GME TX3420 User manual

PAGE 2 INSTRUCTION MANUAL TX3420
INTRODUCTION ..........................2
EMERGENCY CHANNELS. . . . . . . . . . . . . . . . . . . . 2
TELEMETRY CHANNELS.....................2
FEATURES...............................2
GENERAL OPERATION......................3
Function Key...........................3
VolumeKey ...........................3
KeylockFeature ........................3
Selecting Channels ......................4
Transmitting ...........................4
SquelchControl........................4
Squelch Sensitivity . . . . . . . . . . . . . . . . . . . . . . 4
PriorityChannel........................4
DuplexOperation.......................4
CTCSS..................................5
SCANNING ..............................6
OPEN SCAN MODE ........................7
GROUP SCAN MODE.......................7
SELECTIVECALLING.......................8
USINGSELCALL ..........................9
GROUP CALLING. . . . . . . . . . . . . . . . . . . . . . . . . 12
LISTENING CHANNELS . . . . . . . . . . . . . . . . . . . . 13
SEEKMODE ............................14
MENU SETTINGS.........................16
INSTALLATION ..........................18
CTCSS TONE FREQUENCY CHART . . . . . . . . . . . . 21
UHF CB OPERATING FREQUENCIES ...........22
SPECIFICATIONS .........................23
WARRANTY ............................24
GME After Sales service . . . . . . . . . . . . . . . . . 24
CONTENTS
INTrOduCTION
Your GME TX3420 radio is Australian designed and built
and is the most advanced UHF Citizen Band radio available.
The TX3420 combines the very latest in electronic
hardware with the most up-to-date computer aided
design and manufacturing techniques to produce an
extremely compact mobile radio with outstanding
specifications and performance.
The TX3420's small size means it can be mounted in almost
any convenient location and its strong diecast aluminium
chassis makes it the most robust transceiver of its kind.
With just two rotary controls and four touch keys, the
TX3420 is easy to operate.
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
the TX3420 has a transmit inhibit applied to channels 22
and 23.
FEaTurES
•Microprocessor Controlled Frequency Synthesiser:
Allows user programmable control of scanning, channel
memories and selected feature options.
•Permanent Memory: Retains all user settings in non-
volatile memory even when the power has
been removed.
ThE FOllOwINg ITEmS arE INCludEd wITh yOur TX3420
• TX3420 Radio
• Mounting Cradle
• Instruction Manual
• Microphone
• Microphone Clip
• DC Lead
• Screw Pack
If any items are missing or
damaged, please contect your
retailer or place of purchase.

TX3420 INSTRUCTION MANUAL PAGE 3
•Programmable Scan Function: Scans the programmable
UHF CB or Receive-only channels with both Group and
Open scan functions available.
•Remote or Local Installation Option: The TX3420 can
be mounted either remotely using the separate control
head, or locally with the control head attached to the
main unit.
•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.
•Priority Channel: A user programmable priority channel
feature allows your working or local repeater channel to
be instantly recalled at the press of a button.
•High Contrast Liquid Crystal Display: Fully detailed LCD
provides a visual indication of the selected channel and
all selected functions at a glance. Backlit for viewing
at night.
•In-Built Selcall: Selective Calling with five digit ANI
and fully user-adjustable 5 tone transmitted Selcall
Ident. Also allows naming of Idents for easier caller
identification.
•Quiet Mode: Selectable on individual channels, Quiet
mode prevents incoming signals from being heard on
selected channels unless preceded by your Selcall code.
•CTCSS: A built-in Continuous Tone Coded Squelch
System option provides quiet channel operation.
•Overvoltage Protection: Special overvoltage detection
circuitry protects the radio and warns of excessive
voltage conditions by flashing the display.
•Surface Mount Technology: The very latest surface
mount component types, design and assembly
techniques and quality control procedures are used
to ensure the highest performance and reliability.
•Designed and Manufactured in Australia: The TX3420
has been totally designed and manufactured in
Gladesville N.S.W. to meet the demanding needs of
the Australian community.
Channel Selector /
PRI Key Liquid Crystal Display Volume Control
Microphone Port Menu Key /
F Key
Scan Key /
OS/GS
Quiet Key /
Duplex Key
Squelch Key /
Alpha Key
MENU
F
PUSH
SCAN
OS/GS
QUIET
DUP
SQL
ALPHA
TX3420
PRI
gENEral OpEraTION
FUNCTION KEY
The four keys beneath the TX3420’s display have both
primary and secondary functions. Their primary functions
are printed in Black while their secondary functions are
printed in Red.
To access the primary functions
Simply press the required key. e.g. To control the Squelch,
briefly press the SQL key.
To access the secondary functions
Press the Fkey followed immediately by the required
key. e.g. To lock the radio, briefly press the Fkey (‘F’
is displayed), then press the Channel knob. The radio
will lock.
Note: If the secondary key is not pressed within 10 seconds
the Fkey selection will be cancelled.
VOLUME KEY
Rotate the Volume control clockwise past the ‘click’ to turn
the TX3420 ON. Continue to advance the control clockwise
to increase the volume. Rotate the control counter clockwise
to turn the radio OFF.
Note: At minimum volume setting there is still sufficient
volume to be heard in a quiet cabin environment.
KEYLOCK FEATURE
The key locks the keys on the unit to prevent
unintentional key presses from altering your TX3420

PAGE 4 INSTRUCTION MANUAL TX3420
settings. While the keys are locked, only the Push-To-Talk
(PTT), on/off Volume control and the Keylock key will
continue to function.
To lock the keys
Briefly press the Fkey, then press and hold the key
until a high beep is heard. The ‘ ’ symbol will appear
on the display.
To unlock the keys
Briefly press the Fkey, then press and hold the key
until a low beep is heard. The ‘ ’ symbol will disappear
from the display.
SELECTING CHANNELS
Rotate the Channel knob to step upwards or step
downwards one or more channels.
TRANSMITTING
To transmit, press the PTT (Push-to-Talk) button on the
microphone. 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.
SQUELCH CONTROL
Squelch control is used to eliminate the background noise
when there are no signals present. The TX3420 features
a preset Squelch system. The Squelch sensitivity has been
factory set to provide optimum performance in most
environments, however the sensitivity can be altered by the
user if required, to suit varying environmental situations.
The Squelch can be opened or closed with the SQL key.
When the Squelch is open, the receiver’s background noise
can be heard and ‘BUSY’ is displayed. When the Squelch is
closed, the receiver remains quiet when there are no signals
present but an incoming signal will override the squelch
and be heard in the speaker.
To open the Squelch
Briefly press the SQL key. A low beep will be heard. If
there are no signals present you will hear the receiver’s
background noise.
To close the Squelch
Briefly press the SQL key again. A high beep will be heard
and the receiver will become quiet.
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 open the Squelch
to allow the signal to be heard clearly. Alternatively you can
reduce the Squelch sensitivity as described as follows.
SQUELCH SENSITIVITY
The sensitivity of the Squelch to incoming signals can
be set to suit your operating environment. For example,
excessively noisy environments may cause the squelch
to open on local noise. The TX3420 has nine (9) preset
Squelch sensitivity settings that can be selected using the
MENU function.
To adjust the pre-set Squelch sensitivity
Please refer to the MENU SETTINGS on page 16.
PRIORITY CHANNEL
The Priority Channel feature allows you to store one of
the channels as a Priority Channel that can be instantly
recalled at the press of a key. This can be used to provide
instant access to your working channel or your local
repeater channel.
To store a Priority Channel
1. Select the required channel.
2. Press and hold the PRI key until a high beep is heard.
The selected channel will be stored.
To Recall a Priority Channel
Briefly press the PRI key. The radio will switch straight to
the selected Priority Channel. Any active functions (such
as scanning or Quiet) will be cancelled.
DUPLEX OPERATION
Duplex operation allows the radio to transmit on a different
frequency to which it receives. This allows operation
through local repeater stations. These repeater stations
automatically re-transmit your signal over a wider area,
providing greatly increased range.
Duplex operation is only available on channels 1-8. When
duplex is selected on these channels, the radio receives on
that channel but actually transmits 30 channels higher.
e.g.
* Emergency Channel only
The TX3420 allows you to pre-select Duplex operation
individually on each channel.
To select Duplex on individual channels
1. Select the required channel 1-8
2. Briefly press the Fkey followed by the DUP key. ‘DUP’
will appear on the display accompanied by a high beep.
Channel Selected 12345*678
Receive Channel 12345*678
Transmit Channel 31 32 33 34 35* 36 37 38

