RE: Receiver antenna length
I have a JR R700 Reciever in my LT40 that had the antenna broken about three inches from the Rx. I carefully soldered it back together and put heat shrink over it. After the repair, it ended up being right at 1/2" shorter than before. I've flown it many times, and havent had any problems with it, so I would say you are probably alright.