Your GME TX4500S 80 channel radio is Australian
designed and built and is the most advanced UHF
Citizen Band radio available. Combining the very
latest in electronic hardware with the most up-todate computer aided design and manufacturing
techniques has resulted in a mobile radio with
outstanding specifications and performance.
The TX4500S’s DIN sized case allows convenient
installation into a dashboard or console and its
strong die-cast aluminium chassis makes it the
most robust radio of its kind. With just three
rotary controls and five touch keys, the TX4500S’s
extensive features are easy to operate.
IMPORTANT INFORMATION
CONCERNING UHF CB RADIO
The use of the Citizen Band radio service is licensed
in Australia by the ACMA Radio communications
(Citizens Band Radio Stations) Class Licence and
in New Zealand by the Ministry of Economic
Development New Zealand (MED). A General User
Radio Licence for Citizens Band radio and operation
is subject to conditions contained in those licences.
The class licence for users and equipment operating
in the CB/PRS 477 MHz band has been amended.
This radio meets the new 80 channel standard.
In simple terms the same amount of spectrum is
available; however,
operate in a narrower bandwidth and hence use
less spectrum. These radios are generally referred
to as narrowband or 12.5 kHz radios. By using
12.5 kHz channel spacing instead of 25 kHz, the
40 channels originally allocated can now be
expanded to 80 channels thereby doubling the
channel capacity and relieving congestion in the
UHF CB/PRS band.
Original 40 channel wideband Radios will continue
to operate on the original 40 channels, however they
will not be able to converse on the newer channels
41 – 80. The newer narrowband radios will be able
to converse with all older 40 channel wideband
radios on all channels 1 to 40 as well as the newer
channels allocated from 41 to 80.
The mixing of narrowband and wideband radios
in the same spectrum can cause some possible
operating issues of interference and varying levels
of received volume.
radio transceivers can now
POSSIBLE ISSUES
When a new narrowband radio receives a
transmission from an older wideband radio the
speech may sound loud and distorted – simply adjust
your radio volume for best performance.
When an older wideband radio receives a signal
from a new narrowband radio, the speech may
sound quiet – simply adjust your radio volume for
best performance.
Depending on how close your receiving radio is to
another transmitting radio, there can be interference
from the transmitting radio if it is using a channel
adjacent to the channel you are listening to. Simply
try going up or down a few channels from the
currently selected channel.
The above situations are not a fault of the radio
but a symptom of operating wideband and
narrowband radios in the same bandwidth. This
possible interference will decrease over time as the
population of wideband radios ages and decreases.
Further information and updates are available from
the Australian Communications and Media Authority
(ACMA) at www.acma.gov.au and the Ministry of
Economic Development (MED), Radio Spectrum
Management at: www.rsm.govt.nz
EMERGENCY CHANNELS
The ACMA has allocated channels 5/35 for
emergency use only. Channel 5 is the primary
Simplex Emergency Channel. Where a Channel 5
repeater is available, you should select Duplex on
CH 5.
NOTE: Channel 35 is the input channel for the
Channel 5 repeater therefore Channel 35 should
also not be used for anything other than emergency
transmissions.
TELEMETRY CHANNELS
ACMA regulations have allocated channels 22
and 23 for telemetry only applications and have
prohibited the transmission of speech on these
channels. Consequently your radio has a transmit
inhibit applied to channels 22 and 23.
In the event additional telemetry/telecommand
channels are approved by the ACMA, these channels
shall be added to those currently listed where voice
transmission is inhibited. Currently transmissions on
channels 61, 62 and 63 are also inhibited and these
channels are reserved for future allocation.
TX4500S INSTRUCTION MANUAL PAGE 3
FEATURES
TRANSMIT (TX)
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.
RECEIVE (RX)
User Selectable Wide/Narrow Receive Filter
User Programmable Receive-Only Channels: Use the radio’s front panel controls to program up to 95
of your own receive-only channels (in 5 banks of 19 channels) within the 403-520 MHz frequency range.
SCANNING AND MEMORY FUNCTIONS
Microprocessor Controlled Frequency Synthesiser: Allows user programmable control of scanning,
channel memories and selected feature options.
Priority Channels: Two user programmable Priority channels allow your working channels to be instantly
recalled at the press of a key.
Programmable Scan Function: Scans the selected UHF CB channels with Group, Open and Network
Scan functions available.
Auto Skip: Temporarily removes annoying busy channels from the scan group.
SIGNAL PROCESSING
Digital Signal Processing: Measures, filters and compresses
standard analogue audio signals and
converts them into digital format. Allows advanced RF and audio processing techniques to be applied to
maximise the radio’s performance.
