Ocean Crash - Resolved

[Cyberpower678]

Something also stands out to me, not necessarily a reason why the drone was lost, but why were you using DJI Go 4 v4.1.3?

 

[sar104]

^That, and - the logs had several disconnects/reconnects always followed by the same message that the OP's SD card is not fast enough for 4K video. The Mavic's video system shares the camera data with the video transmission stream. If there's a problem with the SD card, this could also affect the transmission of video back to the controller.

Is this confirmed, or are you hypothesing? I haven't looked for any correlations between those issues in logs.

 

[Cyberpower678]

Is this confirmed, or are you hypothesing? I haven't looked for any correlations between those issues in logs.

Have a read of my post on the first page.

Ocean Crash - Resolved

 

[sar104]

Have a read of my post on the first page.

Ocean Crash - Resolved

Yes - I read that. But we know that SD cards can cause problems if they are not properly formatted - my question relates to whether it is known that a well-formatted but slow SD card can cause transmission errors in the control and telemetry.

 

[Cyberpower678]

Yes - I read that. But we know that SD cards can cause problems if they are not properly formatted - my question relates to whether it is known that a well-formatted but slow SD card can cause transmission errors in the control and telemetry.

My hypothesis is yes. Simply because when inserted the drone appears to use it to save additional memory. In essence it becomes a secondary RAM system. We obviously know the SD card is used to save transmission related data to it, most likely to stabilize the connection more. If it can't read and write to it fast enough, it's plausible that the slow speed means the connection stability ends up degrading.

 

[Qoncussion]

Is this confirmed, or are you hypothesing? I haven't looked for any correlations between those issues in logs.

When I learned that raising the video transmission to HD, caused the Mavic to automatically drop out of 4K, down to 2.7K, I reasoned that the video transmission and recording systems were linked together. While I believe it to be a safe assumption ~it is indeed just that...

 

[sar104]

My hypothesis is yes. Simply because when inserted the drone appears to use it to save additional memory. In essence it becomes a secondary RAM system. We obviously know the SD card is used to save transmission related data to it, most likely to stabilize the connection more. If it can't read and write to it fast enough, it's plausible that the slow speed means the connection stability ends up degrading.

When I learned that raising the video transmission to HD, caused the Mavic to automatically drop out of 4K, down to 2.7K, I reasoned that the video transmission and recording systems were linked together. While I believe it to be a safe assumption ~it is indeed just that...

I'm not sure how to safely test the hypothesis, but I'll pay more attention to log entries on that subject in future to look for correlations.

 

[Cyberpower678]

I'm not sure how to safely test the hypothesis, but I'll pay more attention to log entries on that subject in future to look for correlations.

Well here's something to try. Throw an incompatible video file into the DCIM folder of the SD card and pop it into the Mavic. Unless they fixed the big, that should already be enough to throw it off.

 

[Qoncussion]

Is this confirmed, or are you hypothesing? I haven't looked for any correlations between those issues in logs.

Also, from the OP's logs, every time this message appears, "Downlink Restored (after 0m 1.1s)", it is immediately followed by this message, "SD Card Storage Speed Slow. Not Suitable for 4K Video." There *appears* to be a definite link there, although unconfirmed.

 

[sar104]

Also, from the OP's logs, every time this message appears, "Downlink Restored (after 0m 1.1s)", it is immediately followed by this message, "SD Card Storage Speed Slow. Not Suitable for 4K Video." There *appears* to be a definite link there, although unconfirmed.

I saw that too, but we don't know whether the SD card error is triggered by the downlink reconnect (which might lead to a sudden increase in the downlink data rate) or whether the disconnect was somehow caused by the card error. I agree that we have correlation, at least on this flight but, even if there is causation, I can't tell in which direction.

 

[juzzyx]

It still does not address the disconnect problem that many people are having! This includes me too.

Yeah if it had of stayed connected I would of been able to see where it was and at least try to come down. Ah well. I can't believe refresh isn't honoured even when you have video evidence of its final splash, I just pray for it to wash up oneday lol

 

[juzzyx]

Something also stands out to me, not necessarily a reason why the drone was lost, but why were you using DJI Go 4 v4.1.3?

yeah this happened end of August so that would be the reason, the back and forwards with DJI is tremendously slow and i gave it a month before I posted.

 

[juzzyx]

I can probably explain that. Reading the signal data, it rapidly deteriorated the moment he passed that lighthouse. That lighthouse was likely a strong source of interference.

I will just add that the same disconnection problem occurred on the flight previous to this, disconnected from phone/controller most of flight but obviously it made it home with RTH on that account and I just put it down to interference

 

[Cyberpower678]

I will just add that the same disconnection problem occurred on the flight previous to this, disconnected from phone/controller most of flight but obviously it made it home with RTH on that account and I just put it down to interference

Then I’m pegging you used a different SD card than what came with the drone?

 

[sar104]

I will just add that the same disconnection problem occurred on the flight previous to this, disconnected from phone/controller most of flight but obviously it made it home with RTH on that account and I just put it down to interference

I'm puzzled that you would fly again, and in these conditions, with those problems from the previous flight unresolved.

 

[juzzyx]

Then I’m pegging you used a different SD card than what came with the drone?

On that particular flight i used a proper high speed card with no SD warnings. This flight I picked up the slow SD card on the way out resulting in the errors.

 

[shb]

I don't think dji cares about all the disconnects. it's a known problem that they are unable to solve. when I lost my mavic it was very windy and I couldn't get any missions to execute. I think the reason was, the mavic CPU's were overloaded, partly from the high wind, so they couldn't handle their workload.
so that resulted in a disconnect and/or loss of video. I think they have to add a lot more CPU power to future mavics. steve

 

[Youser]

Something also stands out to me, not necessarily a reason why the drone was lost, but why were you using DJI Go 4 v4.1.3?

Why is this a concern?

Reading through the 'Wundertablet' thread, seems like people are using this version and 4.1.9 and are happy.

I'm due to receive my dedicated android device this week and am planning to use .15

 

[ronk]

I'm afraid that DJI is correct in this case. The winds aloft were over 20 mph out of the north, as can be seen if you look at the relationship between pitch/roll and aircraft velocity:

Hi, what software are you using to analyze this? Thanks!

 

[PhilBT]

On 1st January sar104 made a posting which included a detailed chart of velocity against time etc. I've been trying to locate where I would find such a chart. I have discovered "flight record" on the DJI Go 4 app, so it was useful research, but I can't find a chart. How do I find this?
Many thanks.