Friday, December 17, 2021

Making SDR easy with SIGpi


Do you have a Raspberry Pi 4 that needs a new use?  Have you wanted to run your RTL-SDR V3, HackRF, Lime SDR or other SDR on something other than a dedicated computer?  Are you afraid of the word "dependency" when it comes time to compile applications on Linux? Would you like to be able to better sense the RF world around you?

If you answered yes to any of those questions, SIGpi is going to be worth paying attention to.  What Joe Cupano NE2Z has done is created a set of automated installation scripts and menu system to allow for easy automated installation of many popular software defined radio applications and optimized a few things to run on Raspberry OS 64-bit (or 32-bit) systems.

Quick Dare To Compare

Dragon OS is a precompiled Linux operating environment along with many popular SDR and related applications which is quicker to get started with compared to SIGpi.

The major benefit with SIGpi is user customization for what you wish to install as the main applications.  And, when it comes to to update applications like SDRangel or SDR++ as example, a script called "pusher" allows the prior version to get updated to the latest version without breaking dependencies.

Beyond many of the visual applications that may be of interest to those interested in "signal interception" work, many command line and other applications of interest to wireless network or amateur radio professionals are also included.

These are some of the user experience driven benefits of what makes SIGpi unique and beneficial to different users and for those with different levels of technical abilities.

Pre-Education: Getting Started with SIGpi

Go ahead and grab your favorite SDR device which is NOT one of the SDRplay devices and install a fresh copy of either the 32 or 64 bit version of Raspberry OS onto a new 32GB or larger SD card.

A few quick notes:

  • Performance will be better under the 64 bit based Raspberry OS, so you need to decide that now.
  • If you decide to use the 32 bit version, a program called Artemis will be able to better function
  • Artemis is an offline signal analysis database application which has samples of different signals and frequency uses to help determine likely digital mode signals you may come across.

Once you have your fresh SD card ready with Raspberry OS version of choice, it would be a good idea to enable SSH support for later ease of access. 

Enabling SSH access on a Raspberry Pi likely is something our readers should be aware of already.

After you log in to your Raspberry Pi for the first time with the generic credentials,  it may also be a good idea to sudo raspi-config and also enable VNC support for further headless access.

SIGpi has intentionally turned off Wi-Fi interface, so you can also choose to turn that back on if you like while you are in raspi-config when connected over LAN.

A Few Easy Steps

There are only a few steps you need to do now that you have your Raspberry Pi 4 that is hopefully connected to the internet now to now move towards getting SIGpi installed and you have already completed the usual apt-get update and apt-get upgrade sequences.

Below in green are the commands needed via terminal to get ready for SIGpi. Details are also in the Git repository page here.

First, you will need to run sudo apt-get install -y build-essential cmake git .  This will add some other important pieces to your stock Raspberry OS installation.

Next,, you will need to mkdir ~/SIG && cd ~/SIG in order to create the directory where SIGpi will end up and also automatically move you into that directory for our next step.

Use this opportunity now, if not already, to make your terminal screen full screen on your computer which will be helpful for some later steps.

The third thing to run via your terminal is:

git clone

This important step will clone the Git repository for SIGpi to your Raspberry Pi.

Finally, all you have to do now is cd SIGpi so that you can run the set up script for SIGpi.


Now here is where the fun begins. Once you run the ./ and if everything was followed up until this point, you be greeted with a screen like this now in your terminal:

After using your tab key to allow you to hit enter, your next step will be to select the base applications for your installation.  

A 32GB SD card at minimum is suggested for further expansion, but if you wish to use a 16GB card, you can select the options in this article to help keep your installation a little smaller for now.

The reason why we are providing an option for two versions of GNUradio is based on user preference.

 Some people may prefer to still use the older 3.8 version since the architecture for 3.9 changed a bit. For most people who are interested in the more visual applications for SIGpi,  either is fine and 3.8 may be fine for now.

In this step, your base visual SDR applications can be installed and we suggest getting familiar with SDRangel and also SDR++.  Lighter weight applications like GQRX and CubicSDR are provided as options for convenience.

This step will be of more interest to amateur radio people interested in some digital modes specific to those activities mostly. 

You can decide to always come back to install these if you like, but they are all pretty small and could not hurt to include all five in your initial installation.

This selection of useful applications will appeal to different people for different reasons. Some may already be familiar to some readers, but Artemis might be new as well as the HVDN HASviolet project which we snuck in here as well.  

At any point after initial installation you can add these, but if you have a 32GB card or greater, it is more than ok to just select all of these and move on.

It is worth noting that the popular rtl_433, dump1090, radiosonde and a few other command line applications are already going to install automatically since they are small, but we chose to only highlight the larger applications in this menu tree for installation.

And now you are ready to hurry up and wait. Once you move past this menu, you will start to see a flurry of activity taking place with critical milestones highlighted during installation to know what steps you are up to.  

Depending on your options selected, the total installation for the first time will take up to three hours in total.  As the SIGpi progresses you will see colored bars like above letting you know what is comping up and what has just finished installation.

If you decide to include SDRangel, the wisdom files included for FFT will be worth the wait given all the underlying dependencies that F4EXB and his community have built into this great application. 

The Artemis application and hamlib will also take a while, but as long as you can leave your Raspberry Pi connected to the internet and you can check in on it from time to time via your terminal, everything should run pretty smoothly. 

Installed. Now what?

Suggestion from here is to just VNC into your Raspberry Pi and you will be greeted with some localization steps for Raspberry Pi like setting up a keyboard, time zone and warned that now is a great time to change the default password from "raspberry" to something else.

Once you have a look at the menus in the Raspberry OS, you will see many fun things to play with and explore signals around you.

A last recommendation before we close this article is that it is a good idea to plug your SDR into the Raspberry PI 4 USB 3.0 port (the blue ones!)  to get more bandwidth for your SDR.

Perhaps starting with SDR++ or SDRangel is what got you excited, so hope you enjoy SIGpi.

When it comes time to update to a later version of the applications installed, you can learn about how to do that by visiting the SIGpi Git repository.

Future video, article, etc coming up to help better understand how to actually use the software and also how to update things when its needed with SIGpi.

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