Tagged: raspberry pi

Recent Podcasts on Software Defined Radio from Scanner School

Scanner School is an online resource that aims to teach subscribers all about radio scanning. They also run a weekly podcast discussing various topics in the scanning hobby. Recently they've had a bit of a focus on software defined radios, with several of the last podcasts being SDR related.

Episode 170 - SDRplay with Jon Hudson

On today’s episode, host Phil Lichtenberger interviews Jon Hudson, the co-creator of the SDRplay devices. They talk about the evolution of radio scanning software, the advantages of SDRplay and SDRuno, where they think the scanner hobby is headed, and more.

What You Need To Know

Jon Hudson is a co-creator of the SDRplay device. SDRplay manufactures both hardware and software. Before about 20 years ago, processing the radio chain was done exclusively on the hardware. Now computers are powerful enough to support doing most of this work with software. SDRplay was founded in 2014. The RSPDX has multiple antennae, which allows users to switch from one antenna to another quickly and easily. Because SDRplay makes their own software for Windows, they take a lot of time to make sure it works seamlessly out of the box. SDRplay acquired a company called Studio One that manufactured software about five years ago. SDRplay is releasing a scheduler, which will function as an audio recorder for a specific channel at a specific time. An advantage of the scheduler is that it allows users to tune in to certain frequencies at a specified time and then turn it off or move on to something else. All session notes with links to the items we talked about can be found on our website at www.scannerschool.com/session170

170 - SDRplay with Jon Hudson

Episode 169 - SDR++ with Alex Rouma

A cross platform, open source, free SDR software!

In this episode, Phil talks to Alex Rouma, author and creator of SDR++. They discuss how Alex got into SDRs, where SDR++ is now and where he hopes it can go, and how you can contribute to this open source software’s development, whether you’re a programmer or not.

What You Need To Know

SDR++ is free, open-source, cross-platform software for your SDR. Alex got into SDRs after watching a video of someone receiving weather satellites, piquing his interest in radio in general. Alex is currently building SDR++ as general purpose SDR receiver software with more modern functionality like multi-VFO and multi-platform support. SDR++ supports anything Alex has or that companies have sent him, including SDR Play, HackRF, RTLTCP, and more. Alex considers the software still in beta, but thinks he’ll have stable code with the features he wants within 3-4 months. He wants to add audio filtering features and more options for the file source. SDR++ is fully modular so you can add plugins as you need them. Alex aims to make the software as automatic as possible. All session notes with links to the items we talked about can be found on our website at www.scannerschool.com/session169

169 - SDR++ with Alex Rouma

Episode 168 - Using a SDR as Your Scanner

In this episode, Phil talks to listener Greg Weamer about his SDR setup. They get into the history of SDR development, what you can do with an SDR that you can’t do with a hardware-based scanner, and where they think the future of SDRs is heading.

What You Need To Know

Today, Greg does not have a hardware scanner at all, but only a SDR. His area has simulcast problems that the SDR solves. Greg currently uses about 8 RTL-SDR dongles, including 3 on a Raspberry Pi, some on another Raspberry Pi, an old laptop, and more. Greg also uses Trunk Recorder, which is one of the most difficult things he’s ever configured, but he loves that it monitors every voice channel at the same time. RDIO Scanner is a web interface that takes the feeds from the virtual recorders Greg has going and cues up calls on every voice channel so you don’t miss anything. Because it’s a web interface, he can bring it up on his phone or tablet from anywhere. Greg thinks the next major SDR development will eliminate the need for any fully hardware based radios entirely. An SDR can do things that not a single hardware-based scanner out there is capable of. Greg has used his SDR to tune into his utilities smart meters for his water and gas to track his usage. One of Greg’s favorite things about SDR is that you can see the signals and whether they’re strong or not, whether they’re digital or analog, etc. The ability to visualize the signal lets you find a lot more new stuff to listen to. The flexibility of an SDR and ability to do so many things at once with it means you get the equivalent of several premium subscriptions to other services. All session notes with links to the items we talked about an be found on our website at www.scannerschool.com/session168

168 - Using a SDR as Your Scanner

Episode 165 - This is Why You Need an SDR

In this episode, Phil walks through the basics of what an SDR is, its history, and how you can get set up with one. The perfect introduction to his upcoming SDR webinar and course.

