Tag Archives: Aviation Monitoring

Making a FlightAware ADS-B feeder with a Raspberry Pi 3 and RTL-SDR dongle

It’s been nearly a year since I acquired both the RTL-SDR (above) and Rasperry Pi 3 (below)r.

Remember when I made a plea for Pi 3 projects just last year––?

Although many of you suggested some great projects, I never actually got around to doing any of them. Now, don’t get me wrong––I wanted to, of course, but simply got involved with reviews, NPOTA, two months of travel…and, well, life.

Then, last week at the Winter SWL Fest, a common theme emerged in both presentations and discussions:  the numerous applications of the super-cheap, and thus super-ubiquitous, RTL-SDR dongle. In their engaging presentations, both Dan Srebnick and Mark Fahey––SWLing Post contributors and good friends––focused on the power of the RTL-SDR, expounding upon some simple, inexpensive applications in their forums. It was inspiring. Also, buddy Eddie Muro showed me just how easily an ADS-B receiver could be set up using an Android phone.

Back to the Pi. Though I was already aware the Pi 3 and RTL-SDR could be united to make an ADS-B receiver, watching Mark Fahey talk about how simply one could feed the FlightAware network with ADS-B data finally hooked me.  Why not, indeed? Here was fun to be had!

Mark preparing to woo his captive audience at the Winter SWL Fest!

I couldn’t get the idea out of my head, so Tuesday, the day following my return, I set the afternoon aside.  I rolled up my sleeves, and with my long-neglected Pi 3 and RTL-SDR, got ready to cook up a flight sensor.

I figured I was probably missing a component or two, and fully expected the process to be complicated, but decided I wouldn’t let this deter me. And guess what? I was wrong on both counts!

FlightAware ADS-B feeder recipe

Ingredients:

If you only plan to use this SDR and antenna as an ADS-B feeder, you might go for the FlightAware Dongle and 1090 MHz antenna combo.

Directions:

Note: I used this excellent PiAware ADS-B feeder tutorial to build my system–it’s detailed and doesn’t make the lofty assumption that you actually understand formatting cards, building disk images, and/or editing config text files.

Directions below are a highly distilled version of that tutorial. If you’re new to all of this, as I was, follow these directions instead of the above tutorial. Be aware that the directions assume you’re using the Pi 3 and a Windows PC to burn the image file.

  1. Download PiAware image7-zipSD card formatter, and the Win32 Disk Imager. Decompress all compressed files, install and note the folder locations.
  2. Register your username at FlightAware–presuming you don’t already have an account, of course.
  3. Use SD Card Formatter to format your MicroSD card.  Just make sure you’re formatting the correct drive, else you could easily wipe the wrong disk/card!
  4. Use Win32 Disk imager to write the PiAware image to your MicroSD card.
  5. If using WiFi, open Windows Explorer.  Locate text document called piaware-config on the MicroSD card, open it with a text editor, and locate the WiFi ssid and password locations. Per the config comments, edit them to match your WiFi system. Note that any special characters in both the name and password will require the use of quotation marks (again, noted in the config file comments). Save the file in the same location on the disc image.
  6. Remove the microSD card containing the PiAware image; insert it into the Pi 3.
  7. Connect the RTL-SDR or FlightAware dongle to the Raspberry Pi. Attach an appropriate antenna to the RTL-SDR. Note:  You’ll get the best results if you place the antenna outdoors with line of sight to the skies.
  8. Plug the Raspberry Pi 3 into a power source…and cross your fingers!
  9. Grab a cup of coffee, walk the dog, or listen to this 12 minute version of the BBC countdown; it could take at least this long for FlightAware to start receiving data from your ADS-B feeder.
  10. When you see this My ADS-B button in the header of FlightAware (see below), you’ll know you’re in business. Congratulations!  You can now watch the skies.

Feeding FlightAware

After my ADS-B receiver had been in operation for a while, I was very impressed with the data FlightAware was able to pull from my ADS-B feed. I was equally impressed with the number of distant aircraft I could receive with such a modest antenna––a number of them up to 135 miles from my location. Once I find a suitable outdoor location for the mag mount antenna, currently indoors, I expect the reception distance will increase significantly.

You can also connect to the live feed from your ADS-B receiver through your local network. Here’s a screenshot of my live data:

Future plans

At the moment, my ADS-B receiver is located indoors, in a south-facing window.

