UHF CB repeaters in Australia use specific channels within the 476.4125 MHz to 477.4125 MHz range, with repeater input channels typically being channels 31 to 38 and 71 to 78. These repeaters extend the range of UHF CB radios, allowing for communication over longer distances. Specific repeater locations and callsigns vary by region. 

Here's a more detailed look:

UHF CB Repeater Frequencies:
Channels 31 to 38 and 71 to 78 are used as repeater input channels. 
Channels 2, 3, 4, and 5 are duplex (repeater output) channels. 
The frequency spacing between channels is 12.5 KHz. 

Regional Repeater Listings:
Australian Capital Territory (ACT): Channel 1 (CBA01 in Canberra), Channel 3 (BMS03, Brindabella Motorsport Club), Channel 7 (GIN07 on Mt Ginini). 
South Australia: PRC01 (Carrieton), TYN01 (Oodnadatta), VLA3 (Crystal Brook), VLA5 (Port Lincoln). 
Western Australia: LEN01 (Leonora), MKT01 (Poison Hills), PER01 (Perth), WAR01 (Warrakurna). 
New South Wales: COR01 (Corowa), DNQ01 (Deniliquin), GRE01 (Grenfell), GUY01 (Guyra). 

Important Notes:
Emergency channels 5 and 35 are strictly for emergency communications only. 
Channel 40 is used for road safety communication, particularly by heavy vehicles. 
Channel 10 is often used by 4WD clubs and in national parks. 
Channel 18 is commonly used by caravan and camper convoys. 
Users should be aware of the designated repeater input channels (31-38 and 71-78). 

UHF CB Channel Information from ZCG