I do not think it is antenna, as there are 2 inside camera, one each side
I chooses the one with the bast reception, and uses that one! It is more likely extender issue,
With phantom OFF, unplug and replug the wire on camera, and twist a little, may be bad cable connection?
Make sure extender is fully charged as well, I would also check the camera SERVO PLUG,
Under mount, and also open phantom, check for loose connections there as well!
Do you get good FPV reception ( any distance? )
Also make sure you did not accidentally hit the motion icon
On the tilt bar, make sure it is set to manual control, the other way the camera
Moves when the phone moves, manual you control!
Have you done any antenna mods? ( extender, ect? )
Have you ever UNPLUGGED the camera with the phantom ON? ( this can cause MC burnout )
Please let us know?