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Thread: My first collinear antenna

  1. #21
    Passenger skyspotter's Avatar
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    Quote Originally Posted by FR24-BB8 View Post
    Hi guys.

    I'm new at this forum, and new to FR24 to. I've just set up my Raspberry 2 to feed FR24 with data, and with the stock antenna that came with my USB-dongle I get signals from approx. 20-50 nm. Tonight I built an collinear antenna with five segments, unfortunately I can't test it until tomorrow cause I miss some connectors. Anyway, how much do you think I will increase my coverage with my 5 segment collinear vs my 67 mm stock antenna?

    Here is a my antenna assembled
    Attachment 7580
    I tried collinear on my 1st attempt, but achieve better receive on it, but i switched to ground plane and for me its way better and better coverage.

  2. #22
    Flight attendant
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    Yeah, maybe for me to. I will build a ground plane later this week. I hope to get better coverage than 100 nm cause i have clear sky all the way but to the south where i live.

  3. #23
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    Well I can tell right away, that something must have gone wrong with my 8 segment antenna. Did not cover planes 40 nm away. Switched back to my 5 segments and they all starting to show up.. Ill guess my next project will be a ground plane...

  4. #24
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    What dimensions (diameter/mm2) should i use on the copper lines when i build my ground plane? skyspotter? abcd567?

  5. #25
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    have you tried with the normal antenna cutted as the image i posted before?

  6. #26
    Flight attendant
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    My first collinear antenna

    No. I have not tried that yet. Maybe I'll try it today. Best would be if I could mount it at the same place on the roof, but i do not have adapters for the cables.
    Last edited by FR24-BB8; 2016-06-06 at 08:27.

  7. #27
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    Quote Originally Posted by FR24-BB8 View Post
    Well I can tell right away, that something must have gone wrong with my 8 segment antenna. Did not cover planes 40 nm away. Switched back to my 5 segments and they all starting to show up.. Ill guess my next project will be a ground plane...
    Welcome to the world of collinear voodoo, they are frustrating things to get right, you must know the correct velocity factor for the particular coax that you are using so you can get the segments cut to the right length, then trying to tune the sleeve balun is almost impossible without an antenna analyser or spectrum analyser and noise source, and the tuning of the top stub can make a huge difference. even then it is still a lot of trial and error to get it right, I have made a couple but it would be a lot easier and probably cheaper just to buy one in the long run.
    Ben.
    FR24 F-EGLF1, Blitzortung station 878, OGN Aldersht2, PilotAware PWAldersht, PlanePlotter M7.

  8. #28
    Flight attendant
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    Hi Ben.
    Thanks for the information. The first one I built I'm pretty satisfied with. I get up to 100 nm, but I just maybe got lucky on that one. What about diy ground plane antennas? Do you think it's worth a try?


    Sent from my iPhone with Tapatalk

  9. #29
    Captain abcd567's Avatar
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    I use a groundplane (Cantenna & Spider). My range is 200nm+ without amplifier, but my RG6 Coax length between antenna & DVB-T dongle is short, 12 ft / 4 meters. Groundplanes are easy & sure and success rate is nearly 100%, but because of their low gain (2 to 1.5 dBi) they cant sustain long lengths of coax without an amplifier.

  10. #30
    Flight attendant
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    Ok. Thanks. I have about 3 meter coax between antenna and dongle. I will give it a try.


    Sent from my iPhone with Tapatalk

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