Alot of people will just splice in a piece to repair the cut/broken antenna wire. This can lead to range problems if the wire is different in gauge or total length. Also a splice that is not insulated could be grounding out on some CF or metal part(s) causing your problem.
Best to completely replace the antenna wire with a NEW piece of the correct spec, by soldering to the board.

Consider that a crash severe enough for the blades to strike the antenna wire close to the RX, may have damaged the RX or it's crystal.