It's a bird, it's a plane, it's freedom of speech at 1090 MHz

January 29, 2023 7:09 PM

ADS-B Exchange has been sold for 20 million to private equity Jetnet and the volunteer data collectors are are feeling sold out.

Unlike FlightAware, FlightRadar24 or RadarBox, ADSBx is an open source aggregator of ADS-B aircraft tracking data that doesn't rely on official data sources like FAA BARR/LADD. As such ADSBx promised to never censor the flight data of any aircraft, including dictators, billionaires, governments or arms dealer. Or Elon Musk. The flight data is broadcast by planes and captured by volunteers who are mostly running software radios using RTL-SDR usb radios and a Raspberry Pi to process the data feed.

Flight tracking data has been used to uncover FBI spy planes track police circular planes, projects like Dictator Alert and the infamous @elonjet jet tracking account.

Jet tracking and software radio previously on metafilter.

posted by zenon (21 comments total)

workers, means of production transmission, etc. etc.
posted by lalochezia at 7:13 PM on January 29, 2023 [4 favorites]

Is there anything to stop the volunteers from going elsewhere to share their info?
posted by Artifice_Eternity at 7:26 PM on January 29, 2023 [7 favorites]

Not really. There isn't nearly the lock in of CDDB that begat FreeDB that begat gnudb; essentially none for bots like @elonjet which are only interested in current data. The code is already open source and licensed under the GPLv2. From the Reddit thread it appears some of the developers are encumbered by employment contracts until June.

I'd also be surprised if historical data isn't also populated rapidly from personal historical logs assuming there isn't a copy of the DB out there somewhere.
posted by Mitheral at 7:56 PM on January 29, 2023 [4 favorites]

I just stopped my feeder for ADSB Exchange.

I recently wrote a thing that monitors my own ADS-B data and shows interesting planes based on their tail number broadcast, which is correlated to a local table to show interesting planes in my local airspace.
posted by caphector at 8:33 PM on January 29, 2023 [7 favorites]

I wonder if @SkyCirclesLA is going to stop working...
posted by snuffleupagus at 8:43 PM on January 29, 2023 [1 favorite]

There was a circle plane right over my house and my neighbors' houses the other night there long enough for me to look up on one of the flight trackers online. It had N/A as the tail, serial, and the owners.

Good ole state patrol I imagine.
posted by NoThisIsPatrick at 9:34 PM on January 29, 2023 [2 favorites]

That SkyCircles account pulls in pictures of the aircraft based on the broadcast reg, and sometimes the A/C shown are clearly inoperative (shredded tails, missing engines, etc) which makes me wonder if the cops fly around pretending to be junked planes.
posted by snuffleupagus at 9:38 PM on January 29, 2023 [8 favorites]

Private equity people are the orcs of the business world and they will destroy everything that is bright and good in this world unless we end the practice once and for all.
posted by abucci at 4:35 AM on January 30, 2023 [12 favorites]

Many people (including myself) have switched feeds to adsb.fi. It was relatively painless; track aircraft at https://globe.adsbi.fi.
posted by jquinby at 6:33 AM on January 30, 2023 [9 favorites]

Rich people have too much money and are able to use it to be really antisocial. The world needs wealth taxes to cut them down to size, if anybody could figure out how to make that work.
posted by Aardvark Cheeselog at 7:07 AM on January 30, 2023 [12 favorites]

I actually use this at work because it gives us a better eta for the medical flight helicopters than we get from the originating hospital. After I used it for that, I started using it for more curiosity - who's that over my house, oh, there goes that goddamn Patriots bird again - and even considered putting up my own beacon or whatever it's called. Oddly, this makes me more likely to do so if there's a new place to migrate to.
posted by cobaltnine at 8:13 AM on January 30, 2023 [6 favorites]

Setting up an ADSB receiver is fairly straightforward - the key bit is the SDR dongle, but those can be had for about $20. Any computer will work; a raspberry pi or equivalent is the most common. Getting started with FlightAware is probably easiest; you can feed data to other sites as you like once it's set up and running.
posted by jquinby at 10:48 AM on January 30, 2023 [1 favorite]

I am pretty deep into this world (I do the Advisory Circular/sky circles bots, and GPSJam, and that's my discovering-secret-FBI-aerial-surveillance presentation linked), and my take is a bit different. I'm certainly worried about the future of ADS-B Exchange, but I was also worried about its future before this. I think disconnecting your data feed might be a bit rash, and actually hurt the journalists and researchers like Dictator Alert and others.

The current situation is that exactly the same uncensored data is still available from ADS-B Exchange (adsbx) that has always been available. They have stated that it will continue to be uncensored. They are selling data provided by volunteers, just like they have done for the past several years (I don't think it's well known that they're even selling data to U.S. Dept. of Defense-adjacent customers). There is now a formal organizational structure in place where before it was apparently very ad hoc. They now have more resources—One person who previously volunteered has said he'll now be able to take a part-time position working for adsbx.