TX3420 INSTRUCTION MANUAL PAGE 5
To remove Duplex from a channel
1. Select the required channel 1-8. ‘DUP’ will be visible
on the display.
2. Briefly press the Fkey followed by the DUP key.
‘DUP’ will disappear from the display accompanied
by a low beep.
Standard Microphone MC503B
Optional Microphone MC540B
CTCSS
CTCSS (Continuous Tone Coded Squelch System) is a
squelch quieting system that allows several groups of users
to share the same channel without disturbing each other.
It uses a preset sub-audible (very low frequency) tone to
open and close the squelch on your radio. There are up to
50 tones available in two optional tone sets. The system
applies a continuous low-level tone to your transmission
and uses a matching tone decoder to control your receiver’s
squelch. With CTCSS enabled, the channel remains quiet
to all incoming signals unless they carry the correct tone.
When a transmission with the correct tone is received, the
squelch opens and remains open for as long as the signal is
present. When the transmission ends, the channel becomes
quiet again. Transmissions that do not use the correct tone
will not be heard.
The TX3420 allows CTCSS to be enabled or disabled on
individual channels.
Note: The CTCSS tone you select will be used for all CTCSS
enabled channels in your radio.
MONITORING THE CHANNEL
It is useful to be able to temporarily open your radio’s
Squelch to allow you to listen for signals from other CTCSS
users outside your group. Because their CTCSS tone is
different to yours, your Squelch would normally remain
closed, preventing you from hearing them. You can use
the SQL key to open the squelch and listen to the channel
to check that it is clear before transmitting. This will help
prevent you from accidentally transmitting over the top
of another transmission.
To monitor the channel
Press the SQL key. If there are no signals present, you will
hear the usual hiss of an empty channel. Press the SQL key
again to restore the Squelch to its previous setting.
SELECTING THE TONE SET
There are two standard tones sets available, one comprising
50 tones and the other comprising 38 tones. Both tone sets
are included in the TX3420 to provide compatibility with
other GME radio systems.
SELECTING THE REQUIRED CTCSS TONE
To pre-select the CTCSS tone on your radio, please refer to
the MENU SETTINGS on page 16.
ENABLING CTCSS ON A CHANNEL
If a CTCSS tone has been selected, it can be enabled on
individual channels.
Channel
Up
Channel
Down
Push To Talk
PPT
Priority
Skip / Call
Skip / Call
Direct
Channel
Entry
Keypad
Menu/
Enter Key
Clear KeyDown Key
Up Key
Keylock Key
Push to Talk

PAGE 6 INSTRUCTION MANUAL TX3420
1. Rotate the Channel knob to select the required channel.
2. Press and hold the SQL key. A high beep will be heard
and ‘SILENT’ will appear on the display.
You may activate CTCSS on as many channels as you wish
except channel 5 which is designated for emergency use.
DISABLING CTCSS ON A CHANNEL
Repeat steps 1 and 2 above. A low beep will be heard and
‘SILENT’ will disappear from the display.
Note: You will not be able to activate CTCSS if the CTCSS
tone is set to ‘oF’.
Please see the CTCSS Tone Frequency Chart on page 21
SCaNNINg
The TX3420 has a SCAN function that allows groups of user
programmable channels to be scanned for signals. Channels
can be scanned at 20 channels per second. When a signal
is found, scanning will pause on that channel to allow the
signal to be heard, then resume scanning when the channel
is clear again.
SCAN GROUPS
The TX3420 features two scan groups - Open Scan and
Group Scan.
Open Scan
Allows any of the installed channels to be scanned for
activity. If a busy channel is found, scanning will pause to
allow the signal to be heard. Once the channel has been
clear for 5 seconds, scanning will resume automatically.
e.g. Scanning channels 1-8 in Open Scan
Group Scan
Also allows any of the installed channels to be scanned
for activity, but in addition, it also inserts your Priority
Channel into the scan sequence. This means that your
Priority Channel will be monitored regularly while scanning
to ensure that no calls are missed. Any signals received on
your Priority Channel will take precedence over any signals
received on the other channels.
e.g. Scanning channels 1-8 with Priority Channel 20
in Group Scan
SELECTING A SCAN GROUP
To pre-select a scan group
The radio is initially set to Open Scan mode. To change to
Group Scan mode, press the Fkey then the OS/GS key to
select Group Scan.
PROGRAMMING SCAN CHANNELS
Your TX3420 is supplied with all 40 UHF CB channels
programmed into the Open Scan memory. Any channels
not needed, can be removed if required. The Group Scan
memory is empty by default and you will need to add
channels to it before use.
To add or remove channels from either
scan memory:
1. Ensure that the radio is not already scanning. If it is,
briefly press the SCAN key to cancel the scan function.
2. Ensure you have the required scan group pre-selected.
3. Select the required channel by rotating the
channel knob.
• If ‘M’ is visible to the right of the channel number,
the selected channel is already in the scan memory.
To remove the selected channel, press and hold the
SCAN key for a few seconds until a beep is heard.
‘M’ will then disappear indicating the channel is no
longer in memory.
• If ‘M’ is not visible, then the selected channel is not
in the memory. To add the selected channel, press
and hold the SCAN key for a few seconds until
a high beep is heard. ‘M’ will now appear.
4. Repeat step 3 to add or remove other channels in the
scan memory.
To start scanning
To begin scanning, briefly press the SCAN key. A high
beep will be heard, ‘SCAN’ will appear in the display and
the radio will begin scanning. In addition the selected scan
group will be displayed below the channel number.
Note: If there is only one channel programmed into the
Open Scan memory or none in the Group Scan memory,
a long low beep will be heard when you press the SCAN
key and the command will be ignored.
To stop scanning
To cancel the scan, briefly press the SCAN key. A low beep
will be heard and ‘SCAN’ will disappear from the display.
21 345678
213420 567820

