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My first collinear antenna

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  • #61
    My first collinear antenna

    After nearly 24 hrs with the new spider, I can see that it's performing far worse than my coax only spider. Even tried to bend the radials direct at the edge of the washer and cut to correct length, but no improvement. Something must be wrong with the connector or something. Back with my coax only, and back to the drawing board. I'll post my coverage plot with the coax only later tonight.

    EDIT:
    After examining the antenna there is no short circuit and all seams ok. No idea why it did perform so bad.
    Last edited by FR24-BB8; 2016-06-13, 18:26.

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    • #62
      Here is the range plot when running my coax only spider for a couple of days. The outer red ring is 200 nm.

      coax-only.PNG

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      • #63
        Here is my coverage from a (very good) location just south of you;

        F-ESNK4
        Screen shot 2016-06-14 at 23.41.18.png

        If you are interested send me an email on mrmac (a) fastest.cc

        BR, /M
        F-ESDF1, F-ESGG1, F-ESGP1, F-ESNK1, F-ESNV2, F-ESNV3 F-ESSL4, F-LFMN3
        P-ESGR, P-ESIA, P-ESIB, P-ESGF
        mrmac (a) fastest.cc

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        • #64
          Originally posted by MrMac View Post
          Here is my coverage from a (very good) location just south of you;

          F-ESNK4
          [ATTACH=CONFIG]7642[/ATTACH]

          If you are interested send me an email on mrmac (a) fastest.cc

          BR, /M
          Wow.

          You must have really good equipment and a really good location high up to get that coverage.
          Im a very low budget hobby enthusiast that are trying to get as good coverage as possible with as little means as possible. That is why i experiment with these home made simple antennas. But maybe this is as good as i can get at my location with these antennas? But at least at my west, east and north i think i could get a little better coverage, cause theres clear sky that way. The bad south i can live with, and cannot do that much to either.
          Are you located in Sweden or Finland?
          Last edited by FR24-BB8; 2016-06-14, 22:01.

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          • #65
            It's an FR24 receiver and antenna.

            (Placerad p lotsutkiken, Ulvn, 90mh.)

            But, my tests show that a no-name DVBT stick for 8 USD, on the same antennna, gives almost identical range if provided with a good bandpass filter.

            So, a known good antenna, bandpass filter, and very cheap receiver can provide fantastic results. It's very, very difficult to build decent antennas without measuring equipment. I used to work for a very big swedish antenna manufacturer, and I know how much work goes in to quality commercial antennas. But it's a lot of fun experimenting!

            BR /M
            F-ESDF1, F-ESGG1, F-ESGP1, F-ESNK1, F-ESNV2, F-ESNV3 F-ESSL4, F-LFMN3
            P-ESGR, P-ESIA, P-ESIB, P-ESGF
            mrmac (a) fastest.cc

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            • #66
              Aha. (S fint, inte bara hjden ven platsen, jag r ca 10 mh max)

              Ok thx for the info. I sure will test some more variants of antennas and look into bandpass filters.
              Maybe i send you an email later, with some questions.

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              • #67
                @FR24-BB8:
                DIY stuff is fun and low cost, affordable for everyone. I always try to develop system using low cost components.

                Well a japanese Toyata fulfills my need. There is no limit to "best possible". Why Toyota, why not Mercedeze, BMW, Jaguar, Ferrari, RolceRoyce? Human desire has no end.

                There is a possibility that the epoxy glue has entered the hole of barrel connector, and broken the connection between whip & core wire of coax. If you have a multimeter/multitester/continuity tester, check continuity between top tip of whip and the core wire of coax.

                make one more with F barrel connector (female-female) but dont apply glue this time and try it. Some more work for you

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                • #68
                  Originally posted by abcd567 View Post
                  @FR24-BB8:
                  DIY stuff is fun and low cost, affordable for everyone. I always try to develop system using low cost components.

                  Well a japanese Toyata fulfills my need. There is no limit to "best possible". Why Toyota, why not Mercedeze, BMW, Jaguar, Ferrari, RolceRoyce? Human desire has no end.

                  There is a possibility that the epoxy glue has entered the hole of barrel connector, and broken the connection between whip & core wire of coax. If you have a multimeter/multitester/continuity tester, check continuity between top tip of whip and the core wire of coax.

                  make one more with F barrel connector (female-female) but dont apply glue this time and try it. Some more work for you
                  I have already tested with a multimeter, and nothing wrong. Something else must have failed?!?!
                  Thx anyway, and ill try to make another one. I wont give up that easy...

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                  • #69
                    Originally posted by MrMac View Post
                    It's an FR24 receiver and antenna.

