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Just had a fly away.... questions about antennas

Discussion in 'General Discussion' started by bonedoc, Mar 5, 2014.

  1. bonedoc

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    I design circuits and write assembly code for things I design. I know a lot about electronics, but I know NOTHING about antennas!

    I need help!

    I decided to "upgrade" my antennas to improve the range on my vision 2. I wanted to do a clover leaf design. I bought the iBCrazy antennas. I did 2.4 and 5.8 TX and RX antennas, so I had a total of 4. I thought I would try overkill first.

    So, I mounted two 2.4 cloverleaf TX antennas on the vision, one for each antenna on the camera. I also added an adapter to one of the stock 5.8 RX antenna wires, so one of the antennas could be a clover leaf. I also added the 14dB TP Link wifi antenna to my wifi extender. Because of the wire length of the antennas in the phantom, I moved the compass to the left leg. Factory, it was the right leg. I calibrated it after this.

    See a picture below.

    First trial flight, I went up and it seemed a little sluggish to respond....and it took off! It was acting all squrilly and was gone. I found it about 750 feet away. It went downward and smacked a tree branch.I ave a few things to replace. My questions are:

    -Is there something wrong with my setup of antennas below?
    -With improving range of the 5.8, is there ANY DISTANCE benefit to changing the stock RX located on the phantom?
    -If there is a benefit, what type of antenna, which direction, and HOW MANY? There seems to be confusion if the antennas are both used at once
     

    Attached Files:

  2. xgeek

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    I don't have a Phantom, but if you moved the compass to the opposite leg it will be rotated 180 degrees unless you already adjusted for that?
     
  3. mikeydaddio

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    Yeah, I'm not sure calibration can correct for that! Calibration is more like fine tuning so depending on how the software works, it may not be able to handle the compass on the "wrong leg". My guess is it probably can't.

    Mike
     
  4. F6Rider

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    Couple of things, one is already mentioned, the compass was rotated 180º, not sure if this would affect things even after a seemingly good compass dance. As a HAM I would mention that the iBcrazy antenna you have is circularly polarized and the TP-Link is Linear, so your wi-fi range will suck, also if you did not go with the matching control antenna on the bird this will cause problems. Those are good antennas but you nee the tuned matching antenna on the repeater and R/C. That type of flyaway is indicative of compass interference, but if it calibrated correctly and you got the all green lights then I would look at antennas on the bird. You have 3 circularly polarized antennas mounted Horizontal instead of vertical as designed
     
  5. xgeek

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    I have seen people mount them on that leg but they have still kept the compass pointed forward by turning it around. I am sure a guru will chime in and advise but thats my thoughts.
     
  6. xgeek

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    I thought the whole purpose of the circular design was that they operated the same in any orientation?.
     
  7. mikeydaddio

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    Yeah, in thinking about it, I don't see how it could possibly work unless the compass is rotated so that it sits at the same angle relative to forward. All the compass dance does is adjust for your latitude. There's no possible way it could detect that the compass has been rotated. So it'll end up conflicting with GPS.

    Mike
     
  8. Noël

    Noël Guest

    How did you manage to remove the (two) PCI U.FL plug from the receivers antenna? (I'm not talking about the camera)?
    Last time I tried I pulled the complete plug from the PCB!
    To me it looked they used some glue to make it stick!
     
  9. ianwood

    ianwood Taco Wrangler
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    Compass has to face the same direction no matter where it is on the craft. No amount of calibration will correct for a compass that is 180 degrees out of phase.
     
  10. OI Photography

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    Are those 2.4GHz bluebeams on the Phantom designed specifically for the P2V? I was under the impression that the 2.4GHz wifi the P2V uses is not identical to the 2.4GHz signals commonly used for FPV.
     
  11. ianwood

    ianwood Taco Wrangler
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    Also, having your 5.8 and your 2.4 antennas right on top of each other like that will not help.
     
  12. MILLER4PRESIDENT2020

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    i tried moving my compass, thing flew like it was drunk
     
  13. bonedoc

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    Ok, so we definitely established that moving the compass was a bad move. DJI says that it should not be moved. I will fix that.

    As far as the connector goes, I cut it at the and and installed a SMA connector on it. You will destroy the PCB on the receiver if you removed the wire.

    So, here are the remaining points to settle:

    -Every antenna boards on the system has 2 antenna leads (except for the remote control tx). Are these both used at all times? In other words, if you decide to "upgrade" an antenna, will one suffice?

    -The vision camera has 2 tx antennas in it. Will a different antenna boost signal back to the iphone? I dont see how, as the power is not increase (like the TX of the controller pot).

    -Is a clover leaf fine for TX from the controller? I know that the controller can be boosted using the pot, but will the antenna also help? If a clover leaf is used on the controller TX, I assume you must also change the RX for the phantom, as it has wires and not clovers.