Category: Airband

A modified dump1090 with ADS-B Heatmap and Range Alititude View

Dump1090 is one of the most popular ADS-B decoders that is used together with the RTL-SDR dongle. ADS-B stands for Automatic Dependant Surveillance Broadcast and is a system used by aircraft that broadcasts their GPS positions. It is a replacement for traditional reflection based radar systems. We have a tutorial on using the RTL-SDR to decode ADS-B here.

There is now a forked version of dump1090 by tedsluis that incorporates heatmap generation and range/altitude view. A heatmap will allow you to visualize where the most active aircraft paths in your area are and the range/altitude view allows you to see at what altitudes aircraft typically fly at in different locations. The software logs aircraft data in a CSV file, and then after collecting enough data a second program can be used to generate the heatmap. The full explanation of the software and instructions for installing and using it on a Raspberry Pi Linux system together with PiAware are posted on the forums.

A heatmap of aircraft flight paths.
A heatmap of aircraft flight paths.

An Unfiltered ADS-B co-op: ADSBexchange

Recently Dan, a reader of wrote in to let us know about a new web project he’s started called ADSBexchange is similar to services like and, but with one key difference. ADSBExchange explicitly states that they do not and will not filter ADS-B traffic for security reasons. Other similar services all filter FAA BARR (Block Aircraft Registration Request), military and other potentially sensitive ADS-B data. However, Dan argues that filtering the data is simply unneeded security theatre as anyone can build their own unfiltered receiver for very cheap. He writes:

I recently started a website that collects SDR ADS-B and MLAT data (typically from dump1090) worldwide, and displays it unfiltered – . This means that military, “blocked” and other “restricted” traffic is available to see, which is unique as far as I can tell.  We’ve recently tracked a U2 over the UK above 60,000 ft., Air Force One, and various diplomatic aircraft.  Additionally, there is a database of all previous aircraft “sightings” searchable on various parameters.

All of my research indicates this is legal, but perhaps “frowned upon” by local authorities.  The major flight tracking sites seem to not want to make any waves and voluntarily strip this data from their public feeds, even though they are typically fed “unfiltered” data from their volunteer participants.

The service is currently looking for RTL-SDR users who feed ADS-B data to join their feeding program so that they can expand their service coverage.


ADS-B On Android App Now Supports 978 MHz FIS-B NEXRAD Weather and Traffic

The “ADS-B on Android” app has been updated and now supports the reception and display of 978 MHz UAT FIS-B Weather and Traffic data. The app also receives ADS-B data as per normal. To use the app you will need an RTL-SDR dongle and a USB OTG cable.

UAT stands for Universal Access Transceiver and is a protocol similar to ADS-B that is used mainly by smaller aircraft in the USA. 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 in the air to see what ground control sees on their traditional RADAR system. It also provides a Flight Information Service-Broadcast (FIS-B) which includes NEXRAD weather data and other information. NEXRAD is an array of ground station weather radars that are used to provide pilots with accurate maps of precipitation and wind.

The free version of the app has ads and does not display NEXRAD weather radar on the default map. The pro version removes the ads and allows you to display a NEXRAD overlay on the map. It costs $2.50 USD.

Free Version:

Pro Version:

NEXRAD FIS-B precipitation data displayed on map.
NEXRAD FIS-B precipitation data displayed on map on the pro version of “ADS-B On Android”


Creating a FIS-B ADS-B Weather Information Receiver for Pilots with an RTL-SDR

Recently a pilot wrote in to let us know about how he’s been using his RTL-SDR to receive real time FIS-B ADS-B weather updates in ForeFlight while flying in his plane. ForeFlight is an iOS app for pilots that helps with flight planning and provides access to important information like charts, real time weather reports and airport information. However, to access real time weather information usually you need to buy a $549 – 899 Stratus receiver

Now it is possible to use an RTL-SDR to receive the FIS-B weather information that is transmitted on the 978 MHz UAT frequency which is available only in the USA. UAT stands for Universal Access Transmitter and is similar to ADS-B transmitted at 1090 MHz, however 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. UAT is commonly used on small aircraft due to it’s lower cost and additional features. 

To receive UAT FIS-B weather information the pilot used dump978 on a Raspberry Pi 2. Dump978 is a UAT decoder, similar in operation to dump1090. He has also created a program called “Stratux“, which together with a WiFi adapter allows the decoded FIS-B data to be transmitted from the Raspberry Pi by WiFi to an iPad running ForeFlight. Running the software is as simple as piping the 978 MHz signal from rtl_fm into dump978, and then piping the decoded output of dump978 into stratux. Foreflight can then connect to the WiFi signal and work like it is connected to an expensive Stratus receiver.

In the video example below you can see some weather radar animations from FIS-B data received from the RTL-SDR shown on the ForeFlight screen at around 4:29 and onwards.

RTL-SDR, Rasperry Pi, WiFi dongle and portable battery pack for receiving UAT.
RTL-SDR, Rasperry Pi, WiFi dongle and portable battery pack for receiving UAT.
FIS-B UAT Weather Report received on Foreflight from a Raspberry Pi and RTL-SDR running dump978.
FIS-B UAT Weather Report received on Foreflight from a Raspberry Pi and RTL-SDR running dump978.