It works, but clearly isn’t ideal. Since the Pi 3 connects to my network via WiFi, I intend to install the full ADS-B receiver system into a small weatherproof case and mount it outside. My Pi 3 has no case, so I purchased an inexpensive one yesterday. I should be able to feed it power with an outdoor outlet…but I’m very tempted to experiment with making it solar powered.  To find out if this is a logical move, I need to observe and measure the power requirements first, and will be doing that in the next few weeks.

Meantime, I’m thoroughly enjoying watching the (amazingly busy) traffic in the skies…and the kid in me relishes it!

Thanks, Mark, for the great idea!

Have any SWLing Post readers attempted to build a solar-powered or outdoor ADS-B receiver? Please comment!

Guest Post: Colin’s retrospective on monitoring aeronautical communications

Map indicating location of the Shanwick OCA

Many thanks to SWLing Post contributor, Colin McKeeman, who at my request, kindly shares the following guest post:


Monitoring Aeronautical Communications – A Personal Retrospective View

By Colin McKeeman

Hopefully this article will demonstrate that this hobby involves so much more than just listening to ATC (Air Traffic Control) advising “Shamrock 105 you are cleared to land runway 28, report on finals”, etc. My life-long obsession with aviation communications has given me a considerable insight into the day to day working that this critical activity encompasses.

Despite my opening sentence, my first exposure to ATC jargon was during the early 1960’s when I discovered that local airport and over-flight movements could be monitored on a ‘tweaked’ domestic VHF receiver. I recall someone discovered that a well-known Dublin based audio retailer, could retune such sets to cover the aeronautical air band (108 to 137 MHz). As a consequence like- minded enthusiasts soon appeared at the airport carrying bulky portable sets where their regular station names on the dial had been hidden behind pieces of sticky paper with new designators ‘Dublin Centre’, ‘Shannon 131.15’, etc. Although more compact and dedicated air band receivers have been developed over the years and the basic mode of VHF transmission has remained almost unchanged, but this cannot be said of aeronautical short-wave (HF) communications.

Whilst the monitoring of local aircraft movements was a considerable enhancement to the ‘spotters’ hobby, the desire to get more advance notification of ‘interesting’ flights was always regarded as the ‘holy grail’. I can quite vividly recall the breakthrough when at 16:25 on Thursday, the 3rd October 1963, I first heard Shannon Aeradio (located in Ballygirreen, Co. Clare) working a Trans World Airways flight 741 on short-wave. This was whilst flicking across the SW1 band of my 1958 Philips, model B3X85U valve receiver (see image below).

1958 Philips, model B3X85U valve receiver

This set had two short-wave bands comprising, SW1 covering 2.54 to 7.45 MHz and SW2 spanning 6.9 MHz to 22 MHz. My reception was boosted by a length of bell wire jammed into the sets external aerial socket and pinned to the picture rail over my bed. Thankfully this was during the time when Shannon Aeradio still broadcast on AM as this set was not equipped with a BFO for single sideband reception. Suddenly it became possible to hear flights mid-Atlantic that might just route my direction, or better still land at Dublin or even Shannon (well worth the six hour round trip by car!). The next problem was that the aforementioned flight TWA741 didn’t provide identification on the tail number/registration of the aircraft involved, a key element for the ‘spotter’. (Sorry, now more maturely redefined as an ‘aviation enthusiast’!).

I then discovered that many airlines assigned their two tone SelCal (selective calling) codes to individual aircraft and since the ground based radio operator working the flights usually repeated the code when copying a position report, yet another identification opportunity presented itself. A database of code assignment was soon established, thanks to co-operative airlines and diligent monitoring of airport movements. Today these codes still provide a potential method of aircraft identification and even in cases where the SelCal may not be announced by either the flight or repeated by the ground operator, I now utilise a mode of the excellent ‘MULTIPSK’ software to decode and display the four letter characters on screen, for subsequent possible airframe tie-up. It should be noted that not all aircraft operators link the SelCal codes to specific airframes, as some allocate them to the flight number instead.

