Interpreting the "FR24 Feeder Tracked Aircraft List" screen

[RotoruaPete]

Hi there. I am new to this but have managed to set up a ADS-B receiver with a Raspberry Pi. It now working well on my garage roof and seems to be tracking aircraft as will as I can expect considering the geography of where I am. I have been monitoring its performance by watching the "FR24 Feeder Tracked Aircraft List" screen obtained by selecting the local IP address with the :8754 suffix.

Most of that data is obvious but I notice a couple of things. When an aircraft first appears on the horizon and the signal is presumably weak, the only data that appears is the Mode-S ID and the altitude. The other fields usually fill in with time. Sometimes they don't. An aircraft yesterday flew virtually overhead yet it never displayed Lat or Long the whole time. However that flight was correctly displayed on FlightRadar24 the whole time.

As I understand it, all that data is broadcast with ADS-B the whole time. Is there a priority that this data is broadcast at ie. ID and altitude top priority, the rest when the signal is strong enough? Why was the aircraft I saw yesterday (a small commercial operator) not displaying lat & long?
Thanks in anticipation.

[Oblivian]

Nope. Some don't have GPS integration. Especially the Dash-8s so you only get ident, altitude
This is what the server uses for MLAT calculations. They show on the map, but you won't see it as the calculation is not passed back (it does with flightaware and local map)

There's different messages. All have the ident/HEX. But some are airborne position. Some are speed/heading. And they follow each other

1 - 4	Aircraft identification
5 - 8	Surface position
9 - 18	Airborne position (w/ Baro Altitude)
19	Airborne velocities
20 - 22	Airborne position (w/ GNSS Height)
23 - 27	Reserved
28	Aircraft status
29	Target state and status information
31	Aircraft operation status

You can see this if you monitor :30003 with a tool like putty/telnet

MSG,3,333,32312,C821BA,32412,2020/03/07,14:15:56.308,2020/03/07,14:15:56.308,,11150,,,-42.97744,172.84116,,,0,0,0,0 MSG,4,333,32298,C8186E,32398,2020/03/07,14:15:56.357,2020/03/07,14:15:56.357,,,328.0,196.6,,,-1216,,,,, MSG,1,333,32314,C81D25,32414,2020/03/07,14:15:56.357,2020/03/07,14:15:56.357,ZKFDR,,,,,,,,,,, MSG,3,333,32274,C80F41,32374,2020/03/07,14:15:56.410,2020/03/07,14:15:56.410,,8150,,,-43.55143,171.41837,,,0,0,0,0 MSG,4,333,32274,C80F41,32374,2020/03/07,14:15:56.410,2020/03/07,14:15:56.410,,,128.0,223.4,,,128,,,,, MSG,3,333,32295,C821EE,32395,2020/03/07,14:15:56.410,2020/03/07,14:15:56.410,,33025,,,-41.63672,172.03341,,,0,0,0,0 MSG,4,333,32305,7C77FD,32405,2020/03/07,14:15:56.410,2020/03/07,14:15:56.410,,,445.0,271.0,,,0,,,,, MSG,4,333,32300,7C6C95,32400,2020/03/07,14:15:56.410,2020/03/07,14:15:56.410,,,448.0,20.3,,,0,,,,,

https://forum.flightradar24.com/forum/radar-forums/flightradar24-feeding-data-to-flightradar24/9479-fr24feed-uploader-additional-info?p=146602#post146602

[RotoruaPete]

Thanks very much for that. My next question was going to be if the were any more ways to interrogate the data. That 30003 feed is everything I could want.

[Oblivian]

Assuming you have a DVBT stick. Change the :8754 to /dump1090/ And you'll have a local map/list

[RotoruaPete]

Assuming you have a DVBT stick. Change the :8754 to /dump1090/ And you'll have a local map/list

Thanks very much. This is awesome.

[luckylindy]

I just saw this post and am wondering what is suppose to happen if you replace :8754 to /dump1090/ ? When I do it, I just get "404 Not Found". I have a Raspberry Pi running

[Oblivian]

That's specific to standard install with 'dvbt' this user has

A you were asked but didn't say what install you followed, it may not be valid to you

Dump1090-fa uses different address. And it doesn't work of you mess with lighttpd

[luckylindy]

Oblivian, thanks for the info.