Powerwerx DB-750X User manual

VHF/UHF
Dual Band Commercial Radio
Powerwerx DB-750X
User's Manual

Powerwerx offers the best in Land Mobile Commercial
Communications, featuring rugged mobiles and handhelds at
affordable prices. For additional information visit our web site:
www.powerwerx.com
NOTE
This commercial mobile radio ships from the manufacturer “Display Locked” per FCC rules.
You must have the RPS-DB750X-USB programming kit to unlock this radio for the rst time
of use. If you do not want to purchase this optional software, your radio dealer must rst
unlock this radio before regular use.
When programming this radio for the first time with the optional PC Programming kit, it
is recommended you rst READ the radio with software and then save this le for future
reference. In addition, after you READ this radio with software, rst make your programming
and frequency changes, then send this edited le back to your mobile radio. Please contact
the dealer you purchased this radio from or Powerwerx should you have any questions.

Caution
Please observe the following precautions to prevent fire,
personal injury, or transceiver damage:
Do not attempt to program your radio while driving.
Do not place this transceiver in a dusty, humid or wet area.
Do not expose this transceiver to long periods of direct
sunlight.
Do not mount this transceiver or
remote control head near vehicle
heating vents.
Do not transmit in the high power
mode for extended periods of time
as it may overheat the radio. For
longer transmit key downs, it is
recommended you use the “MID1”
or “MID2” medium power level
settings.
V/MHMSCN
LOW
LOWV/MHMSCN
SET
TV/SOL
Thank you for choosing this Powerwerx DB-750X Dual-Band
Land Mobile transceiver. This dual-band mobile is built to rugged
commercial radio standards and features 50 Watts power
output on VHF and 40 Watts output on UHF, seven character
alphanumeric display, AM “Air Band” receive, and direct–flow
heavy duty heat sink with thermostatically-controlled cooling fan
designed for years of trouble free operation.
The DB-750X dual-band radio offers four true dual receive
modes: (V+U, V+V, U+U and U+V). For simple operation this
radio also features single display mode to monitor one channel
at a time. The DB-750X includes 750 memory channels, 10
memory banks, full duplex operation, separate volume and
squelch controls, built-in CTCSS/DCS, DTMF signaling and
optional detachable remote front panel for flexible installation.
This dual-band radio is offered as a mobile or can be congured
as a base station using the optional SS-30DV Power Supply and
MBXCOVR Radio Enclosure.
This mobile transceiver includes a variety of features so we
recommend that you review this manual prior to using this radio.

CONTENTS
New and Innovative Features...................................................1
Frequency Range ...................................................................1
Supplied Accessories/Optional Accessories..........................2
Supplied Accessories..............................................................2
Optional Accessories ..............................................................2
Initial Installation .......................................................................3
Mobile Installation ...................................................................3
DC Power Cable Connection ..................................................4
Antenna Connection ...............................................................6
Accessories Connections........................................................7
Getting Acquainted ...................................................................8
Front Panel .............................................................................8
Rear Panel ..............................................................................9
Display ....................................................................................9
Microphone ...........................................................................10
Basic Operations.....................................................................11
Switching the Power On/Off..................................................11
Adjusting the Volume ...........................................................11
Switch Between VFO and Channel Mode............................. 11
Adjusting Frequency .............................................................11
Adjusting Channel.................................................................11
Switch Between Main Band and Sub Band ..........................12
Selecting the Frequency Band..............................................12
Receiving ..............................................................................12
Squelch Off/Squelch Off Momentary.....................................12
Transmitting ..........................................................................12
Shortcut Operations................................................................13
Squelch Level Setup .............................................................13
Transmit DTMF / 2-Tone / 5-Tone Signaling .........................13
High/Mid/Low Power Switch .................................................13
Frequency Reverse...............................................................13
Bandwidth Selection .............................................................13
Home Channel ......................................................................13
Hyper Memory Channel ........................................................13
Dual Watch............................................................................14
Emergency Alarm..................................................................14
Memory Channel/Frequency Scan .......................................14
Memory Channel Scan Skip .................................................14
Memory Channel Add ...........................................................14
Scan Range Limit .................................................................14
Memory Channel Copy .........................................................14
Memory Channel Delete .......................................................15
General Setting........................................................................16
APO (Automatic Power Off) ..................................................16
Automatic Offset ...................................................................16
Frequency Channel Step Setup............................................16
VFO Band Lockout................................................................17
Beep Function.......................................................................17
CPU Clock Frequency Change.............................................17
2-Tone Encode Select...........................................................17
5-Tone Encode Select...........................................................18
Additional Signaling Feature .................................................18
CTCSS Encode Setup .........................................................18
CTCSS Decode Setup ..........................................................19
Sub Band Display Setup .......................................................19
DTMF Encode Pre-Loading Time .........................................19
DTMF Encode Transmitting Time .........................................20
DTMF Encode Setup ............................................................20

