Flying in flat rural desert terrain and both signals dropped to 3 bars at 200 feet AGL and 10500 feet out. Slid on the inexpensive ($15) passive range extenders from Drone Valley and both went to 4 bars. Flew out to 18500 feet (where I'd lost signal multiple times in the past without the range extenders on) and still had 3 bars but only 60% battery left so I chickened out and flew back home. Still had 20% battery upon landing. I'll have to do more testing...but this is promising.