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Thread: Options for reducing noise into 433 spectrum from Camera and VTX

  1. #1
    KD8YYX. DesignGeek's Avatar
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    Options for reducing noise into 433 spectrum from Camera and VTX

    First time with the EZuhf gear trying to set thing up as clean as possible.

    Plane is a Strix Stratosurfer,
    Cam: Strix Ochi 650
    VTX: RMRC 5.8 Cricket 600mw
    ET Vector
    RMRC 5Amp Ubec

    As a starting point I threw the gear into the plane into roughly the "correct" positions
    wiring is a still a rat's next at this point but I wanted to start somewhere with some data.
    Cam/VTX and REC and Servo runs in the fuse are all twisted wire leads built to length but just piled in there.



    REC is out on the wing. ~26inches from VTX and camera and about 21in from PSU/UBEC and wire mess in fuse
    Cam on the nose,
    Vector, PSU and UBEC in middle
    VTX at mid tail boom


    Scans were looking ok, (I guess?) with the Vector and UBEC.

    but fell apart as I added the Cam and VTX

    Let me know what you think. Im thinking Ferite chokes on the cam and VTX wires as a starting point

    On the wire harness, Im not sure what I will bundle together, and what to separate at this point. ---Could use some sage advice here.
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  2. #2
    Navigator parajared's Avatar
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    I have played with torroid/ferrite rings, CAT 5 cable, and a number of wiring layouts and honestly just plain boring old separation seems to make the biggest impact. Its good to twist your servo wires like you mentioned but on a larger airplane like the Stratosurfer you shouldn't have too difficult a time of finding a spot on your airplane where your DBM values peak out at their very maximum (say unless you are using very EMI noisy equipment).

    When I build I usually put the noisy stuff on the nose (vtx, action cam, BECs) and the stuff that needs things to be quiet on the tail (GPS, rx). Keep the noisy stuff away from the listening stuff.

    I put things center-line on the tail instead of the wing because of symmetry. An airplane with more weight on one wing than the other will fly funny. I like to believe (probably incorrectly) that having different antenna drag on one wing than the other changes aerodynamic flight characteristics.

  3. #3
    KD8YYX. DesignGeek's Avatar
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    I've got loads of separation. Since the last post I Built a pair of mesh + foil shielded cables for the cam and VTX. It eliminated all those jagged spikes from the last plot, but the floor is still too high. I have another identical Strix camera I can try, if that doesn't help I'm going to follow Daemons advice - he says the new foxeer predator mini is super quiet in the 433 band.

    I'm still trying to find the best layout, I can look at putting the VTX on the nose, that would really shorten all the cable runs as well. Maybe I can get the antenna to fit under the canopy and keep the airflow smooth.

    It it ok to put a 433 dipole at the end of a short coax extension so it can go up the vert stab?

  4. #4
    Co-Pilot doobie's Avatar
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    I wrap my cameras and other noisy components with copper tape. seems to help some in most cases
    flyin HIGH

  5. #5
    Navigator
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    This stuff is expensive, but works well when done right. Lightweight and still allows for some air to get through:
    http://www.aaronia.com/products/shie...ld-Ultra-70dB/
    http://www.aaronia.com/products/shie...elding-fleece/
    http://www.aaronia.com/products/shie...-X-Dream-PLUS/

  6. #6
    KD8YYX. DesignGeek's Avatar
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    Do you bother to ground the shielding?

  7. #7
    Navigator
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    I found this mesh works wihout grounding, just needs to cover everything, i.e. no 'holes' where RF can escape.

  8. #8
    Navigator Kreskin's Avatar
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    How are you powering the camera and vtx? Through the vector psu?

  9. #9
    KD8YYX. DesignGeek's Avatar
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    Yes, powering the camera and the VTX thru the Vector per the instructions.

    I was was slammed with work and now I'm sick as a dog, so honestly I haven't been in my shop in a week.

    Still considering how to put the VTX on the nose with the camera and the put the recivever in the tail boom.

    I'd like to do it in such a way that there isn't a bunch of wires getting pulled and moved every time the canopy comes off to get at the batteries, and the channel display and power switch is easy to get at. Still thinking that thru.

    If I go this route, I'll put a dipole into the vertical stab
    Does it kill antenna efficiency to just put a separate coax extension between the reciver and the antenna?

    it would be a lot cleaner to just have a really long coax right off the dipole like the ~12in one the turnstile comes with. Maybe I could build one? hmmm. Antennas still seem a bit like magic I'd Just have to trust in the force with this one.

    Ive got all winter here in To make it clean and quiet.

  10. #10
    KD8YYX. DesignGeek's Avatar
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    I see the dragon link dipoles antennas have various coax lengths available. Are the connectors all sma/compatible?

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