Video interference and blackout

Discussion in 'Cinestar 8' started by Chris Babiana, Apr 2, 2013.

  1. Shaun Stanton

    Shaun Stanton Active Member

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    I find for the cam-op the Lawmate 1.3 is great, not perfect. I use a 900Mhz for my FPV. I use the standard dipole antennas that come with them. The that you have to think about is how the EM wave is propagating. The EM wave on a dipole antenna and how the wave travels to yours. This effects how your reception is when the AC is close versus far away. If the aircraft is high and close to you will get allot of signal loss as you enter the cone of silence if the antennas are vertical. If the AC has enough distance away from you, than the vertical antennas will work perfectly. However if you know most of your shots are going to be close with a steep vertical angle because of altitude to your receiver you want the antennas to be parallel to the ground because the wave will be propagating downward. As you move the craft away from you and start descending will get into the cone of silence again with horizontal antennas.

    It is exacerbated by lower frequencies because of the longer wavelength, the cone of silence is larger. However at longer distances the lower frequencies do not attenuate as much. The opposite is true with higher frequencies, there is always a give and take relationship. The MQ-1B predator uses a 5 ghz 15 Watt transmitter for the video down-link when flying line of sight (of the ground station antenna versus satcom), it even gets video blackouts. So there is no perfect solution out there all of the time.
     
  2. Josh Lambeth

    Josh Lambeth Well-Known Member

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    The best solution would be too.... wait... I may need to try something and report back later with my findings.... hmmmmmmm..... :p

    Josh
     
  3. Shaun Stanton

    Shaun Stanton Active Member

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    Don
    Don't you have a rotatable servo? I want to do that but I am using DX8's with the sattelite and do not have access to a channel to command a servo. Your solution should have worked although you have to orient your receiver antenna as well;)
     
  4. Josh Lambeth

    Josh Lambeth Well-Known Member

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    Yup... right now it's just straight down after takeoff... thinking about adding it to a control for the cam op so they can adjust it as need be... I already have one antenna standing up and the other sticking straight out so they should work either way as the cam op adjusts the servo...
     
  5. Shaun Stanton

    Shaun Stanton Active Member

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    That's a perfect setup. I am going to figure that one out soon. :) Unfortunately the Lawmate does not have two antennas like the passport
     

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