TX3420 INSTRUCTION MANUAL PAGE 7
OpEN SCaN mOdE
USING SCAN IN THE OPEN SCAN MODE
• If a busy channel is found, scanning will pause on that
channel 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.
• If your radio pauses on a busy channel and you don’t
wish to listen to that conversation, briefly press the SKIP
button on the microphone. The radio will skip over that
channel and resume scanning from the next channel in
the sequence.
• If your radio is paused on a busy channel and you wish to
remain there, briefly press the SCAN key. The radio will
exit Scan mode and remain on the busy channel.
• To transmit while paused on a busy channel, simply
press the PTT button. The radio will exit Scan mode and
remain on the busy channel. You can now converse on
that channel in the usual way. When you have finished
your conversation, briefly press the SCAN key to
resume scanning.
• If your radio is scanning and you need to use your
Priority Channel (for an urgent call or an emergency),
briefly press the PRI key. The Scan mode will be
cancelled and the radio will jump straight to the
Priority Channel.
Note: In Open Scan mode your TX3420 will not allow you
to transmit while it is scanning. If the PTT button is pressed
while scanning, the radio will give a low beep and will
ignore the command. Your radio will only transmit while
it is paused on a busy channel.
grOup SCaN mOdE
Group Scan allows you to transmit and receive normally on
your Priority (working) Channel, while continuing to scan
several other channels. 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 button at any time, the
radio will transmit on the Priority Channel in the usual way.
SETTING UP THE GROUP SCAN
Referring to the appropriate sections of this manual:
1. Pre-select the Group Scan mode.
2 . Store your preferred working channel into the Priority
Channel memory (see Priority Channel on page 4).
3. Program the required ‘other’ channels into your Group
Scan memory (see Programming Scan Channels on
page 6).
SCANNING IN THE GROUP SCAN MODE
To scan in the Group Scan mode, briefly press the SCAN
key. A high beep will be heard, ‘SCAN’ will appear in the
display and the radio will begin scanning.
Note: If there are no channels programmed in the Group
Scan memory when you press the SCAN key (or there
is only one channel programmed and it is the same as
the Priority Channel), a low beep will be heard and the
command will be ignored.
When scanning, the TX3420 scans all the channels
programmed into the Group Scan memory, with the Priority
Channel being scanned after every fourth channel (retailer
programmable option, if you require different timing for
your priority channel, please contact your retailer).
• If a signal appears on the Priority Channel - at any
time - the receiver will switch straight to the Priority
Channel and will stay there for as long as the channel
is busy. During this time you can transmit on the Priority
Channel in the usual way. Once there has been no
activity for 5 seconds, the radio will resume scanning
the other channels.
• If a signal appears on one of the other channels,
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 for
signals every 2 seconds, resulting in a series of small
‘breaks’ in the reception of the paused channel. Once
there has been no activity on any channel for 5 seconds,
the radio will resume scanning.
• I f your radio pauses on a busy channel and you don’t
wish to listen to that conversation, briefly press the
SKIP key on the microphone. The radio will skip over
that channel and resume scanning from the next
channel in the sequence.
• If your radio is paused on a busy channel and you wish to
remain there, briefly press the SCAN key. The radio will
exit Scan mode and remain on the busy channel.
Note: The radio will no longer be monitoring
the Priority Channel (unless it is the same as the
busy channel). To resume scanning, press the SCAN
key again.

PAGE 8 INSTRUCTION MANUAL TX3420
• To transmit on the Priority (working) Channel AT ANY
TIME, simply press the PTT key while the radio is
scanning. The radio will switch straight to the Priority
Channel. When you have finished your conversation
and there has been no further activity on the Priority
Channel for 5 seconds, the radio will resume scanning
the other channels.
• To go directly to the Priority Channel, briey press the
PRI key. The radio will exit Scan mode.
USING TWO GROUP SCAN
OR TWO OPEN SCAN MODES
If you prefer, the TX3420 can be re-programmed to have
two Group Scan modes or two Open Scan modes instead
of one of each.
For example there may be applications where you have
no need to scan the Priority Channel and would prefer to
have two separate Open Scan modes. Alternatively you may
have applications where you prefer to have two Group Scan
modes with different Scan groups in each.
Your TX3420 can be retailer programmed to convert the
Group Scan mode into a second Open Scan mode and vice
versa. If you would prefer to have two Group Scan or two
Open Scan modes, you should contact your GME retailer
to arrange for this feature to be enabled (when using two
Group Scan modes the Priority Channel will be the same
channel for both scan groups).
When the second Open or Group Scan mode is enabled,
the resulting two Scan modes become Scan 1 and Scan 2.
To select the required scan mode
When enabled, the two scan modes will be identical in
operation. To program and operate each, refer to the Open
Scan/Group Scan sections above.
Note: Enabling or disabling the second Open or Group
Scan mode is not a user selectable option. Once enabled
by your GME retailer, the changed Scan mode becomes
a permanent part of the TX3420’s features and replaces
the standard Scan selection. If you find later that you need
the original Group or Open Scan function re-enabled,
you will need to return your TX3420 to your retailer for
re-programming.
SElECTIVE CallINg
Your TX3420 has a Selective Calling system known
as Selcall that operates like a telephone. Your radio is
preprogrammed with its unique Selcall Identification
Number. If this number is called by another radio, your
TX3420 will beep to alert you. If you do not want to hear
any other activity while waiting on a channel, you can select
QUIET mode. This will force the radio to remain quiet to all
incoming signals until your Selcall number is called.
Your TX3420 will allow you to store up to ten (10) of your
most frequently called Selcall numbers in memory.
Each number can be labelled with a 5-letter name for
easy identification.
SELCALL IDENTIFICATION NUMBER
Your TX3420 is factory programmed with its own unique
Selcall Identification Number (Ident). This number identifies
your radio from others in your area. Your radio’s own Selcall
Ident will be displayed for a few seconds, directly beneath
the channel display, when you first turn the radio on.
You will need to make your Ident known to anyone who
may need to call you using Selcall. Whenever your TX3420
hears a Selcall signal, it compares the incoming Ident with
its own. If the two Idents match, the radio knows it is being
called and sounds an alarm to alert you, otherwise the call
is ignored.
Note: Although your radio’s Selcall Ident is preprogrammed
at the factory, you can arrange to have your retailer change
it if required.
SELCALL IDENT NAMES
When storing Selcall Idents in memory, the TX3420 allows
you to add a 5 character name to each one, making it easier
to identify whose Ident you are recalling from the memory.
In addition, if an incoming Selcall matches one of the Idents
stored in the memory, the name can be displayed to make it
easier for you to identify the caller.
To add or display names
Your TX3420 must be in ALPHA mode.
To switch between
‘ALPHA’ and ‘NUMERIC’ mode
Briefly press the F(function) key followed by the ALPHA
key. ‘ALPHA’ or ‘NUMER’ will be displayed for 2 seconds
below the channel display to indicate the selected mode.

TX3420 INSTRUCTION MANUAL PAGE 9
QUIET MODE (Q)
Your TX3420 can be set to monitor signals on a busy
channel but remain quiet unless it receives its own Selcall
Ident. In this way, you won’t be disturbed unless someone
calls you. When a signal containing your Selcall Ident is
received, QUIET mode is deactivated and an alarm sounds
to alert you to the call. You can then converse normally on
the channel.
To use QUIET mode
Please refer to the QUIET Mode section on page 11.
Note: QUIET mode overrides the normal Squelch system to
ensure that the radio remains quiet even when the channel
is busy. When QUIET is set, you may see the ‘BUSY’ icon
appear on the display indicating the channel is being used.
However, unless someone transmits your Selcall Ident,
nothing will be heard in the speaker.
You can activate QUIET mode on individual channels i.e.
some channels can be set to remain quiet while others can
remain open to all incoming signals.
TIP: Setting QUIET mode is not mandatory. You can still
use Selcall on any channel whether the QUIET mode is set
or not.
SELCALL MEMORIES
Your TX3420 is fitted with one Call memory and 10 Selcall
Ident memories. The 10 Selcall Ident memories are used
to store frequently used Selcall Idents. The additional Call
memory holds the Ident you last sent or received. The
memories can be viewed by briefly pressing the CALL key.
The initial memory displayed is the Call memory. Rotating
the Channel knob will step through the other 10 Selcall
storage memories in sequence. Selcall memories are
labelled ‘c0’ to ‘c9’.
uSINg SElCall
ENTERING A SELCALL IDENT
1. Press the CALL button. ‘CALL TO’ is displayed, along
with the last sent or received Selcall Ident.
Note: If an ALPHA label is displayed you will need to
switch to NUMERIC Mode. To toggle between ALPHA mode
and NUMERIC mode, briefly press the Fkey followed by the
ALPHA key. A high beep indicates ALPHA mode is selected
while a low beep means the NUMERIC mode is selected.
2. Enter the required Selcall ident as follows:
(a) Press and hold the Channel knob until the radio
beeps. The right-hand digit of the Selcall Ident
will flash.
(b) Rotate the Channel knob to select the required
number in the flashing digit position.
(c) Briefly press the Channel knob again to select the
next digit position.
(d) Repeat steps (b) and (c) to enter all 5 digits as
required. The Selcall number is now ready to send.
SENDING SELCALL
With the Selcall number displayed, press and hold the CALL
button for 2 seconds. A long beep will be heard and the
radio will transmit the Selcall Ident.
Note: If the call is not sent within 10 seconds of entering
the last Ident digit the call mode will time out and the radio
will return to normal mode. To exit CALL TO mode without
sending the Selcall briefly press the CALL button.
CALL ACKNOWLEDGE
If your Selcall transmission is successful, the radio you called
should respond with an ‘acknowledge’ signal - usually two
quick beeps. This will confirm to you that the radio you
called is now alerting its user to your signal.
STORING SELCALL IDENTS
Your TX3420 is fitted with 10 user programmable Selcall
Ident memories, allowing you to store up to 10 frequently
used Selcall Idents. The memories are accessed by pressing
the CALL button, then rotating the Channel knob to scroll
through the memories. Ident memories are labelled ‘c0’
to ‘c9’.
To Store a Selcall Ident in memory
1. Press the CALL button to select the CALL TO mode.
‘CALL TO’ is displayed along with the last sent or
received Selcall Ident.
2. Rotate the Channel knob to select the required Ident
memory (locations ‘c0’ to ‘c9’).
TIP: If the radio displays letters instead of numbers in the
Selcall Ident position, your radio is in ALPHA mode. To
switch back to NUMERIC mode, briefly press the Fkey
followed immediately by the ALPHA key. A low beep will
be heard and ’NUMER’ will be displayed for a few seconds
in the Ident position.
3. With the required memory location displayed, enter the
Selcall ident as follows:

PAGE 10 INSTRUCTION MANUAL TX3420
(a) Press and hold the Channel knob until the radio
beeps. The right-hand digit of the Selcall Ident
will flash.
(b) Rotate the Channel knob to select the required
number in the flashing digit position.
(c) Briefly press the Channel knob again to select
the next digit position.
(d) Repeat steps (b) and (c) to enter all 5 digits
as required.
(e) Now press and hold the Channel knob. The entire
Ident will flash for a few seconds then the radio will
beep as the new Ident is stored.
RECALLING SELCALL IDENTS FROM MEMORY
1 Press the CALL button to select the CALL TO mode.
‘CALL TO’ is displayed along with the last sent or
received Selcall Ident.
2. Rotate the Channel knob to select the required Ident
memory in locations ‘c0’ to ‘c9’.
3. When the required Selcall Memory is displayed, press
and hold the CALL button to send the Ident.
NAMING YOUR SELCALL IDENTS
The TX3420 allows you to name each Selcall Ident using
a 5 character ALPHA name. The name is stored in memory
along with the Ident making it easier to identify whose
Ident you are recalling from the memory. If an incoming
Selcall matches one of those in your radio’s memory,
the name can be displayed instead of the Selcall Ident.
DISPLAYING ALPHA NAMES
To display the Selcall’s ALPHA Name
You must have the radio’s ALPHA display mode selected.
To toggle the ALPHA display mode
Briefly press the Fkey followed by the ALPHA key. ‘ALPHA’
or ‘NUMER’ will be displayed for 2 seconds below the
channel display to indicate the selected mode.
TIP: The normal channel display may give no indication of
which display mode is selected. The selected mode will only
become obvious when displaying Idents.
ENTERING AND STORING A SELCALL NAME
Note: Before adding an ALPHA Name to a Selcall Ident,
you should first store the required Ident in memory as
described above under Storing Selcall Idents on page 9.
1. Ensure the ALPHA mode is selected (briefly press the F
key followed by the ALPHA key to toggle ALPHA mode)
2. Briefly press the CALL button. The CALL TO mode will
be selected and the last-sent Selcall memory location
will be displayed.
3. Rotate the Channel knob to select the required Selcall
memory (locations c0 to c9). If no ALPHA name has been
programmed for that memory the radio will probably
display ‘- - - - -’ otherwise it will display the last ALPHA
name programmed into that memory.
4 With the required memory location displayed, enter the
required ALPHA name as follows:
(a) Press and hold the Channel knob until the radio
beeps. The left-hand character of the ALPHA name
will flash. Rotate the Channel knob to select the
required letter in the flashing character position.
The following characters are available:
A B C D E F G H I J K L M N O P Q
R S T U V W X Y Z _ SPACE - ,
0 1 2 3 4 5 6 7 8 9
(b) Briefly press the Channel knob again to select the
next character position.
(c) Repeat steps (a) and (b) to enter all 5 characters
as required.
(d) Now press and hold the Channel knob. The entire
ALPHA name will flash for a few seconds then the
radio will beep as the name is stored.
Repeat the procedure to add ALPHA names to any other
Selcall Idents stored in memory.
TO EXIT CALL-TO MODE
Briefly press the CALL button. The radio will return to
normal operation.
Note: The radio can be left in the ALPHA display mode
so that an incoming Selcall matching one of those in the
radio’s memory will display the name associated with
that Selcall Ident instead of the Ident itself. Any incoming
Selcalls not matching those in the memory will display
‘-NEW-’. To display the Selcall Ident of that caller, briefly
press the Fkey followed by the ALPHA key to return to the
NUMERIC display mode.

TX3420 INSTRUCTION MANUAL PAGE 11
RECEIVING SELCALLS
When your TX3420 receives its Selcall Ident, an alarm will
sound to alert you to the call. Initially the alarm will beep
urgently at 2 beeps per second for around 10 seconds then
slow to around 1 beep every 3 seconds if the call is not
answered. It will then continue to beep indefinitely until
you cancel it (the way your TX3420 handles the Selcall
alert can be altered by your retailer).
In addition to the alarm, the words ‘CALL FROM’ will appear
on the display along with the callers Selcall Ident or ALPHA
name to inform you of the identity of the person calling.
To switch between the
Selcall Ident and the ALPHA name
Briefly press the Fkey followed by the ALPHA key.
CANCELLING THE SELCALL ALERT
The following are the recommended methods:
To cancel the alarm and talk on the channel
Press the PTT key and talk in the usual way. The alarm
will be cancelled and the channel will be open for normal
communication.
To return the call
Press and hold the CALL key for a few seconds until the
radio beeps. The callers Selcall will be sent to the caller.
To cancel the alarm and listen on the channel
Briefly press the QUIET key (if QUIET has been activated).
The alarm will stop beeping and the channel will remain
open to any incoming signals.
QUIET MODE (Q)
QUIET mode mutes the TX3420’s receiver to prevent any
incoming signals from being heard in the speaker until your
Selcall Ident is received. In this way you can monitor
a busy channel for personal calls without being disturbed
by unwanted signals.
If your Selcall Ident is received, QUIET mode is then
cancelled and all incoming signals are heard in the speaker.
Setting up QUIET Mode
To setup QUIET mode you must first ‘tag’ the channels
that you want to stay quiet, then activate the QUIET mode.
Once QUIET mode is activated, the channels you have
tagged will remain quiet to all incoming signals unless
your Selcall Ident is received. Channels not tagged will
remain open to all signals and will operate normally.
To tag individual
channels for QUIET operation
1. Select the required channel by rotating the
Channel knob.
2. Press and hold the QUIET key until the radio beeps. ‘Q’
will appear to the right of the channel display indicating
the selected channel is now tagged for quiet operation.
To remove the QUIET Tag
from individual Channels:
1. Select a channel that has been tagged for quiet
operation. ‘Q’ will be displayed.
2. Press and hold the QUIET key until the radio beeps. ‘Q’
will disappear indicating this channel is no longer tagged
for quiet operation.
Activating QUIET Mode
1. First, select a channel that has been tagged for quiet
operation (you cannot activate quiet mode unless you
have selected a ‘tagged’ channel). ‘Q’ will be displayed
2. Now briefly press the Fkey followed by the QUIET key.
‘QUIET’ will appear on the display.
Now all channels that were tagged for quiet operation will
be operating in the QUIET Mode.
Deactivating QUIET Mode
1. Select any channel that has been tagged for quiet
operation. ‘Q’ and ‘QUIET’ will be displayed.
2. Briefly press the F key followed by the QUIET key.
‘QUIET’ will disappear from the display and all channels
that were tagged for quiet operation will now operate
normally again.
Receiving Signals in QUIET Mode
• If a normal signal is received on a QUIET channel, the
channel will appear busy (the ‘BUSY’ indicator will be
visible) but no sound will be heard from the speaker.
This means you will not be disturbed by the signal.
• If a normal signal is received on an open channel (one
that is not tagged with ‘Q’) the signal will be heard in
the usual way.
• If a signal containing your Selcall Ident is received
on any channel (Open or QUIET) QUIET mode will be
cancelled and the alarm will beep to alert you to the
call. In addition, the caller’s Ident or ALPHA name will
be displayed. All channels will now be open for normal
transmission and reception.