Advanced Signal Management (ASM): Identifies interference caused by strong local signals on adjacent
channels and prevents it from opening your Squelch. ASM also minimises distortion on reception by fine tuning
the receiver frequency to match that of an incoming signal. This prevents your Squelch from opening to unwanted
interference and ensures incoming signals remain clear and undistorted even when slightly off-frequency.
Dynamic Volume Control (DVC): Automatically compensates for variations in received audio level
resulting in a constant audio output level to the speaker.
PRIVACY FUNCTIONS
Voice Inversion Scrambler: When activated, scrambles your voice so that communications are only
intelligible to others using the same scrambler technology.
In-Built CTCSS & DCS: User selectable Continuous Tone Coded Squelch and Digital Coded Squelch
System option provides silent channel operation on individual channels.
In-Built SelCall with Quiet Mode: Provides selective calling of individuals or groups with fully user-
adjustable 5 tone transmitted SelCall Ident. Also allows alphanumeric naming of up to 10 Idents for easier
caller identification.
PHYSICAL PROPERTIES
Overvoltage Protection: Special overvoltage detection circuitry protects the radio and warns of excessive
voltage conditions by flashing the display.
Dual Microphone Input Sockets: Front and rear microphone sockets to match most installation needs.
Both sockets can be used independently or simultaneously.
USER CONTROLS AND INTERFACE
High Contrast Liquid Crystal Display: Fully detailed LCD provides a visual indication of the selected
channel and all selected functions at a glance.
Full Spectrum Backlighting: User adjustable, totally customisable colour backlight settings to match the
vehicle’s dashboard lighting or drivers preference.
PAGE 4 INSTRUCTION MANUAL TX4500S
FRONT PANEL CONTROLS
GENERAL OPERATION
Liquid Crystal DisplayChannel ControlSpeaker
LCD PANEL
Squelch
Control
Channel Display
SelCall/Alpha Display/
Signal Meter/Battery
CHANNEL
SQUELCH
Menu/
Function
MENU
F
Scan/
OS-GS
SCAN
OS/GS
PRI 1
PRI 2
Priority 1/
Priority 2
SelCall RXSelCall TX
Scan
DUP
ALPHA
Duplex/
Repeater
(Duplex)
SILENT
QUIET
Alpha
Quiet Busy
Quiet
VOLUME
Volume
Control
Front Mic
Socket
Silent/
Quiet
Transmit
CTCSS/DCS
Tag
REAR PANEL
13.8 V DC Socket
13.8V
DC
ANTENNA
Antenna Socket
MIC SPK
Extension Speaker
Socket
Rear Mic Socket
TX4500S INSTRUCTION MANUAL PAGE 5
MICROPHONE
Skip/Call
Channel
Down
Push To
Talk
Priority
Channel
Up
KEYPAD FUNCTIONS
All controls on the TX4500S front panel have
multiple functions. The primary functions are labelled
in BLACK, while the secondary functions are labelled
in RED. To access a primary function simply press the
required key.
To access a secondary function, briefly press the F
key followed immediately by the required key.
NOTE: When using the F key to access other
functions, F is displayed to indicate that ‘Function’
mode is activated. If the required function is not
selected within 6 seconds the F key selection will
time out with a low beep and F will disappear from
the display.
More detailed descriptions of these key functions are
included in this ‘General Operation’ section.
VOLUME
Rotate the Volume control clockwise past the click
to turn the radio on. Rotate the Volume control left
or right to adjust the volume.
If no sound is heard, rotate the Squelch control
fully counter clockwise to un-mute the radio then
adjust the volume while listening to the background
noise. When finished, readjust the Squelch control
to re-mute the radio.
NOTE: At the minimum volume setting there is
still sufficient volume to be heard in a quiet cabin
environment.
SELECTING CHANNELS
To select the required channel, rotate the Channel
control. Rotate the control clockwise to select a
higher channel or counter clockwise to select lower
channels. The selected channel is displayed on
the LCD.
SQUELCH
The Squelch is used to eliminate any annoying
background noise when there are no signals present.
The Squelch can be opened or closed using the
Squelch control. When the Squelch is open the
receiver’s background noise can be heard and the
symbol is displayed. When the Squelch is closed
the receiver remains quiet while there are no signals
present but any incoming signals will override the
Squelch and be heard in the speaker.
Adjusting the Squelch level
The TX4500S features a continuously variable
Squelch control system allowing the user to set the
Squelch for optimum performance.
