Category: RTL-SDR

WXCorrector: Updating Keplers for Linux users of WXtoIMG

Thank you to Hamdy Abou El Anein for submitting news about the release of his software called "WXCorrector".  

WXCorrector is a dedicated solution designed specifically for Linux users who face challenges with the handling of Kepler elements in Wxtoimg. This tool addresses a critical issue where incorrect or outdated Keplerian elements can cause disruptions in tracking software, leading to inaccurate predictions and potential data loss.

It work on Linux, it needs sudo rights and Python3 installed.

https://github.com/hamdyaea/wxcorrector-for-linux

WXtoIMG is a commonly used piece of software for decoding images from NOAA APT weather satellites. However,  WXtoIMG is now considered abandonware as the original website has gone, and the main author has not updated the program in many years. The latest versions from 2017 can be downloaded from Archive.org. An alternative download site is https://www.wraase.de/wxtoimg, where they also provide a way to update Keplers for Windows machines.

Due to it's abandonment, certain features like Kepler updates from the internet appear to have broken over time with changes to the way Kepler files are served. Up to date Kepler files are required for the software to know exactly where satellites are in the sky for tracking and scheduling.

A modern alternative to WXtoIMG is SatDump, which now supports NOAA APT satellites.

WXtoIMG

Spacewalker LNA 434 MHz In Prelaunch at CrowdSupply

Thank you to Zoltan and team for submitting news of the prelaunch of their Spacewalker LNA 434 MHz. Spacewalker LNA is designed to improve reception of PocketSat and Cubesat satellite signals when received with SDR devices like the RTL-SDR. Often these relatively weak signals are drowned out by strong interfering terrestrial signals like DVB-T and GSM. To solve this the triple filter and dual amplification design used in the Spacewalker LNA can help to isolate the satellite signals.

The team write that prototype versions of the LNA are already successfully in use around the world with SatNOGS stations. The device uses two state of the art QPL9547 LNA with 0.2 dB noise figure and 25 dB gain at 434 MHz and three 434 MHz SAW filters. The design also uses an interesting coax stub for ESD protection. It can be powered with 5V USB-C or via bias tee.

The LNA is currently in the prelaunch stages with CrowdSupply, so it will likely be released for crowd funding within the next few months. If you are interested in being notified when the campaign launched, be sure to sign up on the Crowd Supply page for updates.

Spacewalker LNA 434 MHz. Designed for PocketSat and CubeSat signals amidst strong DVB-T, TETRA, FM, and LTE signals from densely packed transmitter towers.
Spacewalker LNA 434 MHz. Designed for PocketSat and CubeSat signals amidst strong DVB-T, TETRA, FM, and LTE signals from densely packed transmitter towers.

RTL433 Plugin for SDRSharp Updated

Back in 2021 we posted about a SDR# plugin that allowed you to interface with rtl_433 from within SDR#. RTL433 (rtl_433) is a commonly used RTL-SDR command line program that provides decoders for a wide range of 433.92 MHz, 868 MHz, 315 MHz, 345 MHz, and 915 MHz ISM band devices. Examples of such devices include weather stations, alarm sensors, utility monitors, tire pressure monitors and more.

Recently there have been a few updates to the plugin after a years hiatus which probably meant that the older version was not compatible with newer versions of SDR#. But there are also several bugfixes and minor changes made to the plugin too which can be read about on the GitHub Readme.

To download the plugin we recommend clicking on the green <>Code button on the GitHub page and choosing Download Zip. You can then browse to the install/1.5.6.2 folder. Copy the three .dll files into the Plugins folder in your SDR# directory. Then open SDR#, go to the main hamburger menu -> plugins -> RTL_433.

RTL433 Plugin for SDR# Updated
RTL433 Plugin for SDR# Updated

Marine Vessel AIS and AirNav ShipXplorer

AirNav systems are a company that run radarbox.com, one of the big ADS-B aggregation tracking sites for tracking aircraft around the world. They also run a similar platform called ShipXplorer for tracking marine vessels using AIS data. The team at AirNav have provided us with a nice explanation of what AIS is and how it works. They note that they also sell a modified RTL-SDR with AIS filters and an LNA built in.

Presumably AirNav are seeking feeder volunteers for their ShipXplorer service with the submission of this post. We receive no compensation for this post and do not endorse one aggregator over another.

Below is the text from AirNav:

How Does the Automatic Identification System (AIS) Work

Introduction

Automatic Identification System (AIS) is a crucial technology used for monitoring and tracking the movements of vessels at sea. It has become an essential tool for ensuring maritime safety, security, and efficiency. In this blog post, we will explore how AIS vessel tracking works, its benefits, limitations, and future prospects.

How Does AIS Vessel Tracking Work?

AIS is an automatic tracking system that uses transceivers installed on ships to transmit vital information such as position, speed, course, name, call sign, type of ship, and destination. This data is then received by terrestrial or satellite-based AIS receivers and transmitted to various stakeholders, including shore-based authorities, other ships, and online platforms. The information is displayed in real-time, allowing users to monitor the movement of vessels with pinpoint accuracy.

