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Mar 31, 2013, 11:16 PM
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Please Help! Video Transmission dies on take off back on landing and so on


Please Help;
I have an FPV setup on my multicopter. The system works fine initially. I can see the video from my camera on my portable monitor. The problem is, as soon as I start the propellors and the helicopter lifts off the ground, the video transmission cuts out.

When I land the heli the video pops back on the monitor. A moment later as soon as I start flying, the video cuts out again. Land = video shows up, take off = cuts out, land again = video shows up again and so on...

I am standing close to the heli and the video dies only when it is a few feet off the ground so distance shouldn't be an issue.

I am really at a loss on what I can try. Do the speed of the propellors effect the video feed? What might be the problem, and what can I do?

---
Here are the specs on my system:

I have an six propellor DJI Naza M helicopter.

My video transmitter is;
TX5400 5.8G 600mW 8 Channel AV Transmitter Module

I am using a gopro Hero 3 Black camera with a mini hdmi cable going to an adapter which is hooked up to the video transmitter.

I am using a RC302 Wireless Video Receiver.

If it helps, I can provide photos of the setup.

Thank you!
Chris
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Mar 31, 2013, 11:20 PM
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Distance - walk away from it on the ground...still happen.

Vibration - start up the motors with it in your hand. Still happen.

Voltage sag ( my guess) - use a separate battery for the video system - still happen?

Some simple tests will get your answer. - Ken
Mar 31, 2013, 11:28 PM
ultra cheap pilot
ican3d's Avatar
Did you power your Vtx using the main battery or standalone for Vtx? If you're using main then you should switch to standalone/dedicated battery to run vtx because i think might not have enough juice after shared with all the motors, esc,rx and stuff.
Apr 01, 2013, 12:42 AM
Registered User
RC302 is a 2.4g vrx.
Apr 01, 2013, 01:40 PM
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I am using a separate battery for the transmitter.

Could it be a vibration issue? When the heli isn't grounded, perhaps it's vibration is causing a problem?

Don't know how I could fix it? And basically just grasping at straws.
Apr 01, 2013, 01:47 PM
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Btw, It's not a distance issue

But I'm thinking it must be a vibration issue...

What can I do to fix this?

Or do I need a different/ more vibration tolerant transmitter?

C
Apr 01, 2013, 05:30 PM
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Daemon's Avatar
If it is a vibration issue, it's likely in your wiring, not the VTX or camera.
Try moving everything around, pushing and poking, shaking by hand
while watching the video.
Apr 01, 2013, 07:20 PM
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great idea, I'll try it tonight?
Apr 01, 2013, 10:56 PM
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Ok, just set up the monitor and the transmitter/camera feed in my apartment.

I walked away from it, the video signal still worked,

shook it like crazy, the signal still worked

poked at pretty much every wire that related to the FPV set up, and the signal still worked.

Any suggestions?

I'm really desperate to get it working
Apr 01, 2013, 11:02 PM
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Daemon's Avatar
That would seem to rule out vibration then. Camera doesn't care
about voltage, having its own battery, and that VTX has a voltage range
that starts at 6.5V so it'd be impossible to pull the voltage that low
and still turn the motors.

You could try holding the frame firmly and safely overhead (suitable eye protection
is also a good idea) and throttle up and see if video goes away under load.
Not sure what that'd indicate but not much else you can do to test.

It may just be a defecting VTX or Gopro cable.
Apr 01, 2013, 11:06 PM
Registered User
secure it to the ground somehow, and attempt to fly it stationary?

maybe run 1 motor at a time to see if this gives any unique results?
Apr 01, 2013, 11:08 PM
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thanks Daemon. I'm a little unsure about your first comment, as the transmitter has a separate battery (it's own power supply from the copter).

I'm not sure if I'm brave enough to try what you had suggested, but I'd be tempted if it would resolve this somehow?

I think I am just going to try flying again with it. Perhaps it was just a bad day? (does that even make any sense?).

Do you know if this transmitter is known for having these types of issues?

Thanks

C
Apr 01, 2013, 11:11 PM
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Daemon,

regarding a potential defective gopro cable or VTX, does it make sense if it still works when i shake it manually?

I was even poking at the cable to see what was happening.
Apr 02, 2013, 12:04 AM
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Daemon's Avatar
Manual shaking is much lower frequency than you'd get from motors while flying
so the G-forces on the VTX and connector would be lower unless you're actually
tapping on them with something hard.
Bad day implies bad Rf conditions, but Rf conditions should affect you the same
whether the quad is on the ground or in the air. The VRX is what would pick up noise and
it doesn't care whether the quad is in the air or not. Only distance and clean LoS
really matters on 5.8Ghz.
Apr 02, 2013, 12:14 AM
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Thread OP
Thanks again Daemon. You're probably right about the vibration then...

It seems to be the only possibility.

So what should I do?

C


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