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  • Antenna, bigger not better?

    Hi!
    I've recycled a super-high-quality antenna which was used for a really big outdoor wifi (2.4 ghz) coverage.
    Used hi-end coax cable and nice adapter (to N-MALE).
    Got all the stuff connected and.... poof.... ZERO ADS-B messages per second.
    Usually I get 100 nautical miles range with my finger-sized bundled antenna!! (from Nooelec).
    Photo of this big antenna attached (the cell phone gives you an idea of the scale).
    Any hints?
    Cheers,
    Francesco - T-LIRF54

    20181009_150828.jpg
    T-NOOB-001

  • #2
    Seems connector mismatch (Connector on cable v/s connector on Nooelec Dongle).

    Nooelec has either SMA type OR MCX type connector.
    The antenna, designed and built for WiFi, has most likely RP-SMA connectors.

    Both the SMA and RP-SMA look and feel identical and fit with each other, but due to opposite center-pin configuration in RP-SMA, connection of center wire is broken.

    SMA vs RP-SMA.jpg

    EDIT:
    Please post close-up photos of:
    (1) Bundled Antenna showing its connector
    (2) Dongle showing its connector
    (3) The Dongle side connector on antenna cable
    Last edited by abcd567; 2018-10-09, 15:02.

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    • #3
      Thank you very much for the reply.
      But no! Connectors are fine as per attached photo

      2018-10-09 16.51.03.jpg
      T-NOOB-001

      Comment


      • #4
        OK, the antenna end N-to-SMA and Cable end SMA are both matching type, so there does not seem to be a problem at the antenna end provided Antenna also has a matching connector to the N-to-SMA adaptor in photo.

        How are the connectors on Nooelec Dongle AND dongle end of Cable? You did not post any photo.

        Comment


        • #5
          Here there are:

          Dongle (from the website):

          nesdr_smart_1_1_1.jpg

          Cable:

          2018-10-09 17.09.07.jpg

          Antenna (w/adapter):

          2018-10-09 17.08.11.jpg

          Thanks a lot,
          Francesco
          T-NOOB-001

          Comment


          • #6
            Adaptors all look OK.
            Now one of the following two things are causing the problem
            (1) Antenna
            (2) Cable

            You can easily check cable by disconnecting cable from WiFi antenna and connecting it to the thumb antenna. If Cable is OK, you will start receiving. In this case, the antenna has a problem. Go ahead and check the cable as above.

            Comment


            • #7
              Good point!
              But the thumb antenna has the far end termination "molded" in the antenna stand! There's no way to bypass it (photo).

              20181009_175208.jpg
              T-NOOB-001

              Comment


              • #8
                If as you say in your first post it is a 2.4Ghz antenna then it isn’t surprising that it doesn’t work, it is tuned to the wrong frequency and will be designed to only work in a narrow band either side of 2.4Ghz, not 1.090Ghz that ADSB uses.
                Antennas of this type are very narrow band and would be useless outside their designed range.
                FR24 F-EGLF1, Blitzortung station 878, OGN Aldersht2, PilotAware PWAldersht, PlanePlotter M7.

                Comment


                • #9
                  If you have a multimeter or continuity tester, check cable for

                  (1) Short between center wire (pin of connector) and shield (nut of connector) - Shoud show open
                  (2) Continuity of center wire from one connector to the other i.e. between pins of two connectors of the cable - Should show continuity/short.

                  Comment


                  • #10
                    Hello EGLF1!
                    I'm afraid you are right!

                    This product fueled my enthusiasm:
                    The best offers for ADS-B Antennas ► Professional Advice ► Pay in Installments ► Compare now!


                    The external similarity made me thought that I'd achieve similar performances!!
                    Burnt a little money but - as Alanis Morrissette sung - "you learn!"

                    Cheers,
                    Francesco
                    T-NOOB-001

                    Comment


                    • #11
                      F-EGLF1
                      You are right, a WiFi 2.4 GHz antenna will be hopeless on 1.090 GHz, but still it will not give ZERO reception.

                      Cauchee has mentioned in his first post ZERO reception, which gives a doubt about short circuit or open circuit either in cable or antenna.

                      Any way it is NOT worth fixing a short/open problem, as the WiFi 2.4 GHz antenna will give a hopeless reception on 1090 MHz even after fixing the defect.
                      Last edited by abcd567; 2018-10-09, 17:36.

                      Comment


                      • #12
                        Originally posted by abcd567 View Post
                        F-EGLF1
                        You are right, a WiFi 2.4 GHz antenna will be hopeless on 1.090 GHz, but still it will not give ZERO reception.

                        Cauchee has mentioned in his first post ZERO reception, which gives a doubt about short circuit or open circuit either in cable or antenna.
                        As we don’t know the specifics of that antenna it is possible it has built in bandpass filters (especially if as he said it came from a high spec setup) if he is in an area with a low number of close aircraft then it is quite possible that he sees nothing, but I agree that he still should see the odd one or 2, however it would perform significantly worse than a random length of wire!
                        FR24 F-EGLF1, Blitzortung station 878, OGN Aldersht2, PilotAware PWAldersht, PlanePlotter M7.

                        Comment


                        • #13
                          Can't dismiss the open/short circuit too...
                          Tomorrow I'll test cable continuity.
                          Antenna specs:

                          I'm 15 miles away from FCO airport
                          Thank you!
                          Last edited by Cauchee; 2018-10-09, 17:45.
                          T-NOOB-001

                          Comment


                          • #14
                            I use Flightaware antenna.
                            It gives me good performance for the Price. In North America (USA & Canada) Shipping is free, but It may be substantial for Europe.





                            Comment


                            • #15
                              Originally posted by Cauchee View Post
                              Can't dismiss the open/short circuit too...
                              Tomorrow I'll test cable continuity.
                              Antenna specs:

                              I'm 15 miles away from FCO airport
                              Thank you!
                              If you have a spare mating connector (either ‘N’ or SMA) then why not knock up one of the simple spider antennas that abcd567 has published designs for, that will confirm that your cable run is good and should give a significant improvement on the little ‘thumb’ antenna you have.
                              FR24 F-EGLF1, Blitzortung station 878, OGN Aldersht2, PilotAware PWAldersht, PlanePlotter M7.

                              Comment

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