PAGE 12 INSTRUCTION MANUAL TX3420
If you wish to respond to the calling radio using Selcall,
press and hold the CALL key for 1.5 seconds until the radio
beeps. The callers Ident will be transmitted back to them
causing the alarm in their radio to be activated.
To cancel the alarm on your radio
Briefly press the PTT key.
To return your radio to the QUIET mode
Briefly press the Fkey followed by the QUIET key. ‘QUIET’
will re-appear on the display.
SCANNING IN QUIET MODE
The TX3420 will allow you to scan while QUIET mode is
active. Using this feature you can monitor a group of quiet
channels or a combination of Quiet and Open channels.
To Scan in QUIET Mode:
1. Pre-select the Scan mode.
2. Select the channels you wish to scan and store them in
the Scan memory.
3. From those channels, select the ones you wish to remain
quiet and tag each one for QUIET operation.
4. Select a tagged channel and activate QUIET Mode
(press the Fkey followed by the QUIET key).
5. Press the SCAN key. The radio will begin scanning
and ‘SCAN’ and ‘QUIET’ will be displayed, indicating
the radio is scanning in QUIET mode.
Receiving Signals while
scanning in QUIET Mode
• If a normal signal is received on an open channel,
scanning will pause while the channel is busy and will
resume scanning 5 seconds after the channel becomes
clear. (If you were scanning in Group Scan mode, the
radio may switch between the Open channel and the
Priority Channel - this is normal).
• If a normal signal is received on a Quiet channel but your
Selcall Ident is not detected, the signal will be ignored
and scanning will continue.
• If a signal containing your Selcall Ident is received on
any channel (Open or Quiet) both Scanning and QUIET
modes will be cancelled and the receiver will stay on
that channel. In addition, the alarm will beep to alert
you to the call and the caller’s Ident or ALPHA name will
be displayed. The channel will now be open for normal
transmission and reception.
TIP: To ensure reliable Selcall detection when scanning in
the QUIET mode, it is recommended that you restrict the
number of channels in the Scan group to 4 or less.
grOup CallINg
The TX3420’s Selcall system includes a Group Call function
which allows you to call up to 1000 radios simultaneously.
This can be useful in an emergency situation where you may
need to transmit a message to a large number of radios in
your group.
By default, your radio is factory-set to allow up to 10 radios
to be called at once. If your application requires more,
you can arrange for your retailer to re-program this option
to allow 100 or 1000 radios to be called. The following
description assumes the default Group Call setting of
10 radios.
The Group Call function works by allowing you to enter a
special ‘group code’ into the last digit position of the Selcall
Ident you are sending. The ‘group code’ appears as ‘A’ when
displayed in the radio. When this ‘group code’ is received, it
substitutes for all other numbers in the last digit position.
As long as the first 4 digits of the Selcall you are sending
match those of the radios you are calling, their Selcall alarm
will be activated as if their full 5 digit Selcall Idents had
been received.
To achieve this, the 10 radios you are calling must be
programmed with sequentially numbered Selcall Idents.
e.g. 12330, 12331, 12332, 12333 . . --> , 12339
• Transmitting the Selcall Ident 12331 will only activate the
alarm in the radio with the Selcall Ident of 12331.
• Transmitting 1233A will activate the alarms in all radios
with Idents 12330 through 12339 (a total of 10 radios).
If the radios in your fleet do not have sequentially numbered
Selcall Idents and you want to make use of this function, you
can arrange for your retailer to re-program the Selcall Idents
in your radios.
PROGRAMMING AND SENDING GROUP CALLS
The process for entering a Group Call Ident is the same as
entering a normal Selcall Ident.
1. Press the CALL button. ‘CALL TO’ is displayed, along
with the last sent or received Selcall Ident.
2. Enter the required Selcall ident as follows:
(a) Press the Channel knob until the radio beeps.
The right-hand digit of the Selcall Ident will flash.
(b) Rotate the Channel knob to select ‘A’ in the
flashing digit position. This is the special code
that will create the Group Call.

TX3420 INSTRUCTION MANUAL PAGE 13
(c) Briefly press the Channel knob again to select the
next digit position.
(d) Repeat steps (b) and (c) to enter the other 4 digits as
required. The last digit will be set to ‘A’.
Once the Ident has been entered you have 10 seconds to
send it otherwise the CALL TO mode will be cancelled and
the Ident you entered will be lost.
Note: Where your TX3420 allows it, programming group
calls for 100 radios is identical except that you will need
to select ‘A’ for the last two digits (e.g. 123AA). For 1000
radios you will need to select ‘A’ for last three digits
(e.g. 12AAA).
e.g.
To send the Selcall Ident
With the required Selcall Ident displayed in the CALL TO
mode, press and hold the CALL button for a few seconds
until the radio beeps. The Selcall Ident will be sent
automatically and the radio will return to normal operation.
Call Acknowledge in Group Mode
There is no call acknowledge when sending group calls.
This is to prevent all the radios in your group from trying
to respond to your Selcall transmission at the same time.
Storing Group Call Idents
Group Call Idents can be stored in memory in the same way
as a standard Selcall Ident.
Receiving Group Calls
Receiving a Group Call is identical to receiving a normal
Selcall except that the alarm sound is a LOW tone beep
instead of the normal HIGH tone beep. The caller’s Ident or
ALPHA Name appears on the display in the usual way.
lISTENINg ChaNNElS
The TX3420 has provision for adding additional 59 user
programmable ‘listening channels’ covering the frequency
range between 403 MHz and 520 MHz. These channels can
be programmed by you using the front panel keys, making
the TX3420 a useful UHF scanning receiver.
SETTING THE FREQUENCY STEP
The listening channels can be programmed in 12.5 kHz or
25 kHz steps. To toggle the current frequency step:
1. Switch the radio OFF.
2. Press and hold the SCAN key while switching the
radio ON.
3. 12.5 k or 25.0 k will be displayed briefly, indicating the
current selected frequency step.
ACTIVATING THE LISTENING CHANNELS
By default, the listening channels are disabled and only the
standard 40 UHF channels can be accessed. Later, once
programmed, the listening channels will show up as CH41-
CH99 and can be accessed and freely edited. However,
to enable a channel for programming that has not been
programmed yet (and therefore it can not be selected for
editing by the Channel knob) the initial programming of
the listening channel(s) has to be performed.
To perform the Initial Programming
of the listening channels
1. Switch the radio OFF.
2. Press and hold the Channel knob while switching
the radio ON again. The radio is now in the ‘All Visible’
mode. In this mode all channels are visible, including
the currently inactive ones, allowing you to select
any listening channel between 41 and 99 for
subsequent editing.
3. Using the Channel knob, select a listening channel that
you wish to activate. At this stage, the display will show
‘-OFF-’ indicating that the current listening channel is
turned OFF.
4. Program a desired frequency into the selected listening
channel, as described in the next section.
5. Repeat steps 3-4 to activate all the desired listening
channels.
6. Once you have enabled and programmed your additional
listening channels, switch the radio OFF to end the
initial programming operation. When you switch it ON
again, normal operation will be restored and only the
listening channels you have enabled will be available
above channel 40.
PROGRAMMING THE LISTENING CHANNELS
The display can show the frequency of the listening channel
when the radio is in NUMERIC mode, or an associated
alpha tag in ALPHA mode. Before programming the channel
frequencies, make sure the radio is in NUMERIC mode by
pressing F(Function) followed by ALPHA until ‘NUMER’
is displayed.
100 Radios Ident Sent: 123AA Idents called: 12300 -> 12399
1000 Radios Ident Sent: 12AAA Idents called: 12000 -> 12999

