UHF Radio @ ExplorOz

Citizen Band Radio Types (CB)	UHF Radio Installation
Important UHF Radio Information	UHF Radio Considerations
General UHF Radio Information	Article Feedback
UHF Radio Features	Related Pages

In this Article

Citizen Band Radio Types (CB)

UHF Radios have become the more popular choice of CB, mainly due to their considerable price drop over the past decade and with repeater locations constantly growing throughout Australia, UHF CB users are gaining more coverage. 27MHz CBs used to be very popular, however with the advantages of UHF Radios and other communications devices such as HF radio, satellite phone and mobile phones, this is starting to diminish.

27MHz CB

This system utilises 40 channels in the High Frequency (HF) range, which covers 26.965Mhz to 27.405MHz. These CBs use Amplitude Modulation (AM) and they usually come with upper and lower sideband (SSB) which helps increase range and performance. AM and SSB are not compatible with one another and for this reason the AM mode is encouraged to be used on channels 1 to 14 and the SSB mode on channels 15 to 40. AM signals can sometimes be fairly noisy and distances can vary from 5km to 10km in normal conditions. When SSB is used on a channel, distances between 15km and 50km can be obtained.

UHF CB

This system utilises 40 channels in the Ultra High Frequency (UHF) range, which covers 476.425MHz to 477.400MHz. These CBs use Frequency Modulation (FM) and have become the preferred mode of operation for many. Since UHF signals travel in a straight line, the terrain plays an important part in how well the signal is transmitted or received. For example, the transmission will perform quite poorly if the signal is blocked by hilly or heavily forested areas. On flat terrains such as open countryside, distances between 5 and 20km may be achieved. Distances of up to 100km can be achieved if one or both UHF CB units are elevated on say a hilltop. UHF signals are less prone to power line noises and can also provide clear and crisp communications without the long distance interference which is evident on 27MHz signals. UHF CBs can utilise a repeater station that retransmits the signals onto another channel. This can provide much further coverage and can be handy when you are out in the bush and you want to scan and talk to other fellow trekkers.

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Important UHF Radio Information

The use of CB radios, which include both 27MHz Radios and UHF Radios are authorised under the Radiocommunications (Citizen Band Radio Stations) Class Licence 2002. This class licence, which is issued by the Australian Communications and Media Authority (ACMA) governs the frequencies that may be used and the equipment standards and technical parameters. The great thing about this class licence is; it does not need to be applied for and there are no licence fees. The only tiny catch under the licence is; all users must operate in the allowed frequency range on a shared and cooperated basis and those users are all subject to the same conditions outlined in the licence.

UHF Radio Technical Standards

All UHF Radios must comply with a technical standard across the board for manufacturers and private hobbyists to adhere to. The three major concerns are:

Transmitting power for UHF Radios must not exceed 5 watts

Operation of UHF Radio stations must only employ FM or PM (Phase Modulation)

Necessary bandwidth of UHF Radios must not exceed 16kHz

Interference Management

In some cases, interferences may occur when a CB is operating near television and radio receivers. The ACMA has produced several booklets and information brochures on how to resolve interference problems. At the end of the day, it comes down to fair cooperation with the affected television viewer or radio listener to resolving any issues.

Breaches of the Class Licence

The operator will no longer be authorised to operate under the class licence and would be liable for prosecution if breaches such as: operating on a frequency which is not permitted and using an emergency channel for non emergency use.

General UHF Radio Information

Repeaters

UHF repeaters are special transmitting/receiving stations that are usually located in high areas to allow extended coverage. These stations, which are usually owned by businesses, farmers and clubs, allow UHF users to use them to re-transmit their signal. It works when you press your microphone button with the “Duplex or Repeater” button selected also. You must transmit between channels 1 to 8 because the “Duplex or Repeater” selection will add 30 channels and will now transmit to channels 31 to 38 on the repeater. The repeater, which previously collected the signal on 31 to 38, then switches to its output channel 1 to 8 to transmit simultaneously to say another radio user on the other side of the hill.

This can be hard to describe with words but if you can picture a device that needs two frequencies to work and it needs to keep these input and output frequencies as far apart as possible to allow the simultaneous receive and transmit (i.e. 31 to 38 for the repeater's input and 1 to 8 for the repeater's output). The further apart these two frequencies, the easier it is to keep the transmitter circuitry from interfering with the receiver circuitry. Therefore, you should not transmit to a repeater on channels 31 to 38. Please respect the fact that repeaters are erected and maintained by private individuals and you should keep the usage relatively short.

See the UHF Repeater Search for an Australia-wide map of repeater locations.

UHF Radio Channel Allocation

Below you will find a list of UHF Radio channel allocations. There are many channels that have been established by law including the Emergency channel 5 and the data transmission channels 22 and 23.