To adjust the Squelch, first rotate the Squelch
control fully counter-clockwise until the background
noise is heard and the
indicator is displayed on
the LCD. Now advance the Squelch control slowly
clockwise until the noise is just extinguished and the
indicator disappears. At this point the receiver
will remain quiet while no signals are present but
an incoming signal will override the Squelch and
be heard in the speaker. As the Squelch control
is advanced further clockwise the Squelch action
is progressively increased and stronger incoming
signals are needed to overcome it.
NOTE: If an incoming signal is very weak and is
close to the minimum Squelch level it may become
broken or ‘chopped’ by the Squelch action. To
prevent this simply turn the Squelch control fully
counter-clockwise to open the Squelch. This will
allow a clearer signal.
SIGNAL METER
The signal meter indicates the relative strength of
the incoming signal in numerical format. Signal
strengths are displayed on the lower right of the
channel display in values from 0 to 9. Signals above
strength 9 are displayed as 9+.
NOTE: Refer to the Configuration menu for
other options that can be displayed in this location.
PAGE 6 INSTRUCTION MANUAL TX4500S
TRANSMITTING
Prior to transmitting, always check the channel is
not being used. This can be done by listening to the
channel or by visually checking that the
icon is
not visible or the signal meter is not indicating a signal.
To transmit, press the PTT switch on the
microphone. The
icon will appear. Hold the
microphone about 5-8 cm from your face and speak
at a normal voice level. The microphone is quite
sensitive so it is not necessary to raise your voice
or shout. Release the PTT when you have finished
talking. The icon will disappear.
IMPORTANT:Always listen to ensure the channel is
free before transmitting.
TIME-OUT TIMER
The radio has a built-in time-out timer that
automatically limits transmissions to a maximum of
3 minutes of continuous operation. This feature is
required by the ACMA to prevent accidental blocking
of the frequency should your PTT switch become
jammed or be otherwise pressed accidentally. The
time-out period can be changed by your dealer.
When the time-out timer activates, the radio will
beep for 5 seconds then the
icon will flash
continuously. Normal operation will be restored once
the PTT is released.
BACKLIGHTING
The Liquid Crystal Display and keys are backlit for
easy viewing at night. The backlight remains on
while the radio is switched on.
Adjusting the Backlighting
The backlight brightness and colour can be adjusted
WHITE (Whiteness Setting): Controls the
whiteness or colour saturation of the selected colour
from full colour to white (no colour).
TIP: For the deepest colour range, reduce the
‘WHITE’ setting.
After making your selection, press and hold the
Channel control to return to normal operation.
NOTE: The backlight setting function will
automatically time-out after 6 seconds if no further
adjustments have been made.
BANDWIDTH FILTER SETTINGS
To accommodate the blending of the newer
narrowband UHF CB 80 channel plan with the
original 40 channel wideband system, your radio is
fitted with two user-selectable receiver bandwidth
filters. While either of these will provide superb
receive audio, selecting the wide filter will further
increase the tolerance of the receiver to 40 channel
wideband radios that might otherwise sound overmodulated or slightly off frequency on channels 1
– 40. Selecting the narrow receive filter will increase
the selectivity of the radio to strong interfering
signals from adjacent channels.
To select the desired filter, press and hold the
MENU key to enter the menu, then press the MENU
key repeatedly until NBFLT (Narrowband Filter) or
WBFLT (Wideband Filter) is displayed. Rotate the
Channel control left or right to make the desired
selection.
When finished, briefly press the PTT to exit from
the Menu.
Narrowband filter selected
for personal preference.
To make adjustments to the backlighting, press
and hold the Channel control for several seconds.
BKLGT will be displayed indicating the Brightness
setting is selected. Briefly press the Channel control
to cycle through the available settings. Rotate the
Channel control left or right to adjust the current
Wideband filter selected
setting.
There are three backlight settings available;
BKLGT (Brightness Setting): Provides a
continuously variable brightness adjustment from
very dim to full brightness.
COLOR (Colour Setting): Provides a continuously
variable colour spectrum change via a smooth blend
of colours.
TX4500S INSTRUCTION MANUAL PAGE 7
NOTE: The wideband receiver filter setting is only
applied to channels 1 – 40. Channels 41 – 80
always use the narrowband filter.
DYNAMIC VOLUME CONTROL (DVC)
The modulation level of signals heard on the UHF
CB band has always varied considerably resulting
in noticeable differences in received audio volume
between stations. Generally users have compensated
for this by adjusting the volume control for each
incoming signal. With the introduction of 80 channel
narrowband transmissions that use lower levels of
modulation, the diversity in received audio volume is
likely to increase further.
Your radio is able to automatically compensate for
these variations in received audio level by utilising a
Dynamic VolumeControl. When activated, this
feature automatically compensates for variations in
received audio level resulting in a constant audio
output level to the speaker.
