LC Filter

[Harveybear]

Cheers mate!

[drambuidhe]

Please can someone help me get rid of motor interference on my Skysurfer.
I have the Eachine 600mw vtx out near the wing tip and have a standard (long) flat servo lead feeding it with +&-. The white wire is bringing the video via one of 3 camera's chosen from my HK 3-way switcher . The "video out" white wire then leaves the switcher , goes through my G-OSD3 osd and then out to the vtx.
I've just tried fitting an LC filter to the power supplied from one of the flight batteries balance leads which only powers the osd and vtx. It made no difference?
SO- I then tried the filter on the other flight batteries balance lead which powers a Ubec which then powers the three camera's - no difference??
SO- I then fitted it in the lead from the ESC to the rc rx  -you guessed it - no difference?
SO- I then tried it on the wing on the +&- supply to the vtx - "bugger all" difference??
Please :-* anymore suggestions ;D

[dogzilla]

You should be filtering your VTX, Camera and OSD. So if they are all powered separately, you need 3 LC filters.

And the filters need to go after any switching regulators. eg. Battery->UBEC->FILTER->Camera

[drambuidhe]

You should be filtering your VTX, Camera and OSD. So if they are all powered separately, you need 3 LC filters.

And the filters need to go after any switching regulators. eg. Battery->UBEC->FILTER->Camera

Thanks for coming back!
So since I need to filter each of the 3 cams plus the vtx, and osd , so should I use 5 filters then?
Could I try ferrite rings first -the lc filter was £6 so five would be pretty expensive  :o

[skyscraper]

I beg to differ. You shouldnt need LC filters at all

It would be interesting to see a circuit diagram showing what is connected to what and a photo or 2 of the reality.

Using servo cable on long runs is not great. It is better to use cctv cable. Also dont have any signal wires going anywhere alone. They should always be paired with a ground return wire. (Current goes one way along signal and the same current returns via ground so cancelling magnetic effects)

You should look at your camera switcher as a "hub" and have power going in there from batt and out to your camera and Vtx as end nodes. If camera switcher cant supply cam/vtx voltage then stick a Switching PSU ( 12v BEC) right by it so you can follow the above ground return rule.

Usually junk on video is cause as ground going to camera is carrying current for other devices, violating ground return rule.

regards
Andy