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Image transmission disconnect- Ocusync 2 specific issue?
643 37 2018-9-14
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Mike-the-cat
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I'm an experienced flyer with multi-DJI aircraft experience. Am documenting a potentially serious issue with inflight data transmission. I flew from a high point with line of sight to aircraft for the entire flight.

I was testing long distance capability of the aircraft. Video transmision to 4.5 km was good. Unprecedented for a DJI aircraft. Superb. At this point I was flickering between 1 bar to 2 bars of image transmission and one bar for flight control. I was using Custom, 5.8 GHz, 10Mhz bandwidth at a signal frequency region with no interference. Autosync HD photo was on.

When switching to photo from video, I first lost ability to control the camera aperture. I could still shoot a photo. This was followed by sudden switch off of the obstacle avoldance sytem  that lasted about 20s. I am aware that in previous versions of OA, the sensors can malfunction if direct sun enters them. Well the M2 has so many cameras, that's hard to avoid but perhaps, the system got confused as I was turning and this occured at close to max range of the flight. Flight control was retained although slightly degraded. DJI engineers auto slow the aircraft under such conditions prior to triggering a RTH.

I headed home.  At around 3km image transmission went completely blank. Suddenly. This has never happened to me on a DJI aircraft except for hardware malfunction on an Inspire 1 X5 camera which was subsequently repaired. I allowed the craft to hover. Flight control was still fine but I was flying blind and using the map and orientation controls to come home.

At about 2 km with 3 bar signals, a RTH was triggered. I accepted and monitored the return flight for a few seconds before switching back to manual flight  Camera still blind. I toggled the transmitter to Auto/ Dual and 20 Mhz bandwidth was automatically selected. I'm not in a high interference area.All camera controls were still not being responded to but all flight controls were fine.
I landed safely.

Upon reboot, the camera came back on. This is a brand new craft with no knocks whatsoever.

This is first time a camera has ever gone blank on me. A few flights ago, toward the end of signal range, I lost camera control to correct aperture or to switch from video to photo. However this was restored when I got closer and I chalked this to a prioritization of flight control over camera control in the case of signal drop out but this happened even when signal strength was restored.

Can DJI engineering get back to me about this? I will correspond by email if necessary. I think that there is a bug in the way Ocusync 2 is working.

2018-9-14
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Kingram
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The first thing they are probably going to ask you is which mobile device are you using ?
2018-9-14
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Alex B.
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Might be isolate issue,could be compatibility with your device.

Fly safe
Alex
2018-9-14
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Glenn Goodlett
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At one place I fly, I regularly see stuff like that. At another place I fly, two valleys and 75 miles away, I never have anything like that happen. I have always thought it was due to some kind of interference. How can you say that your not in a high interference area. Microwave links are all over the place and are highly directional. Do you have an RF Explorer or spectrum analyzer to really check around?

Furthermore, this behavior has occurred with my P4, P4P, Mavic Pro, and M2P. The M2P does seem to especially go berserk when it encounters signal loss or interference.

My best distance from home with M2P is 13K feet at the one location because I run out of signal. At the other location I can hit 23K with plenty of signal, but, turn around due to battery power. Both sites are flat and I'm getting the better range at a more urban location. I'm not sure what else could be going on except interference.

It seems like the M2P has a harder time reacquiring a connection once it is lost. Hopefully new firmware will change some of this.
2018-9-14
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HereForTheBeer
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i been hearing lot of "similar" issues relating to H.265 encoder where screen blanks out or disconnects or device gets laggy and makes you think transmission signals is problematic.  

3 question i have based on what i seen with Mav 2 and my own experience with dji stuff..

1. what device are you using as well as what is the OS version..

2. what encoder are you using.. H.264 or H.265 ?  what resolution and all that as well

3. could the usb cable be causing or promoting app to think signal or data related issues? bad cables can cause blanking and disconnections and live view lag as well


speaking of number 3..i swapped out my mavic air's included lighting connector for a charge cable.. and much of my laggy experiance flying around things vanished..still happens with solid stuctures but flying around trees and stuff, doesnt lag as much anymore with simple cable swap.  also with included cable i was getting a avg range of about 3/4 of a mile.  cable swap for charge cable and im much more easily able to avgerage around 2miles..  ( i dont know the physics or reasoning behind it either, but its something that i have observed and pretty simple thing)

2018-9-14
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Mike-the-cat
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HereForTheBeer Posted at 2018-9-14 17:09
i been hearing lot of "similar" issues relating to H.265 encoder where screen blanks out or disconnects or device gets laggy and makes you think transmission signals is problematic.  