There are two types of AIS messages: Class A and Class B. Class A messages are mandatory for all ships over 300 gross tons, while Class B messages are optional but recommended for smaller vessels. Class A messages have a higher transmission power and update rate than Class B messages, making them more reliable for long-range detection.

AIS operates principally on two dedicated frequencies or VHF channels: AIS 1: Works on 161.975 MHz- Channel 87B (Simplex, for the ship to ship) AIS 2: 162.025 MHz- Channel 88B (Duplex for the ship to shore), which provide a range of up to 20 nautical miles for terrestrial stations and up to 1,000 nautical miles for satellite systems. The system uses Time Division Multiple Access (TDMA) technology to avoid signal collisions and ensure seamless communication between multiple vessels and base stations.

Benefits of AIS Vessel Tracking

AIS vessel tracking offers numerous benefits, including enhanced safety, improved operational efficiency, and better decision-making capabilities. Some of these benefits include:

  1. Improved Collision Avoidance
    By providing accurate information about a vessel&#39;s location, speed, and direction, AIS helps prevent collisions and reduces the risk of accidents. Ships can use this information to maintain safe distances from each other and navigate crowded waterways safely.
  2. Increased Efficiency
    AIS enables ships to optimize their routes and fuel consumption, leading to increased efficiency and cost savings. By sharing their positions and intentions, vessels can coordinate their movements and avoid wasting time and resources on unnecessary maneuvers.
  3. Enhanced Search and Rescue Operations
    In case of emergencies, AIS provides critical information that helps search and rescue teams locate and assist distressed vessels quickly. The real-time data provided by AIS allows responders to make informed decisions and allocate resources effectively.
  4. Better Decision Making
    AIS data can be integrated with other systems, such as weather forecasting tools, to help shipping companies make informed decisions about their operations. For example, they can adjust their schedules based on predicted weather conditions or reroute their vessels to avoid congested areas.

Limitations of AIS Vessel Tracking

While AIS vessel tracking is a powerful tool, it does have some limitations. These include:

  1. Limited Coverage
    Although AIS signals can travel up to 20 nautical miles via terrestrial stations, this coverage may not be sufficient in remote or offshore areas where there are no base stations. Satellite-based AIS systems address this limitation but come at a higher cost.
  2. Potential Security Risks
    Since AIS transmissions are unencrypted, there is a potential risk of interception and misuse by malicious actors. However, measures such as frequency hopping and encryption can mitigate these risks.

Future Prospects of AIS Vessel Tracking

As technology advances, AIS vessel tracking is expected to evolve and offer even greater benefits.

  1. Integration with Autonomous Shipping
    Autonomous ships rely heavily on sensor data for navigation and collision avoidance. AIS integration with autonomous shipping systems could enhance situational awareness and improve overall safety.
  2. Real-Time Cargo Monitoring
    AIS could be used to track individual cargo containers in real-time, enabling logistics companies to monitor their shipments more accurately and efficiently.
  3. Environmental Monitoring
    AIS-equipped vessels could collect environmental data, such as water temperature, salinity, and pollution levels, helping researchers and policymakers better understand and manage marine ecosystems.

Conclusion

AIS vessel tracking is an indispensable tool for enhancing maritime safety, security, and efficiency. While it has some limitations, advancements in technology continue to expand its capabilities and applications. As shipping becomes increasingly digitalized, AIS will remain a cornerstone of maritime communications and surveillance.

The SHipXplorer AIS Optimized RTL-SDR

SatDump V1.1.4 Released

SatDump is a popular program used to receive and decode images and other data from various weather satellites. SatDump works great RTL-SDR Blog dongles and with our Discovery Dish, an easy to use dish and feed for receiving L-band and other weather satellites. Recently the author of SatDump released version 1.1.4 which brings several new features including:

  • Autotrack/Scheduler improvements - multi mode has been added which allows all pipelines to run, even if more than one satellite is overhead at the same time. This is useful for NOAA and METEOR satellites at 137 MHz as there can often be more than one active satellite broadcasting images at different frequencies during a pass.
  • TUBIN Raw/Video Mode
  • ESA Cluster support
  • Additional Pipelines - Including Peregine X-Band TLM, the IM-1 Moon Mission and PRETTY S-band dump.
  • Themes - Choose between Dark, Light, Phosphor and Win98 themes.
  • Android Improvements - Blog V4 support added on Android, OpenCL support added.
  • Added composites - Various composite image products added to various satellites. Including Fog, panchromatic, ice detecting and more.
  • Other Features - support for M1 Mac builds added and various other fixes.
  • Bug Fixes - Memory leaks fixed and various bug fixes including a bug that caused problems with RTL-SDR devices on low power hardware like Raspberry Pi's and Orange Pi's.