It soon became apparent that Ballygirreen was not the only aeronautical ground station that could be heard on HF and so monitoring of the oceanic activity in the various areas managed by, Prestwick, London (station sited at Birdlip, Gloucester – more on this later), Paris, Iceland, Copenhagen, Bodo, Gander, New York, Churchill, Sondre Stromfjord, Santa Maria, Madrid, San Juan, was soon being logged from their various ‘nets’. Today many of these stations either no longer transmit on HF or have been amalgamated into a single unit, e.g. Shanwick, which consolidated Shannon Aeradio and Prestwick (the London station having been previously replaced by Shannon in January 1966). By good fortune some of the major players on the North Atlantic shared common ‘Families’ of frequencies, namely Shannon, Gander, Iceland and New York in the mid-1960’s all transmitted on 5611, 5626, 5641 and 5671 mc/s and thus avoided the need for constant frequency hopping. It should be noted that Shanwick Radio is providing communication support from its location in Ballygirreen whilst the actual clearances and routing decisions are decided at the Oceanic Centre in Prestwick, Scotland, which are then relayed to the flights from the Co. Clare station.

These HF stations handle both civil and military flight movements however some agencies provide a dedicated service for their military traffic. This is particularly appropriate to the United States Air Force, who operate a vast net of HF frequencies and dedicated stations. Stepping back 20 or 30 years, activity on these channels was particularly frantic, a key facility of theirs being Croughton Radio, based in the U.K. at Barford St. John, operating on a primary frequency of 111.75 MHz, still heard today. Because they transmitted on single sideband, monitoring such activity on my old Philips set was frustrated by the lack of a BFO, although I did attempt to create a harmonic on the frequency with another set tuned appropriately. This workaround never proved to be very satisfactory but was sometimes worth the effort.

Gradually single sideband became the norm for aeronautical HF communications and so investment in a dedicated receiver became essential and I saved up for a Trio 9R-59DS and was lucky enough to supplement this with an old American BC-348 set during 1972, both of which are still in my attic. This necessitated the need to erect a more efficient external aerial and so I quickly set up a suitably matched half-wave dipole for the 5 MHz band down the length of the garden, much to the intrigue of the neighbours.

With the advent of home computing another dimension to this hobby presented itself, whilst still retaining use of the communications receiver. In the early days of commercial aviation their communications relied on W/T but by the time my monitoring commenced this had been replaced by R/T. However radio teletype (RTTY) had also become a key feature of communication between the aeronautical ground stations. Whilst Morse code could be copied directly with paper and pencil, a computer (on an in-line teleprinter) was required to copy RTTY transmissions. So in the mid-1970’s, with the help of some simple software, I managed to start decoding Ballygirreen’s remaining RTTY link with Santa Maria, their circuits to Prestwick and other centres having been withdrawn some years earlier. Shannon Aeradio transmitted RTTY to Santa Maria on 3250, 5813.5, 8145 and 11440 mc/s and received traffic from them on 5474, 10540 and 11468.5 mc/s. These circuits, like many others, fell under the umbrella of the worldwide AFTN (Aeronautical Fixed Telecommunications Network) and messages had to conform to standards and structure as laid down by the ICAO (International Civil Aviation Organisation).

An example of such a message, copied by the author from Shannon Aeradio on 22nd March 1995 sent to Santa Maria, in the Azores regarding a KLM flight number 781, where their request for a higher altitude was denied, is reproduced below. The italic text within the { } is my clarification of its structure and so does not form part of the original message:-

ZCZC SMA152 221258 {start of message no. 152 on the Shannon/Maria/A circuit at 12:58}
FF LPPOZOZX LPAZYSYX {flight safety mess’ for the Santa Maria Oceanic & ATC centre’s}
221258 EIAAZZZX {message filed at Ballygirreen at 12:58 on the 22nd}
(RBKB0435-KLM781-EGGX UNA HIER LVL DUE TFC MNTN FL290 REQ HIER LVL WITHDRTN
TOD1252 {the key element of the message}
DFHM TA {selcal code DF-HM was transmitted on frequency TA, i.e. 5598 mc/s}
KLM781 RB TA MTNG F290 {the flight read back the message on 5598 mc/s & will maintain 29,000’}
EIAA RB TAQSYVA) {Ballygirreen read back on 5598 (TA) and advised flight change to 8906 (VA)}
NNNN {end of message signal}

