I’m scraping data from Dump1090’s wep page, and I find a number of unusual Mode-S IDs that are unknown to FlightAware, FR24, and RadarBox. These IDs usually start with 27 (e.g. 2798BC), 2E (e.g. 2E8A4C), 0E (e.g.0E1838), or 30 (e.g.30842A). Some of these report positions at local airports with speed = 0, suggesting that they are airport vehicles. Some report relatively low altitudes and speeds suggesting that they are helicopters or drones. These seem to be valid reports.
Any idea what’s going here? I’d expect airport vehicles to have Mode-S IDs that start with “A”. It’s possible (maybe likely) that some of these are military aircraft.
Several of those look like TIS-B prefixes, which are rebroadcast traffic that are for aircraft without actual hex codes. Examples could be things like mode-a/c only aircraft with primary radar positions.
Traffic Information Services – Broadcast (TIS-B)
Some versions of dump1090 will display those codes with lower-case letters to make them stand out. Some decoders will identify them other ways. If you are seeing the actual data in something like view1099-fa, they will show as DF18.
The last list of codes I have is a bit dated, but a couple match the Washington DC area.
278 (not your 279) = WASHINGTON CENTER AREA
2e8 = REAGAN WASHINGTON NATIONAL SURFACE AREA
308 = WASHINGTON DULLES SURFACE AREA
A few of my local codes have expanded from the latest list I have, so possibly Washington Center has expanded to 279 also.
You’re going to have to enlighten me on this. I don’t know what view1099-fa or DF18 are! I’m not using view1090-fa, I’m just pulling stuff off Dump1090’s web interface on the RPi from another computer.
Very interesting, thanks! Mode-S ID 308997, for example, does indeed give a position within Dulles airport.
I’m going to have to study FAA document that you referenced. On first reading, I didn’t understand TIS-B. Are these fixed stations at known locations?
I’m not using view1099-fa.I’m reading the Dump1090 web page on the RPi from another computer with a Python program. All of the Mode-S IDs are given with lower case letters.
Speaking of IDs starting with 2E8, I’ve gotten reports from more than 300 unique 2E8 IDs. Almost all of them have been a single reception, so far. Does ths make sense? Considering that there aare only 4096 possible 2E8 IDs, someone must be cycling through them.
You have not said exactly which version of dump1090 you are using.
View1090-fa is part of the FA package. If you have the FA package installed on the remote Pi you are using to receive, just use ssh and something like Putty to log in to the Pi. Then run “view1090-fa --help” to see the options. View1090-fa by default will connect to any version of dump1090 on the Pi with beast style data available on port 30005.
View1090-fa can also be used in a non-interactive mode to log all data for a while. You can then review that log to see individual messages decoded with many more fields than normally available on a local web view.
For my area (NW Florida) with a lot of military traffic, TIS-B with those pseudo-hex codes tend to be mode-a/c only aircraft. The position is from FAA primary radar or FAA mlat. There are also mode-s only aircraft (usually military) that are rebroadcast with a position. Those will often have real AExxxx type hex codes. Some of those will be a bit more “blocked” or anonymized, and display with the pseudo-hex to hide the actual real hex.
Sometimes you might see a real ads-b aircraft you are receiving, along with a pseudo-hex rebroadcast when the two tracks have not been correctly matched by the FAA.
Remember, TIS-B is not always broadcast, and usually appears in clusters around an aircraft that is able to receive the data. Take a look at some of the online sources if you are curious.
I’m not using Dump1090-fa. I got the Dump1090, whatever version it is, from an FR24 installation. I’m currently feeding data to both FR24 and RadarBox. Can I also feed it to FA a the same time? That seems like a little too much, but I’ll do it if I can
I have lots more questions and comments. Your responses have been very useful, but I don’t want to wear you out .
First, on TIS-B: Is the information transmitted by ground stations broadcast as regular ADS-B messages with “manufactured” ModeS IDs assigned to specific aircraft?
I receive very few AE… IDs that aren’t identifiable as a specific military aircraft.
I do have Dump1090-mutability installed, but view1090 commands aren’t recognized by my RPi. Would view1090 give me any information that I’m not scraping from Dump1090’s web interface?
My FR24 and Dump1090 config files are already configured as you described, so I should be set to go for FA.
I don’t understand your statement: “TIS-B is not always broadcast, and usually appears in clusters around an aircraft that is able to receive the data.” Would they simply look for any aircraft that has ADS-B/out? In my area, DCA/IAD, there is almost no time where there isn’t an ADS-B/out aircraft around.
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