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Repeated aircraft disconnects

wco81

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I tried to fly from the Path of the Gods on the Amalfi Coast in Italy. This is a hiking path which runs several hundred meters above the coastline between the towns of Amalfi and Positano.

I was in a ravine, at the back of it, with the opening about 1 km wide. Basically took off from a widening of the foot path. Not ideal but I had lugged it up so I thought I'd give it a go.

After it got about 350 ft. or more, the app. would report disconnect and no GPS connection after taking off a couple of minutes. I RTH and it returned. Then it reported the GPS was active so I took off again.

After a few minutes, got the disconnect again. On this second disconnect, I think the app. said it was landing and it was nowhere near home. In fact it was over the ravine which descended hundreds of meters below Home. But I just used the map to fly it towards Home and it flew in low and I pretty much landed it manually. It didn't climb to the preset 200 feet when returning Home.

Again, the GPS connection returned according to the app. so I took off again. This time I tried to keep it in the middle of the ravine so that I could maintain LOS, though I tried to climb to like 350 ft. in order to look over the ridge to see if I could photograph the coastline to the west. While in the middle of shooting 180 panos it disconnected again and I think it initiated RTH on its own, probably either aborted the pano shots or the stitching.

This area is notorious for cell phone signals cutting out as you make one turn after another in a car. Maybe the canyon walls induced some kind of multipath?

On one of the attempts, the screen went black. On all 3 attempts, I noticed it would not draw the map with details. It was blank other than the Home an the aircraft icons. Maybe it needed Internet to download the map details and I wasn't getting Internet to my iPhone? Have to admit I didn't check to see Internet status before flying.

The other oddity is that on two of the landings, bees were swarming around it as it landed. Once it landed and the propellers stopped, they scattered away, though I have to clean up some bees remains from my M2P.

I thought the first time it happened it wouldn't be able to find its way back Home if it lost the GPS signal. Again the GPS icons along the top of the app. were blacked out. Soon as it landed it was okay.

Now does it depend on the app. getting GPS data or does the aircraft have its own GPS and that is what's being shown on the app. display, the status of the GPS connection on the app?
 

Mossiback

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...Now does it depend on the app. getting GPS data or does the aircraft have its own GPS and that is what's being shown on the app. display, the status of the GPS connection on the app?
The M2 has a GPS receiver and does not depend on Go 4. That is how it can return to home even if the RC is shut off.
 
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Bobby for a Day!

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I tried to fly from the Path of the Gods on the Amalfi Coast in Italy. This is a hiking path which runs several hundred meters above the coastline between the towns of Amalfi and Positano.

I was in a ravine, at the back of it, with the opening about 1 km wide. Basically took off from a widening of the foot path. Not ideal but I had lugged it up so I thought I'd give it a go.

After it got about 350 ft. or more, the app. would report disconnect and no GPS connection after taking off a couple of minutes. I RTH and it returned. Then it reported the GPS was active so I took off again.

After a few minutes, got the disconnect again. On this second disconnect, I think the app. said it was landing and it was nowhere near home. In fact it was over the ravine which descended hundreds of meters below Home. But I just used the map to fly it towards Home and it flew in low and I pretty much landed it manually. It didn't climb to the preset 200 feet when returning Home.

Again, the GPS connection returned according to the app. so I took off again. This time I tried to keep it in the middle of the ravine so that I could maintain LOS, though I tried to climb to like 350 ft. in order to look over the ridge to see if I could photograph the coastline to the west. While in the middle of shooting 180 panos it disconnected again and I think it initiated RTH on its own, probably either aborted the pano shots or the stitching.

This area is notorious for cell phone signals cutting out as you make one turn after another in a car. Maybe the canyon walls induced some kind of multipath?

On one of the attempts, the screen went black. On all 3 attempts, I noticed it would not draw the map with details. It was blank other than the Home an the aircraft icons. Maybe it needed Internet to download the map details and I wasn't getting Internet to my iPhone? Have to admit I didn't check to see Internet status before flying.

The other oddity is that on two of the landings, bees were swarming around it as it landed. Once it landed and the propellers stopped, they scattered away, though I have to clean up some bees remains from my M2P.

