My Continued Adventures In FPV Noise Mitigation

Discussion in 'Build & Tune' started by GlassKnees, Mar 30, 2018.

  1. GlassKnees

    GlassKnees Well-Known Member

    I have been trying for some time to get decent FPV video out of my quadcopter. From my initial flight, when the video was totally useless, I've taken as series of small steps, each time the video quality improved a bit. I started with installing a cloverleaf antenna on the vtx, followed by putting a wire mesh around the vtx. Then I added cloverleaf antennas on my receiver/monitor. I've seen improvements in each step, but after watching some videos on YouTube, I've decided to try one last thing: adding low ESR capacitors across the power leads of the ESC's to shunt noise to ground.

    So, I ordered some 25V 470 microfarad capcaitors from Amazon, which arrived today. While in theory this should be a simple installation, it is turning out to be a major job, involving essentially disassembling the aircraft. I have to remove each ESC, solder a capacitor to the power and ground leads and put new heat shrink on the connectors/capacitor leads and gingerly reinstall the ESC.

    Here is the #3 ESC with its capacitor:

    [​IMG]

    And here it is, back in the chassis:

    [​IMG]

    The #3 ESC is on the right. Before removing, I had to mark the leads going to the motor so I don't have to retest the motor spin direction again (though I probably will to be thorough). As you can see from the congestion, this is going to take awhile. I hope the effort will be worth it!

    When I'm done, I will post a video of my results.
     
  2. Jackson

    Jackson USA member at large

    Those ESCs already have caps.

    Cap Capture.JPG

    This from Oscar Liang.

    Caps oscar .JPG
     
    Last edited: Mar 31, 2018
  3. GlassKnees

    GlassKnees Well-Known Member

    Well, that sounds like I'm wasting my time....
     
  4. mozquito1

    mozquito1 Well-Known Member

    Do you have an LC filter. I used to use them off the main lines to clean up vtx signal & it helped alot. I use 35v 470uf
    Capacitor. Just one.
     
  5. mozquito1

    mozquito1 Well-Known Member

    Pretty cheap £3. Whatever goes in comes out clean, no spikes.
     
  6. GlassKnees

    GlassKnees Well-Known Member

    Saw a coup,e of comparisons between LC filters and straight low esr caps - the caps performed better..
     
  7. Jackson

    Jackson USA member at large

    Here ya go.

     
  8. GlassKnees

    GlassKnees Well-Known Member

    I saw this video. My setup is different that the one shown in the video - the guy is tapping his main power source for the camera/vtx; I chose instead to use a separate power source - a small 450 mAH 3s lipo dedicated to the camera/vtx.

    I've sent an email to a couple of buddies who are electronics experts to solicit their opinion regarding the use of an additional capacitor wired across the power/ground leads to clean up my video; if they say yes, it will help, I will probably remove the shrink wrap on my ESCs and solder the cap directly onto the power/ground pads on the ckt board and replace the shrink wrap...
     
  9. Jackson

    Jackson USA member at large

    Well did ya cap that?
     
  10. GlassKnees

    GlassKnees Well-Known Member

    Well, I've given up... Adding caps didn't help much and after trading emails with a couple of E.E. buddies, they have convinced me that I need to shield the three wires going from each ESC to its respective motor. This could be done by taking some coax, cutting along the length and stripping out the core and using the outer shield. This would require pretty much taking apart the aircraft, not to mention adding weight. So, I'm going to live with what I have.
     

Share This Page