Communication is an essential part of four wheel driving in groups. Standard club practice these days is for eveyone travelling on a trip to have either a vehicle mounted or handheld UHF radio.
Mobile UHF CB Radios
Mobile, or vehicle mounted, UHF CB Radios are hardwired into your 4WD, and have an antenna mounted on the vehicle - usually the bullbar. Standard UHF Radios used in four wheel drives are 5W units with 40 channels. Some come with a remote head, allowing you to mount the face of the unit within reach, and the base out of sight - such as underneath the drivers seat.
Handheld UHF Radios
Handheld UHF Radios vary in power and price greatly, and range from around 0.5W upwards. A handheld CB Radio unit is a great thing to have on hand as it enables you to conduct recoveries from outside of your 4WD, navigate a driver through a difficult section, and keep in contact when enjoying activities out of the vehicle such as bushwalking. Handheld UHF Radios are also a great item to give to the kids when you are out camping so that you can keep in touch.
AM CB Radios
AM Radios are not used much these days for 4WD communication, with the prefered option now being UHF.
UHF Antennas
A UHF Antenna is used in conjunction with mobile UHF Radios. Each antenna offers a different gain, and some are more suited to hilly environments, whilst others prefer flat open ground. The one you choose will depend on the type of driving you do, however most opt for a multi-purpose unit.