1 to 8 - These channels, which are established by law, can be used when sending a signal to a repeater which will help increase the communication distance

5 - This channel, which is established by law, can be used by anyone but only in an emergency situation

9 - Used for conversations

10 - Used by 4WD enthusiasts, clubs, convoys and in national parks

11 - Calling channel. This channel, which is established by law, is used to call or locate another station. Parties will then switch to another channel to continue with their conversation

12 to 17 - Used for conversations

18 - Holiday maker’s communication channel (e.g. when in a convoy)

19 to 21 - Used for conversations

22 and 23 - These two channels are used for data transmissions and is established by law. Voice transmissions are not allowed on these two channels

24 to 30 - Used for conversations

29 - Highway Communications which are mainly used by truck drivers and other highway users

31 to 38 - These channels, which are established by law, are received by a repeater and re-transmitted on channels 1 to 8 to help increase the communication distance

35 - Can be used in case of Emergencies also

39 - Used for conversations

40 - Highway Communications which are mainly used by truck drivers and other highway users

Telemetry & Telecommand Systems

This technology describes the transmission of data and related information via a certain frequency such as infra red or UHF. By utilising telemetry and telecommand systems via UHF signals, farmers can remotely control the operation and function of various types of equipment such as electric fences, water pumps and dam levels from many kilometres away.

UHF Radio Features

Below is a list of features you should look out for when choosing your UHF Radio. These include technologies such as: Continuous Tone Coded Squelch System (CTCSS), Programmable Scan Function and Overvoltage Protection.

Programmable Scan Function - Scans up to 40 user programmable channels with both Group and Open scan functions available

Remote or Local Installation Options - This can be mounted either remotely using the separate control head, or locally with the control head attached to the main unit

Unique Page/Transpond Mode - Allows you to transfer an incoming Selcall to another radio if your radio is unattended

Quiet Mode - Selectable on individual channels, the Quiet mode prevents incoming signals from being heard on selected channels unless preceded by your selcall code

Overvoltage Protection - Special overvoltage detection circuitry protects the radio and warns of excessive voltage conditions by flashing the display

Extra Channels - EXTRA receive channels available

Inbuilt Selcall - Selective Calling with 4 or 5 digit ANI and fully user adjustable 5 tone transmitted Selcall Ident. Some units may allow naming of Ident for easier caller identification

User Selectable Priority Channel - Lets you programme your normal working or local repeater channel for instant recall at the press of a button

Feature Disabling Function - Allows scanning, squelch, duplex and priority functions to be enabled or disabled to make the radio simpler to operate

Individually Programmable Duplex function - User selectable for only those individual channels in your area that have repeaters, leaving the others free for use as extra simplex channels

CTCSS Ready - A built-in Continuous Tone Coded Squelch System provides quiet channel operation

UHF Radio Installation

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There can be several questions you need to consider when installing UHF Radios such as: where to mount the radio antenna? where to install the UHF radio itself? and how is the co-axial cable terminated? It is possible to do the installation yourself, although it is recommended to seek additional advice from radio and electronic technicians. These professionals can also install the system for you, which will give you peace of mind knowing that it was done correctly. We have provided some information below that may help you based on our own experiences.

RG-58U series including the RG-58C has a loss factor of 13.5dB over 30m

RG-213 has a loss factor of 5dB over 30m

Terminating the Co-Axial Cable

If you have never done this before it is really very easy. You will need a soldering iron and a sharp knife such as a Stanley knife or similar. Click on the picture below to see a bigger and clearer shot of the steps involved.

A - Carefully cut the black insulation away about 3 cm then cut the outer conductor leaving about 1cm

B - Fold back the outer conductor

C - Cut the inner insulation about 5 mm from the outer conductor

D - Slide some heat shrink and the outer piece of the connector or the entire area, then screw the fitting over the exposed outer conductor

F - Solder the inner conductor to the end of the fitting

G - Slide up to other parts and screw it together then place the heat shrink over the end and heat it

Testing

If you have a multimeter then set it to Beep or resistance check say 200 Ohm range - remove the antenna from the base and make sure that there is no short circuit (i.e no beep or not 0.00 on the Ohms test).

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UHF Radio Considerations

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Handheld UHF Radios

Handheld models are also popular with obvious advantages of portable, the high advances in electronic technology and their increased affordability. These CBs range from as little as $40 to over $400 and provide as much functionality as the base station CBs. There are some top end models that have a range of up to 12km with an impressive 5 watts of TX output power. As well as being lightweight, ruggedly built with waterproof construction, these CBs are no toy. These units can be very handy for travellers in a whole range of situations.

