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  • #91
    Originally posted by Jarod View Post
    MLAT around Schiphol now works down to 6000 feet.

    What is the distance two receivers need to be away from each other in order for MLAT to work properly?
    We don't know exactly but we estimate it to be above about 2000 m to keep good accuracy. We are planning to do some test later this year to get a good value.

    Comment


    • #92
      Originally posted by Mike View Post
      We don't know exactly but we estimate it to be above about 2000 m to keep good accuracy. We are planning to do some test later this year to get a good value.
      Interesting, i have stored your exact post in a .txt file to remind me to check on this later.
      About 1900 meters away there is another building i can place another receiver, once i fix a WiFi link to there (I have tested 20+km wifi links, so that will be no issue, just time).
      This building is about 2.5x the height of where the receiver is running now.

      When your test results are in be sure to share them with us. Then maybe we can plan on how to get MLAT working even on the ground at Schiphol.

      If anywhere: Lelystad (EHLE) is a very good place to put a receiver up high.
      Waypoint Artip is there, a lot of traffic passes over there, Artip also lies very central in The Netherlands, perfect for MLAT. (I currently wouldn't know anyone living in Lelystad, but if needed anyone can be found easily.)

      http://opennav.com/waypoint/NL/ARTIP

      Just sharing some thoughts and information, no idea how far you guys are planning to go with MLAT.
      Last edited by Jarod; 2013-10-26, 17:57.

      Comment


      • #93
        Suggestion, personal request:
        Would it be possible to show on the map, like with an "*" which flights are MLAT?
        Advanced or/and premium setting.

        KLM48 = F-XXXX
        KLM1548* = T-MLAT

        Comment


        • #94
          Originally posted by Jarod View Post
          MLAT around Schiphol now works down to 6000 feet.

          What is the distance two receivers need to be away from each other in order for MLAT to work properly?
          Hallo Jarod,

          Not sure whether you came acrossed this PDF document, please see link here http://forum.flightradar24.com/threa...ll=1#post33571

          better get it printed before the link disappears!

          had to do some searching for that document as it was awhile ago now. I find it interesting and gives a bit more information about MLAT. For low level MLAT it is quoted that receivers should be about 10-20nm apart (page43). No idea about ground level MLAT though. Glad to see FR24 team is going to do some tests to find out the distance of receivers for MLAT to work properly. As you might know, in theory 4 receivers is needed but from Mike's experience they need about 6-8 receivers to get MLAT going at higher FL ( i forgot how high ). Perhaps it is because of the increased distances of the receivers apart. But this tells us what we know in theory is different to the real ground situation sometimes. Finding the distance for optimum or good MLAT (?low level) would benefit FR24 so that they don't send to many receivers too close to each other, keeping things efficient and optimum in relation to costs.

          It would be interesting to see if you get can a 2nd receiver up at 1900 meters away and influence it brings to MLAT, but I wonder whether FR24 is keen to try that?

          Good to have some ideas bouncing though. and let's see whether there's improvement at your reception once the antenna is installed.
          Last edited by North Borneo Radar; 2013-10-27, 00:48. Reason: grammar

          Comment


          • #95
            Originally posted by Jarod View Post
            .....I have tested 20+km wifi links, so that will be no issue......
            Jarod, what kind of equipment do you use on your long range wifi link? Here is a link I setup before using 5.2GHz radios that gave us 30 Mbit up/down over 5Km. Post some photos of your link if you have any... thanks
            Attached Files
            www.ADS-B.ca

            Comment


            • #96
              1090 MHz,

              I don't remember all details, as i have a friend who is an air-link genius.
              But i think we used a:
              http://www.alibaba.com/product-free/...17dBi_BOX.html
              More here as well: http://www.alibaba.com/proconnect-manufacturers.html
              Can't remember the receiving antenna.

              Also, on 5GHz, it took me nearly an hour to remember it by searching all files on my computer:
              http://routerboard.com/RBSXT Mikrotik SXT-5D seemed to work as well.
              The reason i forgot was: http://www.wispforum.net/entry.php?5...ge-Mode-Part-I (hopefully it's gotten easier now)

              I have no idea about the speed measurements, but it was enough for audio streams and should be enough for FR24 upload data i assume.

              Edit:
              P.S. on the second picture is that a http://x264.nl/dump/konig-ant-uhf70-kn.jpg on there? I have that as well.
              A discone is great for vertical signals a long distance away, but the dvb-t antenna is great for picking up low and local ground signals of airplanes and schips.
              I know it's a bit off topic, if needed maybe a mod can make us/move us to a new thread, but to keep it all compact:
              http://x264.nl/dump/108.400mhz-vor-discone-antenna.jpg
              http://x264.nl/dump/108.400mhz-vor-dvbt-antenna.jpg
              HUGE difference!
              Last edited by Jarod; 2013-10-27, 07:58.

