UHF channels Australia: 40, 18, 5 and 35, 22 and 23

When towing

Listen on 40 for trucks wanting to pass and for road conditions, and use 18 to talk to other caravanners. When a truck calls to overtake, a quick reply and easing off helps everyone. Many travellers scan both.

Emergencies

The ACMA reserves UHF channels 5 and 35 (and HF channel 9) for emergency messages only. They are not a substitute for calling Triple Zero, and emergency services do not monitor them. Misusing them can block someone else's call for help.

Do you need a licence?

No individual licence: UHF CB radios operate under the ACMA's citizen band radio class licence, which sets the channel rules for everyone. Breaking those rules is an offence under the Radiocommunications Act.

Choosing a UHF radio

Handheld radios are cheap and portable, good for convoy chat at short range, camp use and spotting while reversing a caravan. Their small antennas and low power limit range.

In-car radios are fixed in the vehicle with an external antenna, giving much better range and clearer audio. Most touring setups have one in-car radio and one or two handhelds.

Power and antennas. UHF CB radios are limited to a maximum transmit power under the class licence, so range depends mostly on the antenna and the terrain. A higher-gain antenna reaches further on flat open roads; a lower-gain antenna works better in hilly country. Mount the antenna high and clear of roof racks where you can.

Repeaters

Repeaters are hilltop stations that receive on one channel and retransmit on another, extending range a long way. Each repeater pair uses a channel and a matching channel 30 numbers higher. To use one, select the repeater channel and turn on duplex mode. Avoid chatting on repeater channels when you do not need the range, because one conversation ties up the repeater for everyone in a wide area.

UHF etiquette

• Listen before you talk, so you do not talk over someone.
• Keep messages short and clear, and use your name or a call sign.
• No swearing, abuse or music; the class licence prohibits offensive transmissions.
• On channel 40, keep talk to road matters and let trucks use it.
• When a truck asks to overtake, reply briefly and ease off when it is safe.
• Move to a general channel for longer chats.

Talking to trucks when towing

When towing a caravan on a highway, monitor channel 40. A truck behind may call "caravan at the 100 km sign" or describe your van. Answer with your position and when it is safe for them to pass, then ease off a little and keep left. Truck drivers appreciate a clear reply, and it makes overtaking safer for both of you.

UHF in national parks and convoys

Four-wheel-drive clubs and tour groups pick a general channel for their convoy and agree on it before setting off. Pick a quiet channel, avoid 5, 35, 22, 23, 40 and repeater channels, and have a backup channel agreed in case yours is busy.

If someone is in danger

In a life-threatening emergency, call Triple Zero (000) first. If you cannot get mobile coverage, try 112 on a mobile phone, and use a satellite messenger or personal locator beacon if you carry one. UHF channels 5 and 35 can reach people nearby who may help, but they are not monitored by emergency services.

Printable card

Keep a list of the main channels in the glovebox or on a card near the radio, so passengers can find the right channel quickly.

UHF channels at a glance

• Channel 40: the road channel used by trucks Australia-wide.
• Channel 18: used by caravanners and campers to talk to each other on the road.
• Channel 29: used by trucks on the Pacific Highway in NSW and Queensland.
• Channels 5 and 35: emergency only, by law.
• Channels 22 and 23: data only, no voice, by law.
• Channel 11: the calling channel; make contact, then move to a general channel.
• Channels 61 to 63: reserved; do not use.

Analogue 40-channel radios

Older UHF radios had 40 channels. Since the move to 80 channels, older 40-channel radios still work, but their users may not hear conversations on the newer channels, and some 40-channel radios no longer meet the current class licence for new sales. If your radio is old, check whether it is 80-channel; a newer radio gives more channels and better reception.

Range in practice

On flat open ground with a good in-car antenna, UHF can reach many kilometres between vehicles, and much further through a repeater. Hills, buildings and trees cut range sharply. Handhelds reach a few kilometres at best in open country. Do not rely on UHF as your only way to call for help in remote areas; carry a satellite messenger or a personal locator beacon too.

Using UHF when you travel in remote areas

On outback roads, UHF is often the only way to talk to other vehicles. Monitor channel 40 for trucks and road conditions, and keep a general channel for your own group. Mining sites, stations and road trains may use their own channels on private roads; follow signs that list them. When crossing a single-lane bridge or a narrow section of road, a quick call on 40 can avoid meeting a road train halfway.

Looking after your radio

Check the antenna mount and cable after rough roads, keep the microphone cable away from sharp edges and the pedals, and test the radio before a trip by calling a friend on a general channel. Handhelds need charged batteries; carry a car charger. If transmissions sound weak or the radio hums, have an auto electrician check the antenna and power connections.

Learning the lingo

Many UHF users use simple radio words. "Copy" means you heard and understood. "Over" means you have finished talking and expect a reply. "Go ahead" means the other person can talk. Truck drivers often identify themselves and you by position, such as "southbound caravan near the rest area". Keep it simple, speak clearly, and you will fit in.

Channel choice for caravan groups

When travelling with friends, agree on a general channel and a backup before you leave, write them on a card in each vehicle, and keep channel 40 on scan for trucks. Avoid channel 18 for long group chats, because other caravanners use it to talk to vehicles they meet on the road, and avoid repeater channels unless you need the extra range. If your group spreads out over many kilometres, a repeater in range can help, but switch back to a simplex channel once you are close again.

Legal penalties

The ACMA can investigate and penalise misuse of UHF CB, such as transmitting on emergency channels without an emergency, sending voice on the data channels, or causing deliberate interference.

Before a long trip

Check the radio works on a general channel with another vehicle, set the scan list to include 40 and 18, note the repeater channels for the regions you will cross, and keep a handheld charged for use around camp and while reversing the caravan into a site. Agree hand signals as a backup if radios fail. Tell someone at home your route and check-in times, especially in remote areas where UHF may be your only link to other travellers, and remember that it does not reach emergency services directly.

UHF and caravan parks

In busy caravan parks and campgrounds, handheld UHF radios are handy for guiding a driver reversing a caravan into a tight site. Use a quiet general channel, keep it brief, and agree simple words such as "stop", "left", "right" and "back" before you start. Turn the volume down early in the morning and late at night, and switch off when you are done so you do not disturb neighbours. A clear set of words agreed in advance makes reversing a large van much easier than shouting across a campsite.

Summary

Monitor 40 on highways, use 18 to talk with other caravanners, keep 5 and 35 for emergencies only, never use voice on 22 and 23, avoid 61 to 63, and keep repeater channels clear unless you need the range. Call Triple Zero first in any emergency, because UHF does not reach emergency services directly.

Common questions