Category: Airband

An ADS-B Decoder for the GOMX-3 Satellite ADS-B Repeater

The GOMX-3 is a CubeSat which carries an experimental ADS-B repeater. Since it is a satellite the experimental receiver hopes to be able to receive ADS-B from orbit, then beam it back down to earth at a frequency of about 437 MHz using a GFSK at 19200 baud high data rate transmission protocol. From space the GOM3-X satellite can see many aircraft at one time and space based tracking allows for aircraft tracking over oceans.

Recently the creators of the satellite, GomSpace released a complete decoder for the ADS-B downlink, and now it has also been turned into a GNU Radio flowgraph by Daniel Estevez which can output decoded aircraft position data directly to a KML file which can then be opened in Google Earth or similar. This blog by DK3WN shows several logged decodes of the satellite and shows what the signal looks like in SDR#. Some of his posts also curiously shows what looks to be a Windows decoder, or logger, though we were unable to find a download for it.

Decoding the downlink should give you real time ADS-B data in your area, but the full log of stored stored data is apparently only downloaded when the satellite passes over the GomSpace groundstations which are mostly located in the EU.

[Also mentioned on Hackaday]
The GOMX-3 ADS-B Downlink Signal.
The GOMX-3 ADS-B Downlink Signal.
Aircraft detected by the GOM3-X Satellite ADS-B Receiver.
Logged aircraft detected by the GOM3-X Satellite ADS-B Receiver. Major flight corridors are visible.

SDRplay Updates: Android Support, ADS-B Decoder Upgrades and Acquisition of Studio1 Software

The SDRplay team have been hard at work during the last few weeks. First they announced beta support for Android via SDRtouch, then they announced an improved ADS-B decoder, and finally they have just announced their acquisition of Studio1. 

The SDRplay is a 12-bit software defined radio with tuning range between 100kHz – 2 GHz. Many consider it along with the Airspy to be the next stage up from an RTL-SDR dongle. 

Android Support

The author of SDRTouch on Android recently announced support for the SDRplay. SDRTouch is a Android program similar in operation to PC based software like SDR#. To access the beta you can sign up at this link. Currently there is support for up to 2 MHz of bandwidth.

Improved ADS-B Decoder

Back in March the SDRplay team released ADS-B decoder software for their SDR with the promise of improving its performance in the near future. 

Recently the SDRplay team released an updated version of their ADS-B decoder for the Raspberry Pi which now fully utilizes the full 12-bits of the ADC and takes advantage of the full 8 MHz bandwidth. Jon, the head of marketing at SDRplay writes the following:

We now have an updated beta version of ADS-B for both the Raspberry Pi 2 and 3. This is based upon the 16bit Mutability version of dump1090 developed by Oliver Jowett and unlocks the full 12 bit performance of the RSP1. People should see a significant performance improvement over the dump1090_sdrplus version, which was based upon 8 bit code. The latest beta version can be downloaded in binary form from . Should anyone have questions or feedback, please contact

We plan to eventually compare the SDRplay with the Airspy and RTL-SDR on ADS-B performance. If you are interested we previously did a review of the SDRplay, Airspy and HackRF here, but as the SDRplay did not have ADS-B back then, that particular test was not done.

Acquisition of Studio1 SDR Software

The last major piece of news is that SDRplay have now acquired the Studio1 SDR software. Studio1 is a paid SDR program, similar in nature to SDR#/HDSDR/SDR-Console. Like HDSDR, Studio1 is a spinoff from the old WinRad software. Their press release reads:

SDRplay Limited has today announced that it has reached an agreement with Sandro Sfregola, (formerly CEO of SDR Applications S.a.s.) to acquire all Rights, Title and Interest in Studio 1 a leading software package for Software Defined Radio applications.

Jon Hudson, SDRplay Marketing Director said: “We are delighted to have reached this agreement with Sandro to acquire Studio 1. Studio 1 is the perfect complement to our SDR hardware products and gives us the ideal platform to deliver a complete class leading SDR solution for our customers. We look forward to working with Sandro and further developing Studio 1 to unlock the full capability of our current and future products”.