I thought the first time it happened it wouldn't be able to find its way back Home if it lost the GPS signal. Again the GPS icons along the top of the app. were blacked out. Soon as it landed it was okay.

Now does it depend on the app. getting GPS data or does the aircraft have its own GPS and that is what's being shown on the app. display, the status of the GPS connection on the app?
Could be bad cables. I keep four new ones in my travel case
 

wco81

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You mean the cable from the controller to the app. would make the app. indicate aircraft disconnect?

As I noted, in one instance, video transmission from the aircraft to the controller was terminated.
 

Mossiback

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You mean the cable from the controller to the app. would make the app. indicate aircraft disconnect?...
Yes. You can even test this by unplugging the cable while connected. When you do Go 4 will display Aircraft Disconnected with a red background. If the RC becomes disconnected from the Mavic, the display will show Disconnected with a grey background.
 

wco81

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Yes. You can even test this by unplugging the cable while connected. When you do Go 4 will display Aircraft Disconnected with a red background. If the RC becomes disconnected from the Mavic, the display will show Disconnected with a grey background.
I did check that the cable was plugged in after the first disconnect.

But after all 3 disconnects, once they returned, they were ready to fly again.

I admit I didn't track the signal strength when the M2P was landed vs. when he few outward from Home.
 

wco81

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But nobody else has seen connection problems within canyons?

I thought I read somewhere about people losing drones in Hawaii when it flew from one canyon or ravine over to another.

So I tried to stay within the same canyon/ravine. Like I said, no more than 350-400 ft. away from home in all cases and at most 350 feet above Home.
 

Mossiback

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There are three main problems with flying in canyons:
  1. Loss of VLOS.
  2. Lost GPS due to reduced sky exposure. With GPS loss It will not maintain position without RC input.
  3. Connection lost to RC. It should activate RTH if it still has GPS.
Any of these can cause loss of aircraft and they can all occur on the same flight. If all three happen in that order you can guarantee a loss. It will drift with the breeze until it hits something or runs out of power.
 
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wco81

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Good info.

This site could use a Wiki with info. like that.
 

FoxhallGH

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There is a problem with GPS while the Mavic is flying in a canyon. It might 'see' a load of GPS satellites, but due to the canyon walls, the sat's may all be in a limited cone above the Mavic. To get the best positional info, the GPS reception should be over a wide arc of sky. If all the sat's visible are directly overhead, then you're not able to get much angular difference. The larger the positional/angular difference between the 'seen' satellites, the more accurate the 3D positional data is ... Something known as 'Horizontal Degrees of Precision' (HDoP). So contrary to the belief that the number of satellites is all that's important, where those sat's are, is actually more important!

 

Live LA

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I a
But nobody else has seen connection problems within canyons?

I thought I read somewhere about people losing drones in Hawaii when it flew from one canyon or ravine over to another.

So I tried to stay within the same canyon/ravine. Like I said, no more than 350-400 ft. away from home in all cases and at most 350 feet above Home.
I ALWAYS get some kind of connection error, low signal, signal interference no matter where I have flown. My first couple times flying I got to around 750 ft away in a canyon and it got disconnected. After cleaning my drawers Iv gone to more open spaces it is inevitable EVERY SINGLE TIME I have flown about I have gottn some kind of error message even just for a second. Sooo Im still pretty new but a lot more flights under my belt. i think the furthest Ive taken her is 1,800 ft away and my pucker factor is just out of controll because of all the previous disconects....Dont get me wrong i am in love with the m2p but scared to death to open her up because of a few scary disconnections over water and forest, unsure if it would be coming back, thats just my experience though.
 

Bobby for a Day!

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I fly from a small hill overlooking a large pasture area. No homes or possible signal interference transmissions. With my CS and short as possible cables regularly fly one mile or more! My record flow till low battery of 20% is 3.2 miles. If I have any problems I land in pasture land which I haven’t had to do. I always fly into the wind at a height of 400-500 feet. You have to trust your equipment. Have plan “B” for a landing area


Drone on..........
 
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wco81

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OK, tried flying again from Capri island, which is maybe 25-30 kilometers west of where I tried to fly as noted before.

First day, it worked okay and I only flew one battery worth as I was hoping to find other places to do more flights. But there was a lot of tree cover in the hiking paths or when there was a clearing, there were a lot of people around so I didn't want to draw attention.

