What happened here?

[Paradigm]

Hi, I'm hoping I can get some help with what happened.

I'm flying my drone in an area I've flown before, no boundary being pushed, when all of the sudden I have a signal drop. No warning, at least I don't remember one -warning being a msg or degradation in transmission quality.

It all goes black for approximately a minute and 4 seconds. The video comes back and it's in RTH mode at it's pre-determined height.

I've looked at the logs, but admittedly I don't know what I'm looking at. I'll provide data from them, but I don't want to upload them due to privacy concerns.

Please bear with me because of that, and thank you in advance. I've provided some screenshots of what I find interesting, but I'm not exactly sure what the data means. My guess is maybe the drone got hit by something and then it recovered and went to RTH mode? But that doesn't exactly explain why I lost signal. Maybe it's a software error?

 

[slup]

The info you have provided doesn't give any info regarding the downlink strength ... provide your TXT log or use below shown CsvView signal to study it yourself.

Also note that if the connection isn't reestablished the log will end ... but that wasn't the case in your flight as I understand it.

 

[Paradigm]

Hmmm, I don't have downlinkSigStrength as an option in my log. I got the log off of my iPad. Looked at the dat and verbose csv from phantomhelp.

I'm also using csvView 3.7 on a Mac because the latest version doesn't work.

 

[slup]

Hmmm, I don't have downlinkSigStrength as an option in my log. I got the log off of my iPad. Looked at the dat and verbose csv from phantomhelp.

I'm also using csvView 3.7 on a Mac because the latest version doesn't work.

You don't have to go over Phantomhelp to be able to use the logs in CsvView ... Go here --> Flight log retrieval and analysis guide

... and read up in point 2 about which logs are available & what they show. Then continue to point 3 and learn how to retrieve them. (Don't bother about the DAT log in the drone itself, it's decrypted for the Mini & can't be read by anyone else then DJI)

CsvView reads both the mobile device TXT log & the mobile device DAT log ... the available signals in CsvView will differ depending on which log you use though. That signal I showed you comes from the TXT log.

 

[Paradigm]

You don't have to go over Phantomhelp to be able to use the logs in CsvView ... Go here --> Flight log retrieval and analysis guide

... and read up in point 2 about which logs are available & what they show. Then continue to point 3 and learn how to retrieve them. (Don't bother about the DAT log in the drone itself, it's decrypted for the Mini & can't be read by anyone else then DJI)

CsvView reads both the mobile device TXT log & the mobile device DAT log ... the available signals in CsvView will differ depending on which log you use though. That signal I showed you comes from the TXT log.

Thanks for the reply.

That's where I'm at, I have the txt file and the dat file from my iPad. However I'm having some software issuesI(versions 3.7.3 not working) and I my overall software availability seems limited due to OS X. I'm going to try to get access to a Windows computer and see what I can do there.

I'll report back.

 

[Paradigm]

@slup You were right, I did lose downlink signal. Now I'd just like to find out why. I've flown there before with no issues and I was only around 2xxx ft away.

 

[new2mavic]

May be some interference sources in the vicinity of the RC suddenly turned on ? If the drone is a Mini, the FLY app will ask you if you want to initiate RTH

This was what's seen on the FLY app when the downlink signal from my Mini was lost :

You can try flying the drone at some other places and see if the same happened

 

[Paradigm]

May be some interference sources in the vicinity of the RC suddenly turned on ? If the drone is a Mini, the FLY app will ask you if you want to initiate RTH

This was what's seen on the FLY app when the downlink signal from my Mini was lost :

You can try flying the drone at some other places and see if the same happened

Interesting.. your telemetry was still moving while it said it lost connection. Mine was just gone. Zero connection, as if someone just snatched the drone out of the sky and turned it off. Or if it entered some sort of location that blocked all of its communication. It was a M2P, btw.

I finally flew it again and I went right to the spot where it lost connection. Absolutely no issue, just like it was the handful or so times before. Super weird.

 

[Sowsalbitters]

Hi, I'm hoping I can get some help with what happened.

I'm flying my drone in an area I've flown before, no boundary being pushed, when all of the sudden I have a signal drop. No warning, at least I don't remember one -warning being a msg or degradation in transmission quality.

It all goes black for approximately a minute and 4 seconds. The video comes back and it's in RTH mode at it's pre-determined height.

I've looked at the logs, but admittedly I don't know what I'm looking at. I'll provide data from them, but I don't want to upload them due to privacy concerns.

Please bear with me because of that, and thank you in advance. I've provided some screenshots of what I find interesting, but I'm not exactly sure what the data means. My guess is maybe the drone got hit by something and then it recovered and went to RTH mode? But that doesn't exactly explain why I lost signal. Maybe it's a software error?

I’m pretty sure it’s supposed to go into RTH when you have a loss of signal. I don’t know the flight data aspect either. Im pumped to try to figure it out. I’ll check back to see if anyone had any good advise or info. Good luck

 

[Paradigm]

I’m pretty sure it’s supposed to go into RTH when you have a loss of signal. I don’t know the flight data aspect either. Im pumped to try to figure it out. I’ll check back to see if anyone had any good advise or info. Good luck

Yeah, I have mine set to RTH. You can choose that or hover or land, iirc. I have mine to a ridiculous RTH height because I haven't changed it since flying around skyscrapers.

Thanks for the help. Stuff like this makes me realize how complex these things are and just how many spinning plates are needed for everything to go right...

 

[new2mavic]

Interesting.. your telemetry was still moving while it said it lost connection. Mine was just gone. Zero connection, as if someone just snatched the drone out of the sky and turned it off.

