Consumer Behaviour UHF Radio Communication

Comms on the Road

17th December, 2020 by rvSafe Team
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You can never be too careful when out and about in Australia and being able to communicate is a huge part of that. But Australia is a vast country and communication can be difficult at times, so here’s what you need.


The beauty of Australia is its size. As the world’s largest island, and a land mass that is about 50 per cent greater than Europe, there are so many places to explore.

Unfortunately, though, with most of our population located on the edges of the country and a huge internal area mainly consisting of semi-arid and desert conditions, there are a lot of places where it can be hard to be heard.

What do you need?

Anyone who has gone anywhere more than a couple of hours outside a capital city will likely have noticed a drop in phone signal. Telstra claims to cover 99 per cent of the population, while Optus has 98.5 per cent. However, as this is based on population, in reality Telstra covers around 2.5 million square kilometres and Optus covers 1.5 million square kilometres. Given Australia’s land mass is around 7.69 million square kilometres, you’re going to need something like a UHF radio for everywhere else.

UHF (Ultra High Frequency) is a range of frequencies between 300MHz and 3GHz often used through citizen band (CB) radios, which generally sits on 477MHz. It can also carry Bluetooth, Wi-Fi, TV signal and mobile phone data.

UHF broadcasting has been around since the 1930s, but CB radios began to be used by truckies in the ‘70s because it’s cheap and easy communication. Nowadays, almost anyone can use it, and it has become particularly important when travelling offroad.

Apart from calling for help, UHF allows drivers to communicate with other road users, particularly truckers but also other RVers and locals, in areas with limited visibility or where it’s difficult to safely overtake.

They can also make communication when reversing into a tight spot that little bit easier, which will make all travellers a little more relaxed.


Using UHF

Most UHF fit outs consist of a handset, head unit and aerial, though a couple of hand-held units are useful too — these are what you grab when reversing or when encountering particularly tough or tight terrain that calls for a spotter or someone outside the RV calling the shots.

‘Line of sight’ is generally the best description of a UHF radio’s range. Flat terrain will allow about five to eight kilometres, while hilly terrain will reduce this. However, there are a range of UHF antennas suited to particular areas.

Antenna performance is measured in gain — how well the antenna converts input to radio waves and transmits them in a given direction, and vice versa when receiving — and dBi (decibels-isotropic). Though it would seem obvious a higher dBi would work better this isn’t always the case.

On flat terrain, a high dBi (9 dBi is considered high here) is great, because all the antenna has to do is transmit over even landscape — imagine a signal spreading out from the antenna like a wide-ranging disc.

Hilly terrain disrupts this disc, so instead a low dBi (around 3dBi) antenna would work better. They radiate in a much more general field, that covers less distance, that creates something like a sphere that reaches out in every direction, down into valleys and up towards hilltops.

If you wanted to be really safe, having both types of antenna on your RV, linked to separate UHF radios or to the same one with a switch, is possible. Otherwise, a mid-range antenna of about 6 dBi is a good all-round solution.

What channels to use?

There are a range of channels to use that include repeater channels, which use stationary antennas to retransmit UHF signal beyond their limited range, emergency channels and general use ones (see below for a full list). Some key ones to remember though, are: Channel 40, the Australia-wide road safety channel, used mainly by trucks and heavy vehicles; Channel 10, used by 4WD clubs or convoys and in national parks; and Channel 18 is for caravan and camper convoys.

Also note that Channel’s 5 and 35 are restricted by law for use as emergency communications, so stay off them!

Waiting for help

Though a UHF radio will likely reach those who can help, you need to be able to stay as safe as possible until they get there. So if you’re in a pickle make sure you:

  • Stay near your RV or vehicle — rescuers will be able to spot an RV far easier than people wandering around the bush. Depending on what’s happened, you can also dig under your RV to make a spot to stay cool if there’s no shade nearby.
  • Have a First Aid kit — you should have a well-stocked First Aid kit (with medications, asthma puffers and the like in date) at all times when out travelling. Before heading off, make sure anything that has been previously used has been replaced, that more than one person travelling has First Aid training, and consider adding items such as a Defibrillator to it.
  • Grab your ‘Bug Out’ Bag — this is the bag to grab when everything has gone to hell and its time to bug out. It should have at least 72 hours’ worth of emergency rations, shelter and survival gear. Make sure it is easily accessible at all times. It can be good to supplement this bag with an Every Day Carry (EDC) bag of odds and ends needed on a daily basis that can also be grabbed in case of emergency.


  • 5 and 35*: Emergency use only (repeater channels)
  • 1–8: Repeater channels (output)
  • 41–48: Repeater channels (output)
  • 31–38: Repeater channels (input)
  • 71–78: Repeater channels (input)
  • 10: 4WD clubs or convoys and national parks
  • 11*: Call channel (find a friend), once contact is made move to another channel
  • 18: Caravan and camper convoys
  • 40: Road safety channel Australia wide, used mainly by truckies and heavy vehicles
  • 22 and 23*: Telemetry and telecommand, used for data only
  • 29: Road safety channel Pacific Highway and Pacific Motorway
  • 61 to 63*: Reserved for future use
  • General chat channels: 9, 12–17, 19–21, 24–28, 30, 39, 49–60, 64–70, 79 and 80

* Channels restricted by law


Other Communication Tools

UHF radios can often be the first port-of-call when help is needed, but, like anything, they can break or be out of range and not all that helpful. So, it’s always good to have another way of communicating as back up, and there are a variety of choices — Personal Locating Beacons (PLB), satellite phones, Satellite Emergency Notification Devices (SEND).
Satellite phones and SEND devices can be good to have but are often limited by ongoing contracts and the fact they use commercial satellites. It’s far better to have a PLB as it will get you out of trouble more reliably. It has more satellites in the air, a worldwide network of government authorities that will respond, doesn’t need a contract, are cheaper and generally have a battery that can last up to 10 years.

Whatever your extra device, it’s not a replacement for a UHF radio as it can’t communicate with other travellers on the road, so always make sure you have both, and multiple people trained in using a UHF radio and the back-up option.


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