Transmission Issue (RC and HD)

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I have a brand new P4 Pro which I upgraded to the most recent firmware, aircraft as well as RC. I'm running DJI GO 4 on an iPad mini. Everything works fine except for spurious transmission errors, independent of the distance (pilot - aircraft). This happens while the aircraft is on the ground as well as in while airborne.

Even in only a few meters distance, suddenly, error messages appear:
  • "Weak Image Transmission Signal and/or
  • "Aircraft Disconnected"
The small field strength indicators (RC and HD) only show 1 (of 5) ticks and turn red sometimes. Very often there are reconnects and disconnects over and over again until the aircraft is rebooted.

Here a brief video with the P4P Pro on the ground (indoor) and the RC just 1-2 meters away:

I have no idea whether this issue is RC- or aircraft- or even firmware-related.
Any help welcome.
 

alokbhargava

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Is your iPad mini in the DJI approved list?

Problem seems to be with DJI Go app installation. Try other iPhone 6 or 7 and check what happens


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I did so.
With my iPhone 6 exactly the same, with DJI GO 4 as well as with the "old" GO app.

I believe it is definitely a transmission issue, not something app-related.
 
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Thanks a lot for the hint, unfortunately re-binding didn't help either.

I have now downgraded the aircraft from 01.01.0203 to 01.01.0201 but trying to downgrade the RC as well doesn't work.
Instead of a choice of firmware versions I get this screen (attached).

The Product (GL300F) is not recognized but the current firmware is: 01.03.00.00.
However, since there is no firmware version to choose from, I cannot downgrade.
 

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alokbhargava

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Please get units replaced.


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Yes, probably I have to but unforntunately my hobby store is sold out ...
 
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You can downgrade firmware through DJI Assistant 2 with USB cable on your PC. Re install Go app 4 and remove all background apps by pressing home button twice on iPad.
Your unlucky if this is found to be a bug in firmware.
 
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I need to downgrade the RC (transmitter), not the copter (already done).
Can I downgrade the RC via Assistent 2 too?
 
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It is possible you have a faulty unit and would need to be replaced.
If you would like to try this it may work.
Upgrade again to the latest AC firmware with Assistant 2 on PC.
The remote and iPad off.
Re install Go app 4.
Test by turning on RC, app then AC.
You should not see any prompt for updates
The firmware update requires IMU calibration.
Wait 20 minutes to do IMU.
If you still have the problem return it.
 
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I did so.
With my iPhone 6 exactly the same, with DJI GO 4 as well as with the "old" GO app.

I believe it is definitely a transmission issue, not something app-related.
You can't even use the old app for the p4pro so how did you test it???
 
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You can't even use the old app for the p4pro so how did you test it???
For all my tests I used GO 4, as you may recognize on the screenshots and video. However, after all the pain my hobby store suggested to try DJI GO (the "old" app). To my surprise it did work, of course I only tried on the ground, props off. It did connect and even the video streaming worked, as far as I remember. And, the transmission errors appeared too, with slightly different error text, IIRC.
 
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It is possible you have a faulty unit and would need to be replaced.
If you would like to try this it may work.
Upgrade again to the latest AC firmware with Assistant 2 on PC.
The remote and iPad off.
Re install Go app 4.
Test by turning on RC, app then AC.
You should not see any prompt for updates
The firmware update requires IMU calibration.
Wait 20 minutes to do IMU.
If you still have the problem return it.
I have
- upgraded the AC firmware to the most recent version 01.01.0203 via Assistant 2 (RC and iPad off)
- deleted GO 4 from my iPad mini
- reinstalled GO 4 from App Store
- turned on RC, launched GO 4 and then turned on AC

The result:
- no IMU calibration enforced (maybe the upgrade was just minor?)
- transmission issues for about 10 seconds, then ok
- after about 2-3 minutes, transmission interrupts again, "Weak Image Transmission Signal" / "Aircraft Disconnected"

My conclusion: It's definitely a hardware problem, either in the RC or in the AC.
 
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During the dropouts described, the RC LED changes from green to red every 1-2 second.
 
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I will bring the P4P to my hobby store today, although they don't have a replacement. Like that it's just useless.
Thanks for your support.
 
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How saturated are the wifi frequencies where you are testing? You can check by dloading a wifi analyzer from the App Store to check.


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I looked at them, they don't look very saturated, especially not outdoor. However, the blue (current) bar jumps around, maybe that's what frequency hopping is all about?

During the stable transmission phases, however, the (blue) channel seems to be fixed.

Speaking for 5.8 GHz, there is no noise on any channel, on 2.4 GHz there are other signals too.
 
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I looks as if the transmission dropouts are related to the channel selecion. As long as the selected channel remains the same, transmission (at least the video stream) looks fine. As soon as it starts to switch the channel, problems arise.

The strange thing is that, on 5.8 GHz, although there is no visible noise at all, the channel selected still switches between 1, 2 and 3.

It might well be a HF-problem, maybe not enough output power or so, which let the transmitters start to switch channels although there is not much noise at all.
 

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