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QUICK SPIDER - No Soldering, No Connector

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  • abcd567
    replied
    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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  • kredittkort
    replied
    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

    Leave a comment:


  • abcd567
    replied
    V-Stub on Mag-mount Base (placed on a metallic plate)

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

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  • abcd567
    replied
    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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  • abcd567
    replied
    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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  • abcd567
    replied
    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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  • apeiron69
    replied
    It doesn't matter the cable RG6 is 75 ohm?

    Leave a comment:


  • Conan_89
    replied
    My first try to biuld a anntenn.
    And the result is:
    The included mini telescopic antenna has better reception than my built -.-
    Attached Files

    Leave a comment:


  • 9944990
    replied
    I make one of these which I use with my Jetvision USB dongle connected to my Pi 3 B+. I get three times more position reports and hits and slightly more plane counts and range than the stock antenna.
    However I am not able to achieve this when i a new one for my second feeder, I tried with 5 new spider.

    I use the same cable, cable length even place in the same position as the first one and connect it to my first feeder results are not good at all, I get around 20% of what I received with my first antenna.

    What am I missing? Where should I look to find the problem?

    Leave a comment:


  • abcd567
    replied
    Originally posted by Conan_89 View Post
    @abcd567
    when i bulid this anntenn.
    Do I need a special cable to connect to my nooelec nesdr Mini 2+?
    Yes. The nooelec nesdr Mini 2+ site says:
    "The connector type on the antenna and USB board is MCX--male MCX on the antenna, female MCX on the SDR"

    NooElec NESDR Mini 2+.jpg


    You will need a pigtail to connect the "nooelec nesdr Mini 2+" (MCX female socket) to RG6 cable of Spider (F-male connector)

    Pigtail F-female to MCX-male Rightangle.jpg OR Pigtail F-female to MCX-male Straight.jpg


    SEARCH RESULTS ON EBAY GERMANY
    https://www.ebay.de/sch/i.html?_from...Pigtail&_sop=2

    SEARCH RESULTS ON AMAZON GERMANY
    https://www.amazon.de/s/ref=nb_sb_no...MCX+Male+RG316
    Last edited by abcd567; 2018-08-01, 16:48.

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  • Conan_89
    replied
    @abcd567
    when i bulid this anntenn.
    Do I need a special cable to connect to my nooelec nesdr Mini 2+?
    Currently I have a reception radius of about 50nm(what is nm suitable?), I would like to expand it, possibly I get the Stuttgart airport in.

    Leave a comment:


  • Coxy
    replied
    Still the best Ant i have made and the best range including against bought ones...

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  • abcd567
    replied
    .
    .

    GROUNDPLANE ANTENNA MADE OF COAX ONLY - Without SO239 or N-Conector

    .

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  • goku1976
    replied
    Following abcd567 post I did my own spider antenna. Here it is.
    I used Thermal tail to isolate metal parts from the rain and also I have lately raised it to get a better performance.

    Leave a comment:


  • abcd567
    replied
    mibock
    I never tried glueing radials to Flightaware anena, so cannot tell you anything. You may try it.


    Following may help

    (1) Reducing gain setting of dongle. Try different values say 45 , 40, 35, 30,25,and at each gain setting run your pi for some period and watch. Since nearby plane's signal is strong, their signals may not be processd due to overload. Reducing gain may result in the nearby planesalso start showing.

    (2) Adding a filter.
    Last edited by abcd567; 2018-07-18, 19:36.

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