Futaba 149 DP as Dual receivers
I am running 2 129dp receivers(predecessor to the 149dp) and my range with the transmitter antenna down is at least 100 feet. Something is wrong with your setup. Whatever you do don't fly the plane until you figure out what is wrong. With a 33% plane you may want to consider using only 1 receiver. In any case you should be getting much better range than 20-30 feet. I wonder if the problem may lie in your transmitter,maybe the antenna connection is loose..etc. Do you have another transmitter on the same frequency to rule this out?