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CB (Citizens Band) Radio
CB Radio provides short-range
radio communication. There is currently no license required to
operate. There are two types HF 27 MHz and UHF 477 MHz. The MHz
(megahertz) refers to the radio frequency on which the equipment operates.
First introduced in
1970, the government initially allocated 18 channels and an annual fee was
payable to obtain a license. In 1982 the band was extended to 40 channels,
and in 1994 the government abolished CB license fees.
The Australian Communications & Media Authority (ACMA)
announced proposed changes from January 2011 increasing the number of
allocated UHF CB channels from 40 to 80. All the changes are not yet
finalised awaiting a second round of comment. Stage
two is expected to take effect after January 2016 when all 80 channels will
become available for narrow band transmissions. These changes are expected
to provide less congestion.
What some of these changes to the UHF CB channels will mean
to you:-
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if you own an old CB UHF radio it will continue to work and you will
be able to talk to another person but only if that person is
on one of the current 40 channels |
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the terms ‘wideband’ will be used to describe older 40 channel and
‘narrowband’ for the newer 80 channel CB radios |
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only the new narrowband CB radios will have additional channels up
to 80 |
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channels 61, 62 & 63 will be temporarily unusable |
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the sound may be a little distorted using the older 40 channel
radios |
GME is one company, who make CB radio
handsets in Australia, that had anticipated these changes so from December
2010 they commenced building UHF CB radios with the existing 40 channel
standard and the new narrowband 80 channel standard.
As of June 2011, GME owners of compatible radios can now
operate on the new 80 channel narrow band
channels. GME radios that are 80-channel compatible can be easily identified
by an ’80 Channel Upgradable’
sticker on the packaging and by the following serial number prefixes. Their
website, under ‘News & Events’ 30 May 2011 provides instructions on how to
upgrade the UHF CB radio.
When having a
conversation always remember CB radio communication is not private. Also,
CB is not like a telephone in that only one person can speak at a time.
For communication in ‘Outback’ Australia it is
recommended you buy or hire a satellite
telephone or HF transceiver.
See HF Radio article
AM
(27MHz) equipment is rarely used these
days as it only provided a small range (approx
1- 3 kilometers) and speech was difficult to
understand. Vehicle noise was also a
problem.
A UHF (FM) CB radio provides a clearer
communication with less interference from such
things as power lines or atmospheric noise. It
uses the 40 channels between 476.425 to 477.400
MHz .
The UHF CB came of age with the introduction of
repeater stations that retransmit signals
received on one channel onto another channel.
Channels 1- 8 are designated as repeater output
channels with channels 31 to 38 the
corresponding designated repeater input
channels. For example, a repeater that
transmits on Channel 1 will always receive on
Channel 31.
Modern transceivers can scan channels and
lock in on a channel when a signal is
heard. UHF communication is often termed ‘line
of sight’ communication as good communication is
available where there are no obstructions such
as hills between yourself and say another
vehicle with whom you are communicating. UHF
has a range, in good conditions, of about 20-30 kilometers. When in areas where repeater
stations are installed this range can improve
the range up to about 300 kms.
Some brand names of radio transceivers are GME
Electrophone, Uniden and Icom.
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