Over on the Google Play store there is a new (released July 2014) RTL-SDR ADS-B Android app available for purchase called “ADS-B Receiver”. This app allows you to with the aid of an RTL-SDR and USB OTG cable, display live aircraft ADS-B data on your Android phone. This app can also be used to display the live ADS-B data in another app called “Avare”, which provides offline FAA aviation charts and other pilot tools on a Android phone.
The app can be downloaded as a trial version with a fixed limit on the number of packets allowed to be received, or the pro version for around $1.99 USD with no limits.
Previously on this blog we mentioned another similar RTL-SDR Android ADS-B app called “ADS-B on USB SDR RTL“.
FLARM signals are transmitted at 868 MHz and are effectively weaker by 100-1000 times compared to standard ADS-B signals. The project recommends use of a high gain collinear antenna for receiving the weak FLARM signals. The open glider network project wiki contains information on how to set up their Linux based FLARM decoder that relies on the RTL-SDR for various embedded devices.
Previously we posted about the Hak5 teams attempt to create an ADS-B quadcopter receiver which carried a coax collinear antenna, ran the ADS-B decoder dump1090 on board and then transmitted the decoded ADS-B data back to a laptop on the ground via WiFi. Their results were poor due to various factors.
In the latest video they read comments from fans which explain why they had such poor results, then apply some of those recommendations to a second experiment. Previously they had trouble keeping the WiFi connection alive due to poor reception, so now they use a WiFi Yagi to boost the signal strength. They also reduced the number of elements on their coax collinear antenna and moved away from the broadcast RF transmitter that they were near in their last video.
There isn’t a big increase in the number of planes picked up in the second experiment but it was much more successful compared to the first.
A Better Aircraft Seeking Drone Antenna, Hak5 1613
Modesdeco is a Windows/Linux/OSX/RPi compatible command line ADS-B Mode S decoder built for the RTL-SDR. It natively supports the BaseStation format and so can be used with the BaseStation software without the need for com port converters.
Modesdeco has recently been updated to allow for the simultaneous reception of Mode S and Mode A/C. Mode S provides location data for ADS-B while Mode A provides an identification code and Mode C provides the aircraft’s pressure altitude.
Over on YouTube user Adam Alicajic has posted a video showing the effect of a filter tuned for 1090 MHz used on ADS-B reception. Adam switches the filter in an out showing the difference in the number of received ADS-B frames. With the filter enabled he is able to receive around 1200 messages per second and without only around 800 messages per second.
A filter (aka preselector) can help to reduce out of band interference from strong signals.
Over on YouTube, Hak5 a electronics enthusiast channel has posted a video showing an interesting ADS-B project they undertook.
The Hak5 team took a quadcopter up on top of a high mountain, attached to it a WiFi Pineapple (a small WiFi equipped Linux computer), an RTL-SDR dongle and a coax collinear antenna and then flew it up high. They ran dump1090, a Linux based ADS-B decoder on the WiFi pineapple and then broadcast the decoded information back to a laptop on the ground.
Although the results were less than favourable, it is still an interesting project to explore. Their poor results may be due to a nearby RF broadcast tower which could have been overloading the dongle, or EMF from the quadcopter motors.
Tracking Aircraft over 300 miles away! Mountain + Drone + SDR, Hak5 1609
The antenna was created by F5ANN, and he used his active antenna together with an RTL-SDR dongle, the RTL1090 ADS-B decoding software and PlanePlotter, and was able to receive 194 simultaneous aircraft signals with a message rate of 556 messages a second at distances of up to 250 nm.
The beta version of the popular ADS-B decoding software RTL1090 has been updated to version 3. Version 3 comes with a simple radar visualization scope built into the software, which allows you to see aircraft directly in the RTL1090 software.