What you will take away from this week's podcast:

An SDR means that anything normally handled by the hardware of the radio is now handled by the computer, and the physical hardware serves as an interface. The only limitation on the SDR hardware you buy is the frequency range and the amount of RF it can digest. SDR receivers have come a long way since they were first hacked into existence. SDRs used to be difficult to set up, but that’s no longer true. You don’t need advanced computer skills to run SDR software. SDR software can run on PC, Linux, Mac, Raspberry PI, and even Android. An SDR is more flexible and less expensive than a traditional radio. You can turn a $30 USB stick into something as powerful as an SDS200 in an afternoon. All you need to get started is an SDR USB stick, a computer, and the free starter software SDR Sharp. Once you get set up with FM broadcast stations, aviation, and other analog systems, Phil’s SDR course will go into how to set up digital reception. If you download DSD+ Fast Lane or Unitrunker you can monitor trunking systems. All session notes with links to the items we talked about an be found on our website at www.scannerschool.com/session165

165 - This is Why You Need an SDR

Episode 164 - Raspberry PI and SDR w/ Fuzz the Pi Guy

In this episode, Phil talks to "Fuzz the Pi Guy".

Fuzz has a large YouTube channel and has a ton of SDR and Raspberry Pi Videos.

Fuzz and I discuss how he uses his Software Defined Radios and how he keeps costs down by using a Raspberry Pi as as his computer for many of these projects.

What you will take away from this week's podcast:

SDR stands for Software Defined Radio, where you plug your hardware into power on one end and your computer on the other end so the computer software can interpret the signal. The Raspberry Pi is essentially a low-cost computer to help teach computer science in schools, and is now used for things like hosting Minecraft servers, learning Linux, and running SDR programs. Fuzz has a YouTube channel where he primarily demonstrates Raspberry Pi projects and tips, as well as a wide variety of small electronics content. He’s using a new setup that involves a Raspberry Pi 3 with an RTL-SDR dongle, connected to a 2m 70cm homemade antenna to receive his local Phase 2 frequencies, uploaded to Broadcastify using the new free software OP25. Using this setup, Fuzz essentially created a Phase 2 scanner for under $100. The FlightAware website gives a good introduction to using the Raspberry Pi with an SDR that can get you set up in under 15 minutes. The Raspberry Pi has the best support system out there for any Pi hardware, but Fuzz has been working with the Atomic Pi lately. This setup provides an inexpensive alternative to buying a pricey scanner if you don’t mind troubleshooting and problem solving to get going. All session notes with links to the items we talked about an be found on our website at www.scannerschool.com/session164

164 - Raspberry PI and SDR w/ Fuzz the Pi Guy

Controlling a Wireless Ceiling Fan with an RTL-SDR and RPiTX on a Raspberry Pi

Over on YouTube River's Educational Channel has uploaded a new video showing how he uses a Raspberry Pi to control a ceiling fan via it's wireless control signal. Back in January we posted about River's first video where he shows him using and RTL-SDR and Universal Radio Hacker (URH) to reverse engineer the control signal.

In this new video River uses the RPiTX software to generate the control signal without requiring any additional transmit hardware. He first explains how RPiTX can generate an arbitrary signal from a square wave and talks a bit about the harmonics this creates. To reduce harmonics he adds a simple low pass filter to the GPIO output.

Next to control the fan he uses the "sendook" program that is included with RPiTX to transmit the binary control string that he reverse engineered in his original video. Finally he creates a simple web server so that he can control his ceiling fans via his phone and integrate it into his smart home.

Abusing Raspberry Pi GPIO pins as a radio transmitter to control my ceiling fan

Etherify Talk from The rC3 Online Conference

The "Chaos Computer Club (CCC)" have recently been uploading videos to YouTube from their "Remote Chaos Experience rC3" online conference. One talk is by Jacek Lipkowski (SQ5BPF) who presents his Etherify project which we have posted about a few times on this blog already. Etherify is a program that allows users to exploit unintentional RF leakage from Ethernet hardware in order to transmit data over the air, essentially creating a primitive software defined radio. In particular the Raspberry Pi 4 was found to have extreme unintentional leakage, with the signal being receivable from over 50m away.

Primitive soft tempest demos: exfiltrating data via leakage from ethernet and more :)

In this talk i will describe shortly the concept of soft tempest, and show a demo of etherify and sonify. Etherify uses radio frequency leakage from ethernet to exfiltrate data. Sonify uses ultrasound.
Both demos by design use very primitive tools and hardware, and are easy to replicate.

#rC3 Etherify - bringing the ether back to ethernet

Etherify 4: Using PC Ethernet RF Leakage to Transmit QRSS CW

Recently we've posted about Etherify a few times, mostly about how the unintentional RF leakage from the Raspberry Pi 4 Ethernet hardware is really strong and can be modulated to transmit data. In one of his latest posts Jacek Lipkowski (SQ5BPF) explores if Ethernet ports on PC's exhibit any sort of RF leakage too, and if it can be modulated into a data signal.

