Over on the official SDRplay blog, head of marketing Jon has announced that the RSP1 & RSP2 is now compatible with their dump1090 ADS-B decoders for the Raspberry Pi 2 & 3. They write:
ADS-B for both RSP1 and RSP2 now available for the Raspberry Pi 2 & 3 – you can get the software from downloads – http://www.sdrplay.com/downloads
If you are an RSP2 user, make sure you use Antenna Port B.
Allaboutcircuits.com contributing writer Mark Hughes has recently posted a tutorial that shows how to use an RTL-SDR dongle with a Raspberry Pi Zero Wireless to track aircraft with ADS-B. As a bonus he also shows how to program and wire up a 64×64 RGB matrix screen to display currently tracked flight numbers.
The Pi Zero is one of the cheapest single board computers available, costing only $5 USD, and the wireless model with WiFi connectivity only costs $10 USD. It is powerful enough with its 1 GHz CPU and 512 MB of RAM to run an RTL-SDR and run several non CPU intensive applications such as ADS-B decoding.
The tutorial starts from the beginning by installing a fresh Raspbian image onto the Pi Zero. He then goes on to show how to install the PiAware tracking and feeding software from flightaware.com. Later in the tutorial he also shows how to collect data straight from the flightaware.com API, and also how to build and control an RGB matrix which can display live flight numbers.
It also seems that FlightAware themselves have recently released PiAware 3.5, which now directly supports the Raspberry Pi Zero Wireless.
The FlightAware ProStick Plus is an modified RTL-SDR designed specifically for ADS-B reception. Its main defining feature is that it has a built in low noise figure LNA, and a 1090 MHz SAW filter. The LNA reduces the noise figure of the RTL-SDR, improving ADS-B reception and thus increasing the number of messages received and the receivable range of aircraft. The SAW filter helps remove out of band signals which can cause the RTL-SDR to overload if they are particularly strong. The Prostick Plus also comes with a TCXO, and SMA connector.
If you are mainly interested in ADS-B reception, or are looking to set up an ADS-B station then the Prostick Plus is one of the best choices you can make. See our previous review here.
We are now reselling some of FlightAware’s Prostick Plus dongles in our store now. They cost $24.95 USD including free shipping worldwide. We intend to sell them mainly to customers outside of the USA, as FlightAware already sell them officially on Amazon, but we offer free shipping anywhere in the world.
Over on his blog ‘Radio for Everyone’ Akos has shared results submitted to him by FlightAware forum user ‘Nitr0’ which compares several ADS-B antennas that cost under $50 USD. The antenna that we most recommend for ADS-B is the FlightAware antenna, but for European buyers there are also many lower cost alternatives available on eBay, most of which are made by fellow radio hobbyists or hams. The tests use the six antennas listed below, comparing each one against the ‘reference’ FlightAware antenna.
In summary the tests seem to show that nothing beats the FlightAware antenna, with the closest in performance being the Bulgarian made antenna. We should mention however, without knowing the real radiation patterns, SWR and various other factors it is hard to say which one will work best for everyone. Different locations/obstacles/mountings could mean that antennas with different designs and therefore radiation patterns work better than others. But it seems that the FlightAware antenna is the top performer in the common scenario of being able to mount the antenna on a roof with a good view of the horizon.
Akos from the radioforeveryone.com blog has recently uploaded some new posts. The first post is a tutorial on setting up a PiAware server with an RTL-SDR. PiAware is the official ADS-B feeder software from FlightAware.com, which is a web service that provides real time tracking of aircraft. Most of the flight data comes from volunteers around the world running a PiAware server with an RTL-SDR, ADS-B antenna and Raspberry Pi. The installation is fairly simple, involves burning an SDcard with the PiAware image, setting up the WiFi and then seeing your receiver online on the PiAware website. From there you can then configure the device further.
In the second post Akos describes how to feed other tracking websites, e.g. not just FlightAware, but also similar sites like Planefinder.net and flightradar24.com. Akos has also mentioned that a single Raspberry Pi can be used to feed all three aggregators simultaneously.
Akos the author of the radioforeveryone.com blog has recently added two new articles to his blog. The first post is a comprehensive guide to setting up your own ADS-B station. The guide focuses on creating a system that is easy to use, has good performance and is value for money. In the post he shows what type of computing hardware is required, what software can be used and what RTL-SDR dongles work best. He also shows what choices are available when it comes to amplification and filtering to improve signal reception and goes on to talk a bit about adapters and the antennas that work best for him.
In the second post Akos shows more on how to build your own beginners antennas for ADS-B reception. The post focuses on showing how to modify the stock magnetic mount antenna that comes with most RTL-SDR dongles, and how to build a half-wave ‘spider’ antenna entirely out of coax cable. The post is full of easy to follow images which make it great for beginners.
