Range and Power Lines

[jondrew]

I have a P2 with Zen GoPro, 600 mw Immersion Tx. I have a nice wooded area behind my house I can fly over. Going south, I've ventured about a mile past a waste treatment plant. I get reasonably decent FPV video (5.8 Ghz) and no control problems (2.4 Ghz radio). I haven't ventured much beyond that, but only because I'm going slowly further and further out over relatively uninhabited area (lots of civilization on either side of the green zone). When I go north to the main road going into my neighborhood, I get about 900-950m out, and I trip a RTH and my phantom turns around and flys back. Its happened twice now. The only difference I can see is that about 3/4 of the way in the Northern direction are some power lines that cross through my neighborhood. I'm flying pretty high going north (200m, maybe a bit more) because of the tree line that obstructs my LOS. I can't really see the phantom, but the tree line is about 100m from where I set up on the ground, and the trees are a bit shy of 20m tall. So some basic math (I hope I remember trig) says as long as I'm over 200m at the high end, I still should be in good LOS. Going South (where I've been out to 1600m, I fly around 150m. The treelike is much further from my control point, so I shouldn't have to fly as high.

So will transmission lines possibly be causing a problem? The transmission lines are 30m high at most, so at 200+m I'd think there would not be any interference.

 

[ElGuano]

Shouldn't be anything to worry about at distance. Just don't get too close to them, they can give off strong EM fields that can mess with the Phantom's compass. There's probably something else that is attenuating or cutting out the TX's RF a bit earlier to the north.

 

[ElGuano]

Shouldn't be anything to worry about at distance. Just don't get too close to them, they can give off strong EM fields that can mess with the Phantom's compass.

How close is "too close"?

I've been right up next to high tension lines with no effect on the compass or TX.

Honestly, I would think you have to be quite close, and most of the time it won't have any effect. If you approach a strong electrical field at the right (or rather, wrong) orientation, it can definitely deflect a compass needle or magnetometer. Some transmitters have cell towers integrated into them, and those can have strong RF output. So I would give them a good margin, but at 100m overhead there's nothing to worry about.

 

[ElGuano]

Honestly, I would think you have to be quite close, and most of the time it won't have any effect. If you approach a strong electrical field at the right (or rather, wrong) orientation, it can definitely deflect a compass needle or magnetometer. Some transmitters have cell towers integrated into them, and those can have strong RF output. So I would give them a good margin, but at 100m overhead there's nothing to worry about.

These kind of claims seem to be grounded in myth and/speculation rather than any experience with EM fields/RF outputs actually affecting a Phantom.

Well I certainly do not have first-hand experience with power lines affecting a Phantom. But it's also not anything worth testing as I have no reason or desire to fly that close to one.

I do have plenty of experience with close-range electrical fields affecting magnetometers, and RF output interference, and shielding of both, and that informs me to give a respectable berth to any such emitters. That may not be good enough reason for some, which is fine. We all have our own risk appetites.

 

[ElGuano]

Reality vs. speculation:

Yep, I've seen that--it's "justsomeguy"'s video.

Also reality:
[vimeo]29519728[/vimeo]

[youtube]http://www.youtube.com/watch?v=HcPDc23ZLEs[/youtube]

Have a good evening.

 

[IrishSights]

Interesting past post although mostly on cell towers!
https://www.phantompilots.com/viewtopic.php?f=4&t=7104


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