If you enjoy SatDump consider donating to the main author at ko-fi.com/aang23.

SatDump Multi-Mode Feature. Receiving data from multiple 137 MHz satellites at the same time.

WarDragon Passive Radar with Blah2 and ADS-B Delay-Doppler Truth

Over on his YouTube channel, Aaron, creator of DragonOS and the WarDragon kit has uploaded a video showing the Blah2 passive radar software working with an SDRplay RSPDuo. In the video Aaron shows some setup steps before showing the passive radar range-doppler graph.

Blah2 is passive radar software that appears to be inspired by the KrakenSDR passive software that was removed for regulatory reasons. We note that it is legal for others to publish open source passive radar software, but KrakenSDR cannot legally publish their own open source passive radar software because it would be tied to their own physical product. Providing code would mean they essentially sell an off the shelf passive radar product which is restricted.

The notes in Blah2 specifiy that it currently only supports the SDRplay RSPduo and USRP devices, but in the future they are looking to add support for the KrakenSDR and modified RTL-SDR and HackRF hardware.

Aaron also briefly demonstrated the related adsbdd software, from the same author as Blah2. This software allows a user to convert ADS-B data to delay-doppler truth. Essentially allowing you to confirm is an aircraft position determined via ADS-B is on the range-doppler ellipse determined via passive radar. In the future the author hopes to be able to plot all aircraft in a 2D delay-doppler space graph. 

WarDragon Passive Radar Setup + Test w/ Open Source Code (RSPDUO, RTLSDR, Blah2)

Windows Binary of GQRX Released

Gqrx has long been one of the most commonly used pieces of software defined radio software for Linux and MacOS. However, it has never had a Windows release until just two days ago when the team released an experimental Windows binary.

We gave the new Windows binary a test with our RTL-SDR Blog V4 and everything works just fine. If you want to give it a go, just be aware that Chrome and many antivirus programs will flag the zip as suspicious. However, this is just a false positive, since this is the first release and the file doesn't have a long history on the web.

To download it, go to the Gqrx releases page on Github, and download the latest Gqrx-2.17.4-Windows.zip file from under Assets.

GQRX now on Windows
GQRX now on Windows

Canada Moves to Ban Flipper Zero and Possibly Software Defined Radios

Dominic LeBlanc, Canada's Minister of Public safety has recently declared that they plan to ban devices "used to steal vehicles by copying the wireless signals for remote keyless entry, such as the Flipper Zero". The text specifically calls out the Flipper Zero, however the wording appears to imply that any device that can copy a signal will be banned. This means the ban could extend to RX/TX SDRs like the HackRF and possibly even RX only SDRs like RTL-SDRs.

The Flipper Zero is an affordable handheld RF device for pentesters and hackers. It is not based on SDR technology, however it uses a CC1101 chip, a digitally controlled RX/TX radio that is capable of demodulating and modulating many common digital modulations such as OOK/ASK/FSK/GFSK/MSK at frequencies below 1 GHz. There are many CC1101 devices on the market, but the Flipper Zero has gained huge popularity on social media because of it's excellent software support, as well as its cute marketing tactic. In the past it was even featured on the popular Linus Tech Tips YouTube channel.

Flipper Zero has had a long line of setbacks including PayPal freezing 1.3M of its cash, and US customs temporarily seizing its shipments, then passing a $70,000 bill on to them for storage fees and Amazon banning the product on their marketplace.

In our opinion, we believe that the ban appears to be misguided. The Flipper Zero is a basic device that can only perform a simple replay attack, which is to record a signal, and replay it at a later time. These sorts of attacks do not work on vehicles built after the 90's which now use rolling codes or more sophisticated security measures. To defeat rolling code security, a more sophisticated attack called Rolljam can be used. A Rolljam device can be built for $30 out of an Arduino and two cheap transceiver modules.

However, according to arstechnica the biggest cause for concern in terms of car theft is a different sort of attack called "signal amplification relay".

The most prevalent form of electronics-assisted car theft these days, for instance, uses what are known as signal amplification relay devices against keyless ignition and entry systems. This form of hack works by holding one device near a key fob and a second device near the vehicle the fob works with. In the most typical scenario, the fob is located on a shelf near a locked front door, and the car is several dozen feet away in a driveway. By placing one device near the front door and another one next to the car, the hack beams the radio signals necessary to unlock and start the device.

This sort of attack is a lot less sophisticated in many ways as all you are doing is amplifying a signal, and no clever hardware like the Flipper Zero or a software defined radio is even required. The X video below demonstrates such a hack where a criminal holds up a loop antenna to a house. The loop antenna is connected to a signal amplifier which amplifies the keyfob signal, tricking the car into thinking the keyfob is nearby, and allowing the door to be unlocked by touching the handle, and then turned on with the push to start button.

Flipper zero note that they have not been consulted about the ban, and replied on X stating that they are not aware of the Flipper Zero being used for car theft.