wut is the difference between a 2 channel radio and 4 channel radio? which is best for a sub or small boat? cuz i found one for 40 bucks and it comes w/ 2 servos that is a 2 channel one. Here http://www2.towerhobbies.com/cgi-bin...I=LXGRM7**&P=0
one more question wut is a reciver?

A two channel radio can only control 2 things ex. (foward bachwards, left right) while a 4 channel radio can do (foward bachwards, left right, faster slower, up down) A reciever is the unit that takes the signal from the radio and makes your r/c vehicle do what you wanted it to do.

wut about a one stick controler or is that bad?like this one? http://www2.towerhobbies.com/cgi-bin...I=LXLGF4**&P=0

Im not sure if that one can change its crystal but usually that radio right there is for airplanes. Its a 72Mhz radio i dont know if you can use them underwater. Look for futaba 3ch radios im sure the have one somewhere.

How about something like this? You will have to put together your own systems on the bottom of the page with what size battery you want to run and servo sizes.
Good luck.

http://www.servocity.com/html/laser_...d_systems.html