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Split Video from Gimbal and use with VTX

Discussion in 'Phantom 2 Vision + Discussion' started by gfo315, Mar 20, 2015.

  1. gfo315

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    Time for another topic regarding a decent FPV system on the Vision Plus! [please, don't trash talk :( ]

    This time, I want to know if anybody has the wiring connections diagram from the cables that comes from Gimbal and goes to Main Board and WiFi Module. Although all of them have the same color, one of these cables must be a regular and "raw" video link, which I could split, and connect to the VTX and WiFi Module at the same time.

    With this setup, I would still have the functional DJI Vision App, with video link, telemetry, ground station and all of that stuff, but I would also have a decent FPV downlink which would give me VIDEO ONLY (since it's directly splitted from video cable).

    Any thoughts? Am I crazy? lol
    Thanks a lot,
    Guido
     
  2. cahutch

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    It's possible. There is an analog composite video signal going into the WiFi module.
    Check this thread...
    http://www.rcgroups.com/forums/showthre ... 815&page=4
    [​IMG]

    Be careful "splitting" the signal. Ideally it would require a distribution amplifier since any attempt to split the signal will half the signal strength at least and almost certainly create an impedance mismatch which will degrade the signal even more.

    Also keep in mind the Phantom 2 Vision + uses the 5.8GHz band for the controls and 2.4GHz for Wifi, so your video TX will need to be outside of those bands.
    In other words if you use one of the common 5.8Ghz video transmitters you'll probably degrade your control range by a significant amount. A 2.4GHz video TX will degrade WiFi range.
    If I'm not mistaken there are UHF video transmitters but those are larger and not compatible with Fatshark goggles.
     
  3. gfo315

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    Excellent info, thanks a lot for that!
    So this tiny single cable on the extreme right is the only one for video? I could cut it and connect to a VTX?

    I don't know a lot about Video Transmitters, but while looking for one of these, I've seen that there are 3 main connections: power input, ground and video. Would I also need to take these apart?

    Regarding frequency, I know about my 2.4 and 5.8 limitations. I was thinking about a 1.2GHz transmitter, like this one from Lawmate, along with a low pass filter so it won't mess with WiFi signal:
    http://www.dronesvision.net/en/wireless ... itter.html
    It comes with a little cable with 4 connections, which is yellow for video, and...? [sorry, I'm really newby about fpv]

    Let me know,
    Guido
     
  4. cahutch

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    1.2GHz would be good. They have a receiver available too and you should be able to patch that into some goggles that have an analog input.
    Yes. Yellow is video, white is audio and black is power.

    If you cut that cable you would of course disconnect the signal from the wifi downlink. If you connected the video to only one system, either wifi OR video TX, but not both, you wouldn't have to worry about an impedance mismatch on the video signal.
    One thing I noticed is that the range listed for that transmitter is 200-500 meters which is less than the wifi video link.
     
  5. gfo315

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    Initially, I don't think I would need more than 500m for video. But when, and if I need it, I may use the "Inverted Vee" antenna which is said to improve signal. Go figure.
    http://www.ebay.com/itm/Inverted-Vee-1- ... 3a9606414e

    Well, we're almost done, in theory. The equipment still needs to be bought lol

    - Yellow wire is connected to Gimbal's gray wire (I hope there isn't any issue regarding image resolution);
    - White wire isn't connected at all, because Vision Plus doesn't offer audio along with the video;
    - Black wire is connected in (?). I still don't know how could I get a 5.5V power signal to connect to the Transmitter. Do I need a power converter or something like this to connect to the main board?

    Thanks a lot for the help,
    Guido
     
  6. gfo315

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    Anyone?
    I need to know if the video cable that comes out of the gimbal transmits "pure" video, that I could connect to a video tx.
     
  7. cahutch

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  8. CityZen

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    You could either use a 5V regulator from a 12V source, or else you can plug a servo cable into the Naza module (use m5 or m6 connector) and get 5.5V that way.
     
  9. gfo315

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    Yeah, I think it's better to use a 12V to 5V regulator, instead of getting power from NAZA. I don't want it to burn if the transmitter requires more energy than NAZA can deliver.
     
  10. burlbark

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    Good thinking...Bec's are cheap these days and good insurance.
     
  11. gfo315

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    Hey guys! Just wanted to add that I could see the crystal clear image that comes from the Video-IN cable without cutting it, or anything.
    I used two pins, one is hooked into the Video-IN cable and the other one is into the GND cable, which is immediate left this video cable. Then, I connected both to a RCA video cable (uninsulated, of course), and then connected it to my TV. Boom! There it was, the no-laggy image. Of course, without the telemetry. Wish I could have it, though.

    Anyway, this way I can prove that my idea is not that crazy, and it can be done. Going to buy the TX/RX kit.
    Do you guys think that I should also buy a Low Pass Filter, so it won't mess with WiFi signal, or even worse, with the radio controller, that works on 5G8?

    Let me know.
    Guido.