Although the transmission of AFTN messages over HF have now ceased there is still much aeronautical activity to monitor, both on R/T or in the digital mode. Indeed the latest statistics from the Irish Aviation Authority shown that North Atlantic communications with Ballygirreen have grown by almost 9% when compared to this time last year, which represents contact with almost 945,000 flights for the first 10 months of 2016. Admittedly the format of the R/T air-ground messages have had their content shortened, especially as a result of the introduction of Controller Pilot Data Link Communication (CPDLC) procedures. Under this digital data transfer system, the ground station having established an initial R/T contact with the flight, all subsequent reporting is completed by data link and so further voice communication is dispensed with. Not all flights are CPDLC equipped and consequently R/T reports can still be monitored for the entire oceanic sector for a reducing number of operators.

Even though this precise mode of long range data communication may not be capable of interrogation by the average enthusiast, it is still possible to capture some of the aeronautical data bursts. For shortwave, this protocol is titled HFDL (HF Data Link), and for closer range the VHF equivalent is entitled ACARS (Aircraft Communications Addressing and Reporting System). To copy HFDL I use the ‘PC-HFDL’ software (Shannon operate on 11384 mc/s, plus others) and for the VHF data transmissions I use the ‘KG-ACARS’ software (the primary European frequency being 131.725 MHz). Incidentally, the United States Air Force utilise a similar HF based system called ALE (Automatic Link Establishment) but this tends to contain a lower level of information and transmissions are less frequent.

I hope this very brief overview gives you some idea of what attracts the current aviation enthusiast with an interest in communications and notably all without recourse to the Internet (except for initial access to the decoding software).


Many thanks, Colin!

If you would like further information, check out Colin’s HF blog or contact him directly at downrange@eircom.net.

As an aviation historian, Colin recently published a book on the history of the U.K. Birdlip communication complex, radio call-sign ‘London’ (mentioned in a post a few days ago).  The cost of Colin’s book including shipping to U.K. addresses, is €22. If you live outside the UK, contact Colin at the above e-mail address for a shipping quote.

Yaesu VX-3R: Monitoring ATC over a cup of coffee

While I have a number of amateur radio handheld radios, one of my favorites is the recently-discontinued Yaesu VX-3R.

Saturday morning, I took my father to the his local regional airport’s café (KHKY). It’s a frequent stop when I’m in town visiting.

While sipping coffee, talking with friends and watching GA aircraft land and take off, I tuned to the airport’s tower. It was a pretty busy morning air traffic-wise and it was fun to monitor communications from our table with a view of the runway.

While the little VX-3R lacks the power output of larger HTs, and doesn’t include digital modes like D-Star or DMR, it is dual-band (2M/70cm) and its wideband receiver covers the shortwave, FM and MW broadcast bands in a pinch. Best of all, the VX-3R is amazingly portable.

I take the VX-3R everywhere in my compact EDC (Everyday Carry) pack:

My Everyday Carry (EDC) pack, loaded with all of the essentials.

I’ve used this little radio while traveling (hitting local repeaters and even simplex), I’ve monitored live air support during a local forest fire, and, on a moment’s notice, even caught an ARISS contact.

This week, I decided it might make sense to purchase another VX-3R to carry in the glove compartment of my truck. Since I already know my way around this radio, and since I already have the software and programming cable through RT Systems--it seems to make sense.

I checked the price at Universal Radio only to find the following notice:

AVAILABILITY UPDATE:
This model is being discontinued. We expect one more shipment in late February which will fill our back-orders.  We are not accepting additional orders at this time.

DX Engineering, Ham Radio Outlet and GigaParts also show no stock.

I feel like $139 was a bargain for this versatile amateur HT.

Late last night, a “New Open Box” unit appeared on eBay for $119 shipped. The seller had 100% positive feedback, so I snagged it.

If you’re interested in the VX-3R, your best bet will be to check with radio retailers like Universal Radio and Ham Radio Outlet for used/demo units.

Of course, you might also follow a VX-3R search on eBay.

Post readers: Any other VX-3R owners in our community? Any other fans of monitoring ATC/aviation traffic?

