Dragonheart,
Careful ! All of the information above applies only to the US and their 72MHz frequency band. Given in good faith I'm sure but by people who forget that America is not the whole world

.
If you are in the UK, using 35MHz (or in the rest of the world) it's much easier because we don't have all that positive/negative rubbish. *All* makes of PPM (sometimes incorrectly called FM) transmitter and receiver will work together. Only for PCM do you have to stay with the same make.
Steve