EDIT: It’s been pointed out in the comments by antenna experts/enthusiasts that the 1/2 wave ground plane antenna described by Akos in his tutorial may not be technically correct. A 1/2 wave antenna has a huge impedance which requires some sort of matching. Without matching there is going to be about 10 dB of loss due to the mismatch, and so the antenna will perform poorly. We recommend sticking with a 1/4 wave design, which is essentially the same as Akos’ 1/2 wave ground plane antenna, just with the element lengths halved.
Akos from the radio for everyone blog (formerly known as the rtlsdr4everyone blog) has uploaded two new posts. On the first post he shows some further tests on the new FlightAware Prostick plus. The Prostick is an RTL-SDR that contains a built in LNA and the Prostick plus adds an additional SAW filter on the stick. For him the Prostick Plus works significantly better than the regular Protstick + external FA cavity filter and also gets about twice the ADS-B reception reports as our V3 which does not use an additional internal LNA. Next week we hope to release our own review of the Prostick Plus, and we’ll hopefully be able to show and explain why some people see better performance with the plus and why some instead see degraded performance.
In his second post Akos shows a tutorial on building an easy helical antenna for Outernet reception. The antenna is constructed from readily available household materials such as a soda bottle, coax cable, electrical tape and a cookie tin. With the cookie tin used he was able to get a SNR reading between 7 – 9 dB, which is pretty good considering that only 3 dB is required for Outernet decoding to work.
Stratux is an RTL-SDR based project that gives small plane pilots access to ADS-B data, without having to purchase an expensive commercial ADS-B installation. It consists of software that runs on a Raspberry Pi, and two RTL-SDR dongles to receive both 1090 MHZ ADS-B, and 978 MHz UAT. The decoded data is then streamed via WiFi to a tablet running navigation aide software with charts for pilots.
Typically Stratux kits come with two standard ‘Nano’ styled RTL-SDR dongles. However, users of the Stratux system have been reporting problems with overheating, and with the Pi struggling with the high current demands of a typical setup which includes two RTL-SDR dongles, active WiFi broadcasting, a GPS unit and an optional cooling fan. A typical RTL-SDR dongle draws 280 mA, so two dongles are already pulling 560 mA.
Chris, creator of the Stratux software and seller of Stratux kits has just released a new low power RTL-SDR dongle (kit with antennas). The cost is $35 USD for two dongles (one for 1090 MHz and one for 978 MHz). The dongle obtains its low power feature by using a switching regulator instead of a linear regulator as the main 3.3V power regulator on the PCB. Normally you would not want to use switching regulator for the main regulator in an RF device because they are very noisy in terms of RF interference generated. However switching regulators are much more efficient compared to linear regulators, and thus save a lot of current wastage. Other dongle manufacturers like ThumbNet have actually gone the other way, removing the secondary 1.2V switching regulator from the standard dongle design, and using a linear regulator instead. The ThumbNets end up with lower noise, but draw 400 mA of current.
With the switching regulator the new Stratux dongles only draw about 185 mA, a saving of almost 100 mA. They also generate 0.5W less heat. Users of the Stratux system have so far been impressed with them and have not noticed any appreciable difference in ADS-B performance. We think that these low power dongles might also be of interest to people using them on mobile phones or battery/solar powered remote installations.
During testing, Chris found that there was no significant noise floor increase visible on the 978 MHz & 1090 MHz frequencies. Most of the switching noise increase appears to be on the lower frequencies, but those frequencies are not relevant for the Stratux use case anyway.
Chris was kind enough to send us some samples of the new low power dongles. First we ran a noise floor scan with rtl_power to determine the effect of the switching regulator. The results show that the spurs and noise floor readings have definitely increased by a significant amount, with an especially large noise floor rise below 400 MHz. In SDR# wandering switching noise spurs are also visible throughout the spectrum, but they tend to weaken in strength once an antenna is connected.
Fortunately, ADS-B is very tolerant to spurs and is generally not affected by this type of noise. We’ve only given the Stratux a quick test on ADS-B so far, but when compared against another ‘nano’ styled dongle the Stratux performed nearly identically (in fact even a little better) in terms of messages received. The two dongles were connected to the same antenna via a splitter and we logged the number of messages received in 10 minutes.
In conclusion the Stratux RTL-SDR set out to solve the mobile power issues suffered by people using the Stratux system. It has achieved that with an over 100mA saving in current use. The new Stratux dongle is much noisier, but the noise does not appear to significantly affect ADS-B reception as seen by our results and from the reports from Stratux users who beta tested this dongle.
Chris has also created a post on Reddit /r/stratux which talks a bit more about the new dongle.
