UHF radio channels in Australia: the ones that matter

UHF CB is the everyday radio of Australian touring. It costs nothing to use, needs no subscription, and it does a specific set of jobs extremely well.

It also does not do the job most people quietly assume it does, which is worth getting clear early.

The channels that are legally reserved

Australian UHF CB runs on a channel plan set by the regulator, and some channels are not available for general use.

Channels 5 and 35 are the emergency pair, with 35 being the input to repeaters that extend 5. Using them for conversation is both illegal and genuinely antisocial, because someone may be trying to call for help.

Channels 22 and 23 carry no voice under any circumstances. They are set aside for data.

Channel 11 is a calling channel. The convention is to make contact there, then agree another channel and move to it rather than holding a conversation on 11.

The channels people actually use

Channel 40 is the highway channel. Road transport uses it across most of the country, and monitoring it while driving is genuinely useful: you hear about oversize loads, crashes, stock on the road and rough sections well before you reach them.

Worth knowing that in parts of Western Australia channel 40 is less universally dominant, and local usage differs.

Channel 18 is the recognised convoy channel for caravans and campers.

Channels 1 to 8 and 41 to 48 are repeater channels, which extend range through fixed repeater stations. Using them requires a duplex-capable radio and the repeater has to be in range, which in remote country it usually is not.

General chat happens across the remaining simplex channels. For a convoy, pick one that is not reserved, agree it before you leave, and test it while everyone is still in sight of each other.

What UHF is actually for

Convoy coordination. Telling the vehicle behind you about a washout, a gate, or that you are stopping. This is the core use and it makes group travel meaningfully safer.

Single-lane tracks. Calling ahead on a blind, narrow section so an oncoming vehicle knows you are there. On some tracks this is close to essential.

Road trains. Hearing a road train before you see it, and being able to confirm when it is safe to overtake, is worth the radio on its own.

Reversing and recovery. Someone outside the vehicle guiding the driver, without shouting.

Local information. Roadhouses, station traffic and other travellers on the same route.

What it is not for

Calling for help.

UHF is line of sight and short range. In practical terrain, expect a few kilometres, sometimes considerably less in timber or hills. It reaches whoever happens to be within that radius and happens to be listening on that channel.

In remote Australia that is frequently nobody. Sitting on channel 5 hoping somebody hears you is not an emergency plan.

For genuine emergencies you need a satellite messenger or a registered personal locator beacon, both of which work almost anywhere with a view of the sky. That is covered properly in communications beyond mobile coverage.

The sensible setup is both: UHF for the everyday coordination that makes travel safer, and a satellite device for the situation where you need outside help.

Getting useful range

Range depends far more on the antenna than on the radio.

Antenna gain is a trade rather than an upgrade. A high-gain antenna, around 6 to 9 dBi, flattens the signal outward and gives better range across open, flat country. A low-gain antenna, around 2 to 3 dBi, radiates in a rounder pattern and works better in hills and timber where you need signal going up and down as well as out.

For most Australian touring, something in the middle is the practical compromise. If you spend all your time in the High Country, go low gain. Crossing the Nullarbor, go high.

Mounting height matters more than power. A well-mounted antenna with a clear view beats a higher-wattage radio with a compromised mount. Bull bar mounts are common and convenient, and a roof mount usually performs better because the ground plane and height are better.

Handhelds are limited. Short antennas and low power mean a handheld may manage a kilometre or two. Useful for talking between vehicles at camp; not a substitute for a fitted radio.

Etiquette worth knowing

Listen before transmitting. Keep transmissions short. Identify which vehicle you are if you are in a convoy. Keep the reserved channels clear. And accept that channel 40 carries some robust language, which is why plenty of people turn it down rather than off.

The short version

Know that 5 and 35 are emergency only and 22 and 23 are no-voice. Monitor 40 on the highway. Agree a convoy channel before you leave. Spend your money on the antenna and the mount rather than the radio.

And do not confuse a UHF for a way of calling help, because that is the assumption that gets people into trouble. The gear that does that job is in communications beyond mobile coverage.