Hudson added: “Studio1 has established a strong customer base with users of many other SDR hardware products. Studio 1 will continue to be available as a stand-alone product from WoodBoxRadio for the foreseeable future , but we also look forward to further developing Studio 1 to specifically benefit present and future owners of our products”

Sandro Sfregola added: “I am very pleased to have reached this agreement with SDRplay. The long term future for SDR lies in complete end to end solutions and I feel the SDRplay RSP combined with Studio 1 software gives users an outstanding combination of performance and affordability”.

About Studio 1:

Studio1 was developed in Italy by SDR Applications S.a.s. and has hundreds of happy customers around the world.Studio 1 is known for its user friendly stylish GUI, CPU efficiency and advanced DSP capabilities, including features notavailable on other SDR software packages.

About SDRplay:

SDRplay limited is a UK company and consists of a small group of engineers with strong connections to the UK Wireless semiconductor industry. SDRplay announced its first product, the RSP1 in August 2014

We believe that this is a good move for SDRplay, as one of the major issues with the RSP SDR was the lack of decently supported software.



A new RTL-SDR based Portable ADS-B Kit for Pilots is on Kickstarter

Back in March we posted about the FlightBox, a portable RTL-SDR ADS-B 1090ES and 978UAT receiver built for use by pilots in small aircraft. 1090ES provides ADS-B which allows a pilot to see on a map where other aircraft are, and 978UAT provides other services such as weather radar. The FlightBox is essentially a Raspberry Pi 2 combined with two RTL-SDR dongles, two antennas, a GPS receiver and is preloaded with the stratux software. The two channel FlightBox receiver currently sells for $250 USD.

Recently a new similar ADS-B product for pilots made by a different company has been released on Kickstarter. The new product is made by a company called RF-Connect and is similar to the FlightBox, but is powered by an Odroid C1. RF-Connect are also the programmers behind the ADS-B on Android app which was one of the first apps to be able to receive FIS-B weather data and display it on a map. 

The product receives 978UAT and 1090ES ADS-B signals using two RTL-SDR dongles, and then transmits the data via WiFi to an Android or iOS tablet running flight navigation software.

The Kickstarter early backer price is $150 USD for a single channel 978UAT only capable receiver or $200 USD for the dual channel 1090ES and 978UAT receiver. This contrasts with the FlightBox price of $200 and $250 USD for similar products, however the standard backer price for the RF-Connect ADS-B receiver is the same as the FlightBox.

The RF-Connect ADS-B Receiver transmitting data to a tablet.
The RF-Connect ADS-B Receiver transmitting data to a tablet.
The parts inside the ADS-B Receiver. Two RTL-SDR dongles, GPS receiver, two antennas, WiFi dongle, Odroid.
The parts inside the ADS-B Receiver. Two RTL-SDR dongles, GPS receiver, two antennas, WiFi dongle, Odroid.

RF-Connect have also uploaded a video showing their ADS-B on Android app in action.

RTLSDR4Everyone: ADS-B Bias-T Filter and External amplification

Akos from the RTLSDR4Everyone blog has recently come out with a new post where he explains how to get the best ADS-B reception with an LNA and filter. In his experiments he uses an LNA4ALL low noise amplifier and and ADS-B Filter, both of which are sold by Adam 9A4QV. New versions of the filter sold by Adam now also include a built in bias-tee circuit which allows you to easily power the LNA4ALL over the coax cable, allowing you to place it externally.

In the post Akos shows where to optimally place the LNA and how you can use your Raspberry Pi together with the ADS-B filter with bias-T in order to power an antenna mounted LNA4ALL. The post also discusses what the cheapest solution is for European customers attempting to optimize their ADS-B reception.

ADS-B Setup including a filter, bias tee, LNA and Raspberry Pi.
ADS-B Setup including a filter, bias tee, LNA and Raspberry Pi.

Review: FlightAware ADS-B RTL-SDR + LNA Positioning

Recently FlightAware released a new RTL-SDR dongle sold at zero profit at $16.95 USD. It’s main feature is that it comes with an ADS-B optimized low noise amplifier (LNA) built directly into the dongle. is a flight tracking service that aims to track aircraft via many volunteer ADS-B contributors around the world who use low cost receivers such as the RTL-SDR. In this post we will review their new dongle and hopefully at the same time provide some basic insights to LNA positioning theory to show in what situations this dongle will work well.

