What kind of a disconnect is this - DJI GO4 app displays disconnected while video feed and telemetry is active

[Deleted member 94047]

This is a new one to me and I don't quite understand it. Took the MA out, did everything as I usually do. Close all open apps on the phone, turn on the remote, slap phone in, let DJI GO launch. Turn on the MA wait for the two to connect. Ignore messages offering flysafe database update and switching to CE mode. Wait for map to load and then put phone in Airplane mode. Check orientation of MA on the map matches its actual orientation on the ground. GPS acquired and ready to fly. All good. I started motors, took her up to 6meters and let her hover for a few seconds as I adjust camera settings. Finally I send her up and out.

As usual I don't really look much at the screen when I send her out at first. I had my eyes on her as she went up and out. She was 380 meters out and 75 meters up, on the edge of the river where I want her to be. I take a look down at the screen to see how I should frame the shot and I notice on the top left corner of the screen was this word in Greyed out background "Disconnected"; right where "Inflight GPS" should have been all in green. At first I think the cable must have disconnected, but wait; I have had cable disconnects before - the whole screen will be grayed out. Not this time, I still have an active video feed. I check the connection indicator led on the remote; it is green. I decide to give the right stick a nudge to see if I still had telemetry; and yes I have telemetry. So I go full down on the right stick and bring her back to me and land. Whole flight lasted 4 minutes. I turn off the MA, turn off, the remote, close the DJI GO4 app. And I start all over again. This time, it went without a hitch.

So my question is, what was this about! I still had a live camera feed, and telemetry. Why did DJI GO display the Disconnected status. I am thinking this was probably an issue with either my phone or the DJI GO app. Has anyone ever gotten this kind of disconnect?

 

[brett8883]

This is a new one to me and I don't quite understand it. Took the MA out, did everything as I usually do. Close all open apps on the phone, turn on the remote, slap phone in, let DJI GO launch. Turn on the MA wait for the two to connect. Ignore messages offering flysafe database update and switching to CE mode. Wait for map to load and then put phone in Airplane mode. Check orientation of MA on the map matches its actual orientation on the ground. GPS acquired and ready to fly. All good. I started motors, took her up to 6meters and let her hover for a few seconds as I adjust camera settings. Finally I send her up and out.

As usual I don't really look much at the screen when I send her out at first. I had my eyes on her as she went up and out. She was 380 meters out and 75 meters up, on the edge of the river where I want her to be. I take a look down at the screen to see how I should frame the shot and I notice on the top left corner of the screen was this word in Greyed out background "Disconnected"; right where "Inflight GPS" should have been all in green. At first I think the cable must have disconnected, but wait; I have had cable disconnects before - the whole screen will be grayed out. Not this time, I still have an active video feed. I check the connection indicator led on the remote; it is green. I decide to give the right stick a nudge to see if I still had telemetry; and yes I have telemetry. So I go full down on the right stick and bring her back to me and land. Whole flight lasted 4 minutes. I turn off the MA, turn off, the remote, close the DJI GO4 app. And I start all over again. This time, it went without a hitch.

So my question is, what was this about! I still had a live camera feed, and telemetry. Why did DJI GO display the Disconnected status. I am thinking this was probably an issue with either my phone or the DJI GO app. Has anyone ever gotten this kind of disconnect?

That’s what we in the business call a bug. Bugs happen. If it keeps happening delete DJI Go 4 and reinstall. I would t worry about it

 

[Deleted member 94047]

Well, I have already established my Mavic Air is was a bug magnet. But so far, it had only attracted the real bugs, not the software ones. I hope this will be the last time I see this new kind of bug.

 

[brett8883]

Well, I have already established my Mavic Air is was a bug magnet. But so far, it had only attracted the real bugs, not the software ones. I hope this will be the last time I see this new kind of bug.

I wouldn’t worry about it. You could delete and uninstall DJI GO 4 proactively if you want. Sounds like a DJI GO 4 bug not a Mavic bug. Force quitting and reopening probably would do it though.

 

[Meta4]

That’s what we in the business call a bug. Bugs happen. If it keeps happening delete DJI Go 4 and reinstall. I would t worry about it

It's not a bug and uninstalling the app is not required.

the top left corner of the screen was this word in Greyed out background "Disconnected"; right where "Inflight GPS" should have been all in green. At first I think the cable must have disconnected, but wait; I have had cable disconnects before - the whole screen will be grayed out. Not this time, I still have an active video feed. I check the connection indicator led on the remote; it is green. I decide to give the right stick a nudge to see if I still had telemetry; and yes I have telemetry. So I go full down on the right stick and bring her back to me and landdisconnect?

You'll find some people will give suggestions when they don't understand the issue as noted above.
There's nothing wrong with your Mavic at all and what you saw was uncommon but quite normal.
There are two signals - uplink (from the controller to the drone) and downlink (from the drone to controller)
Your controller lost it's downlink but since the uplink was not lost, you could still bring the drone back.
Your recorded flight data will confirm this.
Here's a screenshot (from an earlier version of the app) of an incident the same as you describe:

 

[brett8883]

It's not a bug and uninstalling the app is not required.

You'll find some people will give suggestions when they don't understand the issue as noted above.
There's nothing wrong with your Mavic at all and what you saw was uncommon but quite normal.
There are two signals - uplink (from the controller to the drone) and downlink (from the drone to controller)
Your controller lost it's downlink but since the uplink was not lost, you could still bring the drone back.
Your recorded flight data will confirm this.
Here's a screenshot (from an earlier version of the app) of an incident the same as you describe:

Well typically you wouldn’t have an active video feed if you lost downlink right?

