The heng long 2.4 Ghz system works very well and plugs into an existing RX18. Just bind the transmitter to the receiver (a lot of places will just do that for you before they send it like TPA store on amazon) and you are ready to drive your tank. )binding is a very simple chore, you turn on your transmitter, hold down the start button, also hold down the tiny button on the binding wire on the receiver until your tank comes to life. Takes about 15 seconds, and that's it, you are done). Range is at least 75 feet with obstructions around, like building. No need for an external antenna so they don't send you one and you can remove your eye poker now if you wanted to. And almost never do you lose signal and have to watch your tank stop for no reason. Transmitters and Rx are available separately if you burn one up (i've burned up two of them and each time it was my fault, for messing with the wiringon the lights while the system was hot).
I'd have quit the hobby long ago if i hadn't found the 2.4 gig radio system, about $70-80 for the works.