I think it makes sense to be wary of the new owners, but I also think it makes sense to wait and see what happens before disconnecting your feed. It turns out to be relatively easy to start a feed network, and many people already have done so in an attempt to create alternatives, but it's not clear to me that that's the best thing to do right now:

• It's easy to create a network that can handle a few hundred feeders. Scaling to 10K is hard: You need people, and you need money. Even though adsbx reportedly paid people below-market rates and also relied on volunteer work, it still took years before they became (slightly) profitable, and it required them to sell data. They tried to run on donations and it wasn't enough to cover tens of thousands of dollars per month in costs.
• Multiple independent networks are not as good as one big central network. Practically, multiple networks means fewer feeders and inferior coverage per network, so you may have to check several maps to see if any of them have the aircraft you're interested in. And fewer feeders especially significantly degrades the network's ability to do multilateration—"triangulating" the positions of aircraft that aren't actually broadcasting their locations—and multilateration is an important source of data.
• I haven't yet seen an alternative network that has a better organizational structure than what ADS-B Exchange had. Things are moving very quickly, so my information could be out of date, but the alternative with the most momentum right now is adsb.fi, which was started by someone I've never heard of just to learn how the software worked. There is an effort to try to improve that, but it's extremely nascent.

Right now, there simply isn't a viable alternative to ADS-B Exchange for many people. No other network has such good data, especially on aircraft that are trying to evade tracking (especially authoritarian regimes and law enforcement misusing rules that let them fly untracked). If you pull your feed, there is no place else to get that data. If you oppose private equity firms in principle, that's one thing, but be aware of the concrete cost your actions will have on researchers. If ADS-B Exchange loses so many feeders in the next week that its data suffers, or it dies out entirely, so do the Advisory Circular bots, and so does GPSJam. That gives me a selfish interest in it continuing, but almost everyone else using global aircraft tracking data is in the same situation as me. There is a long term advantage in finding an alternative, and I'm glad that people are working on that, but it's going to be a while before there's anything close to a network with the technical, financial, and organizational resiliency that adsbx has now. Add the competitors to the list of networks you feed, but maybe wait and see before pulling your data from adsbx.
posted by jjwiseman at 9:49 AM on February 1, 2023 [7 favorites]

I wonder if @SkyCirclesLA is going to stop working...

The biggest risk to the Advisory Circular bots like @SkyCirclesLA was Elon Musk. His attention seems to have shifted to other topics, so I hope they're safe for a while.

There was a circle plane right over my house and my neighbors' houses the other night there long enough for me to look up on one of the flight trackers online. It had N/A as the tail, serial, and the owners.

That is exactly the situation in which ADS-B Exchange shows its unique advantages. Check their map, and either you'll see the real registration or you'll see something like "no callsign Hex: ~298F6E", which, if it's circling, 99% means it's police.

That SkyCircles account pulls in pictures of the aircraft based on the broadcast reg, and sometimes the A/C shown are clearly inoperative (shredded tails, missing engines, etc) which makes me wonder if the cops fly around pretending to be junked planes.

The source I get those photos from has a bad API that doesn't give me date information, and sometimes it shows very old photos of other aircraft that had that registration years ago, so usually in that case a plane got trashed and the registration was re-used later. Or maybe the plane had an accident and got repaired!

Cops either use the real registration or they just don't broadcast the registration*.

* Of the thousands of law enforcement aircraft flights I've looked at, there were a handful that actually were using the wrong, apparently intentionally spoofed, registration.
posted by jjwiseman at 10:02 AM on February 1, 2023 [3 favorites]

I'd also be surprised if historical data isn't also populated rapidly from personal historical logs assuming there isn't a copy of the DB out there somewhere.

I believe ADS-B Exchange's historical data is in the hundreds-of-terabytes range. AFAIK nobody has a copy. Generally people don't save their logs (at least not at a useful level of detail) either.

I do keep a database of almost every transponder ping received at my station in Los Angeles. It started in 2016, and it's about 2 TB.
posted by jjwiseman at 10:09 AM on February 1, 2023 [2 favorites]

I guess I got here too late for the discussion—I was hoping to get some pushback to help me refine my thinking on this. :)
posted by jjwiseman at 11:38 AM on February 2, 2023

These are totally awesome comments jjswiseman!

I omitted the new owners various promises because those are totally empty and framed the contributors response on reddit as just a feeling because I think that most folks reactions are mostly just emotional. Except those developers who didn't get to cash in on the sale.
posted by zenon at 3:51 PM on February 2, 2023

I have a Pi 3 in my attic that used to feed Flightaware and ADS-B Exchange.

Alas, the antenna I have for it is pretty awful, and I never got anywhere near the performance I had hoped out of it. I guess that means I get to build a new antenna!

In the past I've taken my ADS-B feeder offline to do an operating system refresh - looks like I might be offline for a bit longer this time until I can sort out which of the various systems might be best to feed or not to feed.

73 de Ed W8EMV
posted by edwardvielmetti at 10:28 PM on February 2, 2023

Ed - I made this awhile back and it's worked FB in the attic ever since. I have it sitting on top of a long piece of PVC pipe and as high up as I can get it. I started to hack together a coaxial collinear just for the hell of it but lost interest at some point. Also I hate going into the attic for anything and the groundplane is still working so whatever. 73 de AA4JQ
posted by jquinby at 5:45 AM on February 3, 2023 [1 favorite]

Jack Sweeney, the guy behind the twitter (and Mastodon) ElonJet account, has started a new flight tracking project.
posted by Mitheral at 9:49 PM on February 7, 2023 [1 favorite]

pushback

naw, just some big 73s, well done & thanks
posted by snuffleupagus at 9:56 PM on February 7, 2023 [1 favorite]