Category: HackRF

Controlling a Toy RC Car with a HackRF

Over on his blog Radoslav has created a post showing how he has used a HackRF to wirelessly control a toy RC car by reverse engineering the wireless control protocol, and generating the control signals in a C++ program.

Having already created the rf-car HackRF RC car control software on GitHub a few years ago, Radoslav was easily able to modify it for a new RC car that his daughter received. The process was to simply look up the FCC data on it, finding that it operated with 2.4 GHz and used GFSK modulation. He then used the Inspectrum signal analysis tool to determine the bit strings used to control the car. Finally using, his C++ interface to the HackRF he implemented the new bit string and GFSK modulation.

The video below demonstrates Radoslav controlling the RC car with the keyboard on his laptop.

Controlling 2.4GHz FSK car with HackRF

In the past we've posted about another project that also used a HackRF and computer to control a RC drift car, and another project that used the RPiTX software to control an RC toy car with GNU Radio and a Raspberry Pi.

[Project also seen on Hackaday]

Lightweight Windows Software uSDR Updated to Version 1.5.0

Since 2021 we've posted about Viol Tailor's "uSDR" (microSDR) software a couple of times. uSDR is a lightweight general purpose multimode program for Windows that supports the RTL-SDR, Airspy, BladeRF, HackRF and LimeSDR radios. The software can be downloaded from SourceForce.

Viol notes that recently the project has been updated to V1.5.0 which brings the following new features and changes.

  • lock device frequency on zoom option
  • keep waterfall history – the very great option, do not lose any rare signals
  •  advanced passband IQ recorder
  • passband IQ TCP server for remote processing, C/C++ client source examples included
  • advanced audio player, auto selectable sample rate, separate left/right channels
  • CTCSS decoder
  • markers import option convenient for merge markers 
  • Ctrl+Shift+Drag Up/Down – change spectrum magnitude offset
  • Ctrl+Shift+Mouse Wheel – change spectrum magnitude range (vertical zoom)
  • Ctrl+Mouse Hover – highlight nearest marker
  • Ctrl+Double Click– tune to highlighted nearest marker
  • band plan visualization, simple text format
  • frontend interface improvements
  • GUI improvements
  • spectrum and waterfall popup menus improvements
  • a lot of bug fixes
uSDR aka microSDR. A lightweight SDR receiver program from Windows.

Tesla Charging Ports Opened with HackRF Replay Attack

The charging port on Tesla electric vehicles is protected via a cover that can be opened by charging stations via a wireless signal transmitted at 315 MHz. It turns out that the command to open the port is totally without any security. This means it's possible to record or recreate the signal, and play it back anywhere using a transmit capable SDR device like a HackRF.

Twitter user @IfNotPike has done just that, managing to open the Tesla charging port using a handheld HackRF with Portapack setup. If you cannot record the signal, a repo hosting a valid signal file is available on GitHub from jimilinuxguy. Interestingly jimilinuxguy notes "The range for this is INSANE. I was able to perform this from VERY far away." and the same signal can be used to "open any and all Tesla vehicle charging ports in range"

Fortunately for Tesla owners, the level of damage a malicious party could cause through the charging port is limited, since the charging port is not active until a correct charging cable is connected. It also seems that the charging port on most models will automatically close after some time if no charger is connected.

Tesla Charging Port Opened with HackRF and Portapack | Credit: @IfNotPike

Receiving Analog TV from Turkmenistan Unintentionally Bouncing off a Russian Military Satellite

Over on Twitter @dereksgc has been monitoring the 'Meridian' communications satellites, which are Russian owned and used for civilian and military purposes. The satellites are simple unsecure repeaters, meaning that actually anyone with the hardware can transmit to them, and have their signal automatically rebroadcast over a wide area. This has been taken advantage of recently by anti-Russian invasion war activists who have been trolling the satellite with SSTV images of the Ukrainian flag, as well as audio.  

Apart from intentional abuse, a side effect of being an open repeater is that sometimes the satellite can pick up powerful terrestrial signals unintentionally, such as analogue broadcast TV from Turkmenistan. Over on his blog, @dereksgc has written up an excellent post documenting the background behind this finding, his entire setup involving the hardware he's using and how he's aligning with the satellite, and what software he is using to decode the TV signal. In his hardware setup he notes that he uses a HackRF, but that a RTL-SDR would suffice.

SignalsEverywhere: Review of SDR++ on Android

In our last post we mentioned that a 'pre-release' public version of SDR++ for Android was recently released. Now over on the SignalsEverywhere YouTube channel Sarah has uploaded a new video where she reviews and demonstrates the new SDR++ Android App. 

In the video Sarah demonstrates how to connect and start a SDR, shows SDR++ in action, then tests listening to NOAA weather audio reports, Inmarsat reception via the bias tee support, P25 and broadcast FM. She also shows how it's possible to use the split screen multitasking feature on Android to send audio from SDR++ into APRSdroid for APRS decoding.

She goes on to show how to fine tune the screen PPI resolution for different sized devices, and how to set up multi-VFO listening on the HF bands. Next, she compares the audio decoding quality between SDR++, SDRTouch and RFAnalyzer. Finally she shows that a HackRF running at a wideband 20 MHz of bandwidth can run smoothly. 

The Android SDR App That Beats Them All! Supports RTL-SDR Airspy HackRF and Many More!

SDR++ Android App Public Pre-Release Now Available

SDR++ is an open source program compatible with most software defined radios including the RTL-SDR that has been going through rapid development making it now one of the top software choices.

