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  • Originally posted by Cooler View Post
    I like to setup different Raspberry pi's in this region to see all the General Aviation flying around here using the mlat capabilities of FR24, also at low altitude's.
    On the forum I read a lot about this topic and so far I understood a non ADS-B plane should be seen by minimal one FR24 (F) feeder and three Raspberry pies. They all should see an ADS-B plane as reference.
    In this region I see local mlat planes above 3000ft. At lower altitudes they disappear. During the same flight of those local planes, I see the radar changing from mlat into T-feeders. The T-feeders are all the time of the same four feeders. If the radar is changing from mlat to a T-feeder the plane is jumping to another position (1-2 km) So it's not very accurate.
    Last week I set up my first pi and it's running well.

    My question is: Will a Radarcape receiver be seen as a F-feeder from FR24? So if I use that feeder together with some Rasberry Pi's in the region will I see alle the planes at low altitude?
    1) If you bought your own radarcape it will be assigned a T-feeder code.

    2) Yes, theoretically you are correct. It depends on how you cover the area with the receivers, the bigger the better. If I recall correctly each receiver should be about 50nm away from each other in a square pattern; but in real life that is quite a challenge to achieve. FR24 also did mention they normally need at least 6 FR24 receivers to get MLAT to work. And how well the dongle RPi MLAT software setup is contributing we don't really know for now. There has been some MLAT7s popping up (meaning from the rpi mlat software) and some has been quite 'wild'. It is still in the testing phase however.

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    • Originally posted by Cooler View Post
      My question is: Will a Radarcape receiver be seen as a F-feeder from FR24? So if I use that feeder together with some Rasberry Pi's in the region will I see alle the planes at low altitude?
      The quiestion is rather; Will FR24 treat the Radarcape as a FR24 supplied F-feeder?. You will have to ask support@fr24.com for a definitive answer.

      A further requirement is that the aircraft needs to be seen and interrogated by a secondary surveillance radar (SSR) or another aircraft equiped with ACARS in order for the transponder to transmit data. So to be sure the aircraft is tracked at low level you need line of sight from a radar site or steady traffic overhead

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      • Originally posted by Kpin View Post
        The quiestion is rather; Will FR24 treat the Radarcape as a FR24 supplied F-feeder?. You will have to ask support@fr24.com for a definitive answer.

        A further requirement is that the aircraft needs to be seen and interrogated by a secondary surveillance radar (SSR) or another aircraft equiped with ACARS in order for the transponder to transmit data. So to be sure the aircraft is tracked at low level you need line of sight from a radar site or steady traffic overhead
        I life in the the eastern side of the Netherlands. There is a lot of traffic overhere. Why are the ACARS planes needed for mlat?

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        • So is the general consensus to run D1090-MR FR24feed and then tap into the raw for other apps. As apposed to 2 separate instances on the 1 device of D1090(in say piaware) and D190MR in FR24feed package.

          Shame, fired it all up. Turns out theres not enough Pi users near me :/

          But once I get a 2nd antenna/combo going or a pigtail to attach it to the DPD that may well change.
          Posts not to be taken as official support representation - Just a helpful uploader who tinkers

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          • Originally posted by Oblivian View Post
            So is the general consensus to run D1090-MR FR24feed and then tap into the raw for other apps. As apposed to 2 separate instances on the 1 device of D1090(in say piaware) and D190MR in FR24feed package.

            Shame, fired it all up. Turns out theres not enough Pi users near me :/

            But once I get a 2nd antenna/combo going or a pigtail to attach it to the DPD that may well change.
            As for FR24 I assume you don't need other Pi users nearby. You can be the one RPi in a cluster of 3 FR24 F-feeders + you; or 2xF + 2xT(RPi). And as there are quite a few F-feeders around Christchurch, you might be able to lower the MLAT altitude a bit. Maybe ...

