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Advice on a scan image just created - antenna not performing as expected

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  • Advice on a scan image just created - antenna not performing as expected

    Thank you in advance for any help offered.

    I'm a complete newcomer to Raspberry Pi and ADS-B. I have a little experience with HF antennas and a good basic understanding of electronics and RF.

    I've followed the tutorial from abcd567 on heatmaps and generated the attached file.

    My system: RPI 3b+ running Buster
    Dongle is flightaware prostick plus, the blue one.
    Ant1 is a Discone at 105 feet above sea level, this was my first antenna and I was receiving out to 86 nautical miles
    Ant 2 is a 10 element Collinear for 1090 at a 103 feet above sea level, I had hope to see some improvement with received distance, this has dropped to 66 nautical miles. However, I have noticed improved reception from lower flying aircraft.

    The scan image is from Antenna 2 as I want to run the Pi totally independently from an SDR I use that uses the Discone. Would one of the forum members have a look at the scan and see if there are any issues that need filters adding to correct them, please.

    Best wishes from Liverpool UK

    Kev



    Last edited by Terrierist; 2020-05-11, 20:18.

  • #2
    Addendum. Both antennas are external.

    Comment


    • #3
      In my area, there are almost no passenger aircraft flying.
      I usually see 10-15 aircraft here, 60 miles north of SF, many headed to Japan or China.
      This morning, I see one headed to Seattle.
      Looking back at my history, just one day, I see a drop from 40,000 positions on Feb 13 to 14,000 on April 13.
      The polar plot of coverage looks okay in shape, just down in count.

      Comment


      • #4
        Originally posted by Terrierist View Post
        Thank you in advance for any help offered.

        I'm a complete newcomer to Raspberry Pi and ADS-B. I have a little experience with HF antennas and a good basic understanding of electronics and RF.

        I've followed the tutorial from abcd567 on heatmaps and generated the attached file.

        My system: RPI 3b+ running Buster
        Dongle is flightaware prostick plus, the blue one.
        Ant1 is a Discone at 105 feet above sea level, this was my first antenna and I was receiving out to 86 nautical miles
        Ant 2 is a 10 element Collinear for 1090 at a 103 feet above sea level, I had hope to see some improvement with received distance, this has dropped to 66 nautical miles. However, I have noticed improved reception from lower flying aircraft.

        The scan image is from Antenna 2 as I want to run the Pi totally independently from an SDR I use that uses the Discone. Would one of the forum members have a look at the scan and see if there are any issues that need filters adding to correct them, please.

        Best wishes from Liverpool UK

        Kev


        Your current heatmap shows no need for extra filtering.

        Do not use Discone or Collinear antenna, use 1090 Mhz antennas like Flightaware 26 inch or Jetvision.
        Heatmap with Discone seems OK now, but when you change antenna to a 1090 Mhz one and install it outdoors at its final location, generate heatmap again to determine interference, and if there is any need for a filter. Although ProStick Plus (blue one) has a built-in filter, it fails to remove mobile signal GSM900, and if you have strong GSM900 at your location, you may need to install a filter which can remove GSM900. One such filter available is dark-blue filter from Flaightaware.

        https://thepihut.com/products/flight...ass-sma-filter

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