Doesnt sound like an antenna issue then.
Come to think of it, if it had been a signal issue, the plane would have gone into failsafe mode - probably power off and controlls neutral.
If it was a brown out, that could be caused by a bad or over loaded BEC on the p10 or a poor connection between the esc and rx or the esc lead coming unpluged.
You could also have had a servo hang up or jamming, but you said you tested everything after the crash?
The last possibility I can think of is you got a bum rx. A while back some people were having issues with the 6110E's IIRC, but I thought they got that fixed.
Still, every once in a while you get a lemon even from the good guys.
I wouldnt give up on 2.4 with just one rx issue. Its probably something unique to that particular setup or rx.