3 question i have based on what i seen with Mav 2 and my own experience with dji stuff..

Thanks for the responses. This is not a device issue iP 8S, iOS 11.4.1. cable is the one supplied and is fine. Sorry I wasn't clear. It was a blank video feed not blank screen. .

I roughly know where the microwave towers are (very few where I am)  and I'm not in their sights or height. In any case, we are at different frequencies.

Not a resolution issue but I was using h.265. HLG. even at 4k the system was doing about a 4Mhz transmission so that's fine. Not HD video but good for orienting. Important thing is that video transmission did not recover even after signal strength was normative.

I think the fault is how Ocusync 2 priorities signal handling when signal is weak. Good that control signal and GPS map are always within sight. but bad for failure to reset video transmission upon signal recovery.

2018-9-14
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HereForTheBeer
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Mike-the-cat Posted at 2018-9-14 17:34
Thanks for the responses. This is not a device issue iP 8S, iOS 11.4.1. cable is the one supplied and is fine. Sorry I wasn't clear. It was a blank video feed not blank screen. .

I roughly know where the microwave towers are (very few where I am)  and I'm not in their sights or height. In any case, we are at different frequencies.

iPhone's with ios 11 and up support H.265 playback even if older.  so you are good there..  

cable could still be the issue, because i mean live free blanking out as well, not the whole screen..  a trash town cable in my experience can cause live view lag, glitches, and blanking out live view portion and if cable is really trash,  can even saying aircraft is disconnected even if the RC is still connected.. i have a couple times and was kind of interesting experience, i have to fly over 3 miles back using mavic pro RC screen so basically and completely blind..

microwave towers dont need to be right next to or even on same frequencies.. really depends how its "beam forming"  as microwave towers use beamforming to communicate as well as how much power they are dumping and you can cross into that beam even miles away and have signal issues..   i flown near TV transmission antennas (10+ KW) before which operate on lower band of UHF, way below 1.5Ghz and 1.2Ghz ism bands that GPS works on.. and still lost GPS coverage until i backed away..
2018-9-14
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Mike-the-cat
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HereForTheBeer Posted at 2018-9-14 18:05
iPhone's with ios 11 and up support H.265 playback even if older.  so you are good there..  

cable could still be the issue, because i mean live free blanking out as well, not the whole screen..  a trash town cable in my experience can cause live view lag, glitches, and blanking out live view portion and if cable is really trash,  can even saying aircraft is disconnected even if the RC is still connected.. i have a couple times and was kind of interesting experience, i have to fly over 3 miles back using mavic pro RC screen so basically and completely blind..

GPS was 16-18 satellites all the way through, I never lost control of the craft apart from the 10s of RTH trigger which I concede was (not could be) interference because I used a custom lock on 5.8 GHz at a particular set of frequencies.

My Go App showed telemetry and map info throughout the camera transmission blackout and the blackout continued even with the craft directly in front of me. It was as if some glitch turned off the camera transmission ; pitch control was maintained mind you.
2018-9-15
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HereForTheBeer
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Mike-the-cat Posted at 2018-9-15 07:52
GPS was 16-18 satellites all the way through, I never lost control of the craft apart from the 10s of RTH trigger which I concede was (not could be) interference because I used a custom lock on 5.8 GHz at a particular set of frequencies.

My Go App showed telemetry and map info throughout the camera transmission blackout and the blackout continued even with the craft directly in front of me. It was as if some glitch turned off the camera transmission ; pitch control was maintained mind you.

no i was giving an example of how frequencies dont need to match to still knock something offline..  not saying your GPS got effected, mine did even though i was way off the frequency range..  300-400mhz off towers vs 1.2Ghz and 1.5 ghz from GPS/Glonass still effected it..  that's the power of power.. 10KW+ RF vs a tiny drone.. so just be aware of that is all im saying..

as for it being right there in front of you and still having issues showing video...  the only 2x i ever experianced that was..

1. when i was using my samsung Galaxy S8 and that was one of the many bugs i encountered besides crashing and freezing..  was also grey/black live view at random..  but since using an iPhone seem unlikely to be related..  but could be app related, bug in the dji go app...

