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Thread: Poor man Antenna testing

  1. #1

    Poor man Antenna testing

    Hey, I am builiding the antennas i need for my Duo2400 myself, and got some questions about testing them:

    1. Is the Diversity good enough to use it to compare 2 Antennas? If yes i was planning to get some 1-3dB attentuators to get a rough guess about their gain vs a omni. Would that work?
    2. For the crosshair i planned to get some high dB attentuators until my pic is really bad and use a linear antenna in order to Check my axial ratio on it, if the picture gets worse during Rotation i know that i dont have good axial ratio, if it stays the Same the antenna is good, right?
    3. Checking beam widht vs an omni like in 1)
    Edit 4) Use high DB attentuators until my pic is almost gone, then id use something to further increase the Signal loss by blocking line of sight. After that ill switch channels and try to Check where the Center frequency of the antenna is.
    Is that a good way for doing poor man antenna testing? I dont need perfect results, just a good way to Check if im on the right way. From time to time i also might get acces to a Network Analyzer in my university, but that's some trouble every time because some one has to stay with me because i normally dont have access to it and they cant let me in alone due to the risk of me stealing their precious equipment. Therefore i dont want to test every antenna that way.
    Edit: Thanks IBCrazy for all your awesome work for the FPV Community and sharing All that for free. Youre on of those guys that keeps a Hobby alive by distributing your work and helping those who run into problems! If i fail building my stuff ill support you by buying a VAS antenna!
    Last edited by janmaier27; 6th January 2018 at 07:23 PM.

  2. #2
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    The easiest (and best) way to measure axial ratio is to place a reflector behind the receiving antenna and see how much of a dip/increase in signal strength you get as you move it towards and away from the antenna. An antenna with a perfect axial ratio will see very little change, an antenna with a poor axial ratio will see dramatic swings in signal strength. I have done this in some of my antenna test videos on the RCModelReviews channel so you can take a look and see what I mean if you want.

  3. #3
    Thanks for your reply, that sounds good! What Do i do with antennas that use a reflector themself, like helicals or crosshair?
    Edit: Nevermind got it now, I just test how well it picks up reflected Signal (because that's cross polarized). Thanks!
    Last edited by janmaier27; 8th January 2018 at 03:55 AM.

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