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            • Originally posted by Oblivian View Post
              So is the general consensus to run D1090-MR FR24feed and then tap into the raw for other apps. As apposed to 2 separate instances on the 1 device of D1090(in say piaware) and D190MR in FR24feed package.
              Nope :-)

              install dump1090-mutability, install FR24 and connect via AVR (TCP) on 127.0.0.1:30002, then install piaware and it works out for itself that dump1090 already exists.

              thats how I'm running it here..... (just remember to do the setting to stop the FA produced MLAT getting sent to FR)
              T-YSBK22

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              • Originally posted by rodeo View Post
                Nope :-)

                install dump1090-mutability, install FR24 and connect via AVR (TCP) on 127.0.0.1:30002, then install piaware and it works out for itself that dump1090 already exists.

                thats how I'm running it here..... (just remember to do the setting to stop the FA produced MLAT getting sent to FR)
                Already applied the fix, Awaiting 2nd test ID from FR to not mess my normal stats up

                Ill go down the -MR road now then. Does mean I can't do the FR MLAT as well though wont it for now. Needs direct USB access and all that
                Posts not to be taken as official support representation - Just a helpful uploader who tinkers

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                • Hello all again, while my PI feed worked for last month without problems, it now stopped working for unknown reasons.
                  First it shown this: -- notice the Timestamp error.

                  pi@raspberrypi ~ $ sudo service fr24feed status
                  [ ok ] FR24 Feeder/Decoder Process: running.
                  [ ok ] FR24 Stats Timestamp: 1970-01-10 08:30:15.
                  [FAIL] FR24 Link: unknown ... failed!
                  [ ok ] Receiver: connected (2604879 MSGS/0 SYNC).
                  [FAIL] FR24 MLAT: not running ... failed!

                  Then I tried to manually fix the system time by using
                  sudo date -s "23 SEP 2015 17:19"
                  and it corrected the date on the PI itself, but now even after restarting the fr24feed service, it gives me this

                  pi@raspberrypi ~ $ sudo service fr24feed status
                  [ ok ] FR24 Feeder/Decoder Process: running.
                  [ ok ] FR24 Stats Timestamp: 2015-09-23 17:17:57.
                  [FAIL] FR24 Link: unknown ... failed!
                  [ ok ] Receiver: connected (10313 MSGS/0 SYNC).
                  [FAIL] FR24 MLAT: not running ... failed!

                  And it's still not working. Please help. Maybe I should update the feed, but don't know how to really do that..

                  Comment


                  • Originally posted by cbgsy View Post
                    I've just seen another example of this with flight GR679 from Manchester to Guernsey which is operated by G-VZON, an ATR-72 - definitely MLAT only.

                    T-EGHI62
                    Perhaps we should start a name and shame thread?
                    Name and shame is a bit drastic, but I'll happily out myself.

                    Edit: Reading further it seems there a "setting" to stop this. I'll post back if I can work out what that is before you reply!

                    Can you tell me what you think I've done wrong with my setup that is causing a problem? Unfortunately I've done some work on it, so the setup isn't the same as when you posted. I'm on Linux Mint 17.2 (effectively Ubuntu) with a generic Rafael Micro R820T tuner. At the time I would have been using the FlightRadar dump1090 setup, and feeding piaware from there to share the data with FlightAware.

                    I'm now on dump1090-mutability v1.15~dev and PiAware (Debian Package Add-on) 2.1-3~dev. Nearest airport is EGHI / SOU. I live a couple of miles to the west of it, but don't have line of sight.

                    Something I had been noticing was that planes coming in to land from the north seemed to get to within a mile or so and then circle round and stop about 10 miles to the north of the airport. Obviously this wasn't actually happening, and they were landing and then I was getting bad data from somewhere.
                    Screenshot from 2015-09-23 21:54:56.png

                    I notice that the FlightRadar website has the wrong coordinates for me (they have used the airport itself), and they seem to override the locally (correct) set ones.

