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White Receiver Antennas ?

Discussion in 'Phantom 2 Discussion' started by Xrover, Feb 26, 2014.

  1. Xrover

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    I noticed that the Phantom 2 (Not Vision) has 2 white antennas that run down the inside front right and rear left legs of the landing gear. The DJI manual only shows 1 antenna (Receiver Antenna located on the forward right leg).

    1. What is the second antenna?
    2. Should both antenna wires point straight down or should one of them be bent 90 degrees near the end of the wire (as mine was when it came out of the box)?
    3. I am replacing my landing gear setup with this one. The 2 White antennas do not have long enough wires to run down the new legs. I do not want to let them just hang loose. Any Ideas?

    Thx
     

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  2. ianwood

    ianwood Taco Wrangler
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    They're both receiver antennas going into the same receiver module. The P2 has a diversity set up unlike the P1. As for polarization, I think that they both point down out of the box. Make sure that the tips (the exposed part) are not bent or curved as that can impede performance of the antenna.
     
  3. Xrover

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    Thanks for the info!
    I will correct the bent one.
     
  4. OI Photography

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    Ideally you want to mount them with the last section of each antenna ending up 90deg from the other. Eg: one down the leg and one along the side of the body. Having them mounted side by side in parallel pretty much eliminates the benefit of having two in the first place.
     
  5. Xrover

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    Ok, so you're saying having one mounted vertically pointing down. The other one mounted horizontally pointed either fore or aft. correct?
    I am wondering why DJI wouldn't have attached one of the antennas mounted laterally.
     
  6. OI Photography

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    Correct.

    I wasn't aware DJI mounted them coaxially like that from the factory, I thought they had them going different directions.
     
  7. ianwood

    ianwood Taco Wrangler
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    This is how I have my Futaba set up and it is how they says to do it as well, but on the P2 stock out-of-the-box, I am pretty sure they both point down. And people are getting >4km stock. So it may be a case of "if it ain't broke..."
     
  8. Xrover

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    Thanks guy's!

    The 90 degree orientation seems to be correct from what I have just been reading online. "If it's on the internet then it must be true" :geek:

    Anyway, For those members reading this thread in the future, here is some info from Airtronics and Futaba.
     

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  9. OI Photography

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    Very true, any range benefits from diverse mounting probably won't come in to play until the extreme edges of coverage in most cases, and there are other things you can do to have a bigger impact on range. Dual antennae do more to eliminate dead spots than they necessarily extend range. If your antenna orientation between Tx and Rx and relevant other factors are ideal, one antenna can get you as far as two.
     
  10. Xrover

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    I think it comes down to uninterrupted signal. Since copters fly in a 3D space, One receiving antenna pointing in one specific direction can have a great signal at one moment, then as the copter goes into a completely different orientation, that one antenna can loose full or partial signal strength. The second receiving antenna pointing 90 degrees opposed to the first, most likely will have the better signal when the the other antenna doesn't. 2 is better then one in this case.

    Just my opinion but since we have the 2 antennas, use them to the advantage they give.

    A side note (Then you can tell me to shut the f**k up :D ) A lot of P2 guys just want to fly straight up or in one long direction to see how much range they can get. In those situations, there is probably not much benefit from having the multiple antenna orientations. I think the real benefit comes when flying at all different angles.

    Now i will shut up!
     
  11. OI Photography

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    That's it exactly :)

    When flying straight up, a common mistake is to let the tip of the transmitter's antenna point at the aircraft, which is where the weakest part of the signal is, and that will result in greatly decreased range regardless of number or arrangement of receiver antennae.