South East Queensland UHF Emergency Service Team

Get To Know Your Radio

Alot of Consumers buy radios and 9 out of 10 dont know how to use them properly or its functions. We have put together information to help guide with you and your radio.

UHF CB Radio Controls

Volume

Volume turns level up and down of any signal

May read on radio as.

Volume - Vol -

Duplex

Allows you to access any Repeaters on any Channel from 1 to 8

may read on you radio as

Dup - RPT - Duplex - Repeater

Selcall

Selective Calling lets you call another radio with your SELCALL number installed on your radio mainly GME and Icom units in the consumer market have this feature.

Call

Alot of handhelds have this function and some base units have this feature. If you push the the CALL button you will hear a ringtone type sound to anyone that listnes out on a channel you do it on.

Scan

Scan lets you scan channels thereare three types of scan functions

Open Scan - Scans all channels between 1 to 40

Group Scan - Group Scan allows to scan more than one channel at once

Priority Scan - Priority Scan allows you to choose one channel to be monitored with more frequency than the others. Operator Selectable Scan lets you program the channels in the scan list to be monitored and select a priority channel.

Antennas

The antenna is the most important piece of equipment in an RF communication system. It does not matter how powerful the transmitter or how sensitive the receiver, without a good antenna the propagation and collection of signals will suffer and hence limit the communication range.

It is also important to understand the relation of an antenna's gain to it's radiating pattern. The diagram below shows the radiating pattern of different gain antennas. As the electrical design of the antenna is modified to increase the gain, the omnidirectional pattern is squashed in a vertical plane, therefore furthering the signal's coverage. A high gain antenna will therefore give increased coverage on flat terrain but the elevation will be limited making it unsuitable in mountainous country.

In the following information we will inform you on the basics of UHF antennas and which antenna to choose to suit your travelling requirements.

Hence the antenna choice for undulating and mountainous terrain is different than flat outback conditions.

Radiation Patterns of Different Db Gain Antennas

The illustrations below best demonstrate how radiation patterns differ between antennas.

Australian UHF CB 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 - Emergency Channel

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 - Emergency Channel

39 - Used for conversations

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