My Dx5e have same probleme, i return my Rx to horizon hobby, took like 5 week to receive a brand new Rx ar600. About the distance, maby it's right but the dx5e bind well with orange receiver and dosen't bind with Ar600 receiver??? i didn't try to bind from a certain distance.
I didn't try it yet because during this time i buy a Turnigy 9x Tx/Rx, and im realy happy with this combo. Range test on ground: 1000 meters and still good signal inside a car!!!
yep it's a good choice