Squelch Mode Setup.............................................................20
Compander ...........................................................................21
Scrambler Setup ...................................................................21
Tone Burst ............................................................................21
Keypad Mode Setup .............................................................22
Keypad Lockout ....................................................................23
TX OFF (PTT Lockout) .........................................................23
Squelch Level Setup .............................................................23
Frequency Reverse...............................................................23
Sub Band Mute Setup...........................................................24
Editing Channel Name ..........................................................24
Channel Function Auto Storage Setup..................................24
Microphone PA, PB, PC, PD Key Setup ...............................25
RF Squelch Level Setup .......................................................25
Offset Direction Setup...........................................................25
Scan Dwell Time Setup.........................................................25
Priority Channel Scan ...........................................................26
Offset Frequency Setup ........................................................26
Display Mode Setup..............................................................26
Busy Channel Lockout ..........................................................27
Radio's DTMF Self ID Enquiry ..............................................27
5-Tone Self ID Enquiry..........................................................27
TOT (Time-Out Timer)...........................................................27
VFO Frequency Linkage .......................................................28
Wide/Narrow Band................................................................28
Cross Band Repeat...............................................................28
LCD Backlight .......................................................................28
Keypad Backlight Brightness ................................................29
Calling Record ......................................................................29
AM Function..........................................................................29
Automatic AM Function .........................................................29
External Speaker Port...........................................................29
Beep Volume Control ...........................................................30
Talk Around........................................................................... 30
Microphone Speaker.............................................................30
Password Function ...............................................................30
Microphone Operation ............................................................31
Send DTMF Signaling...........................................................31
Main/Sub Band Switching .....................................................31
Function Operation through PA-PD Keys .............................31
Memory Banks.........................................................................33
Assigning Memory Bank to a Channel..................................33
Choosing Active Bank ...........................................................33
Bank Linking .........................................................................33
Cable Clone..............................................................................34
Reset to Factory Default .......................................................34
Maintenance.............................................................................35
Default Value for Factory Resume ........................................35
Trouble Shooting...................................................................35
Specications ..........................................................................36
Attached Chart.........................................................................37
51 groups CTCSS Tone Frequency (Hz) ..............................37
1024 groups DCS Code........................................................37
Menu Quick Reference List ....................................................39
CONTENTS
DB-750X

1
1
DB-750X FEATURES:
• 750 Memory Channels
• 10 Memory Banks (with bank linking)
• 7 Character Alphanumeric Display
• Power Output: VHF 50 Watts, UHF 40 Watts (4 power levels available for each band)
• Dual Receive Operation (V+U, V+V, U+U, U+V) with separate volume controls
• Narrow Band (2.5 kHz) operation for Land Mobile frequencies (FCC part 90)
• Wide Band (5.0 kHz) operation for Amateur frequencies
• Dual or Single Display / Receive Modes
• Large LCD Display with adjustable Colors and Brightness
• Built-in CTCSS/DCS per channel
• PC programmable with RPS-DB750X-USB Programming Kit
• Base Station Operation w/ optional Power Supply (SS-30DV) and optional Radio Enclosure (MBXCOVR)
Frequency Range
RX: 108~136 MHz AM TX: 136~143.995 MHz FM Narrow
136~174 MHz FM Wide or FM Narrow 144~147.995 MHz FM Wide
220~260 MHz FM Wide 148.000~174 MHz FM Narrow
350~490 MHz FM Wide or FM Narrow 400~429.995 MHz FM Narrow
430~449.995 MHz FM Wide
450~469.995 MHz FM Narrow
470~490 MHz FM Wide
Features

