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skola28

Video Interference from Motor

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Hey guys, I got my entire aircraft wired up last night, and I've discovered a very disturbing problem. My video takes a huge hit when I run the motor on my airplane. I've read many times that its a bad idea to power the camera and the Video Transmitter from the same source b/c of interference, but I have them both isolated (camera has its own battery pack). I'm guessing I'm getting interference from the motor through the video line or transmitter itself.

Here is a wiring diagram which shows my setup. Any suggestions? A little background as well:

Brushless AXI Motor

Panasonic AV100 Video Camera

One of the new ebay special video systems (the ones where the sound doesn't work)

11.1V Lipoly driving the Motor and the Video TX

post-5-1170781037_thumb.jpg

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Your picture shows that you are sharing the main battery with both speedcontroller and video transmitter is this correct ?

Terry

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I've read many times that its a bad idea to power the camera and the Video Transmitter from the same source b/c of interference,

That is incorrect. It is fine to have the video camera and video Tx share the same battery (that is the most popular installation). However, it is not a good idea to share the motor/RC/flight battery with any video equipment; motor commutation ripple will disturb the video quality and video equipment EMI/RFI may couple into the R/C Rx and reduce range.

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That is incorrect. It is fine to have the video camera and video Tx share the same battery (that is the most popular installation). However, it is not a good idea to share the motor/RC/flight battery with any video equipment; motor commutation ripple will disturb the video quality and video equipment EMI/RFI may couple into the R/C Rx and reduce range.

My video transmitter and motor run off of the same battery. I ran a test on a different setup which had separate motor and video TX batteries, but I still got the interference in the video. As the throttle increases, the video disturbances are altered. At full throtttle the distortion lines in the video get nearly horizontal and they are very thin. At about half throttle, they are at about 45° and are wider (this condition is very distracting).

I am thinking it is not a problem with the shared power source (the video problem at least, maybe a range problem as Mr. RC-CAM pointed out).

Do you think its just a problem with my transmitter picking up EMI from the motor? Is there a shielding solution? I guess I could try moving them further apart and see if it helps at all.

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Do you think its just a problem with my transmitter picking up EMI from the motor? Is there a shielding solution?

Very unlikely. Instead, I would suspect the microphone being over-driven with audio or mechanical vibration affecting the Tx components. These are issues that have come up many times before.

I also would put the shared battery high on the list. If I had to put a number on it, I would say that 9 out of 10 folks end up with video noise when they share the flight battery (without adjunct filtering) with the video gear. The symptom is just as you have described. The only time it makes sense to try that is after you get everything working perfectly with a isolated power source.

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It just seems that if it were a power problem relating to the sharing of main battery with the motor and the vid transmitter, then it wouldn't have shown up when the battery sources were independent. I had the system installed on an RC Car where the Camera was powered by the 11.1V Lipoly while the car ran on its own power.

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One battery for tx and camera. Another battery for the r/c planes, begin with that.

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As Mr RC-CAM pointed out the audio channel can give this problem, I had it myself. Start by removing the microphone and soft mount the transmitter. Run the whole video system off its own battery and I will be surprised if you still have a problem.

Terry

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And just because you got the problem (despite separate suppiles) in a car installation, doesn't mean you'll get it in a 'plane installation.

At the very least, try setting up cam & Tx powered separately: you can then try moving them away from your 'ideal' mount point and see what effect that has on the interference you see.

I've learned - all too painfully - that you rush to glue/fix in place _anything_ in these setups at your peril! No matter how good your theoretical chance of success, until you've checked that it works in that setting, all bets are off...

(... and even when you do that, problems that are intermittant can still cause terrible headaches :angry: ...)

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Thanks for the replies everyone! I'll try your suggestions out when I get back to Iowa (in Maryland on work travel right now).

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