PAGE 14 INSTRUCTION MANUAL TX3420
To program a frequency
into a listening channel
1. Rotate the Channel knob to select the required listening
channel to edit (41-99).
2. Press and hold the MENU key until a beep is
heard. The current frequency assigned to the listening
channel will be displayed, or ‘OFF’ if the channel is
currently inactive.
3. Rotate the Channel knob to select the desired
frequency.
4. A quick press on the Channel knob will toggle the
frequency step between 12.5 kHz/25 kHz and 1 MHz.
The corresponding digit will be flashing, indicating the
current frequency step.
5. Once you have the correct frequency displayed, press
and hold the MENU button to store the frequency
and exit the menu, or alternatively, press and hold the
Channel knob to store the frequency, but stay in the
frequency edit menu for further editing of the same
listening channel. Please note however the menu will
time out after 20 seconds of inactivity.
Notes:
• The display only indicates to 10 kHz resolution. The ‘kHz’
digit is not displayed,
e.g. 468.425 MHz will display as:
• While you are selecting the frequency, the receiver is live
and will receive signals on the frequency being displayed.
You can use this feature to manually identify active
frequencies and store them.
• To delete a currently active listening channel, edit the
frequency as described above, but rotate the Channel
knob left until the display shows ‘OFF’. Once the channel
data is saved and the menu exited (by pressing and
holding the MENU key) the deleted listening channel
will only be visible again if the ‘All Visible’ mode is
selected, as described in the Initial Programming
section on page 13.
To program additional listening frequencies
Repeat steps 1-5 above.
Once finished editing all the desired listening channels, they
are immediately available for usage. Rotating the Channel
knob the edited listening channels can immediately be
selected for monitoring. If the radio is in the ‘All Visible’
mode, the currently inactive channels can also be selected,
but on these channels there will be no reception (as the
channels are ‘OFF’).
ASSIGNING ALPHA LABELS
TO LISTENING CHANNELS
Your listening channels can be tagged with a five
digit alpha label. To program the alpha label for the
listening channel:
1. Ensure the radio is in ALPHA mode by pressing Fand
ALPHA until the display shows ‘ALPHA’.
2. Rotate the Channel knob to select the required listening
channel for which you wish to edit the alpha tag.
3. Press and hold the MENU button until a beep is heard.
The current alpha tag for the selected listening channel
will be displayed with the first character will be flashing.
4. Rotate the Channel knob to select the required letter
for the first digit.
5. Briefly press the Channel knob to select the next digit
to edit.
6. Repeat steps 4-5 until the display shows the desired
alpha tag.
7. Once the correct alpha tag is displayed, press and hold
the MENU button to store the alpha tag and exit the
menu. Alternatively, press and hold the Channel knob
to store the alpha tag but stay in the Listening Channel
Edit menu for further editing, for example to edit the
channel frequency too.
SEEK mOdE
During programming of a listening channel, the actual
frequency to program may not be known in advance. Seek
mode is a unique feature that allows you to continuously
scan a band of frequencies for activity, and assign the
frequency of interest to the current listening channel.
USING SEEK MODE
Before using Seek mode you should
1. Select your preferred frequency step (12.5 kHz or
25 kHz).
2. Enable the listening channel numbers in which you wish
to store active frequencies. You cannot use Seek mode
unless at least one channel is enabled.
3. Select NUMERIC mode so that the frequency can be
displayed (rather than the alpha label).
46842
10 kHz
100 kHz
1 MHz
10 MHz
100 MHz

TX3420 INSTRUCTION MANUAL PAGE 15
To scan for active frequencies
and store them into a listening channel
1. Select the required listening channel (41-99).
The frequency currently stored in that channel will
be displayed.
2. Enter the Frequency edit mode by pressing and holding
MENU key until a beep is heard.
3. Briefly press the SCAN key. The radio will begin
scanning, using the selected channel step, starting from
the current frequency. The channel number will remain
constant (because the radio is scanning frequencies not
channels) but the frequency will change as the scan
advances through the band.
4. When a signal is found, scanning will pause on that
frequency. Once the signal has disappeared and the
frequency remains clear for 5 seconds, scanning
will resume.
5. To manually skip over an active frequency and continue
scanning press the CALL/SKIP button.
6. When you find a frequency you wish to store, press
and hold the Channel knob until a beep is heard.
The frequency will be stored under the selected listening
channel number, but the Frequency Edit Menu will
still be active, ready for further Seeking. To store the
frequency and exit the menu, press and hold the
MENU button.
7. To exit the Frequency Edit menu without saving the
current displayed frequency, briefly press the MENU key.
The next menu item will be shown (typically the Squelch
Set menu). At this stage, press and hold the MENU
button until a beep is heard to exit.
SETTING SEEK MODE FREQUENCY LIMITS
When in Seek mode, the default frequency band to scan is
the entire receiver tuning bandwidth of 403 MHz-520 MHz.
However, in many cases you may only be interested
in searching for signals within a small section of the
available frequency band. To make searching easier the
TX3420 allows you to set upper and lower frequency limits.
The Seek function will then only search within the specified
range, thereby increasing the chance of finding an active
frequency of interest.
There are two seek limit points available, LIM-1 and
LIM-2. While in the frequency edit mode, press and hold
the SCAN key until a beep is heard to store the current
frequency as a limit. To select and jump to the next limit,
press the VOL knob.
To select and display a limit point
While in frequency edit mode, briefly press the VOL knob.
The next frequency limit point will be selected, the display
will briefly show ‘LIM-1’ or ‘LIM2’ and then the frequency
of the limit point will be shown. At this stage the radio is
also tuned to this frequency, and if there is activity on this
frequency, it can be heard in the speaker.
To set or edit a limit point
1. Select the desired limit point to edit as described in the
previous paragraph.
2. Rotate the Channel knob until the display shows the
frequency of the desired limit point.
3. Press and hold the SCAN key until a beep is heard.
The current frequency is now stored to the current limit
point. The display will briefly show ‘LIM-1’ or ‘LIM-2’,
and then revert to showing the frequency again.
4. Repeat steps 2-3 to update the current limit point with
a new frequency if desired.
To erase a limit point
1. Select the desired limit point to erase as described above.
2. Rotate the Channel knob counter clockwise until the
frequency display reads ‘OFF’.
3. Press and hold the SCAN key until a low beep is heard.
The selected seek limit point is now erased.
USING THE FREQUENCY LIMITS TO SCAN
Once the Seek mode frequency limits are set, the frequency
band is effectively split into three segments.
TIP: It is easiest to picture the limit points as the first limit
being lower in frequency than the second, but this is not
really necessary. Even if the frequencies are programmed so
that the limit points are reversed, the TX3420 will always
scan inside a selected frequency range, in the upwards
direction. The initial frequency where the seek was started
determines which frequency band will be scanned.
To start seeking between
the first and second frequency limit
1. While in Frequency Edit mode, rotate the Channel knob
to select a frequency that is between the two frequency
limit points.
2. Start seeking by briefly pressing the SCAN button.
520
MHz
Limit 1 Limit 2403

