Hello!
Well the most important thing to do first is to range check the radio.
All JR and Futaba radios should have at least 100m range with the transmitter antenna fully collapsed. Range in this case means that the servos should work as normal with no servo jidder.
I hope you use a new battery pack, either a welded together 4,8-6V pack or a pack sweat soldered together by yourself. Nicad batteries could be used but better yet is to use Nickel metall hydrid batteries . these cells are available everywhere (GP green cells or Sanyo )and are much better than the "old "Nickel cadmium cells. 2300mAh cells is what I use (both GP and Sanyo) and these cells weight the same as ordinary 500-1100mAh Ni-cad cells but contains much more energy.

Regards!
Jan K
Sweden