I have repaired the receiver antennas on the receiver that came with my Blade Conspiracy 220. It came with an AR400 style receiver, although it was a satellite receiver since it connected in to the FC, but it wasn't hard at all to fix. I had tried to solder the antenna together, but for all the hassle of trying to find shrink tubing that would go over the soldered piece, it wasn't worth it, especially when you can get 20 of them for $9 from Amazon.
I ordered this exact item:
https://www.amazon.com/dp/B01FEEQTQ0/?tag=lstir-20
This particular order, per Amazon, is out of stock, but it's only for 5 antennas; 20 of them are $9 if you look at some of the "similar items".
When you go to do it, there's a little allen key screw at the bottom of the receiver that may have to be undone (at least, there was on mine), and then just pry the top of the receiver off GENTLY (if I remember correctly, there are little slots on each side that you can stick a precision flat tip screwdriver into and pop it loose on each side). Once you open it up, the antennae should be able to be popped off/pried off gently from their fixtures at the top, and the new antennae pressed on GENTLY (you don't need brute force for this; as it is, most of them will be held in place/pressed into place when you put the cover of the receiver back on).
Once you have popped off the old antennas and put the new ones on, follow the process in reverse to get the receiver put back together and get you flying again!