2. bad cables... infact even my new mavic air, the lag improved using a charge cable and full size usb port on bottom vs the included side cable.. not sure why or what is going on... but yea..
2018-9-15
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Yummyburger
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lost my mavic 2 pro yesterday night. had visual on the lights on return back. at maybe slightly more than 1km. it disappeared together with connection. there is a split second of it the system initiating return and i pressed ok and what was weird is remote n my ios go 4 app shows near to full bar reception but zero for visual, however i could not control anything. feels like both got hang. i was sitting on my motorcycle, so i rode around n towards the last known spot and returning to home , it never got connected back again, nor did it returned. could not even find the damn drone again.

Usually i fly with my crystalsky, yesterday decided to use my iphone x, not sure if its the phone , the drone or just me.
2018-12-4
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Mike-the-cat
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Yummyburger Posted at 12-4 00:35
lost my mavic 2 pro yesterday night. had visual on the lights on return back. at maybe slightly more than 1km. it disappeared together with connection. there is a split second of it the system initiating return and i pressed ok and what was weird is remote n my ios go 4 app shows near to full bar reception but zero for visual, however i could not control anything. feels like both got hang. i was sitting on my motorcycle, so i rode around n towards the last known spot and returning to home , it never got connected back again, nor did it returned. could not even find the damn drone again.

Usually i fly with my crystalsky, yesterday decided to use my iphone x, not sure if its the phone , the drone or just me.

Sorry to hear about your loss.

If you had a clear GPS lock, and obstacle avoidance turned on, the drone would have returned if there was enough battery power. DJI equipment is very reliable on this count. Doesn't matter what device you use unless you inadvertently cancelled RTH.

If you are in Singapore, unless you were on elevated ground with clear line of sight, or at the coast, it is pretty unsafe to fly 1+km away from the home point.
2018-12-4
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davidmartingraf
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You need to have at least 4GB of RAM on your device for GO 4...
2018-12-4
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Mike-the-cat
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HereForTheBeer Posted at 9-15 10:26
no i was giving an example of how frequencies dont need to match to still knock something offline..  not saying your GPS got effected, mine did even though i was way off the frequency range..  300-400mhz off towers vs 1.2Ghz and 1.5 ghz from GPS/Glonass still effected it..  that's the power of power.. 10KW+ RF vs a tiny drone.. so just be aware of that is all im saying..

as for it being right there in front of you and still having issues showing video...  the only 2x i ever experianced that was..

Just a long term follow up statement. The bug happened twice and since then I've flown >50 flights without issues. No change in cables or phone.

Nobody else has reported such an issue so I'll put it down to a loss of comms at the end of the operating range of the system causing jumbled instructions.   
2018-12-4
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kykmavic
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I had similar experience with my M2P. Video went completely blank and never came back until landed and rebooted. Note that, I was not recording or taking photos, but just testing the range.
2018-12-4
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Mike-the-cat
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kykmavic Posted at 12-4 01:20
I had similar experience with my M2P. Video went completely blank and never came back until landed and rebooted. Note that, I was not recording or taking photos, but just testing the range.

DJI has likely assessed that this problem is too small to put engineering resources to solve.
2018-12-5
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El Diablo
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2018-12-5
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El Diablo
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2018-12-5
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Mike-the-cat
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El Diablo Posted at 12-5 00:21
Reading all this makes me think that all of us flying within VLOS are very lucky

A little cynical....

I'm not complaining. DJI is a business. They care for users insofar as it benefits / profits them. Overall, their equipment works.

Under conditions where VLOS is possible, I would push distance. Otherwise, no point tempting fate. Bad things happen if you fly enough.
2018-12-5
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El Diablo
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2018-12-5
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Mike-the-cat
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El Diablo Posted at 12-5 02:04
Not cynical, honest.

You are complaining about the drone losing connection at distances that although are allowed by the hardware are prohibited by law.

Cool, we are on the same page. I get your point about VLOS.
2018-12-7
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Alex B.
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El Diablo Posted at 12-5 00:20
Man what are you talking about???

iPhone 7 =  2 GB of RAM

It’s 4gb for android devices.
It’s very different on iOS

Flysafely
Alex
2018-12-7
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davidmartingraf
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El Diablo Posted at 12-5 00:20
Man what are you talking about???

iPhone 7 =  2 GB of RAM

Thank you for your post. You are incorrect quoting the amount of iPhone RAM. If you go back and do little more research you'll find the true amount of RAM for iPhones are not the same amounts you referenced.  
2018-12-7
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Dirty Bird
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I have experienced the video blackout with the Mavic 2.  If it happens again power cycle the RC.  The video returned once the RC reconnected.
2018-12-7
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Keule
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davidmartingraf Posted at 12-7 17:28
Thank you for your post. You are incorrect quoting the amount of iPhone RAM. If you go back and do little more research you'll find the true amount of RAM for iPhones are not the same amounts you referenced.