FlightAware Dongle Outside
FlightAware Dongle Outside

A good LNA has a low noise figure and a high IIP3 value. Here is what these things mean.

Continue reading

Recent Updates to the JAERO L-Band and C-Band AERO Decoder

JAERO is a program by Jonti that was released late last year which allows us to use a SDR such as an RTL-SDR to receive L-band and C-Band AERO messages. AERO is essentially the satellite based version of ACARS, and the L-band signals contains short ground to air messages with things like weather reports and flight plans intended to be transmitted to aircraft. The C-band signals are the air to ground portion of AERO and more difficult to receive as they require an LNB and large dish. However they are much more interesting as they contain flight position data, like ADS-B.

Over March JAERO has had some minor updates. It is now possible to display planes on a map by using it’s SBS1 protocol output and outputting the data to Virtual Radar Server. The second more recent update now allows JAERO to simultaneously monitor up to two C-band AERO channels. To do this you will need to use the AUX VFO plugin for SDR#.

If you enjoy JAERO, please remember consider donating to Jonti.

Plotting flights positions out of regular ADS-B range which were demodulated from C-Band AERO signals by JAERO.
Plotting flight positions that are out of regular ADS-B range. Demodulated from C-Band AERO signals with JAERO.
Monitoring two C-Band channels in SDR# with the AUX VFO plugin.
Monitoring two C-Band channels in SDR# with the AUX VFO plugin.

RTLSDR4Everyone: ADS-B with an LNA and more Comparisons

Over on the RTLSDR4Everyone blog author Akos has uploaded two new posts. In the first post he discusses his opinion on the recently announced FlightAware ADS-B Optimized ProStick, which is an RTL-SDR with an 1090 MHz optimized LNA built into the front end. He writes that he believes that the claimed 30% increase is not possible with the ProStick as his own tests using an LNA4ALL at the front end only showed a 10% increase in range at most. In his post he also shows that the updated Nooelec R820T2 stick comes with a suction cup holder for it’s supplied antenna.

To add to his post, while we haven’t received the ProStick unit we bought for review yet we believe that the ProStick will improve ADS-B reception a certain amount in some situations, especially for those using the stick in such a way where it is placed right at the antenna, or with a small desktop style antenna with little coax, both with an appropriate ADS-B filter used. However, as Akos also suggests in his post we believe that the superior solution is an external type LNA, like the LNA4ALL.

In his second post Akos also compares our RTL-SDR Blog dongle and two Nooelec dongles using some rtl_power scans. He finds that the latest Nooelec dongle has some further improved components such as a lower noise 3.3V LDO and shielded inductors which appear to further reduce the noise floor. 

ADS-B Filter + LNA4HF + RTL-SDR + Rasberry Pi.
ADS-B Filter + LNA4HF + RTL-SDR + Rasberry Pi.
Noise floor scans
Noise floor scans

Comparing ADS-B Reception with the RTL-SDR, Airspy and Beast Receivers

Over on the author has set up a page showing live statistics of his ADS-B reception for the RTL-SDR and Airspy software defined radios, and also for the Beast ADS-B receiver. The Airspy is a $199 software defined radio that many consider as a next stage up from the RTL-SDR, and the Beast is a ~$270 USD dedicated ADS-B receiver.

Unsurprisingly the results clearly show that the Airspy receives ADS-B signals significantly better than the RTL-SDR. However, what comes as a surprise is that it is actually appears to be outperforming the dedicated Beast receiver. In the tests with the outside vertical antenna, the Airspy running on a Raspberry Pi appears to receive a significant higher number of messages and also sees planes out to a further range.

Not too long ago the Airspy team released their ADS-B software for the Raspberry Pi 2. They write that this software uses the full 10 MHz bandwidth and can even decode messages that are overlapping one another. We’ve also been told by the Airspy team that the Airspy is already in professional use as an ADS-B receiver amongst several small airports.

In the future we hope to compare the Airspy against the RTL-SDR on ADS-B reception ourselves, and also compare it against the 8 MHz bandwidth SDRplay whose development team have also recently released a new ADS-B decoder, as well as the recently released FlightAware ADS-B Prostick RTL-SDR.

Beast and Airspy comparison on ADS-B Reception.
Beast and Airspy comparison on ADS-B Reception.