I initially calibrated my drone and flew, and there was no issue. I tried to fly again 10 minutes later. But mid-flight, i received a msg that no signal. I was only 30meters above ground and just before this i had 18 satellites.  I brought the drone down, tried to re-calibrate  but the the drone would not calibrate. It was open space and non metalic interference. Any suggestions please.

     Try these ideas on the links posted below:  Make sure  your antennas are not crossed , or faulty cable from Transmittter to your device , Watch the antenna tutorial.  The compas calibration wont help this problem,  what hat I believe you are  descibing ( NO signal Video) .  I want to give you some advice on how to perform compass and imu cal.



When calibrating compass, do  it in a wide open field with no metal around you or on your person, no keys in pocket, no wrist watch, no change  in pocket.  Also dont do it over concrete becuse of  possible re-bar within it,  also keep transmiiter at least 3 meters away.  Do you compass calibration well on time and only repeat after a hard landing, or firmware update, also do it if you travel more than 150 miles from the original calibration point.  Same with IMU Calibrationa do it once on a PERFECTLY firm FLAT Surface  and dont even breath or come near it till finished , about 10 min.  The reason is the IMU is SUPER sensitive to vibration, even in the floor  vibration when approaching it.

Keep in mind there is a difference beteween" No Video signal "  and " No RC signal"   or "GPS Lost " What I believe you are describing is No Video Signal, meaning you had full control of the aircraft just no live video from the aircraft . The first link  tutorial below will help with your settings.      




Good Luck- Donnie

http://forum.dji.com/thread-39021-1-1.html                               Items to check to insure good video reception.

http://www.youtube.com/embed/HoTdK7izUAA                           Compass and pre-flight basics

What did the app show when you're calibrating the compass? Can you calibrate it in another place?

Hi Donnie Thanks for your in depth information, it is very helpful. The information's you have provided answers my concern.  The issue i was experiencing was, that i lost Gps Signal, not video signal. After losing Gps signal Drone returned home safe. But this i tried to calibrate the drone, it wouldn't calibrate. The information you have shared, tells me, why it didn't calibrate. I had the controller on a Lanyard around my neck, when i was trying to calibrate the Drone.

But i still have to check, why I lost Gps signal. When few seconds before this i had 18 satellites. And i was in the same location.