To activate the Dynamic Volume Control, press
and hold the MENU key to enter the menu, then
press the MENU key repeatedly until DVCOF
(Dynamic Volume Control Off) or DVCON (Dynamic
Volume Control On) is displayed. Rotate the
Channel control left or right to make the desired
selection.
When finished, briefly press the PTT to exit from
the menu.
Dynamic Volume Control ON
Dynamic Volume Control OFF
To Enable or Disable the Silent Squelch Tail
1. Press and hold the MENU key to enter
the menu.
2. Press the MENU key repeatedly until ‘SSTxx’ is
displayed (where xx = ON or OF).
3. Rotate the Channel control clockwise to enable
the Silent Squelch Tail. ‘SSTON’ will be displayed
and the Squelch Tail will now be silent.
4. Rotate the Channel control counter-clockwise to
disable the Silent Squelch Tail. ‘SSTOF’ will be
displayed and the Squelch Tail will be restored.
5. Press the PTT to exit the menu.
VOICE SCRAMBLER
Your radio incorporates a simple voice scrambler
using band inversion. The scrambler is compatible
with the majority of scramblers used by other
manufacturers, allowing you to enjoy scrambled
communications with owners of non-GME radios.
Once the scrambler has been activated your
transmission and reception will only be intelligible to
others using the same scrambler technology.
To enable or disable the voice scrambler:
1. Press and hold the MENU key until the
radio beeps.
2. Briefly press the MENU key repeatedly until
ENCOF or ENCON is displayed.
3. Rotate the Channel control left or right to make
your selection. Select ENCON to activate the
scrambler encoder or ENCOF to disable it.
4. Press the PTT to exit the menu.
SILENT SQUELCH TAIL
The Squelch Tail is the short burst of noise that is
heard in the speaker at the end of a transmission
before the Squelch closes.
Scrambler Encoder OFF
REPEATERS AND DUPLEX MODE
Duplex operation allows the radio to transmit on
a different frequency to that which it receives. This
allows operation through repeater stations.
Scrambler Encoder ON
To some it is a reassuring confirmation
that it’s their turn to transmit, but in some
applications it may be an annoyance
especially when listening through an
earpiece or headphones.
The Silent Squelch Tail function removes
this Squelch Tail, reducing it to a faint
SIMPLEX
REPEATER
OPERATION
CHANNEL 31
CHANNEL 1
REPEATER
STATION
CHANNEL 1
CHANNEL 31
click as the Squelch closes.
VEHICLE
PAGE 8 INSTRUCTION MANUAL TX4500S
VEHICLE
A repeater station consists of a linked transmitter/
receiver combination installed in a prominent
location. The repeater is designed to receive signals
on a designated channel and retransmit them on
another channel. Repeaters are usually mounted on
hills or tall buildings. The increased elevation greatly
improves both the receiving and transmitting range
of the repeater allowing it to receive and retransmit
signals to radios that would otherwise be out of
range of each other.
Normally, UHF radios transmit and receive on the
same frequency – known as Simplex operation.
However to communicate through repeaters, your
radio must be able to transmit and receive on
different channels – otherwise known as Duplex
operation. Your radio is fitted with a Duplex key to
allow you to operate through repeaters.
The Duplex function can only be selected on
channels 1–8 and 41–48 as these are the channels
that have been allocated for repeater use. When
Duplex is selected, your radio receives on the
selected channel (e.g. CH 1) but transmits 30
channels higher (CH 31). The repeater hears your
signal on CH 31 and retransmits it on CH 1 for
others to hear.
Channel
Selected
Receive
Channel
Transmit
Channel
1131
2232
3333
4434
5*5*35*
6636
7737
8838
414171
424272
434373
444474
454575
464676
474777
484878
*Emergency channel only
TX4500S INSTRUCTION MANUAL PAGE 9
Your radio allows you to enable or disable Duplex
mode on individual repeater channels. In this way
any repeater channels that are not being used with
repeaters in your area can be used in Simplex mode
for normal direct radio-to-radio communications.
To Enable Duplex on a Repeater Channel
1. Select the required repeater channel (1-8, 41-48).
2. Briefly press the DUP key. The duplex symbol
will appear on the display accompanied by a
high beep.
To Remove Duplex from a Repeater Channel
1. Select the required repeater channel (1-8, 41-48).
If Duplex is currently selected, the Duplex symbol
will be displayed.
2. Briefly press the DUP key. The Duplex symbol
will disappear from the display accompanied
by a low beep.
