There is a mo to the OEM antennas on the bird that is told to have great results. Just bring the OEM antennas to the outside of the bird, and instead of putting the sideways, mount them in front and back.
THere are several posts on that.
I'm talking about the wifi antennas. Normally you loose FPV before RC.
Most people see the message of signal lost and think they have lost RC, but most of the time its only the FPV signal that was gone.