UHF CB channel guide: all 80 channels explained

The 80-channel UHF CB system

Australian UHF CB radio runs in the 476.4250–477.4125 MHz band and has 80 channels. It operates under an ACMA class licence, which means that as long as your radio is an approved 80-channel UHF CB set, anyone can use it — there's no individual licence and no fee. Maximum transmit power is 5 watts.

The 80-channel plan grew out of the older 40-channel band. Back then channels were spaced 25 kHz apart; the extra 40 channels were squeezed in between them at 12.5 kHz spacing. That history matters for one practical reason: the in-between channels sit close to the original ones, so a strong signal on one can bleed onto its neighbour. It's why some narrow-band radios and older sets don't see all 80 channels, and why a few channels are best avoided for casual chat.

Not every channel is a free-for-all. A handful are set aside for emergencies, a couple carry data only, three are reserved, and many are tied up by the repeater system. The rest are general "simplex" channels you can talk on directly, radio to radio. Here's the whole picture.

Full UHF CB channel allocation

This is the legal band plan — the channel groups defined under the class licence. The "by convention" road and recreation channels are listed separately further down, because they're custom, not law.

Note: channels 31–38 and 71–78 are the inputs that feed repeaters whose outputs are 1–8 and 41–48. In a region with an active repeater on those channels, the input channels are effectively occupied — use a different general channel for simplex chat so you don't key into the repeater.

Emergency channels: 5 and 35

Channel 5 is the designated UHF CB emergency channel across Australia, and Channel 35 is its repeater input. Volunteer monitoring groups and some emergency services listen on Channel 5, and in many areas an emergency repeater can lift a weak Channel 5 call out over a much wider area — which is exactly why Channel 35 has to stay clear too.

Keep both channels free of normal chatter. Don't use Channel 5 to call your mates, run a convoy or test your radio. The one time it matters — when someone genuinely needs help — a clear channel can be the difference. If you have a real emergency and no other means, Channel 5 is the place to call; in a life-threatening situation always try Triple Zero (000) first if you have phone coverage.

Data-only channels: 22 and 23

Channels 22 and 23 are set aside for telemetry and telecommand — that is, data and remote-control signals sent by machines, not people. Think automated gate controllers, remote monitoring gear and similar devices.

There is no voice on 22 or 23. Most modern radios won't even let you transmit voice on them. Skip these two when you're looking for a chat channel.

Reserved channels: 61, 62 and 63

Channels 61, 62 and 63 are reserved and should not be used. They were held back when the band expanded to 80 channels. Many radios block them; if yours doesn't, leave them alone.

Repeater channels and how they work

A repeater is a radio installed somewhere high — a hill, a tower, a tall building — that listens on one channel and instantly re-transmits on another, much further than any handheld or vehicle set could reach on its own. That's how you talk across a whole valley or city.

Repeaters use channel pairs. The output channels (the ones you listen to) are 1–8 and 41–48. The matching input channels (the ones your radio transmits on when "duplex" or "repeater" mode is switched on) are 31–38 and 71–78. Channel 1 pairs with 31, 2 with 32, and so on; 41 pairs with 71, 42 with 72, and so on.

To use a repeater you select the output channel (say, Channel 1) and turn on duplex/repeater mode — the radio then transmits on the input (Channel 31) and you listen on the output (Channel 1). The big practical rule: don't use the repeater-input channels (31–38, 71–78) for direct simplex chat in an area that has an active repeater on them, because you'll be keying straight into the repeater and stepping on everyone using it. Out in the bush with no repeater around, those channels are fair game for simplex.

Channels used by convention

These are the famous ones — the road channel, the 4WD channel, the caravan channel. None of this is law. They're customs that have built up over the years so that people doing the same thing can find each other. They're widely followed, but they vary by region and they change, so treat them as etiquette, not rules.

Channel etiquette

UHF CB is a shared, open band — everyone within range hears everything on the channel. A bit of courtesy keeps it usable for the next person.

• Listen before you transmit. Make sure the channel is clear so you don't talk over an existing conversation.
• Leave 5 and 35 alone. The emergency channel and its repeater input are for emergencies, full stop.
• Use the right road channel. On the highway, Channel 40 (or 29 on the Pacific Hwy) lets you hear oversize-load and traffic warnings — and lets truckies hear you.
• Move off the call channel. Make contact on 11, then shift to a free channel for the long yarn.
• Keep it short and clear. Say who you're calling, wait, and don't hog the channel — others may need it.
• Mind repeater channels. In repeater country, don't use 31–38 or 71–78 for simplex; pick a general channel instead.
• Keep it clean. The class licence prohibits offensive and harassing transmissions — anyone can be listening, including kids.

For the hardware side — handheld versus vehicle-mount, antennas and range — see our guides on UHF radio range and how to choose a two-way radio. If you're not sure whether you need any kind of licence, the short answer is on our licence rules page.