DJI Warning System : Very Connected and Powerful. Forces RTH

[Phantomrain.org]

This is the Second Day Video of the Long Distance attempt over the Water with much more
Clarity as i compare it to the First Video posted.

Screen Recorded Adventure:

Phantomrain.org
Gear to fly in the Rain and land on the Water.

 

[GFields]

Greetings! Awesome, thanks for sharing!

 

[sage32]

I thought you were home free at 5000 ft , are you going to attempt that flight again ?
Also you do think that those mini ones are better than the stock antennas ?

 

[Zbip57]

Primary Mission Failed. :

There were lots of different things going on here. It is very unlikely that the loss of signal had anything to do with the Altitude Zone warning message. It is much more likely the signal was being blocked by the trees between you and the drone.

Those omni directional antennae are not actually equal in strength in "omni" directions. If you stand the antenna pointing vertically straight up, then the signal radiates out in a donut shape extending equally toward the horizons in every direction. But your body will block a significant portion of the signal radiating out behind you. You never want the tip of the antenna pointing toward the drone, as that is the weakest orientation. With the tip of the antenna pointing at the drone, you're essentially pointing the empty hole of the donut at the drone.

At 6:00 in your video you can still see the drone just above the tree, as you make the phone call to your spotter. But as you fly further out over the lake, the drone will be lost from sight behind the tree. Gaining altitude brought the drone higher up to a point where the tree blocks less of the signal.

Fly from the marina with a clear line-of-sight, rather than from your balcony, and I'm sure you'll have better signal strength.

The antennae really shouldn't be floppy like that either. Here's an ancient, but still relevant, video from DJI on the importance of proper antenna orientation.

I could not comprehend what the warning was saying to me , I must have read it 10 times in flight.

As for the Altitude Zone message, in this instance it was merely a warning that you are near the zone for the Burke Lakefront Airport. Your Wildwood Marina lies under DJI's 150m (492ft) Altitude GEO Zone for Burke Lakefront. You were merely at a height of 46m (152ft) when that warning was triggered.

It's just a friendly warning at this point. But it's a significant warning. If you try to climb higher than 150m (492ft) straight above the Marina, you would hit the ceiling and be prevented from climbing any higher into the GEO zone altitude restriction. That's obvious. But you're not prevented from flying through this area as long as you stay below that ceiling.

The warning message is trying to alert you to a potentially more dangerous scenario. Note on the image below, the grey fan-shaped area is the GEO altitude zone. Let's say you continued to fly further out over the lake beyond the edge of that altitude zone, then for some reason (loss of signal?) decided to climb to a height greater than 150m (492ft), or you actually lost control signal and had your failsafe RTH configured to return at a height greater than 150m. The drone would only come back at that altitude until it bumped into the outer edge of that GEO altitude zone, where it would be automatically prevented from coming any further toward the shoreline.

As long as you had control to command the drone to descend below the 150m GEO ceiling, there'd be no problem. But if you had no control signal, or didn't know why it suddenly stopped and refused to come back any further, that might cause some panic when the drone suddenly hits an invisible wall in the sky.



This map is viewable at Geo Zone Map - Fly Safe - DJI

The DJI GEO zones are also directly viewable on the DJI Go and Fly app map displays. Here's a really excellent tutorial explaining the many map functions of the app. Starting at 1:35 he talks about how to display the GEO zones. These are REALLY important. DJI's interpretation of where to allow you to fly, or not, often do NOT align with actual legal FAA requirements. But they certainly can and will affect how your DJI drone behaves when encountering these zones...

 

[Phantomrain.org]

There were lots of different things going on here. It is very unlikely that the loss of signal had anything to do with the Altitude Zone warning message. It is much more likely the signal was being blocked by the trees between you and the drone.

Thank you for taking the time:

I know one thing that threw me off was that it was 150 m and not 492 ft.
I was aware of that Geo Zone Wall to the left of me as I tested those limits .

I think its worth another Run at 200 Ft alt at 5000 Ft distance it will be interesting to see if it duplicates the panic sequence of events.

FYI: I was using the Alien Mini Antennas System which I think are Omni Directional , different than the Stock ones.
I may try with both Alien Antennas to see if the Result is that much different.

Phatnomrain.org
Coal

 

[Phantomrain.org]

There were lots of different things going on here. It is very unlikely that the loss of signal had anything to do with the Altitude Zone warning message. It is much more likely the signal was being blocked by the trees between you and the drone.

I just had my second flight tonight , and wanted your thoughts about the Warning being connected to the Mayhem.

 

[Phantomrain.org]

I thought you were home free at 5000 ft , are you going to attempt that flight again ?
Also you do think that those mini ones are better than the stock antennas ?

So at this point after my second flight I just updated on the post I dont think the Alien Dual Antennas would make any difference as I battle the built in sequence of Panic Warnings .

I may try a 3 flight to test one more idea that the 5000 ft Warning Events extends all the way down the lake front even though it does not show on the map.

Phantomrain.org
Gear to fly in the Rain.

 

[Zbip57]

FYI: I was using the Alien Mini Antennas System which I think are Omni Directional , different than the Stock ones.

The stock ones are flat blades, whereas the Aliens are cylindrical, correct. The signal radiates out from the surface of the antenna, very little from the tip of the antenna. The difference is the flat blades tend to focus the beam out either side of the flat surfaces (forward or backward), not so much out the edges. The cylindrical "Omni directional" antenna sends the signal out equally in all directions out the circular sides of the cylinder, but still very little out the tip. It's a donut shape.

