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  • @abcd567 I have a question , is it possible build a antenna limited in short range like 100nm , goal is more position report .

    Regard

    Griffin
    T-ZSSS32 F-ZSSS1 force shutdown by local regulation

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    • Originally posted by iamnothere View Post
      @abcd567 I have a question , is it possible build a antenna limited in short range like 100nm , goal is more position report .

      Regard

      Griffin
      Just use a known working antenna... and then limit the RF gain on the receiver (if you are using an RTL dongle etc)
      Otherwise fit an attenuator to the feeder.

      Comment


      • Originally posted by Rooster View Post
        Just use a known working antenna... and then limit the RF gain on the receiver (if you are using an RTL dongle etc)
        Otherwise fit an attenuator to the feeder.
        Thanks replay , yes I am use RTL dongle .

        If reduce the RF gain could it influences position report ?
        T-ZSSS32 F-ZSSS1 force shutdown by local regulation

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        • Originally posted by iamnothere View Post
          @abcd567 I have a question , is it possible build a antenna limited in short range like 100nm , goal is more position report .

          Regard

          Griffin
          Originally posted by Rooster View Post
          Just use a known working antenna... and then limit the RF gain on the receiver (if you are using an RTL dongle etc)
          Otherwise fit an attenuator to the feeder.
          In addition to what rooster has rightly suggested:

          (1) Remove amplifier if there is one.

          (2) Use a low gain antenna such as wave whip with groundplane (Spider, Cantenna etc), instead of a high gain antenna (high gain commercial antenna or a good DIY CoCo).

          Comment


          • What is this "position report" ?

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            • feed_stats
              Screen Shot 2015-07-23 at 11.40.30 PM.jpg
              T-ZSSS32 F-ZSSS1 force shutdown by local regulation

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              • Originally posted by iamnothere View Post
                feed_stats
                [ATTACH=CONFIG]6272[/ATTACH]
                Reducing/limiting the range will REDUCE the number of hits/positions reported.

                If you want to increase the number of hits/positions reported, you should try to INCREASE the maximum range to its theoretical limit of 450 kms / 250 nm. This requires:

                (1) Use higher gain antenna.
                (2) Raise antenna above obstructions such as buildings, trees etc so that your antenna can "see" the horizon. Imagine your eye in place of the antenna, and if your eye can see the horizon, the antenna can also "see" the horizon. Once your antenna starts seeing horizon, no need to raise antenna any further.
                (3) Use Amplifier between antenna & receiver.
                (4) Set DVB-T's (or any other receiver's) gain to maximum, or better to AGC.
                Last edited by abcd567; 2015-07-23, 17:33.

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                • Thanks , currently average covered up range from 230nm to 255nm , was hoping hit more plant if reduce and limited the range , must be a stupid idea : P
                  T-ZSSS32 F-ZSSS1 force shutdown by local regulation

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                  • Originally posted by abcd567 View Post
                    Reducing/limiting the range will REDUCE the number of hits/positions reported.

                    If you want to increase the number of hits/positions reported, you should try to INCREASE the maximum range to its theoretical limit of 450 kms / 250 nm. This requires:

                    (1) Use higher gain antenna.
                    (2) Raise antenna above obstructions such as buildings, trees etc so that your antenna can "see" the horizon. Imagine your eye in place of the antenna, and if your eye can see the horizon, the antenna can also "see" the horizon. Once your antenna starts seeing horizon, no need to raise antenna any further.
                    (3) Use Amplifier between antenna & receiver.
                    (4) Set DVB-T's (or any other receiver's) gain to maximum, or better to AGC.
                    No use !

                    If FR24 current method of data selection continues - it will frustrate any attempt to increase the range by improving the antenna system.

                    When the number of feeders in WSSS was only a few - I enjoyed seeing my extended range of coverage. As more and more F-feeders came online ( in Johore Bahru, Batam Island and Kuching ) - I even saw my range reduced to ZERO nm - i.e. not a single airplane displayed in FR24 site.

                    I have the best antenna system :

                    1). High Gain antenna
                    2). LNA ( hardly used )
                    3). Short LOW LOSS cable ( 5 metre )
                    4). FR 24 receiver

                    Regularly, i am not seeing ANY plane under my radar in FR24 - even though VRS showed 50 planes.
                    F-WSSS1 - Cats refused to Pee & Pooh on RadarBox - Running a FR24 Receiver & DVB-T Dongle 24/7 to piss off The Chief Thief.

                    Comment


                    • Originally posted by Birdie View Post
                      No use !

                      If FR24 current method of data selection continues - it will frustrate any attempt to increase the range by improving the antenna system.

                      When the number of feeders in WSSS was only a few - I enjoyed seeing my extended range of coverage. As more and more F-feeders came online ( in Johore Bahru, Batam Island and Kuching ) - I even saw my range reduced to ZERO nm - i.e. not a single airplane displayed in FR24 site.

                      I have the best antenna system :

                      1). High Gain antenna
                      2). LNA ( hardly used )
                      3). Short LOW LOSS cable ( 5 metre )
                      4). FR 24 receiver

                      Regularly, i am not seeing ANY plane under my radar in FR24 - even though VRS showed 50 planes.
                      Your argument does not apply in case of @iamnothere, as you are referring to plane attributed to a particular radar Like in image 1 below, while @iamnothere is referring to hits shown in image 2 below:

                      IMAGE 1




                      IMAGE 2

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                      • At least 10 radarcape station in range of 300 nautical miles , some of station rare display on website .

                        My understanding is , all of the data collect and send to FR24 server , display on website or iPhone apps etc after selection , when people playing around the
                        apps they want to see the plant on smooth tracking line , they don't know who and maybe don't care who is feeding the data , only feeder care include myself .

                        I guess to fit FR24 needed , more hit rate seems more reasonable , not long range but jumping plant on display screen.

                        image show one of my host F-ZSSS1 half way to Korea Jeju island, sure there are much much more plant I pick up but no display .

                        Please forgive me my oddly English .
                        Screen Shot 2015-07-24 at 2.06.00 PM.jpg
                        T-ZSSS32 F-ZSSS1 force shutdown by local regulation

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                        • @iamnothere:
                          Jumping is caused by tall buildings around antenna location. When the plane is at one side of tall building, your antenna gets signal. When plane goes behind building, signal disappears, plane looks stationary on map. When plane comes out from l behind tall building, signal again received, and plane on map suddenly jumps to new position.

                          To stop the jumping, you should raise your antenna above the height of nearby tall building. The antenna will then continously see the plane, and motion of plane on map will be smooth, not jumping.

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                          • @abcd567
                            Well , there do have a very tall building block one side of my view , my station alt is 137m , that building is like 280m or 300m I am not sure : (
                            T-ZSSS32 F-ZSSS1 force shutdown by local regulation

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                            • @iamnothere:
                              Your situation is like shown in the diagram below. Are the planes jumping when passing behind the building?

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                              • @abcd567

                                Yes , just like the pic show . I still able picked up signal from the direction , it depends on the plant alt , Shanghai downtown is just like a concrete city , I stay here only because $ and save traffic time , I'd move far far away when I retired .

                                The jumping mostly happened while I use RTL1090 on Windows system , after I switch to dump1090 its getting much better I think , and the --ppm correction do help a lot .
                                T-ZSSS32 F-ZSSS1 force shutdown by local regulation

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