The answer is yes, there is some RF leakage, however unlike the Pi 4 the speed at which the leakage can be modulated is much slower, and also the signal strength is much lower. Despite the slow modulation speed, Jacek was still able to transmit data by using QRSS CW, which is essentially just very slow morse code. Using this idea he was able to transmit, and receive the CW signal with an RTL-SDR over a distance of 3 meters at 375 MHz, 625 MHz and 250 MHz. The signal strength is nothing like the Pi 4's Ethernet RF leakage which can be received strongly from over 50 meters away however.

Etherify: Transmitting QRSS CW via Ethernet RF leakage from PC to PC

Etherify: Pi 4 Exhibits Very Strong Ethernet RF Leakage

Not too long ago we posted about Jacek Lipkowski (SQ5BPF)'s project called "Etherify" which seeks to use unintentional RF radiation from Ethernet hardware/cables to transmit arbitrary signals such as morse code and FSK. During his earlier experiments he noted how he felt that the Raspberry Pi 4 had an unusually strong radiated Ethernet signal. In his recent post Jacek investigates this further.

Indeed his new tests seem to confirm that the Pi 4 has excessive RF leakage from the Ethernet hardware. His latest results have shown that he was able to receive the Ethernet leakage strongly from 50 meters away without any cable connected to the Ethernet port to act as a radiator. Jacek's post contains a number of demonstration videos such as the one below.

He admits that his particular Pi 4 unit might be unique in this regard. If anyone else tests this and can confirm excessive leakage, please let us know in the comments.

Ethernet RF leakage received strongly from 50m away without any antenna on the Pi 4

Etherify 3 demo

Etherify: Transmitting Morse Code via Raspberry Pi Ethernet RF Leakage

Over on his blog SQ5BPF has been documenting a TEMPEST experiment where he's been able to transmit data via RF being leaked from a Raspberry Pi's Ethernet connection. The idea was born when he found that his Raspberry Pi 4 was leaking a strong RF signal at 125 MHz from the Ethernet cable. He went on to find that it was easy to turn a tone on and off simply changing the Ethernet link speed with the "ethtool" command line tool. Once this was known it is a simple matter of creating a bash script to generate some morse code.

Quite amazingly the Ethernet RF leakage is very strong. With the Raspberry Pi 10 meters away, and a steel reinforced concrete wall in between, SQ5BPF was able to receive the generated morse code via an RTL-SDR connected to a PC. Further experiments show that with a Yagi antenna he was able to receive the signal from 100 meters away.

His post explains some further experiments with data bursting, and provides links to the scripts he created, so you can try this at home.

Update - SQ5BPF also notes the following:

The leakage differs a lot with the hardware used. The Raspberry Pi 4 is exceptional and also allows to switch the link speed quickly, so was a nice candidate for a demo, but other hardware works as well.

The first tests were done on some old laptops I had laying around, and they leak as well. Maybe someday I will publish this, but everyone of them behaves differently.

Etherify 1 demo receiving via SDR and decoding via fldigi

GOES Weather Satellite Images on an E-Ink Display

Thank you to a few users who have submitted links to u/ThePhotoChemist's Reddit post showing his e-ink display for his live GOES-16 weather satellite images. The post doesn't go into much detail about the setup, however it seems that he is using a Raspberry Pi, and displaying the images via a 9.7 inch E-Ink display which he notes does not come cheaply. He also notes that the resolution is quite low, and that it's limited to 16 shades of grey, however the images do still look good on it. The display is mounted into a picture frame which makes a very nice display piece.

If you're interested in receiving live GOES (or GK-2A) weather satellite images with an RTL-SDR we have a tutorial available here

An e-ink display with live GOES images from space

RPiTX Beta for Raspberry Pi 4 Released

Evariste (F5OEO) has just announced the release of an update to RPiTX which allows it to now be used on a Raspberry Pi 4. If you are unfamiliar with it, RPiTX is a program for Raspberry Pi single board computers that allows you to transmit almost any type of signal on frequencies between 5 KHz up to 1500 MHz with nothing more than a piece of wire connected to a GPIO pin. Evariste also notes that the new version is compatible with the beta 64-bit version of Raspbian.

Some examples of signals you can transmit with RPiTX include a simple carrier, chirp, a spectrum waterfall image, broadcast FM with RDS, SSB, SSTV, Pocsag, Freedv and Opera. You can also use an RTL-SDR to record a signal, and replay the IQ file with RPiTX. However, please remember that transmitting with RPiTX you must ensure that your transmission is legal, and appropriately filtered.

RPiTX Logo