Using a HackRF to convert ADS-B packets into Bluetooth packets for reception on your Smartphone/Tablet

HackRF experimenter Jiao Xianjun has recently posted about his new firmware which allows a single HackRF to receive an ADS-B data packet at 1090 MHz, and then retransmit it as a Bluetooth low energy (BTLE) packet at 2.4 GHz. A smartphone or tablet can then be used to view the ADS-B data. It appears that the system works by broadcasting several fake Bluetooth peripheral names as the received flight data, so there is no way to currently view the data on a map.

The firmware needs to be flashed into the HackRF RAM or ROM, and he provides instructions for this over on his post. The video below shows the HackRF and software in action on an iPad.

ADS-B to BTLE HackRF Relay
ADS-B to BTLE HackRF Relay

Some new RF filters from Adam 9A4QV

Adam 9A4QAV is mostly known as the manufacturer of the popular LNA4ALL, a low cost low noise amplifier which is often used together with the RTL-SDR to improve reception of weak signals. He also sells an ADS-B bandpass filter and an ADS-B antenna, the latter of which we reviewed in a previous post.

Now Adam has come out with two new RF bandpass filters which are for sale. RF filters are used to block unwanted interference from other strong signals which can cause trouble, especially with low cost receivers such as the RTL-SDR. 

The first new filter that he has developed is for FLARM (FLight Alarm System). FLARM broadcasts at 868 MHz and is a protocol similar to ADS-B. It is used by Gliders and some Helicopters for collision avoidance. It is possible to decode FLARM with an RTL-SDR which allows you to track gliders on a map, as discussed in one of our previous posts.

Characteristics of Adam's FLARM Filter.
Characteristics of Adam’s FLARM Filter.

The second filter is for amateur radio astronomers who wish to detect the Hydrogen Line at 1420 MHz. Hydrogen molecules in space occasionally emit a photon at 1420 MHz. A single emission can’t be easily detected, but space and the galaxy is full of Hydrogen and the net result is an observable RF power spike at 1420 MHz. This can be detected with a high gain antenna, LNA, RF filter and radio like the RTL-SDR. The Hydrogen line can be used to measure things like the rotation and number of arms in our galaxy. Filters are very important for radio astronomy work as man made interference can easily drown out the relatively weak cosmic signals.

Characteristics of Adam's Hydrogen Line Filter.
Characteristics of Adam’s Hydrogen Line Filter.

Adam sells all his fully assembled filters for 20 euros, plus 5 euros worldwide shipping.

One of the ADS-B/FLARM/HLine Filters by Adam 9A4QAV.
One of the ADS-B/FLARM/HLine Filters by Adam 9A4QAV.

Tutorial on using an RTL-SDR for ADS-B on a BeagleBone Black from Make Magazine

Make magazine has recently released a tutorial and uploaded a video showing a nice overview on how to get an RTL-SDR set up for ADS-B decoding on a BeagleBone Black embedded Linux computer. In the tutorial and video they show you the parts you will need and show you how to compile and install the RTL-SDR drivers and dump1090 ADS-B decoder on the BeagleBone.

ADS-B decoding allows you to receive GPS and other information from aircraft in your vicinity. We also have a tutorial about ADS-B decoding available here.

The BeagleBone Black is a small embedded Linux computer, similar to the Raspberry Pi. It has enough computational power to run the RTL-SDR and ADS-B decoder. 

Monitoring FBI Surveillance Aircraft with ADS-B and an RTL-SDR

After reading an article by the Washington Post about FBI surveillance aircraft spotted in the air after the West Balimore riots, John Wiseman decided to look for more information about these aircraft. Fortunately, John had on his hands a database of about 2 months of ADS-B data that was collected by his continuously running RTL-SDR + BeagleBone Black ADS-B decoder set up.

From reports on the internet John found out that FBI aircraft squawked with 4414 or 4415 codes, and used call signs like JENNA or JENA. With this information John decided to take a look through his ADS-B logs to see if if he could find anything similar. Out of 15,000 aircraft he had tracked, he found 9 aircraft in his logs that matched the criteria, and saw that they did exhibit suspicious behaviour such as circling over LA for hours at a time. Then by looking up their FAA records of the tail numbers of the suspicious aircraft, he was able to discover that these aircraft where licensed to companies with names like NG Research, OBR Leasing, Aerographics Inc. and PXW Services which are suspected Department of Justice front companies. John also writes:

If you Google the tail numbers of aircraft registered to those companies, you start to find forum and mailing list posts (often at sites that tilt toward paranoid/conspiracy/right wing, but not always) with people discussing these specific tail numbers and linking them to the FBI. Some of the supposed evidence includes details of radio communications that people have heard, e.g. talking about “being on station” or using callsigns that start with JENNA, JENA or ROSS, which are supposedly used by the FBI. Other posts claim that DOJ/FBI surveillance aircraft often squawk 4414 or 4415 on their transponders.

An article from the startribune talks about the surveillance planes and says:

The planes use “persistent wide-area surveillance” to photograph large areas for hours at a time, Stanley said. The captured images allow authorities to go back in time, if necessary, to trace pedestrians and vehicles who come to their attention.

Other devices known as “dirtboxes,” “Stingrays” or “IMSI catchers” can capture cellphone data. Stanley said it’s still unclear what technologies have been used in the surveillance flights.


Possible FBI Surviellance Aircraft Path from
Possible FBI Surviellance Aircraft Path from