UHF CB radio can
now transmit data
A
fter having been lobbied for
many years by rural users, the
Australian Communications
Authority (ACA) has announced
changes to Citizens band (CB) radio
licences to allow the transmission of
data on UHF CB channels 22 & 23.
The changes announced by the ACA
regarding these two channels will
allow for the use of selective calling
techniques such as CTCSS (Continuous Tone Coded Squelch System) and
telemetry and telecommand systems.
Tone squelch allows a system of
selective calling, where a number of
transceivers share one channel but
will only “wake up” and listen if they
receive the same preset tones as they
have had previously programmed.
Telemetry and telecommand will
allow data to be transmitted between
sets. Previously the regulations for-
The Uniden UH-100 is already equipped with
CTCSS. Now it – and data transmission – will
be legal. Courtesy Dick Smith Electronics.
bade this, citing CB as a “voice only”
medium.
The use of these techniques will
allow the design of cheap equipment
to remotely monitor various parameters on farms including water levels
in dams and rainfall in paddocks over
a period. They could also be used to
control irrigation pumps and even to
open and close gates.
Similar techniques could be used
to remotely monitor equipment on
boats, such as bilge water levels,
battery voltages and even weather
conditions - why go down to the boat
if it is blowing a gale? Or maybe you
might want to check the boat if it is
blowing a gale!
And how about security? Remote
burglar alarms, remote control and
monitoring and so on? The list of
possible uses is endless. Which may
be why some CB users are objecting
to the changes.
One change which has not been
included is “packet radio”, currently
allowed on the Amateur Radio bands.
The ACA is also seeking to amend
the UHF CB radio equipment standard
to reflect the above changes.
This will require the fitting of a
“channel busy” light to indicate the
presence of any signal on the channel
concerned and a switch to disable any
selective calling facility to create a
“listen before transmit” function.
Now that the change to allow data
transmission has been made, channels
22 and 23 will no longer be available
for voice transmission.
If you want more information on the
changes to the CB class licence and
related topics go to:
SC
www.acma.gov.au
MARCH 2001 29
