HamRadio360 is a bi-weekly podcast all about ham radio and related topics. On their June 13 podcast Nick, KK6LHR came on to discuss his experiences with decoding ADS-B with cheap SDR radio like the RTL-SDR. In the podcast they talk about the history of ADS-B, what it is, the difference between the 1090 MHz and 978 MHz frequencies, what all of the terms and acronyms mean, feeding sites like flightaware and flightradar24 and of course how to decode it with various forms of software packages.
These days it’s quite easy to share your ADS-B reception on the internet with giant worldwide aggregation sites like flightaware.com and flightradar24.com. These sites aggregate received ADS-B plane location data received by RTL-SDR users from all around the world and display it all together on a web based map.
However, what if you don’t want to share your data on these sites but still want to share it over the internet with friends or others without directly revealing your IP address? Some of the team at beame.io have uploaded a post that shows how to use their beame.io service to securely share your ADS-B reception over the internet. Beame.io appears to be a service that can be used to expose local network applications to the internet via secure HTTPS tunneling. Essentially this can allow someone to connect to a service on your PC (e.g. ADS-B mapping), without you revealing your public IP address and therefore exposing your PC to hacking.
On their post they show how to set up the RTL-SDR compatible dump1090 ADS-B decoder on a Raspberry Pi, and then connect it to their beame-instal-ssl service.
Over on YouTube user icholakov has uploaded a new video showing how easy it can be to build a cheap ADS-B antenna out of a simple paper clip and coax connector. Modern aircraft carry an ADS-B transceiver and antenna which broadcasts the current GPS location of the aircraft. This is used for collision avoidance and air traffic control, but anyone with a receiver like an RTL-SDR can also receive and decode these signals, and plot locally received air traffic on Google maps. We have a tutorial for decoding ADS-B signals available here.
In the video Thomas Cholakov (N1SPY) explains the concept behind the antenna design, which is a standard 1/4 wave ground plane cut to the correct dimensions for ADS-B at 1090 MHz. He cuts 5 pieces of the same length, with one piece used as the active whip element, and four pieces used in the ground plane element. The paper clip pieces are then soldered onto a coaxial connector and then the antenna is ready to be used.
Amazon Echo is a smart home device which is essentially a hands free speaker that responds to voice commands in a similar way to ‘Okay Google’ and Siri does on your phone. With voice commands you can ask it to do things like play music, make a call or send a message, answer any question, control smart home devices like fans and locks and order items from Amazon.
Over on his blog Nick Sypteras has written about teaching his Amazon Echo a new ‘skill’ which allows it to automatically detect and read out what aircraft is flying outside his window, and where it is going. A skill is basically a plugin that you can code up to give your Amazon Echo new voice command functions and behavior.
The Echo skill gathers the live local ADS-B plane data via dump1090’s json output which runs on a networked Raspberry Pi with RTL-SDR dongle attached. The data is loaded into a database, which is then queried for the closest plane to the Echo’s location. Finally the program scrapes the closest flights departure and arrival data from FlightRadar24 before speaking it through the Echo’s speaker. Nicks code is freely available over on his GitHub page.
This project reminds us of a previous post where we posted about Simon Aubury’s work in creating a Raspberry Pi and RTL-SDR based aircraft camera tracking system. Simon’s system used live ADS-B data to point a camera directly at aircraft as they passed over his house.
It also reminded us of this British Airways video billboard that was popular a few years ago. The ad featured a young boy who would point directly at passing aircraft with text displaying the flight information. They used a commercial networked ADS-B device to gather live ADS-B data (internet based ADS-B data from sites like flightradar24.com has a time lag, so it is not suitable for time sensitive applications like this), and whenever a passing British Airways aircraft was detected the ad would play.
Thanks to Manuel aka Tysonpower for submitting to us his extremely cheap ADS-B antenna build. Manuels ADS-B antenna consists of a simple SMA connector with flange and some wires cut to the correct resonant length for 1090 MHz ADS-B. This ground plane design has been around for years on the internet with atouk’s guide being the most commonly used, although atouk’s design uses a larger SO-239 connector instead. Manuel takes the design one step cheaper by using cheap single core copper wire for the elements, and a low cost SMA connector. The wires are soldered onto the SMA connector flange so you will need to know how to solder to complete the antenna.
Manuel has uploaded a video which shows the build steps for his cheap antenna in a step by step guide. We note that the video is narrated in German, but there are English subtitles.
Over on his blog Akos has uploaded several new posts all relating to ADS-B reception. His first post shows how to build a very simple yet effective “Coketenna” ADS-B antenna which can be built with an empty coke can and some coax cable. This antenna is essentially a 1/4 wave ground plane antenna with the ground plane being a coke can cut in half and mounted upside down. The whip sticking up is simply the coax inner wire. In his post Akos shows exactly how to construct one.
In his second post Akos offers some advice on mounting and positioning ADS-B antennas, discusses the ‘range myth’, talks a bit about LNA’s and filters and shows the differences between a stock RTL-SDR dongle, and one optimized for ADS-B reception like a FlightAware Protstick.
In his third post Akos shows his results from long term ADS-B reception comparisons between a generic RTL-SDR dongle, an RTL-SDR.com V3 dongle with 1090 MHz LNA powered by bias tee, a FlightAware Prostick and a FlightAware Prostick Plus. The V3 dongle with bias tee powered LNA is used as the benchmark receiver and the results show that it received the most signals. The next best was the Prostick Plus, followed by the Prostick and finally the generic dongle.
Over on YouTube the official MATLAB channel has uploaded a new video that is a tutorial on setting up ADS-B decoding in MATLAB. MATLAB is a technical computing language that is frequently used by many scientists and engineers around the world. They write:
Use the software-defined radio capabilities that are part of Communications System Toolbox™ to capture and decode ADS-B messages. ADS-B is a relatively simple standard used by commercial aircraft to transmit flight data such as aircraft ID, position, velocity, and altitude to air traffic control centers. ADS-B messages are 56 or 112 bits long, the data rate is 1 Mbit/sec, and the messages are amplitude modulated signals, transmitted at a carrier frequency of 1090 MHz
The video goes over what ADS-B is, how to receive it, and then goes on to explain a bit of the MATLAB code. This is a good introduction for people wanting to use an RTL-SDR in MATLAB, or for anyone wanting to learn about ADS-B.
RadarBox.com is an ADS-B aggregator which is very similar to other aggregators like FlightAware.com and FlightRadar24.com. These services use ADS-B data provided from volunteers all around the world to create a live worldwide snapshot of current air traffic. The data is then used by airlines, airports, aerospace companies, as well as enthusiasts and regular people to track aircraft and estimate arrival times.
Typically contributors to these services use an RTL-SDR combined with a Raspberry Pi as the receiver. Some sites also use their own proprietary hardware, but they seem to be slowly falling out of favor as the RTL-SDR solution tends to be cheaper and more effective.
Over on their blog RadarBox have uploaded a new tutorial that shows how you can contribute to their service using an RTL-SDR, Raspberry Pi and their new RBFeeder client software. The set up procedure is very simple as they provide a script which downloads and installs the software automatically.
On their store they also sell an ADS-B antenna and 1090 MHz preamp which may be of interest to some ADS-B enthusiasts.