Category: Applications

Running GR-GSM and IMSI Catcher on a Raspberry Pi 4 with Dragon OS

DragonOS is a ready to use Ubuntu Linux image that comes preinstalled with multiple SDR software packages. The creator Aaron also runs a YouTube channel showing how to use the various packages installed. 

In his latest video Aaron tests his Pi64 image with GR-GSM and IMSI Catcher running with the GNU Radio 3.10 platform on a Raspberry Pi 4. He tests operation with an RTL-SDR and LimeSDR.

GR-GSM is a GNU Radio based program capable of receiving and analyzing mobile GSM data. We note that it cannot decode actual messages without additional information about the encryption key, but it can be interesting to investigate the metadata. GSM is mostly outdated these days, but still used in some areas by some older phones and devices. IMSI Catcher is a script that will record all detected GSM 'IMSI' numbers received by the mobile tower which can be used to uniquely identify devices.

Short video setting up and testing GR-GSM on DragonOS Pi64 w/ GNU Radio 3.10 and the RTL-SDR. The current DragonOS Pi64 build has GNU Radio 3.8 and all the necessary tools to accomplish what's shown in this video. If you'd like to test the build shown in this video, it's temporarily available here until I finish and put it on Source Forge.

https://drive.google.com/drive/u/1/fo...

A LimeSDR and DragonOS Focal's Osmo-NITB-Scripts was used to create the GSM900 lab environment. The RTL-SDR was able to see and decode the GSM900 network and although only briefly shown in the video, the IMSI Catcher script works.

Here's the fork used for this video and for testing. There's also a pull request on the main GR-GSM repo for this code to be added.

https://github.com/bkerler/gr-gsm

DragonOS Pi64 Testing GR-GSM + IMSI Catcher w/ GNU Radio 3.10 (RTLSDR, Pi4, LimeSDR, OSMO-NITB)

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.

Skies-ADSB: A Browser Based 3D Aircraft Tracker with RTL-SDR ADS-B Receiver

Thank you to Don for submitting news about the release of his new software titled "Skies-ADSB". Skies-ADSB is a browser based app that provides a 3D view of the air traffic around your area. The software can be served on a local networked Raspberry Pi, with ADS-B data being provided by an RTL-SDR connected to the Pi.

skies-adsb is a virtual plane spotting progressive web app (PWA) / virtual aquarium (with aircraft instead of fish) / interactive real-time simulation.

Aircraft are tracked via unfiltered ADS-B transponder data in real-time and rendered in 3D.

The ADS-B data source is meant to be a RTL-SDR receiver connected to a Raspberry Pi running on your home network.

Flight status data is provided by the FlightAware AeroAPI v2.

The aircraft photos are provided by Planespotters.net.

An RTL-SDR Panadapter for the TECSUN PL660 Shortwave Radio

Thank you to Joseph IT9YBG for submitting his article describing how he has made an RTL-SDR based panadapter for his TECSUN PL660 portable shortwave radio. The post is a series of pictures that show how Joseph was able to open the PL660 and connect a coax cable to the IF output, and mount the connector on the plastic cover for easy access. He then connects that IF output to the RTL-SDR via a 10pF capacitor.

The result is that Joseph is able to receive the IF output of the PL660 at 451 kHz in SDRUno with his RTL-SDR Blog V3 running in Q-Branch direct sampling mode. He notes that although the IF bandwidth from the PL660 is small, it is possible to decode digital signals by passing the audio demodulated by SDRUno into decoding software. 

RTL-SDR Blog V3 Panadapter for the Tecsun PL660

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.

Testing Tire Pressure Monitoring System Sensors with RTL-SDR and rtl_433

Thank you to Ross for writing in and sharing with an articles that he's written about testing Tire Pressure Monitoring System (TPMS) sensors using an RTL-SDR and the rtl_433 decoder.

TPMS is a system installed on many modern cars (or retrofitted on older cars) that wirelessly monitors the tire pressure on vehicles in order to provide dashboard information that can improve safety and fuel economy. TPMS system typically transmit on license free bands, such as 315 MHz which can easily be received with an RTL-SDR.

Ross owns a 2008 Toyota Tacoma which has a built in TPMS system. Unfortunately he found that one of his sensors was broken as the TPMS warning light was consistently on, despite knowing that his tire pressure was correct.

Instead of purchasing an expensive TPMS diagnostic tool, Ross broke out his RTL-SDR and fired up rtl_433 which already contains a ready to use TPMS decoder. From the data received, Ross was able to determine that only three sensors were transmitting. Ross then goes on to use the RSSI signal power strength measurements provided by the rtl_433 output, while moving the antenna next to each wheel to determine exactly which wheel had the faulty sensor.

Ross's post goes into further details about his setup and the data he received from the sensors. He also created a follow up post, describing a bash script he wrote to automate the process.

TPMS Data Received

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