IMPORTANT:Channels 1-8, 31-38, 41-48 and 71-
78 should only be used in Simplex mode if there are
no repeaters in or near your location that operate on
the selected channel. In particular, avoid operating
in Simplex mode on any of the repeater input
channels 31-38 and 71-78 unless you are absolutely
sure that there are no repeaters in range using that
channel. Inadvertently transmitting on an active
repeater input frequency in Simplex mode could
cause interference to other users on that repeater
that would not be audible to your radio.
PRIORITY CHANNELS
The Priority channel feature allows you to instantly
recall any of the 80 channels in your radio. This
feature can be used to provide instant access to your
working channel or your local repeater channel at
the press of a key. It can also be used in conjunction
with the Group Scan function.
Your TX4500S has provision for two separate
Priority channels.
To Store Priority Channel 1
1. Select the required channel.
2. Press and hold the PRI1 key. The channel
number will flash then a high beep will be heard
as the channel is stored. 'PRI-1' will be displayed
briefly.
To Store Priority Channel 2
1. Select the required channel.
2. Press F then immediately press and hold the PRI 2
key. The channel number will flash then a high
beep will be heard as the channel is stored.
'PRI-2' will be displayed briefly.
To Recall Priority Channel 1
1. Briefly press the PRI 1 key. The radio will
immediately switch to the Priority 1 channel and
'PRI-1' will be displayed briefly.
To Recall Priority Channel 2
1. Press F then briefly press the PRI 2 key. The radio
will immediately switch to the Priority 2 channel
and 'PRI-2' will be displayed for a few seconds.
NOTE: If the radio was scanning when either of the
Priority channels were selected, the scan will
be cancelled.
SCANNING
Overview
Your radio incorporates a Scan function that allows
groups of user programmable channels to be
scanned for signals. Channels can be scanned at a
rate of 40 channels per second. When a signal is
found, scanning will pause to allow the signal to be
heard then resume scanning when the channel is
clear again.
Scan Groups
The TX4500S features three scan groups - Open
Scan, Group Scan and Network Scan. Each scan
group has a separate channel memory allowing you
to program your choice of channels into each group
for scanning.
To cycle between Open Scan, Group Scan or
Network Scan, briefly press the MENU key followed
by the OS/GS key. ‘OPEN’, ‘GROUP’ or ‘NETWK’ will
be displayed briefly.
NOTE: Network scan is disabled by default and if
required, will need to be enabled through the menu.
Quick Select
To quickly determine which channels are currently
programmed into the selected scan group.
1. Briefly press the F key. ‘F’ will be displayed
2. Rotate the channel control to step through the
channels. Only channels that have been stored
into the memory of the selected scan group will
be displayed.
When finished, press the F key to exit.
Auto Skip
While scanning, if an active channel in your scan
group becomes a nuisance by constantly interrupting
the scan, briefly press the SKIP key on the
microphone. The radio will temporarily remove the
busy channel from the scan group for 30 seconds to
allow time for the channel to become clear again.
Scanning will then continue from the next channel in
the sequence. After 30 seconds the skipped channel
will be reinstated in the scan sequence.
If the unwanted active channel continues to interrupt
the scan even after the 30 second skip period has
elapsed, hold the SCAN key while the radio is
paused on that channel. The ‘nuisance’ channel will
be completely removed from the scan group for the
duration of that scan session. To restore the channel,
simply stop and restart the scan session using the
SCAN key (or switch the radio Off then On again).
NOTE: You can skip as many busy channels from
the scan group as you wish, however if you attempt
to skip the last remaining channel, all the previously
skipped channels will be restored to the scan group.
OPEN SCAN
Open Scan allows a group of channels to be scanned
in an ascending sequence. If a signal is found, the
scan will pause on that channel. During this time
you can press the PTT switch on the microphone
and talk on the channel. Once the channel has
been clear for 5 seconds the scan will resume.
1 - 2 - 3 - 4 - 5 - 6 - 7 - 8
Selecting Open Scan
Briefly press the F key followed by the OS/GS key
until ‘OPEN’ is displayed briefly.
Programming the Scan Memory
Your radio has all 80 channels factory-programmed
into the Open Scan memory. Any channels not
required can be removed.
To Add or Remove Channels from the Open
Scan Memory
1. Select the required channel using the
channel control.
2. Check to see if the Scan symbol
on that channel.
a. If
is displayed, the selected channel is
already in the Scan memory. Press and hold the
is displayed
PAGE 10 INSTRUCTION MANUAL TX4500S
SCAN key to remove it.
b. If
Repeat to add or remove other channels in the scan
memory.
Default Working Channel in Open Scan Mode
In the Open Scan mode, your default working
channel is the channel your radio switches to when
you press the PTT while scanning. To define your
working channel simply select the required channel
before you press the SCAN key. e.g. to make
channel 24 your working channel, simply select
channel 24 before pressing the SCAN key.