Then the next day, I found another relatively isolated place and was able to fly for about 22-24 minutes before it initiated RTH as the battery drew down to about 23-24% and it was 3000 feet away.

On the next battery though, it started with the aircraft disconnects. I tried making sure the Lightning plug was secure in my iPhone but it stayed disconnected and lost video transmission.

So I initiated RTH on the controller.

After it landed, it would show it was connected again so I took off again and got maybe 250 feet away from Home before it disconnected. After it returned Home, it wouldn't reconnect.

I checked the cable again and restarted the aircraft, controller and quit the app. and restarted. Screen was completely dark, even as the controller display showed it was ready to take off.

Again I cycled through power and the app. remained dark. I unconnected the cable at both the Lightning end and the micro USB end and eventually it reconnected.

But then after it took off, it wasn't long before it disconnected again.

Maybe the cable is the problem. I've had some cheap no-name Lightning charge cables which stop making solid contact after a few hundred cycles of disconnect/connect.

I don't know if bluetooth would be more reliable. Actually it may not have the bandwidth to transmit video to the app.

Maybe that's why DJI sells that expensive standalone controller with its own screen.
 

FisherRam19

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Yes. You can even test this by unplugging the cable while connected. When you do Go 4 will display Aircraft Disconnected with a red background. If the RC becomes disconnected from the Mavic, the display will show Disconnected with a grey background.
I just received mine and have flown it twice with no problems and then this weekend I got this connection problem and lost control of it and went straight up to 317 feet and just hovered.
Of course I freaked! I could not control it with the phone app or the controller. It would not RTH. I unplugged the cable and plugged back up and it finally cleared up and it came straight back down. Now of course I am scared to fly it. Are there some limits I could set or what can I do? THX!
 

Mossiback

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I just received mine and have flown it twice with no problems and then this weekend I got this connection problem and lost control of it and went straight up to 317 feet and just hovered.
Of course I freaked! I could not control it with the phone app or the controller. It would not RTH. I unplugged the cable and plugged back up and it finally cleared up and it came straight back down. Now of course I am scared to fly it. Are there some limits I could set or what can I do? THX!
That is strange and does not make sense to me. If you cannot control with the RC then that indicates a disconnect between the RC and AC that should have triggered Failsafe RTH. Unplugging and plugging in the cable should not have fixed it. I would think that restarting the RC would be the thing to do but it still does not explain no RTH. Was 317 feet (97 meters) your RTH height setting?
 

FisherRam19

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That is strange and does not make sense to me. If you cannot control with the RC then that indicates a disconnect between the RC and AC that should have triggered Failsafe RTH. Unplugging and plugging in the cable should not have fixed it. I would think that restarting the RC would be the thing to do but it still does not explain no RTH. Was 317 feet (97 meters) your RTH height setting?
I am not sure about the RTH setting. I will have to read more on this. I am going through videos to learn more. Any suggestions on tutorials is extremely apprciated!!!
 

m0j0

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... Something known as 'Horizontal Degrees of Precision' (HDoP). So contrary to the belief that the number of satellites is all that's important, where those sat's are, is actually more important!
I think that is probably the best explanation I have ever heard for the loss of GPS in valley's. Makes complete sense
 
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wco81

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Yes. You can even test this by unplugging the cable while connected. When you do Go 4 will display Aircraft Disconnected with a red background. If the RC becomes disconnected from the Mavic, the display will show Disconnected with a grey background.
So what are people using for replacement cables?

The original DJI or third-party cables, which all seem to be 1-feet?

They seem to all have Made for iPhone/iPad certification, like this one, but about the same price or cheaper than the DJI 3-.5 inch, such as this one:


I wonder if the slack of the longer cable will make it more reliable?
 

Mossiback

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So what are people using for replacement cables?...
You can search for cable ideas. Here is one result:
...The original DJI or third-party cables, which all seem to be 1-feet?...
People have not been having good luck with the DJI cables.
...I wonder if the slack of the longer cable will make it more reliable?
Cable length does not affect quality under six feet. Shorter will be better for cosmetic reasons and right angle connectors make for a neater fit.
 

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