FPV Cloverleaf antenna

Discussion in 'ALTA' started by Stefan Helborg, Nov 14, 2015.

  1. Stefan Helborg

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    Hi

    How can it be that the FPV cloverleaf antenna is ment to be mounted upword? Should you not think that it ought to point down and preferably in the direction of the pilot?
     
  2. Chris Jordan

    Chris Jordan Member

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    Mount it however you want :) Mine is aimed down. It rotates for when I put it in the case, via slip ring.
     
  3. Andy Johnson-Laird

    Andy Johnson-Laird Administrator
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    Not strictly true, Chris. The radiation pattern for a skew planar antenna is highly asymmetric.
    See http://www.freeblog4u.com/blog/2014/02/radiation-patterns/

    One thing I have not yet been able to determine is whether, if the transmitter antenna points down, should the receiver antenna also point down -- the better to match the circular polarization...

    Do we have any antenna gurus on the forum?

    Andy.
     
  4. Chris Jordan

    Chris Jordan Member

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    I did extensive testing over the past few years, patterns, frequencies, built antennas, etc. on my "experience" down has always resulted in the best performance regardless of ship. BUT I'm all ears if Freefly says different, maybe there's a reason! :) cheers Andy.
     
  5. Andy Johnson-Laird

    Andy Johnson-Laird Administrator
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    I think pointing the antenna down or up is less of an issue than the "dead zone" that's directly above and below the Transmitter antenna.

    Skew Planar Deadzones.png

    With the antennae pointing up or down, if the copter is directly overhead then both Tx and Rx would be in their respective deadzones. That's been my experience out in the field (more specifically out in the sky). :)

    I could certainly see that antenna down on the copter might position it where there's less carbon fiber blocking the RF propagation line down to the ground.

    Andy.
     

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