The Land Rover Register of SA uses UHF transceivers only for communication between vehicles on club trips and activities. The minimum requirement for each vehicle on all Register trips is a hand-held UHF CB radio. The main club channel is 15, while other channels may be used if 15 is "crowded". The trip leader will advise if a change of channel is required.
For trips in remote areas at least one vehicle should be fitted with an HF (High Frequency) radio or satellite telephone for communication with the Royal Flying Doctor Service in case of an emergency. Some HF radios may also allow the making and receiving of telephone calls.
Below is guidance on the use of UHF channels.
UHF CHANNEL USAGE GUIDE (Click to follow link)
Please note that those channels marked as emergency use should only be used in an emergency. 99% of the time these channels will be silent.
If you hear anyone on one of these channels it should be an emergency and should be treated as such.
Max Erskine of the West Coast Caravan Club has written a very good article that explains the fundamentals of radio communication in a very easy to understand way.
Max's article can be found by clicking HERE
More information about repeater stations can be found HERE