 

[Meta4]

Well typically you wouldn’t have an active video feed if you lost downlink right?

You'd think so but there are plenty of cases reported where there's still video feed despite the lost downlink.
Perhaps the drone is right on the edge of connection/no connection or maybe there is a delay before the disconnected message clears.
The screenshot I posted was from a flight where I had full control for half a minute despite the screen message.

Either way, it's not a bug, it's just the way things work in those circumstances..
A look at the recorded flight data would be interesting.

 

[brett8883]

You'd think so but there are plenty of cases reported where there's still video feed despite the lost downlink.
Perhaps the drone is right on the edge of connection/no connection or maybe there is a delay before the disconnected message clears.
The screenshot I posted was from a flight where I had full control for half a minute despite the screen message.

Either way, it's not a bug, it's just the way things work in those circumstances..
A look at the recorded flight data would be interesting.

In that picture it shows you have full HD? If you didn’t have a downlink then that’s surely a bug.

 

[Meta4]

In that picture it shows you have full HD? If you didn’t have a downlink then that’s surely a bug.

It had full control signal (uplink).

 

[brett8883]

It had full control signal (uplink).

At least on the iOS version the signal bars next to the tiny remote indicate the the reception of the uplink and the bars next to the [HD] indicate the downlink signal strength. Is this different on... What is this? Is this the crystal sky version?

 

[brett8883]

Now dumb question here but does the Mavic Air even have a separate uplink and downlink? It uses WiFi which is like a “two-way street” kinda thing. It would be like connecting your Mavic Pro via WiFi. The uplink and down link are indistinguishable.

This occurred to me reading the manual.
Can you even have uplink without downlink?

 

[Deleted member 94047]

I don't think this was a signal issue. The status stayed disconnected until I landed. Plus I definitely had down-link; video feed and telemetry were active. I will post the flight log shortly so you guys can have a look.

 

[brett8883]

I don't think this was a signal issue. The status stayed disconnected until I landed. Plus I definitely had down-link; video feed and telemetry were active. I will post the flight log shortly so you guys can have a look.

Do you have the .dat file to upload too? This one doesn’t seem to have anything about signal quality unless I missed it.

 

[Deleted member 94047]

Hummmm, very odd. There is no DAT file for that flight. Only for the one after it (after I landed and restarted everything).

EDIT: So may be this was an issue with the app after all?

 

[brett8883]

Hummmm, very odd. There is no DAT file for that flight. Only for the one after it (after I landed and restarted everything).

EDIT: So may be this was an issue with the app after all?

Thats my theory. From what I can see in the .txt file it only gives you two warnings and never doesn’t have data loss. The first warning was that you were in class D airspace and the second was that the home point was recorded and to check it on the map. If the app was disconnected or not getting downlink it doesn’t report this and is consist with your report of what happened.

The telemetry package obviously comes from the downlink(if there’s even such a thing on the Mavic Air) it’s called OSD “on screen display”and this never disconnects or has any data loss.

Now I’m open to other explanations and maybe @Meta4 can find something I missed that turns my theory on its head and that would make me happy to just get to the bottom of it.

 

[Meta4]

Now dumb question here but does the Mavic Air even have a separate uplink and downlink?
Can you even have uplink without downlink?

The telemetry package obviously comes from the downlink(if there’s even such a thing on the Mavic Air) and this never disconnects or has any data loss.

Loss of Downlink for 0.9 sec ... See 2:37.5 in his flight data here: DJI Flight Log Viewer - PhantomHelp.com
The incident that started the thread was earlier .. perhaps about 1:48.8 (when 0.3 seconds are missing) but does not have recorded any message in the data.

 

[brett8883]

Loss of Downlink for 0.9 sec ... See 2:37.5 in his flight data here: DJI Flight Log Viewer - PhantomHelp.com
The incident that started the thread was earlier .. perhaps about 1:48.8 (when 0.3 seconds are missing) but does not have recorded any message in the data.

Ok so it skips a beat and then fails to remove the warning from the app? Are you sure it loses connection there and doesn’t just stop record something in that time span? Wouldn’t we see a time stamp with no information if that happened.

 

[Deleted member 94047]

At 2m 38.4s - "Downlink Restored (after 0m 0.9s)" Yes, I see that. I was bringing it back at that time. There might have been a down-link interruption there but that still doesn't really explain why the app displayed "Disconnected" and stayed that way till the end of the flight.

 

[brett8883]

At 2m 38.4s - "Downlink Restored (after 0m 0.9s)" Yes, I see that. I was bringing it back at that time. There might have been a down-link interruption there but that still doesn't really explain why the app displayed "Disconnected" and stayed that way till the end of the flight.

That doesn't appear in the actual data log. That must be added by phantom help because in the verbose data log it shows repeating time stamps so Phantom Help probably removes those entries as duplicate data
However they do contain unique data

I don't know why the time stamps repeat but we are looking at such a tiny amount of time here. The drone shows no warnings for this time period and it happens several times actually but I assume Phantom Pilots removes it as junk data but Idk.

We might have to have the final authority on these matters take a look if hes willing. @sar104 do you mind taking checking this? I dont want to give the wrong information and Im just not sure here,

 

[Deleted member 94047]

If it helps, this is the only recorded DAT file for that date. I made two flights that day. The first one with the disconnected status lasted for about 4 minutes. The second, about 8 minutes. I initially thought this was for the second flight; but is there a chance the two might have been combined? I would appreciate it if you guys can take a look.

Edit: I don't think I turned off the Aircraft as I initially thought. So the first four minutes or so of that flight record may be from the first flight.