I was experiencing video disconnection problems since I updated the RC...I thought the problem HAD to be the firmware for the RC.  It looks like I was wrong, I added the 32 channel config file to the DJI Go (2.4) app and did a completely COLD calibration of the IMU and the problem seems to be fixed.  I have flown thru 3 full batteries now with no loss of video at all.  In case you don't know what a COLD calibration is...put your Phantom in the refrigerator for 30 to 45 min, find a truly LEVEL surface, and run the IMU calibration immediately after removing the Phantom from the fridge.  It sounds weird, but it worked!!

Also, I use the 32 channel hack to set a "custom" channel for video transmission.  I use channel 31 or 32 and have no issues with interference...

Also after cold calibration, aircraft supposed to spend less time to warm up before the flight.

Rebel Posted at 2015-11-10 11:23
Is that sarcasm?

no, seriously. cold calibration cuts down the aircraft warming up time

No, not sarcasm...100% correct!!  One of the other issues I was having was that ever since they replaced my shell at Drones Plus, it was taking 3 to 5 minutes to "warm up"...it never did this before the shell replacement.  Then I realized that when they had my P3P in the shop, it was during a "heat wave" in the Bay Area.  The temperature inside their warehouse (where they did the IMU calibration) was upwards of 90 degrees.  After the cold calibration, it is ready to fly in less than 30 seconds.

Something else I learned...I was under the impression that the IMU had nothing at all to do with the video signal/transmission.  I was incorrect.  The tech/owner of Drones plus told me that the IMU is not just the flight controller but more of a CPU for the whole P3P.  It does not only control the ESCs and Gyroscope, but many other background functions as well, one of which has something to do with the video processing.  This would explain why it seems to have fixed my issue.  He says that if the IMU is taking too long to "warm up", other background processes necessary for the video and app functions may "fail" at startup and then not reboot correctly.  I'm not a drone expert, and have not been able to "verify" any of this, but it does make sense if you think about it...

I don't know of any other specific "benefits", but I know from my own experience as a network engineer (I work with copiers and computers all day long) that silicon chips function/respond better when they are cool...this is why large computers are "liquid cooled" and why computer "clean rooms" have huge fan systems to keep the rooms at optimal temperatures.

Yeah, it was taking a good 5 minutes to warm up...by the time I could "take off" the battery was at 95%

Believe it or not, I tried that first...I calibrated it on my kitchen table in the middle of the afternoon.  It did not change the 5 minute warm up time at all.  It didn't fix the video loss issue either...the "cold" calibration seems to have fixed both.  

Believe me, I've been pulling my hair out for the last couple weeks since this "video disconnection" issue started after the RC update.  I was convinced that the RC firmware was to blame.  I didn't change anything on the RC, or even re-bind it to the P3P...but the cold calibration of the P3P itself fixed the problem.  I would have never even tried it, but the owner of Drones plus suggested it.  

The cold IMU cal does work. I have seen it myself.

After calibrating mine at 37 degrees (F), it takes only seconds, maybe 20-30 sec at most to warm up, instead of the 2-3 minutes it used to.  Not sure I would recommend the fridge.  Air conditioning vents run fairly cool, and for some of us, winter is nearby.  I'm going to recal again when I get time, right down about freezing, and be done with it.

The IMU calibration need a  "cold" startup, where "cold" means the lowest temperature you are going to use P3. So ambient/outside temp is ok, but only if your P3 is not yet used for a while. Someone could argument that flying at 500mt AGL can be few degree colder and this is true, but anyway not a critical difference.
You don't need a freezer anyway. Don't calibrate IMU after a flight !
Technically, I don't think IMU has something to do with video lag, except when error (due to noise of miscalibration) is very big. In this case IMU is poor responsive to the firmware routines, but it may create many other issue (not only video lag). In this case I hope the app gives an "IMU Error" signal.  

Well I got excited after reading this yesterday and went home and tried it.  Sadly the results for me had no change.  With in 20 sec after take off the no signal came back up.  Guess I will be calling this afternoon and send the bird in.  I have tried everything and am sick of this happening.

Mudcon Posted at 2015-11-11 22:10
Well I got excited after reading this yesterday and went home and tried it.  Sadly the results for m ...

One further thought that has not been suggested. I have found that if you have cell service in your monitor, or if Bluetooth is on or if Wi-Fi is on, they can cause various activities inside the phone or tablet that could well interfere with the video lag or cut out. So shut off Wi-Fi and Bluetooth on the monitor and try again. I do that and it did solve my issues. So did the cold IMU calibration. I do that at night. The cool air at night is cold enough to give good results. It is usually colder at night than the day, so that is why it works. Putting the drone in the fridge or freezer, disturbs the food as the drone doesn't belong there. And after all we don't want the food to be disturbed do we???? Good luck.

yea I always fly in airplane mode.

Mudcon Posted at 2015-11-11 16:06
yea I always fly in airplane mode.

Every case is special with this issue. If I fly with data cellular disabled, video lag is verrryyy heavy. Switching it on, video lag doesn't appear. I normally use IPad Air, but same result on a iphone 6+.

IMU has nothing to do with video transmission problems as the video is active during warm up.

Regards