PAGE 16 INSTRUCTION MANUAL TX3420
To start seeking between
the higher frequency limit point and 520 MHz
1. While in Frequency Edit mode, rotate the Channel knob
to select a frequency that is above the frequency of the
higher limit point.
2. Start seeking by briefly pressing the SCAN button.
To start seeking between
403 MHz and the lower frequency limit point
1. While in Frequency Edit mode, rotate the Channel knob
to select a frequency that is below the frequency of the
lower frequency limit point.
2. Start seeking by briefly pressing the SCAN button.
If the SCAN button is pressed while seeking, the radio will
exit seek mode immediately and stay tuned to the current
frequency.
Note: at this point that the menu will time out after
20 seconds of inactivity.
If a busy frequency is found during Seek mode, the radio
will pause on this frequency for 5 seconds before resuming
scan. To save this frequency to the current listening channel,
press and hold the Channel knob to exit seek, save the
frequency and stay in the menu or press and hold the
MENU key to save the frequency and exit the menu.
mENu SETTINgS
The MENU feature provides a convenient method of
customizing or storing some of the radio’s functions. The
following Menu Options are available. Note that some items
are only available on certain channels.
Menu Settings Ch 1-8 Ch 9-40 RX Only Ch
Frequency /
ALPHA Adjustment •
Squelch Settings • • •
CTCSS Tones • • •
Lamp Colour Light • • •
Battery / S-Meter
Selection • •
Battery / S-Meter
ALPHA Selection •
To access the Menu functions
1. Press and hold the MENU key. The first Menu function
is displayed.
2. Briefly press the MENU key again to cycle through each
available function in the order listed above. After the
last function has been selected, the cycle returns to
the beginning.
3. Rotate the Channel knob to alter the parameters of the
selected function.
4. Press and hold the MENU key to exit and store
any changes.
FREQUENCY
The Frequency adjustment is only available when a user
programmable listening channel is selected. It allows you
to manually adjust the channel frequency or, if ALPHA
mode is selected, lets you edit the ALPHA label for that
listening channel.
1. Select a user channel between 41 and 99.
2. Press and hold the MENU key until the radio beeps.
If the radio is in NUMERIC mode, the channel frequency will
be displayed. If the radio is in ALPHA mode, your selected
ALPHA label will be displayed (if you have not set a label
for this channel, ‘ALPHA’ will be displayed).
3. Rotate the Channel knob to change the character or
number in the flashing digit position.
4. Briefly press the Channel knob to move to the next
flashing digit position.
5. Once you are happy with your selection, press and hold
the MENU key to store the new setting.
SETTING THE SQUELCH SENSITIVITY
The sensitivity of the Squelch to incoming signals can be set
to suit your operating environment. In quiet rural locations
a low setting will allow the weakest signals to be received
while still keeping the radio quiet between transmissions.
In city locations, a higher setting might be needed to ensure
the squelch remains closed when subjected to the higher
interference levels often encountered in high density areas.
The TX3420 has nine (9) preset Squelch sensitivity settings
(labelled SQL-1 to SQL-9) that can be selected using the
Menu function. The minimum Squelch setting (SQL-1) will
open the Squelch on weak signals. SQL-9 is the maximum
setting, requiring very strong signals to open the squelch.
The factory default is SQL-2 which generally provides
reliable squelch operation for most applications.
To pre-select the Squelch sensitivity
1. Select a Channel between 1 and 40.
2. Press and hold the MENU key until the radio beeps.
SQL-x will be displayed where x is a number from 1 to 9.
3. Rotate the Channel knob increase or decrease the
preset squelch to the desired setting.
4. Press and hold the MENU key to store the new setting.

TX3420 INSTRUCTION MANUAL PAGE 17
SELECTING DUPLEX
Duplex operation allows the radio to transmit on a different
frequency to that which is receives. This allows operation
through repeater stations. Repeaters automatically
re-transmit your signal over a wider area, providing
greatly increased range.
Duplex operation operates only on channels 1-8. When
duplex is selected on these channels, the radio receives on
that channel but actually transmits 30 channels higher.
e.g.
* Emergency Channel only
The TX3420 allows you to select Duplex operation
individually on each channel.
To enable or disable Duplex on a channel
1. Select the required channel 1-8 (the Duplex setting
feature is only available on these channels).
CTCSS TONES
CTCSS (Continuous Tone Coded Squelch System) is a
squelch quieting system that allows several groups of users
to share the same channel without disturbing each other. It
uses one of a set of sub-audible (very low frequency) tones
to open and close the squelch on your radio.
There are two standard tones sets, one comprising 50 tones
and the other comprising 38 tones. Both tone sets are
included in the TX3420 to provide compatibility with other
radio systems.
To toggle the required tone set
1. Switch the radio OFF.
2. Press and hold the SQL key while switching the radio
ON again.
3. ‘CTC50’ or ‘CTC38’ will be displayed indicating which
tone set is selected.
Note: When switching up from CTC38 to CTC50, the
radio will retain the selected CTCSS tone frequency and
automatically update the tone set number to reflect its new
position in the CTC50 tone set table.
e.g. If CTCSS tone frequency 233.6 Hz (CTC38 tone set #36)
was selected, the radio will then display equivalent CTC50
tone set #47.When switching down from CTC50 to CTC38,
if there is no equivalent CTC38 frequency, the CTCSS
tone will be set to ‘oF’ (0 Hz). You will need to re-select
a new tone.
To pre-select a CTCSS tone
1. Press and hold the MENU key until the radio beeps.
2. Briefly press the MENU key repeatedly until ‘CTCXX’
is displayed, where XX is a number between 1 and 50
or ‘oF’.
3. Rotate the Channel knob to select the required CTCSS
tone number (see CTCSS Tone Frequency Chart on
page 21). If the CTC38 tone set is enabled there will be
38 tones available otherwise there will be 50 tones.
Note: To display the CTCSS frequency instead of the
tone number, briefly press the Channel knob. The CTCSS
frequency (in Hz) will be displayed. Briefly press the SQL
key again to return to the tone number.
4. To turn CTCSS tones OFF select CTCoF.
5. Press and hold the MENU key until the radio beeps,
to store the setting.
BACKLIGHTING
Backlighting can be set to ON or OFF to satisfy
personal preference.
1. Press and hold the MENU key until the radio beeps.
2. Briefly press the MENU key repeatedly until ‘LIGHT’
is displayed.
3. Rotate keys to cycle through the Channel knob to either
ON or OFF.
4. Press and hold the MENU key until the radio beeps,
to store the setting.
BATTERY / S-METER / ALPHA SELECTION
The TX3420 has the option of displaying either the battery
voltage or the incoming signal strength (S-meter) in the area
beneath the channel display. In addition, when ‘Listening’
channels (41-99) are selected, the radio provides an extra
option of displaying the frequency of the selected user
channel or a custom ALPHA label (when ALPHA mode
is selected).
The listening channels are treated independently to the
normal UHF CB channels in that you can for example,
Vechicle
Simplex/Duplex Range Comparison
Simplex
Repeater
operation
Channel 31
Channel 1
Repeater
Station
Channel 1
Channel 31
Vechicle
Channel Selected 12345*678
Receive Channel 12345*678
Transmit Channel 31 32 33 34 35* 36 37 38