The signal degradation in my video was just due to distance so the change was gradual. As the video feed requires higher radio channel quality, it went out first but the channel was still good enough for telemetry data to be received. If a strong interference source suddenly turned on close to me, the downlink would be killed completely and nothing could be seen but just a black screen. It looks like that has happened in your case. Unless you can identify the source of interference and find a way to avoid it, it will not be safe to fly there.

 

[Paradigm]

The signal degradation in my video was just due to distance so the change was gradual. As the video feed requires higher radio channel quality, it went out first but the channel was still good enough for telemetry data to be received. If a strong interference source suddenly turned on close to me, the downlink would be killed completely and nothing could be seen but just a black screen. It looks like that has happened in your case. Unless you can identify the source of interference and find a way to avoid it, it will not be safe to fly there.

Other than some sort of error, I think interference is likely what caused it.

Assuming it was interference, the first question is where was the interference? Was it at the remote or was it at the aircraft?

My guess is aircraft. As the remote location is somewhere I've flown from countless times.

Also, after the 1:40 second loss of signal, I was able to fly for quite a bit longer away from the spot where it went out.

To recap, I'm flying right towards this barn/house at around 250 ft (approx.) and it completely loses signal instantaneously. The aircraft then after a certain time initiates RTH and goes to it's RTH height of 900 ft. and begins coming back. The remote then gains signal again.

I have to look further into where it was when it gained signal. Was it in the same spot or did it start going home?

 

[Paradigm]

I'd like to add an update. First off, thanks to BudWalker for getting the latest version of CSvView to work on OS X.

I've flown back to that spot and I encountered 0 problems.

However, I did encounter the same problem of dropped video/controller signal numerous times at numerous locations, all in the same day.

First time it happened I was flying in a park. The drone wasn't too far away and all of the sudden the signal degrades and then it goes out. The drone correctly goes to RTH mode and gets back safely. That happened at least couple more times on that same batter, in a different location.

The next time it happened it did not gain signal, either video or controller, even while the drone was RIGHT ABOVE ME. That's odd to me, because it lost connection further away, it then goes into RTH, and then I see it doing it's route and the drone is in a position where it was previously in range, but it's not connecting. It then finally connects when it gets low enough, I want to say in the range of 100-200 ft above the home point.

I looked at the logs and it's the same, lost connection and then it regains it on the way home.

After it did that on multiple batteries in multiple locations, I got the idea to use the little folding parabolic signal boosters I had. Now mind you, I bought these and tried them out and didn't get much use out of them. I didn't test them out scientifically or anything, but I was getting the same range with them. HOWEVER, in this scenario where the drone was within normal range but it was dropping connection, they actually worked! I was able to fly back to the same location where I just lost signal strength, on the same battery where I couldn't gain signal even while the drone was right above me, and the parabolic signal boosters allowed me to fly through the lost signal spots! Not only that, but the next time I went to the other spots where I lost signal, they worked and I didn't lose signal again!

My guess is that they boost the signal enough, I'm not sure in which direction (to the drone or from the drone, maybe both?), for me to maintain signal in those areas. It all doesn't make complete sense to me, because like I said, the drone wasn't super far away and there weren't large obstacles between us, heck I could even see it right above in a spot where I had perfect connection, and it wasn't connecting.

My guess right now is that maybe I was flying during a period of high Kp Index and that was affecting my signal, which would explain why it would drop one day and not the next and under what circumstances it was dropping. If you're not familiar with the Kp Index, it's a variable in the UAV Forecast app that helps you know if it's a good time to fly or not. It's supposed to measure "geomagnetic disruption caused by solar activity."

Thanks for getting through that if you did, lol. If one of the well known log analyzers here wants to take a look, I'm willing to share, just PM me. The other flights I just talked about were in a common area that aren't invading privacy. I looked at them and I didn't see much, which is why I didn't just post them. But I'm no expert...

 

[The Editor]

The aircraft then after a certain time initiates RTH and goes to it's RTH height of 900 ft. and begins coming back.

Assume that’s a typo and you don’t actually have your RTH height set to twice the legal limit.

 

[Paradigm]

Assume that’s a typo and you don’t actually have your RTH height set to twice the legal limit.

My understanding is you're allowed to be 400ft above a structure's high point if you're within 400 ft of it. I like to do photography of tall buildings, and in case the drone loses signal and I can't control it's path, I want it to go straight up well above anything it might hit on it's return home. I vary it, but I usually like to keep it high incase I forget to turn it up. RTH has been activated automatically on under 1% of the flights I've done.

 

[sar104]

My understanding is you're allowed to be 400ft above a structure's high point if you're within 400 ft of it. I like to do photography of tall buildings, and in case the drone loses signal and I can't control it's path, I want it to go straight up well above anything it might hit on it's return home. I vary it, but I usually like to keep it high incase I forget to turn it up. RTH has been activated automatically on under 1% of the flights I've done.

That's true for Part 107 flights, but not for recreational.

 

[Mossiback]

...To recap, I'm flying right towards this barn/house at around 250 ft (approx.) and it completely loses signal instantaneously. The aircraft then after a certain time initiates RTH and goes to it's RTH height of 900 ft...

You should set your RTH height applicable for the current flight. Rising to 900 ft burns more battery and potentially puts it in high enough wind speeds to blow it away.

 

[Paradigm]

You should set your RTH height applicable for the current flight. Rising to 900 ft burns more battery and potentially puts it in high enough wind speeds to blow it away.

Point taken. I will do the research and figure out what the best height is, instead of taking the easy way out.