Announcement

Collapse
No announcement yet.

FR Receive Antenna + DVB-T Dongle

Collapse
X
 
  • Filter
  • Time
  • Show
Clear All
new posts

  • #16
    The FR24 (A3 ADSB) antenna is DC-grounded inside, while most other (Flightaware, Stanislav etc) is not. This is good, a sign of a quality antenna, but it means that it can not be tested easily without an SWR analyzer for an RF short.

    /M
    F-ESDF1, F-ESGG1, F-ESGP1, F-ESNK1, F-ESNV2, F-ESNV3 F-ESSL4, F-ESNZ7, F-LFMN3
    T-ESNL1, T-ESNL2, T-ESGR15
    P-ESIA, P-ESIB, P-ESGF, P-ESSN, P-EFMA
    mrmac (a) fastest.cc

    Comment


    • #17
      Originally posted by MrMac View Post
      The FR24 (A3 ADSB) antenna is DC-grounded inside, while most other (Flightaware, Stanislav etc) is not. This is good, a sign of a quality antenna, but it means that it can not be tested easily without an SWR analyzer for an RF short.

      /M
      So, good chances are that I have a bad antenna even it being visually perfect?

      Being that, I may reuse the hardware (mounting, cables, etc) and build one of those DIY antennas using coax cables.

      Comment


      • #18
        Originally posted by lucianosr View Post
        So, good chances are that I have a bad antenna even it being visually perfect?

        Being that, I may reuse the hardware (mounting, cables, etc) and build one of those DIY antennas using coax cables.
        The fact that an antenna is DC-grounded does not necessarily increase the chances that your antenna has a fault. Your original post says that a power outage caused the fault with your FR feeder, presumably that was a power surge and not a lightning strike. Have you checked the cable for conductivity or shorts yet? Stating the obvious, but don't test it with the antenna attached.

        Comment


        • #19
          Cables are okay, just checked them. No short and there is conductivity on each pole....

          Very strange indeed!

          Comment


          • #20
            Originally posted by lucianosr View Post
            Cables are okay, just checked them. No short and there is conductivity on each pole....

            Very strange indeed!
            One final check could be to connect another antenna to the end of the cable and see if you get any signals. If you do, then it will confirm that either the FR antenna is definitely broken or that there is still a problem with the cable and/or connectors.

            Because of the antenna's printed circuit board construction, you should be able to see any physical damage to the PCB and its tracks. Also check the connectivity between the centre pin of the antenna socket and the PCB track.

            Comment


            • #21
              Originally posted by lucianosr View Post
              So, good chances are that I have a bad antenna even it being visually perfect?
              No, it is the least likely possibility that the antenna is damaged, and it would also be visible. During my many years with this, I hve seen one antenna with water inside, and one antenna damaged from lightning, the conductors inside were burnt off and missing.

              It is much more likely that the problem is in cables or connectors. Just make a new, short cable and connect for testing.

              You haven't answered my question about water ingress. Why isn't the N-connector protected? It looks like it has corroded from being unprotected. Water can go inside the cable and cause corrosion that you can not see. Sometimes a cable can measure OK with DC instrument, but still be unusable for RF. I see this many times per year in boats that have not cared enough about water proofing at the mast top.

              BR /M
              F-ESDF1, F-ESGG1, F-ESGP1, F-ESNK1, F-ESNV2, F-ESNV3 F-ESSL4, F-ESNZ7, F-LFMN3
              T-ESNL1, T-ESNL2, T-ESGR15
              P-ESIA, P-ESIB, P-ESGF, P-ESSN, P-EFMA
              mrmac (a) fastest.cc

              Comment


              • #22
                Originally posted by MrMac View Post
                ....Just make a new, short cable and connect for testing....
                Thumbs x 3.png .. Fully agree.

                Comment


                • #23
                  I got over the problems of cable loss by putting the dongle and antenna with a connecting cable of a few inches inside a plastic pipe "radome" mounted above our sky dish and ran a boosted USB cable down to the (in my case) Raspberry Pi.
                  In actual fact I run two boosted USB cables in series to achieve the length I needed.
                  Obviously signal loss through the connecting coax is not an issue. My worry is wondering how long the USB cables will stand up the the elements. Two years so far.

                  Comment


                  • #24
                    Originally posted by Keith Browning View Post
                    I got over the problems of cable loss by putting the dongle and antenna with a connecting cable of a few inches inside a plastic pipe "radome" mounted above our sky dish and ran a boosted USB cable down to the (in my case) Raspberry Pi.
                    In actual fact I run two boosted USB cables in series to achieve the length I needed.
                    Obviously signal loss through the connecting coax is not an issue. My worry is wondering how long the USB cables will stand up the the elements. Two years so far.
                    Thanks for the idea!