              Comment


              • #97
                This is the radios we used: http://www.tranzeo.com/products/radios/TR-5Plus-Series
                Antenna... plus I added the radomes: http://www.tranzeo.com/products/ante...Hz-Directional
                This stuff is kind of out of date from 2007.


                I've been asked to design a 1 Gbps link between 2 data-centers. This is what we're looking at using: http://www.ubnt.com/airfiber Airfiber is the latest in technology when it comes to this.

                As for the FR24 a 1Mbit link would do just fine, as long as you have low latency.
                Last edited by 1090 MHz; 2013-10-27, 08:13.
                www.ADS-B.ca

                Comment


                • #98
                  Originally posted by Jarod View Post
                  Interesting, i have stored your exact post in a .txt file to remind me to check on this later.
                  About 1900 meters away there is another building i can place another receiver, once i fix a WiFi link to there (I have tested 20+km wifi links, so that will be no issue, just time).
                  This building is about 2.5x the height of where the receiver is running now.

                  When your test results are in be sure to share them with us. Then maybe we can plan on how to get MLAT working even on the ground at Schiphol.

                  If anywhere: Lelystad (EHLE) is a very good place to put a receiver up high.
                  Waypoint Artip is there, a lot of traffic passes over there, Artip also lies very central in The Netherlands, perfect for MLAT. (I currently wouldn't know anyone living in Lelystad, but if needed anyone can be found easily.)

                  http://opennav.com/waypoint/NL/ARTIP

                  Just sharing some thoughts and information, no idea how far you guys are planning to go with MLAT.
                  I suggest that you apply and include all information in your application. When we have all applications in one place it's easier to plan for network expansion.

                  Comment


                  • #99
                    Hey Mike , regarding to your post on the Malta region if you want I can host another receiver on Malta apart from the one I already have. If you are interested tell me.
                    Thanks
                    I host F-LMML1
                    Last edited by jawivana; 2013-10-27, 17:07.

                    Comment


                    • Testing the FR24 receiver + antenna on the roof now with RG-59 coax cable.
                      The H155 coax cable will be placed hopefully this week and i have already checked: it fits from outside in!

                      Even with RG-59 cable the reception is quite well.
                      I also learned where i must place the antenna, a little too low and the building edge blocks a lot of on the horizon signals.

                      10 meter cable is just enough to reach it inside i think, it's going to be funny hanging the FR24 receiver on a string from the ceiling.
                      Luckily it's not very heavy or large!

                      Edit: I just love seeing MLAT expand around Schiphol when my receiver is online. Should be tomorrow or the day after tomorrow when i am fully operational and done testing.
                      Last edited by Jarod; 2013-10-28, 18:24.

                      Comment


                      • I called SAS828 and asked if it could circle around my receiver, i guess i have more pull than i thought:

                        http://x264.nl/dump/sas828-2013-10-2...y-receiver.jpg

                        Comment


                        • Sorry for the spam... but i LOVE MLAT!
                          http://x264.nl/dump/dwt552-mlat-2013-10-28.jpg
                          http://www.flightradar24.com/DWT552
                          MLAT down to 10000 feet now over the North Sea!

                          Comment


                          • Originally posted by Jarod View Post
                            Testing the FR24 receiver + antenna on the roof now with RG-59 coax cable.
                            The H155 coax cable will be placed hopefully this week and i have already checked: it fits from outside in!

                            Even with RG-59 cable the reception is quite well.
                            I also learned where i must place the antenna, a little too low and the building edge blocks a lot of on the horizon signals.

                            10 meter cable is just enough to reach it inside i think, it's going to be funny hanging the FR24 receiver on a string from the ceiling.
                            Luckily it's not very heavy or large!

                            Edit: I just love seeing MLAT expand around Schiphol when my receiver is online. Should be tomorrow or the day after tomorrow when i am fully operational and done testing.
                            Thanks for your updates. MLAT coverage expansion has gone faster than we expected. It looks like we can have FL150 coverage in most parts of Europe and FL50 coverage on some strategic airports within about 3 months.

                            Comment


                            • It would be good to see MLAT in Ireland and Scotland - to see more of those transatlantic flights to and from the heart of Europe.

                              Comment


                              • http://x264.nl/dump/redsk51-mlat-2013-10-29.jpg
                                http://x264.nl/dump/redsk52-mlat-2013-10-29.jpg

                                http://x264.nl/dump/redsk51-redsk52-...2013-10-29.jpg

                                http://www.airframes.org/reg/q01
                                http://www.airframes.org/reg/q04

                                Edit: seen down to 3800 feet!
                                http://x264.nl/dump/redsk52-mlat-3800ft-2013-10-29.jpg

                                We need moar MLAT receivers!


                                Edit2:
                                Nice to see: AMS to LHR MLAT up to 8000 feet down to 8000 feet.
                                And reverse also for the first time:
                                http://x264.nl/dump/bee3vx-mlat-2013-10-29.jpg

                                After MLAT is lost i can continue tracking the planes visually.
                                Last edited by Jarod; 2013-10-29, 15:01.

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