Nigel replied:

AM CB doesn't seem to be used much anymore, but I often make contact on 27MHz SSB with people in Victoria (I'm in Far North Queensland). Of course 27MHz SSB isn't a reliable method of communication, but having SSB makes it much more useful than just an AM set. More 4WDers seem to have UHF than 27MHz these days, so it may be useful to have a UHF if you want to make contact with other travellers. A recent test showed that a UHF with a 20km range in open areas, only had a 3km range in a forestry plantation. If you need reliable communication in remote areas then you really should look at HF radio or sat phone (see the comms section on ExplorOz) but it is better to have anything than nothing.

tim replied:

Robert,
I have both in my 4WD simply because not all people have 27Mhz or UHF. The 27Mhz is not dependable over any distance whereas the UHF can go alot further, espiecially with repeater stations. I wouldn't take the 27Mhz radio out, I would just add a UHF and as for HF, before you purchase one of them you need to take a look at the price tag and think if you really need it.
Tim

Darryn replied:

Robert 27mhz ssb radios are worth keeping as you can always yell help and someone in the country will eventually hear you. Uhf is however the best for vehicle to vehicle comms when travelling and there is a large number of repeaters in the area that you say you travel in so help shouldn't be too far away if you need it. Hf (as in flying doctor) radios aren't really necessary in this area. I suggest you find a 4wd club or organisation that runs a repeater and they will be able to tell you everything you need to know and help with set up and checking.
Regd's Darryn