Other SDR Windows Software Compatible with RTL-SDR
HDSDR – An advanced version of the WinRad SDR software. A free software defined radio package.
SDR-Radio v2 – A Windows program for software defined radio.
SDR-J – Windows program capable of also decoding DAB signals in software.
Getting Started on Linux
A good guide to getting started on Linux and GNU Radio can be found at this blog post here.
Note that if you want to run Linux in a virtual machine it has been reported that performance with VirtualBox is rather poor due to it’s slow USB connection. VMWare Player on the other hand has good performance.