PAGE 18 INSTRUCTION MANUAL TX3420
select S-Meter or Battery Voltage on Channels 1-40
yet display the channel frequency (or an ALPHA label)
on channels 41-99.
To display S-Meter
or Battery Voltage on channels 1-40
1. Select a channel from 1-40.
2. Press and hold the MENU key until the radio beeps.
3. Briefly press the MENU key repeatedly until ‘S-MET’
(S Meter) or ‘bATT’ (Battery) is displayed.
4. Rotate the Channel knob to select your preferred choice
of S-MET and bATT.
5. Press and hold the MENU key until the radio beeps,
to store the setting.
To display S-Meter, Battery Voltage
or Frequency/Alpha label on Listening
channels (41-99):
1. Select a channel from 41-99.
2. Press and hold the MENU key until the radio beeps.
3. Briefly press the MENU key repeatedly until ‘S-MET’
(S Meter), ‘bATT’ (Battery) or ‘ALPHA’ is displayed.
4. Rotate the Channel knob to select your preferred choice
of S-MET (S Meter), bATT (Battery) or ALPHA.
5. Press and hold the MENU key until the radio beeps,
to store the setting.
INSTallaTION
The TX3420 main unit is supplied with a slim, slide-on
mounting cradle. The cradle can be screwed or bolted in
any convenient location in your vehicle (under or above the
dash, on the centre console, under the seat, in the boot,
etc.) using the mounting slots provided in the base. The
main unit contains a built-in speaker, and can be installed
in a convenient location in the vehicle’s cabin as the radio’s
loud speaker. Alternatively it can be installed ‘out of the
way’ and an extension speaker used instead.
The remote head comes complete with a slim mounting
bracket and gimbal knobs. Its small size and light weight
design allows it to be mounted in almost any convenient
position accessible to the driver.
NOTE: If your installation does not require the use of a
remotely mounted control head, you can convert your
TX3420 to a compact underdash radio by fitting the remote
head front panel directly to the main unit as described on
page 20.
When installing the radio, avoid mounting it close to
heaters or air conditioners. Screw the mounting cradle and
the remote head bracket to firm surfaces. Slide the TX3420
main unit into the cradle from the front until it clicks into
place. Position the remote head in its mounting bracket,
adjust it for the correct viewing angle and tighten the
gimbal knobs securely. Finally, plug the remote head into
the front panel of the TX3420 and the power and antenna
leads to the sockets provided on the rear of the radio.
ANTENNA INSTALLATION
It is essential to select a good quality, high efficiency,
477 MHz antenna. A poor quality antenna or one not
designed for the specific frequency band you are using
will give very poor performance.
GME have a wide range of suitable 477 MHz UHF CB
antennas to suit most installations and applications.
We recommend contacting your local GME retailer for advice .
Connect to the antenna cable to the rear antenna socket
using a PL259 coaxial connector.
NOISE SUPPRESSION
The inherent design of FM transceivers results in a high level
of resistance to ignition and electrical interference. However
in some installations it may be necessary to take additional
steps to help reduce or eliminate noise interference.
During installation, try to route the DC battery leads, the
antenna lead or any accessory wires away from the engine
compartment, ignition or alternator wiring. If the noise
continues, it may be necessary to fit a suppression kit in
which case we recommend you consult an auto electrician
for advice specific to your installation.
Higher frequency electrical interference cause by electric
motors can be suppressed directly at the motor terminals.
Fitting Remote Head Bracket
TX3420

TX3420 INSTRUCTION MANUAL PAGE 19
Mounting the Cradle
Fitting the Radio
Slide radio fully into cradle until it clicks into place.
Removing the Radio
Fitting the Microphone
The microphone uses a miniature 6 pin telephone style plug
and socket. To fit the microphone:
1. Position the microphone plug so the plastic tab faces
downwards, and press the plug into the socket until
it ‘clicks’.
2. Gently press the rubber strain relief into the hole
surrounding the socket so that the slot around the
strain relief fits neatly inside the lip of the hole.
Removing the Microphone
1. Squeeze the rubber strain relief near the front panel to
disengage the slot, and slide the strain relief back along
the microphone cord.
2. Squeeze the plastic tab on the microphone plug
towards the plug to unlock it while gently pulling the
plug outwards. If the plug does not come out easily,
the tab has not released correctly and should be
squeezed again.
Disconnecting the Microphone
It is recommended that the microphone be left permanently
connected to the TX3420, but if it must be disconnected,
proceed as follows:
1. Insert a small screwdriver between the rubber boot and
the lip of the raised area on the front panel.
2. Ease the rubber boot out of the cable entry hole and
slide it along the cable away from the front panel.
3. Identify the plug locking lever, work the screwdriver
blade behind it and move the lever towards the plug
body. At the same time gently pull the plug from the
socket (see diagram below).
If required, replacement microphones are available with
plug and rubber boot already fitted.
Cable
Screwdriver
Locking Lever
move to left to
release Plug
Cable entry hole
Gently
spread
tabs
Slide radio
from cradle
Gently
spread
tabs
SQL
Plastic tab
UHF RADIO

PAGE 20 INSTRUCTION MANUAL TX3420
CONVERTING THE TX3420
INTO AN UNDERDASH RADIO
If your installation does not require the use of a remotely
mounted control head, you can convert your TX3420 to a
compact underdash radio by fitting the remote head front
panel directly to the main unit as follows.
Remote Head Unit Disassembly
1. Remove the two black screws from the metal cable-
clamp plate at the rear of the remote unit.
2. Remove the 4 screws from the remote unit’s rear case
and remove the case.
3. Slide the rear case down the connecting cable and
carefully unplug the cable from the PCB.
Main Unit Disassemble.
1. Remove the top and bottom covers from the main unit.
2. Pull the dummy front panel away from the chassis and
carefully unplug the connecting cable.
Reassembly
1. Plug the connecting cable from the main unit into the
remote head front panel.
2. The remote front panel can be oriented so that the
speaker in the main unit is facing either up or down.
Position the front panel as required and slide it onto the
main chassis. If the front panel is oriented so the speaker
is facing UP, ensure the connecting cable is not crushed
between the front panel PCB and the chassis. Align the
holes in the top and bottom of the plastic front panel
with the case screw holes in the chassis.
3. Refit the top and bottom covers and install the
cover screws.
Console Mounting the TX3420
For console mounting, a flush mounting DIN Adaptor
MBD001 is available as an optional accessory. The adaptor
includes mounting brackets and a specially designed
front panel escutcheon to suit most vehicle installations.
The console mount is particularly suitable for dashboard
mounting TX3420’s that have been converted from remote
units to under-dash units (as described above). Installation
instructions are provided with the bracket. See your nearest
GME retailer for details.
DC POWER CONNECTION
The TX3420 is designed for 13.8 Volt DC, negative earth
installations only (i.e. where the negative terminal of the
battery is connected to the chassis or frame of the vehicle).
There are two recommended methods of installation.
Radio remains ON when
the ignition switch is OFF
Connect the radio's negative (black) lead to the vehicle's
chassis, or if preferred, directly to the battery's
negative terminal.
The radio's positive (red) lead should be connected via the
2 Amp fuse to the battery's positive terminal. Alternatively,
the positive lead could be connected into the fuse box
at a point that has +13.8 Volts continuously available
(preferably the battery side of the ignition switch) via
the 2 Amp fuse.
Radio turns OFF with the ignition switch
Connect the radio's negative (black) lead to the vehicle's
chassis, or if preferred, directly to the battery's
negative terminal.
The radio's positive (red) lead should connect to an
accessory point in the vehicle's fuse box via the 2 Amp fuse.
This point should supply +13.8 Volts only when the ignition
switch is turned ON or in the ACCESSORY position.
Connect plug Align holes
TX3420