Update: Hoax Radio transmissions at Melbourne and Avalon airports

The Melbourne Airport (Source: melbourneairport.com.au)

The Melbourne Airport (Source: melbourneairport.com.au)

Many thanks to SWLing Post contributor, Phil Brennan, who writes:

Just a follow up from last week’s story regarding hoax transmissions on airline frequencies at Melbourne airports. An arrest has been made and, if found guilty, the person may face up to 20 years imprisonment. Heavy stuff. Here’s a link to the Aust Federal Police media release:


Man charged following unauthorised radio transmissions at Victorian airports

This is a joint media release with Airservices Australia and the Australian Communications and Media Authority

The Australian Federal Police (AFP) has charged a 19-year-old Rockbank (Victorian) man with serious offences related to the alleged unlawful interference with air traffic control and endangering the safety of aircraft at two Victorian airports.

The arrest follows an AFP-led investigation with the assistance of Airservices Australia, the Australian Communications and Media Authority (ACMA) and Victoria Police.

Between 5 September 2016 and 3 November 2016, there were 16 separate unauthorised radio transmissions at Melbourne Airport and Avalon Airport causing interference with air traffic control.

On 21 November 2016, the AFP arrested a man and subsequently charged him with:

  • four counts of endangering the safety of aircraft contrary to Section 25(2)(b) of the Crimes (Aviation) Act 1991 (Cth); and
  • one count of interference likely to endanger safety or cause loss or damage contrary to Section 194 of the Radiocommunications Act 1992 (Cth)

The man is scheduled to appear before the Melbourne Magistrates Court this afternoon.

The AFP’s head of Crime Operations, acting Assistant Commissioner Chris Sheehan said this arrest demonstrates how law enforcement takes the safety of the airline industry very seriously.

“The current security measures in place for the airline industry are robust, and the traveling public should be reassured we are treating this matter appropriately,” acting Assistant Commissioner Chris Sheehan said.

“These incidents were thoroughly investigated by the AFP with the technical support of Airservices and the ACMA.

“The offences this 19-year-old man faces carry a maximum penalty of up to 20 years imprisonment.”

“The AFP also acknowledges the close working relationship with Qantas and Virgin Australia Group and the assistance provided particularly during the early stages of the investigation,” he said.

Airservices said there is no current threat to the safety and security of the travelling public as a result of these alleged radio transmissions in Victoria.

“Airservices worked closely with the AFP throughout this investigation to ensure the safety and security of the travelling public,” Airservices Southern Operations Manager Steven Clarke said.

“Airservices has appropriate procedures, processes and systems in place to ensure the safety of aviation operations at Melbourne and Avalon airports, and across the country and for the travelling public,” Mr Clarke said.

The ACMA uses a range of technologies and techniques to investigate and locate the sources of unauthorized or interfering transmissions across the radio frequency spectrum.

The ACMA reminds members of the public that making unauthorised transmissions may constitute a serious offence under the Radiocommunications Act 1992 (Cth).

https://www.afp.gov.au/news-media/media-releases/man-charged-following-unauthorised-radio-transmissions-victorian-airports

Hoax Radio transmissions at Melbourne and Avalon airports

The Melbourne Airport (Source: melbourneairport.com.au)

The Melbourne Airport (Source: melbourneairport.com.au)

Many thanks to SWLing Post contributor, Phil Brennan, who writes:

Your readers might be interested in this article from today’s Guardian

Hoax radio transmission at Melbourne airport forces plane to abort landing

Police are investigating 15 incidents of illegal radio transmissions with aircraft at Melbourne and Avalon airports, including hoax calls that forced at least one aircraft to abort its landing.

In a statement issued on Monday night, the Australian federal police said there had been “unlawful interference with air traffic control broadcasts over several weeks”.

Audio obtained by the ABC revealed that, during one of the calls, the hoax caller pretended to be the pilot of a light aircraft as he spoke to an air traffic controller.

“I can see you there now. Roger your mayday. Could you please advise what your situation is,” the air traffic control operator asks.

“Engine failure,” the hoax caller replies. “Descending passing through 4,500.”

In another incident a Virgin Australia flight en route from the Gold Coast to Melbourne was forced to change course under the instruction of the hoax caller transmitting from an unknown location, the ABC reported.

Continue reading…

Such behaviour could have disastrous consequences.

You’re right, Phil. It angers me to no end when people intentionally cause interference or disrupt operations at airports. So many lives depend on air traffic control and flight communications systems.

Thank you for sharing.