To talk on your working channel while scanning,
simply press the PTT. The scan will pause and your
radio will switch to your working channel allowing
you to transmit and receive on that channel. Once
your communication has finished and the channel
has been clear for 5 seconds, scanning will resume.
If your radio pauses on a busy channel (other than
your working channel) and you wish to talk on that
channel, simply press the PTT during a break in
the conversation. The busy channel now becomes
your new working channel, replacing your previous
working channel. Once your communication has
finished and the channel has been clear for 5
seconds, scanning will resume.
To Begin Scanning
is not displayed, the selected channel
is not in the Scan memory. Press and hold the
SCAN key to add the selected channel to the
Scan memory. will now be displayed on
that channel.
will disappear.
Briefly press the SCAN key. A high beep will be
heard and the icon will animate. During this
time the channel numbers will change rapidly
as the channels are scanned and the display
will show ‘OS-XX’ where ‘XX’ is your working
channel.
NOTE: If there are less than 2 channels programmed
into the Open Scan memory, a long low beep will
be heard when you press the SCAN key and the
command will be ignored.
Operating in the Open Scan Mode
If a busy channel is located, scanning will pause to
allow the signal to be heard and will remain there
for as long as the channel remains busy. Once the
channel has been clear for 5 seconds, scanning will
resume automatically.
TX4500S INSTRUCTION MANUAL PAGE 11
If you don’t wish to listen to a busy channel, briefly
press the SKIP key on the microphone to skip over
that channel and resume scanning from the next
channel in the sequence (see Auto Skip on page 10).
If you press the PTT while the radio is scanning, the
scan will pause and the radio will transmit on the
working channel. After the channel has remained
been clear for 5 seconds scanning will resume.
If you press the PTT while the radio is paused on a
busy channel, it will transmit on the busy channel
and that channel will then become the new working
channel. After the channel has remained clear for 5
seconds scanning will resume and ‘OS-XX’ on the
display will be updated to show the new working
channel.
If you need to use your Priority channel (for an
urgent call), briefly press the PRI1 key at any time.
The scan will be cancelled and the radio will jump
straight to the Priority channel.
GROUP SCAN
Group Scan allows you to scan a number of channels
for activity while also monitoring your Priority
channel. The receiver will scan the other channels
ONLY WHILE THERE ARE NO SIGNALS ON THE
PRIORITY CHANNEL. If a signal appears on the
priority channel it will override any signals being
received on any of the other channels. In addition, if
you press the PTT switch at any time, the radio will
transmit on the priority channel.
1 - 2 - 3 - 4 - 20 - 5 - 6 - 7 - 8 - 20
Selecting Group Scan
Briefly press the F key followed by the OS/GS key
until ‘GROUP’ is displayed briefly.
Programming the Scan Memory
1. Select the required channel using the channel
control.
2. Check to see if the Scan symbol
on that channel.
a. If
is displayed, the selected channel is
already in the Scan memory. Press and hold the
SCAN key to remove it.
is not displayed, the selected channel
b. If
is not in the Scan memory. Press and hold the
SCAN key to add the selected channel to the
Scan memory.
that channel.
will now be displayed on
is displayed
will disappear.
Repeat to add or remove other channels in the scan
memory.
Select your Priority channel
Program your Priority channels as described earlier
under ‘Priority Channel’ then select which of the
two Priority channels you wish to use for this Group
Scan session. You must select your preferred Priority
channel prior to scanning.
• PressthePRI 1/PRI 2 key to use Priority
channel 1.
• PressF then the PRI 1/PRI 2 key to use Priority
channel 2.
To Begin Scanning
Press the SCAN key. A high beep will be heard and
the
icon will animate. During this time the
channel numbers will change rapidly as the channels
are scanned with the Priority channel will be
scanned every fourth channel. During this time the
display will show ‘GS-XX’ where ‘XX’ is your selected
Priority channel.
If a signal appears on the Priority channel – at any
time – the radio will switch directly to the Priority
channel. The radio will now stay on the Priority
channel for as long as the channel remains busy.
During this time you can transmit and receive on the
Priority channel. Once the Priority channel has been
clear for 5 seconds the radio will resume scanning
the other channels.
If a signal appears on any other channel, scanning
will pause on that channel and will remain there
while the channel is busy – as long as there are no
signals on the Priority channel. During this time, the
receiver will continue to check the Priority channel
every 2 seconds resulting in a series of small breaks
in the reception of the busy channel. Once the
signal has gone and there has been no activity on
any channel for 5 seconds, the radio will resume
scanning.
