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Radar coverage has dropped from 90 nm to 36 nm

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  • Radar coverage has dropped from 90 nm to 36 nm

    Hi, Just wondering why my coverage is showing 36 nm now - was 90 nm and has been dropping slowly.
    Is this normal or do I have to go up on the roof and sort out the aerial to fix problem???
    Happy 2020 to all
    Wayne

  • #2
    With aerial on roof, even 90nm is too small.
    Please provide these details.

    - Aerial type/model/make
    - Length of Coax from aerial to receiver
    - Type of coax
    - Type of receiver (DVB-T etc)

    Comment


    • #3
      Hello Captain
      I understand audio/video electronics, but this radar stuff leaves me cold.
      Aerial is about 10 inches long, spiral in middle. Magnetic base. Aerial is only abut 12 ft above ground (on a metal carport roof).
      Coax about 10 feet, - ordinary TV coax
      Receiver dvb-t+fm+dab - USB type.
      I used to get 110 - 120 nm when first set up, so maybe I need to replace everything.
      I don't want to go overboard with equipment (At 78 years of age I like things simple)
      Thanks for your help
      Wayne

      Comment


      • #4
        Where are you located?

        Most likely water got into your coax or your antenna.

        Is this even an aerial meant for 1090 MHz?

        Comment


        • #5
          Originally posted by wiedehopf View Post
          Where are you located?
          Most likely UK, as he uses word "aerial" and not "antenna"

          Comment


          • #6
            bribiewayne:
            If you can spare some money, purchase a good 1090 mhz aerial. I use Flightaware 26" 1090 mhz aerial, and it gives me good reception.

            https://thepihut.com/products/flight...enna-66cm-26in


            https://www.amazon.com/1090MHz-ADS-B.../dp/B00WZL6WPO
            Last edited by abcd567; 2020-01-19, 12:45.

            Comment


            • #7
              There are also good guides on the forum for building your own antenna from some satellite TV coax (RG6)

              This would be quite a bit cheaper probably

              https://forum.flightradar24.com/foru...g-no-connector

              Note that the connector is not necessary and can be omitted if you wish, the antenna can just be the end of the coax.
              Obviously you want to put epoxy glue or maybe better, window silicone on the end of the coax to avoid any water ingress.
              Last edited by wiedehopf; 2020-01-20, 07:22.

              Comment


              • #8
                Thank you all for your ideas offered up. BTW I am in AUSTRALIA (that big bit of dirt down there). The DIY antenna looks like it's for me - can put some electronics knowledge to use.
                I think captain wiedehopf's suggestion on water entry is probably right on the money. Looks like a trip to outer space is called for and burial of one antenna.
                I've got all the bits to build antenna, so will get a pushback and ther you go.
                Thanks all, nice to have a ready source of answers.
                Wayne - luggage handler.

                Comment


                • #9
                  320mm of rain in 24hrs.. yeah there will be a few in that pain.

                  The antenna, may not be specifically tuned also. But the diy/62mm test should prove that.
                  Posts not to be taken as official support representation - Just a helpful uploader who tinkers

                  Comment


                  • #10
                    Hello All

                    Well the materials are ready to go, but I must ask a question - In wiedehopf's cheap antenna project, why is there a 1.8cm length of coax, then a joiner then more coax??? Or is this to attach to the mount (blue plastic lid)????
                    Could I mount the antenna on say a 3m plastic pole and run the coax straight to the receiver (one continuous run of cable)????
                    And Oblivian you are on the money - 200 mils of rain here, but very welcome - Antenna problems not as important.
                    Happy 2020 to all
                    bribiewayne


                    Comment


                    • #11
                      I had a typo in there: Note that the connector is not necessary and can be omitted if you wish, the antenna can just be the end of the coax.


                      The 18 cm is an irrelevant dimension, you don't need to build it with a connector.
                      As usual with antennas, only where you split up the shield and the core is where the antenna "begins".

                      Comment


                      • #12
                        Originally posted by bribiewayne View Post
                        Hello All

                        Well the materials are ready to go, but I must ask a question - In wiedehopf's cheap antenna project, why is there a 1.8cm length of coax, then a joiner then more coax??? Or is this to attach to the mount (blue plastic lid)????
                        Could I mount the antenna on say a 3m plastic pole and run the coax straight to the receiver (one continuous run of cable)????
                        The blue lid was my mounting platform. I used to frequently test varaious antenna designs. I simply unscrewed one antenna and fitted another keeping coax run undisturbed. This will be clear from photos below.

                        If you are not interchanging antennas then a continous jointless length of coax with antenna built on one end and other end terminated in dvbt is better.

                        Standard Cantenna 480x640.jpg

                        Franklin Spider.jpg



                        Quick Spider-2.jpg
                        .



                        .

                        Comment


                        • #13
                          Morning All
                          Have completed my antenna as per specs, and will mount in next few days. Just a question, is there an ideal height for the antenna - I am 70km from BNE/YBBN so is it critical???
                          I daren't post a photo of item as my Trades Teacher from school would probably turn in his grave.
                          Had a lot of fun building the "Thing" so thanks to all involved
                          Happy journeys
                          bribiewayne

                          Comment


                          • #14
                            ADS-B is basically line of sight.

                            So once you can see the horizon, further height is of little benefit.
                            Overlooking nearby houses and trees is of definite benefit.

                            Comment


                            • #15
                              bribiewayne:
                              You can determine what maximum range you can get using the method given in this post:

                              What is the Maximum Range I can Get?


                              .

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