                    (Placerad p lotsutkiken, Ulvn, 90mh.)

                    But, my tests show that a no-name DVBT stick for 8 USD, on the same antennna, gives almost identical range if provided with a good bandpass filter.

                    So, a known good antenna, bandpass filter, and very cheap receiver can provide fantastic results. It's very, very difficult to build decent antennas without measuring equipment. I used to work for a very big swedish antenna manufacturer, and I know how much work goes in to quality commercial antennas. But it's a lot of fun experimenting!

                    BR /M
                    Yes, you are right, I agree with you. A high gain antenna is very sensetive to dimensions, and to get optimum performance, test equipment are required to trim & tune it.

                    The beauty of 1/4 wavelength groundplane (Spider, Cantenna, etc) is that it is naturally tuned, and has a lot of dimensional tolerance. It has an impedance 30 ohm (horizontal radials), 50 ohms (45 degree slanting radials) and 75 ohm (vertical radials). This is close match to 50 ohm and 75 ohm reveivers, and SWR is nearly 1.5, a decent value. The only disadvantage is its low gain (2 to 1.5 dBi).

                    Filter is required because the $8 dvb-t dongle is very wide band. Filter is needed where there are strong TV and mobile phone signals. I solved this by using a low cost diplexer (which is used to split/combine tv & satellite signals), and a low cost satellite amplifier which has a narrow band 950 to 2050 Mhz. I use the satellite ports of diplexer,which rejects lower frquency tv & mobile phone signals.
                    Last edited by abcd567; 2016-06-14, 23:00.

                    Comment


                    • #70
                      Originally posted by abcd567 View Post
                      Filter is required because the $8 dvb-t dongle is very wide band. Filter is needed where there are strong TV and mobile phone signals. I solved this by using a low cost diplexer (which is used to split/combine tv & satellite signals), and a low cost satellite amplifier which has a narrow band 950 to 2050 Mhz. I use the satellite ports of diplexer,which rejects lower frquency tv & mobile phone signals.
                      FM and DVB transmitters are relatively easy to get rid of, the problem is the part of the GSM900 downlink which is at 960 MHz. Neither your SAT filter, nor the FA bandpass will help there. See my post about that here : http://forum.flightradar24.com/threa...ll=1#post79610

                      A strong 23cm ham transmitter (and beacons) can also create a great deal of interference at 1290 MHz.

                      /M
                      F-ESDF1, F-ESGG1, F-ESGP1, F-ESNK1, F-ESNV2, F-ESNV3 F-ESSL4, F-LFMN3
                      P-ESGR, P-ESIA, P-ESIB, P-ESGF
                      mrmac (a) fastest.cc

                      Comment


                      • #71
                        My System #1 described above = $9 Black DVB-T+Satellite Amplifier + Diplexer + Cantenna.

                        My system #2 was identical to system #1, which I recently changed to : $16 FlightAware Pro Stick (dvb-t with built-in rf amplifier) + Flightaware Filter + Flight Aware 1090 mhz antenna. After change, I got a 30% increase in plane count and message rate.

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                        • #72
                          Tonight im mounting this one:

                          coax-only.JPG

                          Ill let you know the result.

                          /P

                          Edit:
                          Sorry for the image. Dont know why it got the wrong way.

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                          • #73
                            @FR24-BB8
                            Looks great! Waiting for results.



                            The photo rotates because some cameras include meta data with photos, which include orientation information also. The display is oriented according to meta data. The photo hosting site I use can display both with orientation as posted, and with orientation given by mete data.

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                            • #74
                              @FR24-BB8
                              You can remove the metadata by a trick.
                              Open the photo in Paintshop (or any other photo program like Windows built in MS Paint) >> Select All >> Copy.

                              Open a new blank document in Photoshop (or MS Paint) >> Paste >> Save As. The saved picture will have no meta data as "select all >> copy" from original only copies photo, and leaves out metadata. You can then post the copy without metadata to FR24 forum, and it will show ok.

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                              • #75
                                Originally posted by abcd567 View Post
                                @FR24-BB8
                                You can remove the metadata by a trick.
                                Open the photo in Paintshop (or any other photo program like Windows built in MS Paint) >> Select All >> Copy.

                                Open a new blank document in Photoshop (or MS Paint) >> Paste >> Save As. The saved picture will have no meta data as "select all >> copy" from original only copies photo, and leaves out metadata. You can then post the copy without metadata to FR24 forum, and it will show ok.
                                Ive also ordered a flightaware bandpass filter that i will connect as soon as it arrives.

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