Category: Applications

dump978: UAT Decoder for the RTL-SDR + FlightAware App now supports UAT

In most of the world aircraft use the ADS-B standard for location tracking which transmits at a frequency of 1090 MHz. However, in the USA there is the option for aircraft to instead use the Universal Access Transceiver (UAT) protocol which transmits at 978 MHz.

UAT has some extra features for pilots compared to ADS-B. In addition to location information UAT provides a Traffic Information Service (TIS/B) which allows pilots to see what ground control sees on their traditional RADAR system. It also provides a Flight Information Service-Broadcast (FIS/B) which includes weather and other information. It seems that most small aircraft in the USA prefer to use the UAT system due to it’s lower cost and additional features. 

A few months ago an experimental version of dump978 MHz was released which is what we believe to be the first working UAT decoder for the RTL-SDR. It’s still in experimental development, however the FlightAware team have already referenced it for developing their Android ADS-B app which we posted about a few days ago. Because of the work done with dump978, the beta version of the FlightAware Android app has recently been updated and can now support UAT decoding. To download the beta version with UAT you may need to sign up to their public beta. More information about the beta can be found on their Google+ beta testing community page.

FlightAware ADS-B App which now supports UAT decoding.
FlightAware ADS-B App which now supports UAT decoding.

ADSBox: New ADS-B Decoding Software for Linux

Recently Roman, a programmer and reader of RTL-SDR.com wrote in to let us know about his ADSBox software which is a free opensource Linux based ADS-B decoder (page in Russian, use Google Translate) with several interesting features. ADSBox contains a decoder and a nice web interface which allows you to view flight information in a table or in Google maps, or even through a Google Earth interface. The software also automatically loads up a photo of an aircraft if you click on it in the map. Roman has actually been working on ADSBox since 2011 and seems to have recently added RTL-SDR support.

The software can be compiled on a PC with gcc, or on an embedded ARM device with arm-linux-gcc. We gave the software a quick test on an Ubuntu PC and found that it worked as expected. Install instructions are on the page linked above, but just in case here are our notes on compiling the software.

  1. Download and extract the latest version from the bottom of the page into a folder called adsbox on your Linux system. (Latest version at the time of writing: adsbox-20150409.tar.gz. Note that the Google translated download link did not work for us, use the original untranslated link if you need to)
  2. Download and extract the latest sqlite source files from http://www.sqlite.org/download.html (at the time of writing: sqlite-amalgamation-3080900.zip) into a folder called sqlite3 on the same level as the extracted adsbbox folder (not inside adsbbox folder)
  3. Edit the Makefile and set “WITH_RTLSDR = yes”. If cross-compiling for an ARM device set CC = arm-linux-gcc, otherwise leave this setting alone.
  4. Run “make”.
  5. Now you can run ADSBox with ./adsbox –rtlsdr.
  6. Go to 127.0.0.1:8080 in your browser to see and use the interface.
Screenshot of the ADSBox web interface.
Screenshot of the ADSBox web interface.

A self contained ADS-B Receiver using a Raspberry Pi and RTL-SDR

Over on the Raspberry Pi Reddit discussion board user spfoamer has posted about his Raspberry Pi + RTL-SDR based outdoor ADS-B receiver. ADS-B stands for Automatic Dependent Surveillance Broadcast and is a signal broadcast by aircraft that contains information about their locations. With a receiver like the RTL-SDR and correct software you can make an aircraft radar.

In his design the Raspberry Pi transmits location data back to a PC via an Ethernet cable. In addition the Raspberry Pi is also cleverly powered via power over Ethernet (POE) which uses unused wires in the Ethernet cable itself to carry the power. Since he uses a 12V power source, to obtain the needed 5V to power the Raspberry Pi spfoamer uses a UBEC (Universal Battery Elimination Circuit) which is an efficient device that converts voltages from up to 23V down to 5V. Additionally, he uses a 1/4 wave ground plane antenna and a 1090 MHz bandpass filter to eliminate out of band interference.

On the Pi itself he runs PiAware and contributes his data to the FlightAware network.

ADS-B with a Raspberry Pi, RTL-SDR, Bandpass Filter all powered via Ethernet cable.
ADS-B with a Raspberry Pi, RTL-SDR, Bandpass Filter all powered via Ethernet cable.
ADS-B with a Raspberry Pi, RTL-SDR, Bandpass Filter all powered via Ethernet cable.
Close up of the inside of the box.

BigWhoop: Global Spectrum Monitoring Network with RTL-SDR Dongles

The American space agency NASA runs a yearly challenge called the “International Space Apps Challenge”. The challenge encourages global collaboration in solving several space and Earth related problems. This year one of the challengers is creating a system called the “BigWhoop” which will be a global networked system of radio receivers that will be used to continuously monitor the radio spectrum. They write:

[BigWhoop] is a full system for collecting data from small radio-receivers measuring everything within the radio spectrum around the world. BigWhoop schedules the monitoring, the collection of data via the internet, the database handling and the final analysis as well as visualization.

As well as being able to constantly track aircraft through ADS-B signals, they write that BigWhoop will have the following other applications:

We can detect places of high spectrum activities such as radio towers and tell you, when a new music channel starts its broadcast service. Or we can find sweet spots of radio silence where radio telescopes can be placed and listen to weak cosmic radio sources, that would have been drowned in man-made radio noise otherwise.

The BigWhoop code is still in “pre-alpha”, but they are currently asking for owners of RTL-SDR dongles to be volunteer testers.

Recently we also posted about some similar networked radio projects. One called ThumbNet which has a greater emphasis on education and promotion of the sciences, and another called SatNOGs which focuses on the receiving and global networking of satellite communications.