                    Today I'm running a similar setup. A RaspPiW mounted on my roof (under the roof titles) and the stock dongle antenna (cut to match 1009MHz wavelength) outside the roof.

                    Still annoyed to not be using the "big" antenna I have, but I gave up after all testing and try/error trying to make it work with the dongle...

                    Comment


                    • #25
                      Mmm interesting antenna, way different from the FA one

                      Comment


                      • #26
                        Hi Lucianosr,
                        If your larger antenna won't work with the same radio and coax that does work with the short antenna, could you check if your large antenna presents a DC short to the dongle and if the dongle has some DC isolation between the active devices and the antenna socket.
                        Some dongles can be arranged to have a DC voltage at the socket which would be shorted by an antenna that has a DC path to the coax outer. Some dongles have a coupling capacitor that allows signals to pass, but not the circuit DC. If it fails, The dongle will probably not work or fail.
                        It does seem to be a real waste if you can't make use of your "gain" antenna and I'm sure we should be able to figure out what is causing your problem.

                        Comment


                        • #27
                          Any chance you have a photo of your setup Keith?

                          Comment


                          • #28
                            Not easily Coxy,
                            I guess you mean a photo of the antenna setup. The current one is installed and looks like a plastic pipe mounted behind/above my TV dish.
                            I do have a photo of one of my earlier antennas displayed dismantled which should describe what I have done.Antenna, RX, Pi Radome .jpg
                            I think I've attached a picture here.
                            You will see the brown USB cable at the left passes through a clip on Ferrite choke. The cable tie is to stop the choke sliding down the cable.
                            The black object is the USB cable boosted plug which is plugged into the Dongle. (the dongle casing was removed and a metal shielding cover fitted to the board.
                            The dongle antenna socket at the right hand end is connected to thin, double screened coax which passes through another ferrite choke and into the base of the antenna.
                            The antenna was an experimental ground plane with the radials folded down to go inside the tube. The active part of the aerial was a colinear of half wave sections separated by half wave stubs. The stubs were curved to slide inside the tube.
                            You may be able to see some nylon line attached to the ground plane base which continues up the antenna. This is to drag the antenna through the pipe until the tip is neat the tube top end. The nylon was held in place with the cap fitted to the top and supports all the parts.
                            The pipe is clamped at the base to whatever the main mast will be.
                            I have found the boosted USB cables to be really useful and I currently us two in series to get enough length for my installation.
                            The main object was to avoid long runs of coax and the inherent loss of signal. Once the signal is converted to digital data at the dongle there is no more signal loss.
                            I hope this is what you requested.
                            Keith
                            Last edited by Keith Browning; 2018-07-15, 06:55.

                            Comment


                            • #29
                              Keith Browning:

                              Nice setup, excellent write-up.
                              thumb-single.jpg thumb-single.jpg thumb-single.jpg

                              Comment


                              • #30
                                Originally posted by Keith Browning View Post
                                Not easily Coxy,
                                I guess you mean a photo of the antenna setup. The current one is installed and looks like a plastic pipe mounted behind/above my TV dish.
                                I do have a photo of one of my earlier antennas displayed dismantled which should describe what I have done.[ATTACH=CONFIG]9655[/ATTACH]
                                I think I've attached a picture here.
                                You will see the brown USB cable at the left passes through a clip on Ferrite choke. The cable tie is to stop the choke sliding down the cable.
                                The black object is the USB cable boosted plug which is plugged into the Dongle. (the dongle casing was removed and a metal shielding cover fitted to the board.
                                The dongle antenna socket at the right hand end is connected to thin, double screened coax which passes through another ferrite choke and into the base of the antenna.
                                The antenna was an experimental ground plane with the radials folded down to go inside the tube. The active part of the aerial was a colinear of half wave sections separated by half wave stubs. The stubs were curved to slide inside the tube.
                                You may be able to see some nylon line attached to the ground plane base which continues up the antenna. This is to drag the antenna through the pipe until the tip is neat the tube top end. The nylon was held in place with the cap fitted to the top and supports all the parts.
                                The pipe is clamped at the base to whatever the main mast will be.
                                I have found the boosted USB cables to be really useful and I currently us two in series to get enough length for my installation.
                                The main object was to avoid long runs of coax and the inherent loss of signal. Once the signal is converted to digital data at the dongle there is no more signal loss.
                                I hope this is what you requested.
                                Keith
                                Looks good, did you notice an improvement with removing the coax and placing the dongle closer to the Antenna?... I have 5 meters of RG6 from my Antenna to dongle and question if I should also move the dongle into my pipe...

                                Comment

                                Working...
                                X