(Continued from Part 1. This concludes the article.)
I will devote the rest of this article to a USB “dongle” type radio receiver that I have on hand, and the amazing things you can do with it. I also intend to make mention of a device called a “Tiny SA” a signal analyzer that was made more for spectrum analyzing signals on the test bench but can also be used for SIGINT as well.
The USB dongle I am currently using is the RTL2832U. This is a low-price unit costing just $40. But I do advise you consider buying the full package unit at $114 with all the items needed to get on the air. I have in fact just ordered this package since my current unit is not as up to date as this package is, and I wanted to compare it with this new one.
One word of caution: there are a lot of fake SDR modules and dongles coming out of China and other countries in Asia. The main RTL-SDR website is a reputable seller of these units. Also see the website for one of the original developers.
So, buyer beware of what you are buying, and from whom you buy it.
WHERE TO BEGIN
So you have bought your SDR dongle, and let’s just assume you bought the V4 type unit from the authorized vendor for $43.95 + shipping. This is a get-you-started kit with antenna and all you need to make this dongle work. See the website for their starter guide.
Here is an excerpt with some important installation and set-up information from the SDRSharp website:
This page is essential for you to read and follow so that your dongle will work properly. The drivers needed to operate your radio are located
SDR# (SDRSharp) Set Up Guide (Tested on Windows 11/10/8/7) (XP/Vista Incompatible) (Works with RTL-SDR Blog V4/V3)
SDR# is the most commonly used SDR program on Windows. We recommend it as one of the easiest to setup and use with the RTL-SDR.
Purchase an RTL-SDR dongle. We recommend purchasing one of our RTL-SDR Blog V3 or V4 dongles. Information on purchasing one can be found here.
You must have the Microsoft .NET 8.0 x86 Desktop Runtime installed to use SDRSharp. Most modern PCs will have automatically updated to this already unless you have specifically blocked these updates on your PC.
You will also need the Microsoft Visual C++ redistributable installed. Most PCs will have this already installed, but if you do not you can download the x86 version from here.
Go to www.airspy.com and find the downloads button on the top menu. Next to the “Software Defined Radio Package” heading click on the download button to download sdrsharp-x86.zip. Do not download the community managed edition, as this is often broken.
Extract (unzip) sdrsharp-x86.zip to a folder on your PC. (Important! Many people who have issues forget this step! DO NOT run the files from within the zip file or the following steps will fail). (Also, do not extract into a folder within the Program Files directory, or installation may fail as these folders are often automatically made read only by Windows).
Double click on install-rtlsdr.bat from within the extracted folder. On some versions of Windows you may get a SmartScreen warning. Click on More Info, then Run Anyway. This will start a command prompt that will download all the drivers required to make SDRSharp work with RTL-SDR. Once completed, press any key to close the command prompt. If the batch file ran successfully the files rtlsdr.dll and zadig.exe will be downloaded into the SDR# directory. If they were not downloaded then your PC or anti-virus solution may be misconfigured and may have trouble running batch files (Check that the folder is not read only, and not located in the Program Files directory). If install-rtlsdr.bat fails to download the dll or zadig, do a manual driver installation. If Zadig is smaller than 5000kB (5MB), the download has failed and you should download Zadig manually.
Plug in your dongle. Do not install any of the software that it came with (if any), and ensure that you wait a few seconds for plug and play to finish attempting to install the dongle (it will either fail or install Windows DVB-T TV drivers). If you’ve already installed the DVB-T drivers that came on the CD bundled with some dongles, uninstall them first.
In the folder where you extracted the sdrsharp files find the file called zadig.exe. Right click this file and select “Run as administrator”.
In Zadig, go to “Options->List All Devices” and make sure this option is checked. If you are using Windows 10 or 11, in some cases you may need to also uncheck “Ignore Hubs or Composite Parents”.
Select “Bulk-In, Interface (Interface 0)” from the drop down list. Make sure it is Interface 0 (ZERO), and not “1”. Note on some PCs you may see something like RTL2832UHIDIR or RTL2832U or Blog V4 instead of the bulk in interface. This is also a valid selection. Double check that USB ID shows “0BDA 2838 00” as this indicates that the dongle is selected.
WARNING: DO NOT select anything else or you will overwrite that device’s driver! DO NOT click around randomly in Zadig. If you do you are likely to overwrite your mouse, keyboard, printer, soundcard etc drivers. Many bad reviews we get are due to people clicking around randomly in Zadig, so PLEASE check what you are doing first.
Make sure the box to the right of the arrow shows WinUSB. The box to the left of the green arrow is not important, and it may show (NONE) or (RTL…). This left hand box indicates the currently installed driver, and the box to the right the driver that will be installed after clicking Replace/Install Driver.
Click on Replace Driver. On some PC’s 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.
Open SDRSharp.dotnet8.exe and set the “Source” to ‘RTL-SDR USB’. The source menu is in the top left Hamburger Menu (the three horizontal lines).
Press the Play button (the right facing triangle in the top left of the program). 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.
Important! Don’t forget to also adjust the RF gain settings by adjusting it in the Source window, in the lower left of SDR#. By default, the RF gain is set at zero. A gain of zero will probably receive nothing but very strong broadcast FM – increase the gain until you start seeing other signals. To receive HF signals below 24 MHz with an RTL-SDR Blog V3, please see our V3 users guide.
What’s Next?
After getting your RTL-SDR set up with SDR# we recommend investigating the following:
If you are using a RTL-SDR.com V3 dongle, view our V3 users guide to learn how to use the special features like HF direct sampling and the bias tee. If it is a newer V4 dongle, visit our V4 users guide.
Read the SDR# Users Guide to learn what each setting in SDR# does. You may also want to check out the more up to date and comprehensive “SDR# Big Book” which is available on the Airspy downloads page.
Check out all our featured articles on this blog for various RTL-SDR related projects and tutorials.
Upgrade from the stock antenna. For optimal reception you should use an outdoor roof-mounted antenna. The optimal antenna will depend on the frequency and project you are interested in, but for a general all purpose antenna we recommend a Discone or planar disk antenna (pdf).
If you are using your RTL-SDR for HF with direct sampling mode or an upconverter then we recommended using SDR# with the special decimation drivers. This will allow you to zoom in on the small bandwidth signals used on HF without loosing resolution.
Check out our store for various RF accessories such as filters, LNA’s and antennas.
Also check out the official list of SDRSharp plugins which can be found here and also our unofficial list of plugins which can be found here.
https://dotnet.microsoft.com/en-us/download/dotnet/thank-you/runtime-desktop-8.0.6-windows-x86-installer
https://airspy.com/ [End of excerpt]
A word of warning: my SDR Sharp dongle was damaged by my Windows 11 platform. For some reason, the Windows 11 USB assignments of interrupts caused the dongle to stop operating if another USB device is also being used at the same time. Something on the programming of the Windows 11 platform loses its task load timing and hangs up the SDR dongle which caused it to go into a feedback mode and overheat the chip.
I have bought a new dongle (Version 4) which hasn’t yet arrived, but I also bought an older laptop computer that has Windows 10 installed, and I will not upgrade it to Windows 11 since this laptop cannot handle the Windows 11 upgrades. I don’t care about the Windows 11 features for this project. I am also going to explore using a Raspberry Pi to load the dongle on, as a stand-alone SIGINT receiver.
Addendum
There is a very useful program called Artemis that can be used in conjunction with the SDR Dongle to intercept signals, to identify the signal type.