I upgraded to the latest DJI GO app on iOS 9.3.3 on an iPhone 6s+ on the 28th. On the 29th I flew my p4 on a beach up to 1000m  away no probs. today, the 30th, I started up the p4about 500m from the flight yesterday  and the first sign something wasn't right was a meassage saying the imu was initialising. It got stuck in this state so after5 mins I switched the p4 off and on again.  This time it started fine. And I flew off as soon as I got good GPS lock.  Then about 400m out I lost all data connection.  No video or other info like battery etc.  it gave me the option to return to home so I pressed that and she came home ok.
After several more flights I lost connection anywhere from 10 to 400m. RTH works.  Not sure if it is because I press RTH or that the p4 comes home anyway when it looses connection.  I found that the only way to connect again was to kill the app and reload it.

Bit worried as I don't know why this is happening.  There was unlikely to be interference as I was several in from the nearest radio tower.

its not just radio towers that interfear with signal, trees and buildings do as well. I fly to the south of my area and I can go over 4500 feet with out signal loss. When I fly to the north ( over/following the railway tracks) I cant get 2000 feet, there are a lot of power lines that way, I figure thats why. As for thr RTH she will return when signals lost, you dont have to push the button, tho I dont think it matters if you do. Make sure antennas are pointed upwards and in the direction of your Bird. You can try and reload the app, but I dont think its that

Heebus Posted at 2016-7-31 22:42
its not just radio towers that interfear with signal, trees and buildings do as well. I fly to the s ...

It's not power lines or buildings.  My last flight was north and south along a beach with clear line of site. It was in a national park so there are no buildings or power lines.  The lost connections were at random distances. Yes I know about the antennas and that should have been fine especially when the last disconnect was only a few meters from me.

Hello neil, I'd suggest you to try with other device or earlier version app (if possible) or reinstall the app (sync the flight records before reinstalling).Then test it again. Keep your eyes on the transmission condition and lower the transmission quality when necessary.

DJI-Paladin Posted at 2016-8-1 16:00
Hello neil, I'd suggest you to try with other device or earlier version app (if possible) or reinsta ...

Thanks Paladin,  I have synced, deleted and reloaded.  Just have to go fly when I can.

neil@barker.com Posted at 2016-8-2 18:06
Thanks Paladin,  I have synced, deleted and reloaded.  Just have to go fly when I can.

I eventually had time for several flights over the weekend.  AT first I used my iPad Pro just to see the huge screen.  Great.  No problems at all.  So I had changed both the screen and the lightning cable.

Then I changed back to the iPhone 6S+.  It took off and I flew it out about 500m and 100m up.  Suddenly no signal again.  I had used the same cable as I used on the iPad pro.  Panic sets in - shes just sitting there no RTH - nothing.  I kill the iphone app and restart it.  Still no connection.  Kill and restart again plus cycle the power on the controller.  Still no signal.  Plenty of battery so I have time to rig up the iPad pro again.  Success!!!  We bring here home safely under full control using the pro.

So the common issue here is my iPhone 6S+.  Its either an issue with my individual iphone or generally with the 6S+ model.  My wife has a 6S+ as well so that's the next test.  Today I backed up my iPhone and restored after a full reset to flush out any issues there. Still to test this as well.

I do note the app crashes a bit esp when you review old flights.
Any ideas?  

neil@barker.com Posted at 2016-8-8 05:53
I eventually had time for several flights over the weekend.  AT first I used my iPad Pro just to s ...

I am willing to bet its the app in the phone, u can try uninstalling it and reinstalling it, but more then likely will have to wait for the next firmware upgrade, this seems to happen to the odd ipad/iphone, weird I kno... ur RTH not working is weird tho, be sure to have it set before you take off, and wjhen signal is lost it should kick in on its own... I fly out till I get signal loss 3 or 4 times a week, rth works everytime, I never use the button itself, tho keep in mind it takes 15-20 seconds to kick in, then first thing it does is raise up to set height before it comes home... maybe test it a few times to see how it works to confirm... glad ur bird returned home... happy flying

Heebus Posted at 2016-8-8 18:21
I am willing to bet its the app in the phone, u can try uninstalling it and reinstalling it, but m ...

I think it's an issue with the app on the 6s+ as well.  But I want to follow a scientific method to prove it.

neil@barker.com Posted at 2016-8-8 08:59
I think it's an issue with the app on the 6s+ as well.  But I want to follow a scientific method t ...

I dont kno how u can prove it scientifically, but I kno if u look in the thread were it was originally posted you will find many posts about peeps having disconnect issues with the ipad/iphone app... and I found this very interesting cuz when I bought my phantom 4 I noticed on the side of the box it stated it was made for ipad/iphone, and yet seems to have more issues with them then android devices... maybe its just me tho, it is still a fairly new product and I am sure the bugs will be work out, its a wide market that they have to compensate for and I am sure it takes some time, and feed back for them to get all devices down solid... I am interested to see what u find tho... happy flying

Heebus Posted at 2016-8-8 23:21
I dont kno how u can prove it scientifically, but I kno if u look in the thread were it was origin ...

Ok got my next flight in today.  Used my iPad Pro which had proven to be reliable. I flew around quite away from me and behind trees at times no trouble at all.  At about 40% battery we had enough video so I brought the p4 back towards me.  Suddenly no connection.  No warning about rth but I still had stick control. I'm starting to think it is a hardware or software fault in the video/telemetry unit either in the p4 or the controller once it warms up.  Either way I couldn't get video back so since it was close to me I was able to safely land it.  Distance doesn't be an issue with this problem.
I packed up and went home.

An hour latter I dug the p4 out to recharge the battery. I had forgotten to turn off the controller and it was quite warm.  It still had about 50% charge so I powered up the phantom (which was cool) to see if the warn controller had issues.  It worked fine.  So I'm now thinking its in the phantom itself as it warms up.  Not sure though.

I just upgraded to the P4 from the P3 pro, I seem to be having both distance and video transmission problems. In the same place I flew th P3 2000 ft with flawless video , with the P4 I can't fly 800 ft without video breaking up , had a warning under 1000 out of range ?????

I just upgraded to the P4 from the P3 pro, I seem to be having both distance and video transmission problems. In the same place I flew th P3 2000 ft with flawless video , with the P4 I can't fly 800 ft without video breaking up , had a warning under 1000 out of range ?????

ngeorge1157 Posted at 2016-8-11 23:59
I just upgraded to the P4 from the P3 pro, I seem to be having both distance and video transmission  ...

I flew again early in the morning.  This time using my iPhone 6s+ and Litchi instead of Djibouti go.  There were no issues but I didn't go too far.  It was cold so still unsure if heat is an issue.  More tests tomorrow

ngeorge1157 Posted at 2016-8-11 23:59
I just upgraded to the P4 from the P3 pro, I seem to be having both distance and video transmission  ...

I flew early in the morning when the ambient temp was about 12 C. I used my iphone6s+ and Litchi instead of  DJI GO. I had no issues but I still am unsure about heat issues and my max distance was only 248m.
But it is a good start.  I like the Litchi app.

neil@barker.com Posted at 2016-8-13 17:14
I flew early in the morning when the ambient temp was about 12 C. I used my iphone6s+ and Litchi i ...

2 more flights today. One in the morning with air temp about 15c (18 mins) and another this afternoon with air temp 21 (16 mins) both with iPhone 6s+ and both running Litchi.  All software and iOS the latest.
Max dist was 535m and some places behind a small hill.  
Absolutely perfect.  So I am thinking either it's still not warm enough or the issue is in the DJI GO app.