iPhone 7 = 2 GB LPDDR4 DRAM
iPhone 7plus = 3 GB LPDDR4 DRAM        

iPhone 8 = 2 GB LPDDR4X DRAM        
iPhone 8plus = 3 GB LPDDR4X DRAM        

iPhone XS = 4 GB LPDDR4X DRAM
iPhone XS max = 4 GB LPDDR4X DRAM        

iPhone XR = 3 GB LPDDR4X DRAM
2018-12-7
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kykmavic
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Dirty Bird Posted at 12-7 18:22
I have experienced the video blackout with the Mavic 2.  If it happens again power cycle the RC.  The video returned once the RC reconnected.

This issue must be corrected by DJI and rectified with another firmware update.
2018-12-8
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Viper Pilot
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Not to hyjack this thread, but is it possible to cycle power on the R/C while the M2P is flying?  Will the aircraft just loiter there while rebooting the R/C?
2018-12-8
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nixuspix
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If the AC has enough sats in position and behaves normally, i always reboot either CS or RC or both if needed and the light always come back
2018-12-8
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Dirty Bird
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Viper Pilot Posted at 12-8 04:48
Not to hyjack this thread, but is it possible to cycle power on the R/C while the M2P is flying?  Will the aircraft just loiter there while rebooting the R/C?
Assuming you have GPS lock the aircraft will engage RTH as you restart the RC.  Just cancel the RTH once you reconnect.
2018-12-8
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Mike Mas
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So what does this tell us . .  Don’t test your range unnesserarly. While I realize there is an error, there is no excuse for flying at any remote distance. In 20+ years if aerial work I’m yet to fly at any great distance from the launch site. Be safe losing a drone will make you Cry!

Regards Mike
2018-12-8
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Viper Pilot
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Dirty Bird Posted at 12-8 07:27
Assuming you have GPS lock the aircraft will engage RTH as you restart the RC.  Just cancel the RTH once you reconnect.

Ah, ok.  Thanks.  I'll have to give it a try some time.

Thanks again.
2018-12-8
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Mike-the-cat
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Dirty Bird Posted at 12-7 18:22
I have experienced the video blackout with the Mavic 2.  If it happens again power cycle the RC.  The video returned once the RC reconnected.

Yes, this was my experience with the video blackout too but I have not tried recycling the RC midflight. Anyway this post is redundant given those following your OP... Thanks for sharing.
2018-12-8
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El Diablo
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2018-12-9
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El Diablo
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2018-12-9
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jpap
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I just want to share my relatively not good experience on MP2 with Occusync 2.0

My previous drone was the MP1 and the connection was always rock solid! Never ever had a complaint on this. Although I usually fly within VLOS and above the sea, with MP1 I never had signal issues in a range of 1-1.5Km. Please note that I leave in Greece, hence under the CE transmission levels.

With MP2 I completely get an opposite experience. More specifically, the signal bars start to drop at much shorter distance  (i.e. 600m) distance even when flying in a suburban area.

Signal bars can even change with drone's orientation! More specifically I have noticed that when drone's noise looks backward (towards home point) the connection get stronger and signal bar elevate from 1 to 3. Pixeled image as a result of a bad signal is much more frequent for me in MP2 than MP1.

Overall, it feels that Occusync 2.0 became much more sensitive to interference than Occusync 1.0
2018-12-10
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davidmartingraf
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El Diablo Posted at 12-9 23:44
Ok David, would you be so kind and tell us the 'real' amount as it seems I am not able to copy - paste. Thanks.

I think we have the correct information quoted in a previous post.
2018-12-10
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El Diablo
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2018-12-10
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El Diablo
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2018-12-11
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Mike-the-cat
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jpap Posted at 12-10 06:18
I just want to share my relatively not good experience on MP2 with Occusync 2.0

My previous drone was the MP1 and the connection was always rock solid! Never ever had a complaint on this. Although I usually fly within VLOS and above the sea, with MP1 I never had signal issues in a range of 1-1.5Km. Please note that I leave in Greece, hence under the CE transmission levels.

I have to disagree with this. My experience is that the new system is better overall. Perhaps there are new sources of interference in your location.

Best of luck flying
2018-12-12
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