See: Wikipedia Omnidirectional Antenna

The benefit of an omni directional antenna is that, as long as the antenna is standing vertically straight up, the signal radiates equally in every direction to the horizon. You don't need to worry as much about keeping a focused beam "aimed" at the aircraft. However, you only need to be aware that if the antenna is pointing straight up, then straight above you is where the signal is weakest.

The omni directional advantage of the cylindrical antenna is also its biggest disadvantage. Because the signal is radiated equally in every direction toward the horizon, the signal gets significantly weaker the further away it goes. An antenna of similar power, but which focuses a narrow beam in one direction, will extend much further but must then be kept carefully aimed at the aircraft.

That's the antenna on the transmitter. You also need to consider the antenna on the aircraft. I believe those are standing vertically in the front legs of the Mavic. The worst reception would be with the transmitter antenna standing vertically and the Mavic directly above you, as then both the transmitter and receiver antennas would be oriented tip-to-tip.

I don't know why you are getting a weak signal at that exact range (5000ft), coming back but not on the way out, or on the way out on your first flight. I still think it's just a coincidence that the edge of the Geo Altitude Zone is located right at that range, and I suspect the tall trees between you and the aircraft are to blame.

I see you've fixed the antennae so they're standing straight up this time. That alone will have made a significant improvement over their floppy misaligned positioning in your first flight. I still think it's an antenna issue totally unrelated to the Geo Altitude Zone.

From your takeoff location to the far edge of the Geo Altitude Zone is almost exactly 5000 ft, and you can see how far along the beach that zone extends.





You've flown before from the parking lot of Wildwood Park. From there, you have a better unobstructed path for the antenna signal, and the same outer edge of the Altitude Zone would be only 3000 ft away.



Try flying from the parking lot. I'll bet you get much better range without the signal loss at the edge of the GEO zone.

The warning message for the "Altitude Zone nearby (150m)" is still the same issue as before. As long as you stay below the 150m (492ft) ceiling you should have no problem. That altitude warning is still only indirectly related to the weak control signal warning, same as before.

If you have a strong signal and remain below the GEO zone ceiling, there'd be no issue. But if the signal is lost completely and if the drone's RTH height were configured higher than 150m (492ft), then it wouldn't be able to come home by itself because the GEO zone would stop it dead the moment it hit the outer edge of that zone. The other scrolling messages give ever more dire warnings saying the drone would stop and hover at that edge until the battery ran out (or you managed to regain control signal) and it would eventually auto-land with low battery in the lake.

People get into trouble with these Geo Zones if they don't know they're there and somehow get stuck on the far side of a restricted zone. You fly out and around the zone, then try to fly a straight line home, and the drone bumps up against an invisible wall and refuses to come back. If you know what's there and know how to steer around it, no problem. But if it's a mystery, that's when panic sets in. Eventually the battery runs dry, then it's bye-bye.

 

[Phantomrain.org]

The stock ones are flat blades, whereas the Aliens are cylindrical, correct. The signal radiates out from the surface of the antenna, very little from the tip of the antenna. The difference is the flat blades tend to focus the beam out either side of the flat surfaces (forward or backward), not so much out the edges. The cylindrical "Omni directional" antenna sends the signal out equally in all directions out the circular sides of the cylinder, but still very little out the tip. It's a donut shape.

I am pretty much convinced that the Warning System is designed for a Panic series of events to trigger from that Warning message.

I am going to do another flight out with the Alien Dual Antennas System, but I suspect that the same series of events will trigger , but that I can go past it , but not without the Wrath of the Warning Bells .

So 8000 ft was the 2 bar
and 5000 ft was the Warning System - No Signal.

Stay tuned. ITs going to be $460 worth of antenna power coming soon.

Phantomrain.org
Gear to fly your AIR 2S in the Rain.

 

[Zbip57]

One thing I'm curious about is this particular warning message that pops up. It says, "Aircraft in Altitude Zone (Altitude limit: 0ft). Fly with caution"

That's nonsensical. The Altitude Zone in this location starts at 150m (492ft). You are currently at a height of only 352ft. That's still safely 140ft below the Altitude restriction.



In any case, it is an alarming set of only warnings. As long as you're not flying higher than 150m (492ft), you are not prevented from crossing underneath this Altitude Zone. And evidently your drone flying in RTH mode at its current height (352ft) is also not prevented from crossing underneath the Altitude Zone.

It's only going to create a headache for you if your drone is flying higher than 150m (492ft).

I still think the weak controller signal and the Altitude Zone warning are only related in that a failed control signal will trigger a failsafe response, typically RTH. And if your RTH height was configured to higher than 150m (492ft), then it's smart enough to realize you're going to be in big trouble when the drone encounters the outer edge of that Altitude Zone, because the drone will be prevented from returning to home at that altitude or higher.

But if it was that smart, it would also have already noticed that it's already returning home at a height of only 352ft, safely well below the Altitude Zone.

 

[Zbip57]

You seem to suspect the Altitude Zone warnings are somehow causing the loss of control signal. I'm still convinced that's just a coincidence and is probably a result of the trees blocking your signal.

That can be easily tested by flying from the Marina, maybe even out on the pier, rather than from your balcony.

Another thing to be aware of is Fresnel Zones. The radio signal bounces off other surfaces. When the bounced signal intersects with the direct signal, depending on the phase shift whether it's a crest meeting another crest, or a crest meeting a trough, the signal will either be boosted or suppressed at that intersection.

Bruce Simpson (Xjet) explains it in this video.

 

[Phantomrain.org]

You seem to suspect the Altitude Zone warnings are somehow causing the loss of control signal. I'm still convinced that's just low signal

Had a very interesting flight 9500 ft out without any Geo Warnings. ??
Makes me think now the complete opposite : Loss of signal triggers Warning ?