                    Any suggestions what I should be looking for in my setup to see how I'm feeding FR from FA?
                    Last edited by fr241a; 2015-09-23, 20:58.

                    Comment


                    • @ dakky
                      Don't know your network-configuration but I had simmilar errors. (Not the timestamp error thou)
                      I checked my network connections and detached and re-attached the UTP-cable. Then re-signed-up again. After that it worked fine again....
                      ___________

                      Another general question... what's the difference between F-feeders and T-feeders??
                      Last edited by peerke63; 2015-09-24, 00:20. Reason: adressing
                      T-EHVK11 / RPi-2

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                      • Originally posted by rodeo View Post
                        Nope :-)

                        install dump1090-mutability, install FR24 and connect via AVR (TCP) on 127.0.0.1:30002, then install piaware and it works out for itself that dump1090 already exists.

                        thats how I'm running it here..... (just remember to do the setting to stop the FA produced MLAT getting sent to FR)
                        Going to go out on a limb here and guess this isn't good

                        Code:
                        mlat-mode="UDP"
                        mlat-number-seen="0"
                        mlat-ok="YES"
                        mlat-started="YES"
                        As I went the manual MR route, of course the connection type is TCPAVR via 30002. Can it actually still do helpful MLAT data with that

                        //edit

                        Stand-down. Now says 1 with a contact in range. However:
                        Code:
                        mlat-uplink-stats="0"
                        mlat_problem="no-config"
                        Last edited by Oblivian; 2015-09-24, 07:53.
                        Posts not to be taken as official support representation - Just a helpful uploader who tinkers

                        Comment


                        • Originally posted by obj View Post
                          Note that the standard FlightAware/piaware sdcard images, which is the large majority of installs, do not forward mlat outside their own systems unless explictly told to. mlat-client sends synthetic position messages to dump1090, but dump1090 is configured not to forward those messages further (e.g. it will not send them back out on port 30005). They can only escape if the user explicitly asks to forward them, or if piaware is installed on top of an existing system that forwards them.
                          obj,

                          I've never used the piaware SD card image, all my Pi's have raspbian on them.. I am not sure about any latest versions of your dump1090-mutability, but even when using piaware with bog standard config which is to feed mlat data back into dump1090-mutability, and bog standard settings for fr24feed, the MLAT data leaks out of dump1090-mut into fr24feed ... I think this might be because fr24feed adds "--mlat" onto the end of the dump1090 CLI commands when starting dump1090.. As far as I am aware this was meant for FR24's version of dump1090 and it was designed to tell its dump1090 to do the timestamp mod and send mode-s packets into fr24feed ... I could be wrong, I am no programmer, but the switch isn't there if I turn off mlat in fr24feed.ini ... so maybe this will clear some things up?
                          T-YBBN50 - Kallangur, QLD, Australia

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                          • For Mlat Must be Two Receiver Distance More Than 5 Km?? If two Receiver Distance Be under 5 Km It Not Work?

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                            • There are no exact numbers for MLAT.
                              MLAT = calculating the position based on speed of light.
                              If you have 2 receivers 5 meters from each other, you can't measure any difference in time = no MLAT.
                              If you have 6 receivers in a straight line 25 km from each other, it's very hard to calculate the MLAT position = no MLAT
                              If you have 4 receivers 3 km from each other you will maybe have MLAT but with very bad precision and big jumps.
                              Many receivers spread out in big area you will get better MLAT and better data.

                              Comment


                              • Silly question but ....

                                Going to update to the new FR24 RPi software this weekend - I'm going to make a fresh install Raspian SD card - do I still have to install the rtl drivers and disable the DVB drivers in Raspian first or does the FR24 software do this as well ?

                                Thanks guys, I'm a bit dim on these matters

                                John
                                T-EGMC14 -- RTL2832U / R820T+ Raspberry Pi + Dump1090 with home made 8 element colinear 12m above ground level.

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