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QUICK SPIDER - No Soldering, No Connector

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  • #31
    It doesn't matter the cable RG6 is 75 ohm?

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    • #32
      Originally posted by apeiron69 View Post
      It doesn't matter the cable RG6 is 75 ohm?

      No, it does not make any difference as the DVB-T dongle has input impedance of 75 ohms. The DVB-T is designed for TV reception, and the TV system uses 75 ohm.

      Even if the dongle was 50 ohms, in receiving situation like we are, the mismatch between 50 and 75 ohms does not cause an appreciable loss in performance (the SWR for 50 to 75 transition is 1.5, and mismatch loss is only 0.177 dB). As in receiving scenario, the power levels are in milli or even micro watts, which are easily compensated by front end circuits of the dongle.

      For transmitting equipment the 50 to 75 ohm mismatch should be avoided to reduce reflected power, as the power levels involved are in watts or tens of watts or even hundreds of watts.
      Last edited by abcd567; 2020-06-15, 14:48.

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      • #33
        QuickSpider Ver2

        Part -1: Design



        Designed By Computer Simulation



        V-Spider-Horizontal-Radials-3.png


        V-Spider 84-45-141-SWR.png

        V-Spider-84-45-141-Radiation-2D.png


        V-Spider-84-45-141-Radiation-3D.png






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        • #34
          QuickSpider Ver2

          Part -2: Building & Testing of Prototype



          Comparison of V-Stub QuickSpider with Bench Mark Antenna (Flightaware Antenna)


          FA Antenna >> 30cm RG316 pigtail >> FA light Blue Filter >> FA ProStickPlus (blue) >> OrangePiPC
          V-Stub Antenna >> 100cm RG174 pigtail >> Radarbox24 FlightStick (green) >> RPi4

          Flightaware 26" Antenna on left side of window
          V-Stub Quick Spider on right side of window
          Horizontal spacing between antennas = 30 cm

          NOTE: The paper behind V-Stub was placed while taking snapshot, as without it the thin wire of V-Stub was not clearly visible in the photo.

          V-Stub with FA.jpg



          Pilot Antenna's Dimensions & SWR


          V-Spider-Pilot-Built and SWR-3.png


          Comparison: Number of Aircrafts Tracked

          V-Spider-Comparison-Aircrafts.png



          Comparison: Message Rate

          V-Spider-Comparison-Rate.png




          Comparison: Maximum Range

          V-Spider-Comparison-Range.png



          Last edited by abcd567; 2020-10-17, 19:53.

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          • #35
            V-Stub on Mag-mount Base (placed on a metallic plate)

            V-stub wire collinear-35pc-E2.jpg

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            • #36
              I've made e version of this antenna a couple years ago, it has been outside at least 2 years feeding fr24 24/7.
              Performance has been dropping lately and I discovered corrosion in the connector, decided to make a new version similar to my old one.

              I bought a VNA called nanoVNA V2 and wanted to be able to test and tune my new "quick spider" antenna. I got some readings, but for me with my limited radio technology knowledge I find them almost to good to be true or did I get lucky? I did cut a little bit off the center wire two times to tune it, but that's it.
              I have calibrated the nanoVNA for the short frequency band 900-1150 mhz as shown in the screenshot, antenna coax lenght is about 2-3 meters.
              Antenna is made of RG6 coax and spider is weather sealed with epoxy.

              IMG_3548.JPEG
              IMG_3554.JPEG

              Any comments to the screenshot above would be appreciated.

              Attached Files

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              • #37
                Originally posted by kredittkort View Post

                Any comments to the screenshot above would be appreciated.

                Excellent


                .
                Last edited by abcd567; 2020-11-03, 18:09.

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                • #38
                  abcd567 which one of these I should buy https://www.daraz.pk/products/tv-con...paFpQ&search=1
                  https://www.daraz.pk/products/mcx-ma...paFpQ&search=1
                  https://www.daraz.pk/products/flyeer...paFpQ&search=1
                  I do have spare coaxial cable lying around.

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                  • #39
                    The end connector for DVB is ok as it should mcx-male.

                    Straight or right-angle is matter of convinience, both are ok.

                    The cable end of pigtail cable has sma-female connector. It can connect to a coax with sma-male connector. Which coax you have? If it is Satellite or dish TV cable, it is usually RG6 which has F type connector, like thw one in photo of first post of this thread. You will need a pigtail with one end mcx-male connector, other end F-female connector.

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                    • #40
                      Originally posted by abcd567 View Post

                      The end connector for DVB is ok as it should mcx-male.

                      Straight or right-angle is matter of convinience, both are ok.

                      The cable end of pigtail cable has sma-female connector. It can connect to a coax with sma-male connector. Which coax you have? If it is Satellite or dish TV cable, it is usually RG6 which has F type connector, like thw one in photo of first post of this thread. You will need a pigtail with one end mcx-male connector, other end F-female connector.

                      I have a normal RG6 cable without any connector. really cheap.
                      Do I need SMA Female to Two SMA Female Adapter Connector? https://www.daraz.pk/products/2-pcs-...EkGAo&search=1. This deal is Pkr 646 after 10% discount it will be 582. while pigtail alone is Pkr 484 after discount will be Pk436.
                      So the plan is to use the RG6 cable with one end SMA male and the other end spider antenna.
                      does this plan works?

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                      • #41


                        First thing you have to find is which type connector is available for RG6 cable. You can check local shops who install Satellite Dish and show a piece of your cable to them. You can get connector for it from them very cheap. As far as I know RG6 cable uses F-male connector. Most common and cheapest is F-male twist-on type.

                        The pigtail cable OR adaptor should have one end MCX-male to fit the DVB-T, other end should have a female connector of type which matches the male connector type on RG6 coax

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                        • #42
                          F type male connector for RG6 coax:

                          330060042_MainImage_001_l.jpg

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                          • #43
                            Originally posted by abcd567 View Post
                            F type male connector for RG6 coax:

                            330060042_MainImage_001_l.jpg
                            this connector is quite common here, I have a few of those lying around in the house too. but I can't find mcx to F pigtail in the local market or online store

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                            • #44
                              Originally posted by abcd567 View Post

                              First thing you have to find is which type connector is available for RG6 cable. You can check local shops who install Satellite Dish and show a piece of your cable to them. You can get connector for it from them very cheap. As far as I know RG6 cable uses F-male connector. Most common and cheapest is F-male twist-on type.

                              The pigtail cable OR adaptor should have one end MCX-male to fit the DVB-T, other end should have a female connector of type which matches the male connector type on RG6 coax
                              https://www.aliexpress.com/item/3303...46323936%22%7D found it on Aliexpress. which cable length can be a longer component of the two, RG6 or RG174?

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                              • #45
                                Originally posted by raptor22 View Post

                                https://www.aliexpress.com/item/3303...46323936%22%7D found it on Aliexpress. which cable length can be a longer component of the two, RG6 or RG174?

                                This pigtail is right one, as per photo, and as per description "RG174 Cable F TV Female Jack Bulkhead to MCX Male Plug".


                                Use RG174 short length, 6 inch or 8inch or 12 inch. It is high loss cable, longer the length, higher the attenuation, reducing range/plane count.

                                RG6 has much lower attenuation than RG174, and should be longer part. You can make it long enough to go to window or a balcony or roof to make antenna clear of obstructions. This will considerably increase range. Dont use RG6 longer than 20 feet due to attenuation.
                                Last edited by abcd567; 2021-09-21, 20:25.

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