Yesterday a public 'pre-release' Android version of SDR++ was made available for download. The release is announced as a 'pre-release' due to various bugs still existing. However, we note that we have been testing a private release for the past few weeks, and we can say that it is working great most of the time. The Android App replicates most of the desktop experience perfectly, and it operates very smoothly on most modern devices.

The author Alexandre Rouma writes:

I'm happy to release the first public pre-release of SDR++ for android. It's still quite early and has a few bugs and quirks that you might run into:

  • SDR MUST be plugged in before starting SDR++ and you MUST press refresh in the SDR source you're using before pressing play if you first plugged in the SDR or unplugged/replugged, otherwise expect a crash. The USB handling still needs some work.
  • There are still a few UI glitches
  • There is no easy way to select a path for recording or file for playback
  • The audio sink on Android may have higher latency
  • All menus sometimes close when app goes in the background.
  • Resizing the menu and/or waterfall is kinda fiddly, be precise when trying to grab the resize bar!!!
  • At some size menu sizes, the app crashes. If this happens, start in landscape
  • On Samsung devices, the keyboard doesn't always work for some obscure reason...

MINIMUM REQUIREMENTS:

  • Android 9.0
  • OpenGL 2.1

Since phones usually have a high screen resolution, set the DPI scaling in the Display menu or you'll have a hard time using the app.

Current Device/Protocol Support:

  • Airspy
  • Airspy HF+
  • HackRF
  • PlutoSDR (network only)
  • RFspace
  • RTL-SDR
  • RTL-TCP
  • SDR++ Server
  • SpyServer

In any case, I'd love to get some feedback on it, so feel free to try it out and let me know!

Download Here: https://www.sdrpp.org/

PS: If you like this work, feel free to support me on Patreon, since putting it on the App Store won't be cheap and I want to make sure it's completely free with no ads!

SDR++ Android App Screenshot. Credit: goscickiw https://github.com/AlexandreRouma/SDRPlusPlus/discussions/703

Turbine: Capture and Stream all Frequencies in a Trunked Radio System with a HackRF

Over on Reddit we've discovered an interesting program called 'Turbine' that has recently been open sourced by the author. This program connects to a wideband capable SDR such as a HackRF and captures and streams all frequencies in a trunked radio system. Users can then browse the recordings online. On his reddit post u/norasector introduces Turbine, and his application for it called 'NoraSector'.

I am open sourcing the SDR code for NoraSector, which currently captures and streams the radio systems for both King and Snohomish County, WA. It uses a HackRF One to capture every channel concurrently, and can even process multiple systems at the same time, provided they are within the same bandwidth that is captured by the SDR and there's adequate reception. I plumb the output through a WebRTC streaming infrastructure I built to stream audio to clients over the web with very low latency. My goal was to give complete access to an entire system to anyone over the web, just as they would have if they were using a handheld scanner, and with comparable latency.

Turbine is a bit different other SDR software out there. It's written entirely in Go, and was built explicitly to only use a single SDR rather than bonding multiple SDRs together.

Turbine works by tuning known control frequencies and then tuning all voice frequencies it learns from them. Voice transmissions are encoded using the Opus audio codec for compatibility with WebRTC and blasted out as frames over UDP. It also includes a functional-but-janky built-in visualization web server to look at each stage of the DSP pipeline for each frequency, which was crucial for debugging as I was building it.

Right now, it only supports legacy Motorola SmartZone systems (which is what is used near me), but it shouldn't be a large lift to make it support P25. The code is heavily influenced by op25 and GNURadio (and in some places just outright copying them). I built it in Go because a) it's what I'm most familiar with and b) the sheer density of GNURadio made it hard for me to piece things together how I wanted. Go's concurrency model is a natural fit for doing many concurrent operations on the byte stream, and I haven't had issues with garbage collection pausing execution in a detrimental way.

Turbine isn't intended for use with lower sample rate SDRs like the RTLSDR. It has a driver for it, but doesn't support bonding multiple SDRs together. If an entire system fits within the 2MHz sample rate, it would probably be fine. You should be able to fire it up with a RTLSDR but it will not be able to capture very much. It currently only officially supports the HackRF One, but adding other SDRs should be relatively trivial. Note that the HackRF I am using is the model with the upgraded TCXO, as I found that the built-in oscillator was not accurate enough.

Turbine has only been tested to run on Linux and is very CPU-intensive; the production radio runs on a dedicated i7-11700k 8c/16t CPU and consumes about 60% of all cores decoding both systems. There are some potential optimizations that could be made that would lower CPU consumption during periods of low activity, but I built it for the worst case of having to encode every voice frequency at once.

The usual disclaimers about OSS apply. I hope you find it interesting or perhaps useful, and maybe portions can be adapted so Go can be used more in SDR projects.

There have been similar projects in the past like radiocapture-rf, scaneyes, and broadcastify calls, but Turbine looks like one of the most comprehensive.

Norasector: An implementation of the Turbine Trunk Recording software

SDR++ Server Beta Now Available

SDR++ is a general purpose receiver program compatible with almost any software defined radio including the RTL-SDR. Recent developments have seen the author release a beta of  "SDR++ server" which is a program that allows users to access SDRs remotely, by connecting to them over a network connection. This is similar to existing server applications like rtl_tcp and Spyserver, however like SDR++ itself, SDR++ Server is compatible with almost any SDR and that is a major drawcard.

The server is still in development and the author notes that he is still working on adding new features like lossless compression techniques in order to reduce network bandwidth requirements. However, it has already seen to be running well in tests with a remote server positioned half way around the world, even without compression enabled.

We note that SDR++ author 'Ryzerth' has a Patreon. If you like seeing these SDR++ developments please consider support him.