I was flying my P4P today at -7°C, sunshine and no wind.
I warmed battery, so when I take off it was on 26°C, and rising during flight.
After of 6-7 minutes of flight I was receiving warning message of "image transmition signal low".
A minute after that aircraft was disconnected, and RTH is initiated.
I have maybe 2-3 returning of signal, but on blink.
So aircraft landed safely an even I was close to aircraft, still I was disconnected.
After one minute, remote connected to aircraft, 2-3 times shortly, and at last, have full connection.
Take of again, flying close by, everything ok, try to go further, coll, then again lost of signal. Distance was max 300m on 2,4GHz and 5,8GHz same.
Remote was inside of car, outside...

So I guess, under the -5°C, aircraft loosing signal, because I was flying on -3°C, -4°C and -5°C, with no problem at all.

Have some one any idea?

Considering you are operating the AC below the minimum spec (0-40 Deg C) I wouldn't be surprised. Something would likely have frozen I'd say.

Temperature has nothing to do with it.

'Remote was inside of car, outside... '

There is your problem, you are trying to fly with the RC unit inside a tin can, get out of the car.

Geebax Posted at 2017-1-8 15:16
Temperature has nothing to do with it.

'Remote was inside of car, outside... '

I wasn't talking about the remote. The AC was probably freezing up.

Hendo Posted at 2017-1-8 20:42
I wasn't talking about the remote. The AC was probably freezing up.

And I was not replying to you. But in any event, there is nothing in the aircraft to freeze up, providing the battery is warm, which it was.

Geebax is right, get out of the car, it is like sitting in a steel container.

There have been some tests where flying behind your self, and your iPad or what ever used is shading for the antenna. It can loose connection even on fairly short distance.

I have been flying at below -11c with heated batt , no problems

jetforce Posted at 2017-1-8 22:22
Geebax is right, get out of the car, it is like sitting in a steel container.

There have been some tests where flying behind your self, and your iPad or what ever used is shading for the antenna. It can loose connection even on fairly short distance.

I was inside of the car, and flying so many times from the car, and also I know about Faraday cage.
But even when I get out of the car, still no signal, still no connection.
After leaving AC for a minute, turned on, and propeller off, it recover connection.

Srange...

Hello LjupceM, I agree with Geebax.
RC signal probably be interfered. Please try to stay away from the car and fly again.

Thought I would chime in... I fly from within a car and sometimes even buildings when the occasion calls for it (extreme cold).  Today it was -24 C and I flew from indoors for the duration of my mission.  I find that from the comfort of my truck my remote connection rarely ever dips below 80% connection to the uav.  This is when flying within 2km of the RC.  I have been testing the P4P in cold conditions for a client this past week and the only issue I had was today when the compass required calibration but no matter where I tried to calibrate the thing just wouldn't work.  I suspect the cold had something to do with it because once I warmed the unit up, calibration worked fine.  

With my testing so far I am very happy with the cold weather capabilities of the p4p as well as the batteries.

Just my experience, and for sure is not the best conditions, but I did fly from inside a car myself, even driving the car and flying for a few km with no problem at all (always VLOS do).

image transmission signal low is simply you are getting a bad video sigmanl and it is warning you.

image transmission signal low message  is simply you are getting a bad video sigmal and it is warning you.

The -5C had no part in the fact you lost video. It is a function of range, antenna orientation and line of site to phantom (or lack of it).
The fact you mention remote is inside the car pretty much sums it up.

make sure you keep antenna properly aimed at quad
when you are loosing signal , give the quad more altitude.

The RC will still work most of the time even when video is lost.

Good luck and have fun flying!