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Thread: Maximum Range with ADS-B USB Dongle (R820T2)

  1. #1
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    Maximum Range with ADS-B USB Dongle (R820T2)

    Hello guys,

    I recently started feeding to FR24 and purchased: ADS-B USB Dongle (R820T2) from Jetvision. I am using Raspberry Pi 3 B+ and have placed the indoor antenna outside and the feeder currently has a maximum range of 120nm and average of 33nm .

    Here comes my questions:
    • What is the maximum range one can achieve using this dongle?
    • Can you achieve 350nm by changing the antenna or do I need to purchase a better feeder hardware as well?


    My feeder: T-ESGG44

  2. #2
    Captain abcd567's Avatar
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    Quote Originally Posted by 9944990 View Post
    What is the maximum range one can achieve using this dongle?
    First determine what is the maximum range which you can get by the method given in this post:
    What is the Maximum Range I can Get?


    Quote Originally Posted by 9944990 View Post
    Can you achieve 350nm by changing the antenna or do I need to purchase a better feeder hardware as well?
    Jetvison antenna is a good one, and you dont need to buy another one.

    Is you current max range of 120 nm less than max possible determined by above method?
    If yes, then are you surrounded by objects higher than your antenna? The objects may be houses buldings, tall trees, surrounding hills etc.
    In case your answer is yes to these questions, then you can improve you range by
    (1) Increasing height of antenna
    (2) Adding an RF amplifier between dongle and antenna.
    (3) If length of coax cable between antenna and dongle is greater than 20 ft, try to reduce it. If not possible to reduce, then add an amplifier.

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    Thank you for helping me understand this:

    I created the panorama I guess the range seems to be more than what I receive, range is not presented with distance in nautical miles and I don not know how to get nm from this map. : https://www.heywhatsthat.com/?view=KXL896VK
    1. I have tall trees around me and buildings at north only south and south east have good view.
    2. I am currently not using and RF amplifier but have placed the antenna at the highest level I can install it.
    3. I use the default antenna and cable which comes with the dongle so cable length is not a problem.

    What I understand here is that the dongle can achieve up to 350nm if placed in a good position with clear view no need for new hardware antenna?

  4. #4
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    I think that's just about the expected range for the scenario you have described. If I understand correctly, you are using the stock antenna that comes with the dongle. As you have obstacles around, you definitely need a proper external antenna for better coverage.
    --

  5. #5
    Captain abcd567's Avatar
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    Mr. Khan is right.
    You have to install antenna above roof or mast, above height of obstructions like high trees, houses etc.

    The antenna supplied with DVB-T will not suite outdoor roof/mast installation. You will need another antenna suitable for installation on roof/mast.
    Jetvision DVB-T + Antenna.png

    You have plotted your heywhatsthat plot using wrong elevation below ground level:
    elevation 81 ft above sea level (-168 ft above ground).

    I have re plotted it with antenna at
    elevation 269 ft above sea level (20 ft above ground)

    https://www.heywhatsthat.com/?view=X5U96K6X


    As you were facing difficulty in finding distances on heywhatsthat plot, I have measured and marked it in the plot attached below.

    Gr-antenna-20-ft-above-ground-heywhatsthat.png

    The plot shows that due to terrain, you cannot get more than 251 nm in best direction, even if antenna is installed at 20 ft (6 meter) above ground, and clear of tall trees houses etc.
    Last edited by abcd567; 2018-09-12 at 19:03.

  6. #6
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    Thanks from both of you, now I understand that i need a better outdoor antenna to increase the range and the USB dongle can achieve more than 100nm if installed with a proper antenna and in a proper position.

    You are right it supposed to be 81 meters not feet messed the units

    Now I am going to purchase a better outdoor antenna and continue my experiments.

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