More videos can be found here.

Running an RTL-SDR on OpenWRT

OpenWRT is a special custom Linux based firmware designed to create a fully functional Linux system on a internet router by replacing the stock firmware. Since OpenWRT is Linux based, it is possible to install the RTL-SDR software and run it on the router itself. On his blog Tom Jones has posted a brief tutorial showing how he got the RTL-SDR working on a WR703N router that is running OpenWRT. Basically he just installs the RTL-SDR package which is available through the OpenWRT package manager and runs rtl_tcp, but he talks about a few adjustments he had to make to the rtl_tcp buffers to make it run smoothly. The WR703N is a mini wireless router that goes for about $30 USD on Amazon.

We also looked around for more information about running RTL-SDR on OpenWRT and found this older post from Yuval Adams showing how he got dump1090 and the flightradar24.com feeder running also on an OpenWRT’d WR703N router.

The WR703N wireless router which is capable of running OpenWRT and RTL-SDR.
The WR703N wireless router which is capable of running OpenWRT and RTL-SDR.

How to Setup CWSkimmer with an RTL-SDR and HDSDR

Over on YouTube user Brent Crier has uploaded a tutorial video showing how to set up CWSkimmer with an RTL-SDR and HDSDR. CWSkimmer is regarded as one of the best pieces of software that can be used to decode CW a.k.a Morse code.

Morse code is a communications technique still used widely by the amateur radio community in the HF bands. The RTL-SDR can receive HF frequencies and Morse code with an upconverter or direct sampling modification.

In the video Brent goes over the installation of HDSDR, Virtual Audio Cable, and a program called Virtual Serial Port (VSP) manager as well as the needed settings for each program. The set up he shows allows CWSkimmer to automatically change the frequency in HDSDR when tuning in CWSkimmer.

ThumbNet – A Low Cost Satellite Groundstation Network using modified RTL-SDRs

The ThumbNet project is a project that is aiming to provide low cost satellite receivers to students and any other interested communities in order to promote worldwide education in science, technology and engineering.

In addition to ThumbNet, there is also the ThumbSat project which hopes to launch it’s own satellites sometime next year. However, at the moment the focus is on ThumbNet where the team are currently building their ground station network by supplying customized RTL-SDR dongles to schools and interested communities all around the world for free.

Once the satellites are launched the receive stations will be used to download data from the ThumbSat satellites, creating a large network of receivers. To raise the incentive for participation, in the future they also hope to provide a small amount of money to each actively participating school or organisation. They write that the RTL-SDR’s could also be used for receiving other educational signals such as communications from the ISS. More information about the project can be found on their website www.thumbsat.com, and in this white paper (pdf).

As generic RTL-SDR dongles were not up to their specifications they decided to develop their own. Their RTL-SDR receivers are custom made to have a 1 PPM accuracy Temperature Controlled Oscillator (TCXO), a R820T2 tuner chip and a F-Type connector. The Type-F connector was chosen as they found that it was the most commonly found connector around the world and would be the easiest for students in remote areas to have access to.

If you are interested in getting one of these dongles and you meet their criteria (school or similar), you can either ask to participate in the ThumbNet program for free, or alternatively if you just want a dongle for your own use you can buy one through us. We have decided to help with the ThumbSat project by helping them advertise and sell off some of their surplus units through our blog.

In their official blurb ThumbSat writes:

Scoutek LTD, in the United Kingdom and ThumbSat Inc, in the United States are proud to have partnered together to provide an opportunity for schools and educational groups around the globe to promote radio science, technology, engineering and mathematics to their students and attempt to influence the next generation of scientists and engineers.  By donating small radio kits to each school or educational group, the project has already begun making a positive change in the lives of hundreds of students.

ThumbSat has been working with schools and educational groups around the globe and to date, more than 20 groups have committed to volunteering where students and staff members will operate the satellite monitoring stations as part of their science courses!  As a few examples, stations are being operated in diverse areas the Cook Islands, Christmas Island, Singapore, Ecuador, Tanzania and Botswana. One individual in Micronesia was operating the station by himself at 12 years old!

ThumbNet is open to anyone who is interested in participating and has a desire to setup and operate a small ground based radio listening station. No permits or licenses are required, since there is no transmission of any sort and no permanently installed antenna systems.

ThumbSat and Scoutek encourage education for everyone and is looking for anyone young, old, educated or uneducated, individuals or groups to participate.

Questions can be directed to info@thumbsat.com, or by visiting the company websites: www.thumbsat.com or www.scoutek.com .

ThumbNet SDR Dongles
ThumbNet SDR Dongles with Wade, one of the people behind the project.

New ADS-B Mapping and Decoder App for Android from FlightAware

Flightaware.com is a web based online radar service for aircraft. The plane position data is obtained from contributors running ADS-B decoding hardware, such as a special ADS-B receiver box or simply an RTL-SDR dongle.

To increase the number of contributors, the team at FlightAware have released a new RTL-SDR compatible ADS-B decoder app for Android devices. The App is totally free and is also ad free. It can be downloaded from the Google Play store at https://play.google.com/store/apps/details?id=com.flightaware.android.flightfeeder. The intention of the app is to target users who may have an old Android device lying around, which can be put to good use in contributing data to FlightAware. More information about running the app can be found on their webpage.

When sharing data with FlightAware you are then eligible for a free enterprise account valued at $89.95 a month which allows you to access several advanced flight tracking features.

To use the app you’ll need an Android device, a USB OTG cable (ideally with external power port) and an RTL-SDR dongle. The USB OTG cable should ideally have an external power port and be powered from the mains with a power adapter as the battery can drain fast.

FlightAware ADS-B App
FlightAware ADS-B App