To transmit on the Priority channel at any time,
simply press the PTT. The radio will switch straight
to the Priority channel. When you have finished your
conversation and there has been no further activity
for 5 seconds, the radio will resume scanning the
other channels.
If the scan pauses on a busy channel and you don’t
wish to listen to that conversation, press the SKIP
key on the microphone to temporarily skip that
channel and resume scanning (see Auto Skip on
page 10).
PAGE 12 INSTRUCTION MANUAL TX4500S
If the radio is paused on a busy channel and you
want to remain there, briefly press the SCAN
key. The radio will exit Scan and remain on the
busy channel. At this point you will no longer be
monitoring the Priority channel.
To resume Group scanning press the SCAN key
again.
ADDITIONAL OPEN/GROUP SCAN
OPTIONS
By default your radio has one Open Scan mode and
one Group Scan mode. There may be applications
where you have no need to monitor a Priority
channel and would prefer to have two separate
Open Scan modes.
Alternately you may prefer to have two separate
Group Scan modes with different Scan channels in
each. Your radio can be programmed to convert the
Group Scan into an Open Scan and vice versa. If
this is required, please contact your GME retailer to
arrange for this feature to be activated.
When two Open Scan or two Group Scan modes are
enabled, the Scan Group selection screen will display
Open1 and Open2 for the Open Scan groups or
GRP1 and GRP2 for the Group Scan groups. See the
section ‘Scanning’ on page 10.
NOTE: Enabling or disabling a second Open or
Group Scan mode is not a user selectable option.
Once enabled or disabled, the new Scan mode
becomes a permanent part of your radio’s features.
If you decide later that you need the original Scan
mode settings restored you will need to return your
radio to your GME retailer for re-programming.
NETWORK SCAN (NET-SCAN)
Net-Scan allows a group of radio users to maintain
communications even when the band is congested.
To achieve this all members of the Net-Scan group
must share a common CTCSS/DCS code and a
common set of scan channels.
Once activated, Net-Scan’s intelligent scanning
software keeps track of clear channels within
your scan group. When any member of the group
transmits, their radio automatically selects a clear
channel to transmit on. Other radios scanning
in the same Net-scan group will lock onto that
channel allowing all members of the group to join
the conversation. If a signal from outside your
Net-Scan group appears on the chosen channel
(either with no code or the wrong code), the group
will automatically switch to a new clear channel at
the next transmission. In this way the group can
continue to communicate with minimal interference
to or from other users.
Enabling Net-Scan
Net-Scan is normally switched off by default but can
be enabled through your radio’s menu.
NOTE: When you enable Net-Scan you will also be
prompted to choose a suitable CTCSS or DCS tone
to be used by your Net-Scan group. All members of
your Net-Scan group must use this same code.
To Enable Net-Scan
1. Hold the MENU key until the radio beeps. The
radio will enter the menu mode.
2. Briefly press the MENU key repeatedly until ‘NS-
OF’ is displayed.
3. Rotate the Channel control clockwise to enable
Net-Scan then continue rotating to select a
suitable CTCSS or DCS tone.
•CTCSStonesforNet-Scanarelabelled
NS-01 – NS-50.
•DCStonesforNet-Scanarelabelled
NS001 – NS104.
To quickly determine which channels are
currently programmed into the Net-Scan
group
1. With the NETWORK scan group selected, briefly
press the MENU key. ‘F’ will be displayed
2. Rotate the Channel control to step through the
channels. Only channels that are stored in the
Net-Scan memory will be displayed. Take a note
of the channel numbers to compare with the
other radios in your Net-Scan group.
When finished, press the MENU key to exit.
To Add or Remove Net-Scan Channels
With Net-Scan mode enabled, select the require
channel using the Channel control.
the
display. To remove the channel, hold the SCAN
key until a low beep is heard. will disappear
indicating the channel is no longer in memory.
• Ifthe
icon is not visible above the channel
display, the selected channel is not in the NetScan memory. To add it, hold the SCAN key until
a high beep is heard. will appear to confirm
the channel is now in memory.
Repeat to add or remove further Net-Scan channels.
IMPORTANT:When adding channels to Net-Scan,
e.g. Netscan CTCSS tone 50 e.g. Netscan DCS tone
104
4. When the required CTCSS/DCS tone is displayed,
press the PTT to exit.
Selecting Net-Scan
When Net-Scan is enabled, a new Network scan
option becomes available on the OS/GS key. To
select the Network Scan option, press the MENU
key followed by the OS/GS key to cycle through the
available scan groups until ‘NETWK’ is displayed.
The radio is now in the Network Scan mode.
Programming channels into Net-Scan.