Usually sold in sets of 2 handheld units you can lend one unit to another vehicle/person to enable UHF communication in an instant such as in the following scenarios;

passenger leaves vehicle to check the track ahead and can use handheld unit to communicate back to the vehicle with information

search and resuce situations involving 2 people (or as many handheld units are available) spreading out in different directions used in conjunction with an installed UHF system in a vehicle is an effective and sensible capability you can coordinate if planning a remote trip

one party may wish to stay behind at the campsite whilst another member goes boating, fishing, bushwalking etc.

With handhelds UHFs you have an extra level of safety and peace of mind when heading off on solo excursions away from the vehicle, or campsite for minimal cost.

Vehicle Shower
Water is the single most precious commodity you need to carry for your trip. Although heavy, we need to carry it for drinking, cooking and washing. When it comes to personal hygiene during remote travels, we often scrimp on the luxuries and make do with a quick wash of the arm pits and other spots. [Feature Story]

Roof Racks, Luggage Trays & Boxes
In this article we look at the pros and cons of using the roof of your vehicle for storage when travelling; discuss what not to carry on your roof; provide some helpful packing hints and finally some useful buying tips with links to suppliers who sell roof rack luggage trays and storage systems.

HF Radio
HF Radios are a wise consideration if you intend to travel throughout remote regions of Australia. In this article we discuss the usefulness of HF radio in practical situations and explain the many featues and services avaialble to enhance your use of the equipment including links to suppliers and manufacturers.

Cargo Drawers
This Article looks at gearing up for a 4WD camping trip and the need to find a sturdy, compact storage solution that won't rattle, break or allow loose items to fly around the cabin. We look at cargo drawers and list the features you should look for.

Snorkel
Although significantly different, both petrol and diesel engines require a steady flow of air to operate. If the vehicle is not fitted with a snorkel, they do this by sucking air through the inner guard of the bonnet or just behind the grill. These open airways will also allow water to enter the engine if submerged - with disastrous results!

Suspension
There is an unfortunate but realistic fact about purchasing a new 4WD - it won't come fitted with a suspension system designed to carry the kind of load you'll pack for a serious outback trip. In this article we explain why it is important to consider fitting a new suspension system and what is involved.

Water Tank
Water storage is a critical issue for all four wheel drivers. Not only do you need to carry large amounts of fresh water, you also need 2 alternate supplies in case of contamination from one source. We suggest a couple of small plastic jerry cans for backup but for the main supply, the best water carrying solution is a stainless steel water tank.

Recovery Gear Needs
The majority of situations that will stop a 4WD from moving are tyre punctures or getting yourself bogged in mud or sand - and these can happen in the simplest of situations, and for no real fault of the driver.

Aftermarket Seats
Unfortunately, car manufacturers don't always expect us to actually take our vehicles offroad - so when it comes to fitting out your vehicle for a major trip you replace your suspension to improve the ride so ... why not replace your seats?

HF Radio Installation
In this article, we discuss the procedures for installing a HF radio and the modifications that can be considered for a successful installation. We look at the different options and locations on the vehicle to mount the antenna base and provide some cabling and console tips to give that professional look.

Winches
All travellers should be capable and equipped for winching so in this article we will discuss the various winching methods and equipment on the market.

Driving Lights
If you plan to do any night driving in the outback then a strong reliable light source is a must. Bad weather, night driving and the possibility of stray animals all demand the need for a clear view of the road and the standard vehicle high beam is not enough.

Portable Fridges
The debate over which fridge is the best on the market is one of the most contested discussions in the camping recreation. In this article we look at the range of features and the major issues to consider when comparing brands and models.

Long Range Fuel Tanks
A large number of outback treks involve long distances between fuel outlets. Jerry cans are dangerous, difficult to store and not as convenient as a long range fuel tank. Fitting a long range fuel tank is a common modification and there are many good manufacturers.

Bull Bars, Rails & Steps
A vehicle's bull bar, sides steps and rails are known as its "bar work". Some critics might suggest that bar work is not necessary but for people actually using their vehicles for offroad touring, the bar work provides critical strength and protection and should therefore be considered as essentials.

Bike Carriers
Using a recreational vehicle such as a 4WD is all about exploring places and enjoying yourself. Taking a push bike can provide you with the added advantage of exercise and exploring that little further in the nice open air.

Accessories
Detailed articles on the complete list of vehicle accessories and equipment on today's market - includes basic essentials for weekend camping and must-have gear for setting up a 4WD for serious offroad use.

Topics Index
Each Topic contains a range of detailed and useful articles on products, services and issues. This section is full of practical tips, ideas, photos and factual information.

Accessories	Cargo Drawers	Long Range Fuel Tanks	Water Tank
Topics Index	Snorkel	Recovery Gear Needs	Bike Carriers
Suspension	Bull Bars, Rails & Steps	Winches	Aftermarket Seats
Driving Lights	Roof Racks, Luggage Trays & Boxes	Vehicle Shower	HF Radio Installation
Portable Fridges	HF Radio