All radios in your Net-Scan group must have the
same channels programmed into their Net-Scan
memory. Your radio’s Net-Scan memory has already
been factory programmed with 43 of the available
80 channels. The remaining 37 channels, which
consist of the 32 repeater input/output channels,
2 telemetry channels and 3 guard-band channels,
have not been included to minimise the risk of
interference to other services on these channels.
channels 22, 23 and channels 61, 62, 63
as required by the ACMA. This makes these
channels unsuitable for use as Net-Scan channels.
• Youshouldnotincludeanyrepeaterchannels
unless you have confirmed that the channel is not
allocated to a repeater in your area. If you add
an active repeater channel into your Net-Scan,
you or others in your Net-Scan group may cause
interference to other repeater users on that
channel.
Starting Net-Scan
With Net-Scan mode enabled, press SCAN. The
radio will begin scanning and ‘NSxxx’ (where xxx is
the selected CTCSS or DCS tone) will be displayed.
Using Net-Scan
When a member of the group initiates a transmission
their radio will automatically select a clear channel
to transmit on. Other radios scanning in the same
Net-Scan group will locate the transmission by
identifying the group’s CTCSS/DCS code and open
their Squelch allowing the transmission to be heard
across the entire group. When the transmission
ends, all radios in the group will immediately resume
scanning.
If a member of the group responds to the initial
transmission, they will automatically re-use the
same channel as long as the channel remains free of
other signals. This allows the radios in the group to
respond more quickly to further transmissions from
others in the group.
If at any time, a signal from outside your Net-Scan
group appears on the channel (either with no code
or the wrong code), the channel will be discarded
and a new clear channel will be selected at the next
transmission. The other radios in the group will then
locate the new channel allowing the conversation to
continue seamlessly without any input from the user.
Ending the Scan
To stop scanning, briefly press the SCAN key. A
low beep will be heard and the animated
icon will stop. As long as the radio was not on a
busy channel, it will return to the last channel you
selected, otherwise it will stay on the busy channel.
mode and you need to use your Priority channel
(for an urgent call or an emergency), briefly press
the PRI1 key. The scan will be cancelled and the
radio will jump straight to the Priority 1 channel.
When your conversation has finished, press the
SCAN key to continue scanning.
• IfyourradioisscanninginGroupScanmode
simply press the PTT. The radio will automatically
transmit on the Priority 1 channel. When your
conversation has finished, the radio will resume
scanning 5 seconds after the channel has become
clear.
CTCSS & DCS
The standard Squelch system is fine for quieting the
radio in most applications. However, it operates
solely on signal strength which means that it will
always open to any signal that is strong enough. If
the channel is busy with other stations the Squelch
will be constantly opening making it difficult to
determine which calls are meant for you.
CTCSS/DCS provides selective audio muting using
sub-audible signalling. When enabled, only signals
with a matching sub-tone will be heard in the
speaker. This effectively creates a channel that is
silent to all traffic except those you wish to hear.
Choosing CTCSS or DCS
CTCSS uses a continuous analogue sub tone while
DCS uses a digitally encoded sub tone. Choosing
which tone system to use will largely depend on
the other radios you talk with. If others already use
CTCSS or DCS, you should select the tone system
that matches theirs. If the users you talk to don’t
currently use CTCSS or DCS then you can make your
own choice. There is no difference in performance or
function between the different tone sets. Both types
are included in the radio to maintain compatibility
with other radio systems.
CTCSS Tone Set
The GME CTCSS tone set comprises a table of 50
tones made up of the standard CCIR-38 Tone Set
plus an additional 12 tones added to the end. If
communicating with other brands of radios that only
use the CCIR-38 tone set, please select from one of
the first 38 tones to ensure compatibility with these
radios.
If communicating with other GME radios, you may
choose from any of the 50 tones. However, please
refer to the tone set tables listed in each radio’s
Instruction manual for compatibility because,
although the same 50 tones are available in all GME
radios, the tones used in older GME models may be
listed in a different order to those in your radio.
DCS Tone Set
There are 104 DCS tones available (see the DCS tone
chart at the rear of this manual).
To Select a CTCSS or DCS Tone
1. Press and hold the MENU key until the radio
beeps. The CTCSS menu option will be displayed.
2. If ‘CTCOF’ is displayed, CTCSS/DCS tones are
currently switched off (default). To enable CTCSS
tones, rotate the Channel control to the right.
CTCSS tones will be displayed as CTC01 – CTC50.
Continue rotating the
3.
Channel control to scroll
past CTCSS tone 50 to access the DCS tones. DCS
tones are displayed as DT001 – DT104.
PAGE 14 INSTRUCTION MANUAL TX4500S
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