2
DB-750X
2
Supplied Accessories/Optional Accessories
SUPPLIED ACCESSORIES
OPTIONAL ACCESSORIES
After carefully unpacking the transceiver, identify the items listed in the table below. We suggest you keep the box and packaging.
Transceiver
Spare Fuses
(15 A)
User Manual
Front Panel Remote Kit
(MBXRMK)
Dual
Band Mobile Mag
Mount Antenna
(MBXGAIN)
Mobile Mounting
Bracket (MBXBRKT)
DC Power Cable with
Fuse Holder
(OEM-FM-CAB)
Microphone with DTMF
Keypad (MBXDTMF)
Plain Microphone
(MBXMIC)
S-Washer
4pcs
Hardware Kit for Bracket
Black screws
(M4X8mm)
4pcs
Tapping screws
(M5X8mm)
4pcs
Programming Kit
(RPS-DB750X-USB)
Cigarette Lighter Plug
Connection - 6 Feet
(TMCG-72)
Desktop
Microphone
(MBXDESK)
Power supply
(SS-30DV)
External Speaker
(MBXSPK)
V/MHMSCN
LOW
LOWV/MHMSCN
SET
TV/SOL
1
4
789
0#
56
23PA
MIC
PB
AB
A
A/B B
PC
PD
MAIN
Base Station Radio
Enclosure (MBXCOVR)
Includes Power Adapter (MBXRPA)
Power Line
Filter (LF-1-OEM)
Y Cable
(MBXYCBL)
Clone Cable
(MBXCLON)
LOWV/MHMSCN
SET
TV/SOL
V/MHMSCN
LOW
Power Adapter
(MBXRPA)
For a complete listing of current accessories see: www.powerwerx.com/mobile

3
3
MOBILE INSTALLATION
To install the transceiver, select a safe, convenient location inside your
vehicle that minimizes danger to your passengers and yourself while the
vehicle is in motion. Consider installing the unit at an appropriate position
so that knees or legs will not strike it during sudden braking of your
vehicle. Try to pick a well ventilated location that is shielded from direct
sunlight.
1. Install the mounting bracket in the vehicle using the supplied self-
tapping screws (4pcs) and at washers (4pcs).
2. Position the transceiver, then insert and tighten the supplied hexagon
SEMS screws.
Car body
Mounting bracket
Washer (M5)
Tapping screw
(M5X20mm)
• Double check that all screws are tightened to prevent vehicle
vibration from loosening the bracket or transceiver.
Initial Installation
• Determine the appropriate angle of the transceiver, using the 3
screw hole positions on the side of the mounting bracket.
LOW
V/MHMSCN
SET
TV/SOL
V/MHMSCN
LOW

4
DB-750X
3
Initial Installation
DC POWER CABLE CONNECTION
For best operation, connect directly to vehicle battery.
MOBILE OPERATION
The vehicle battery voltage must be between 11.5 ~ 14.5 Volts
DC. Be sure to use a battery that has sufficient current capacity.
If the current to the transceiver is insufficient, the display may
darken during transmission, or transmitting output power may drop
excessively.
1. Route the DC power cable supplied with the transceiver directly
to the vehicle's battery terminals using the shortest path from the
transceiver.
2. If using the supplied power cable make sure the entire length of
the cable is dressed so it is isolated from heat, moisture, and the
engine high voltage ignition system.
3. If using the optional Powerwerx TMCG-72 cigarette lighter plug
make sure your cigarette lighter socket in your vehicle can handle
12 VDC @ 12 Amps.
• Conrm the correct polarity of the connections, then attach
the power cable to the battery terminals; red connects to
the positive (+) terminal and black connects to the negative
(-) terminal.
• Use the length of cable nessary to reach your battery. In
particular, never remove the fuse holders from the cable.
4. Reconnect any wiring removed from the negative terminal.
5. Connect the DC power cable to the transceiver's power supply
connector.
• Press the connectors rmly together until the locking tab clicks.
Red
Black
DC power cable
NOTE

5
3Initial Installation
• Do not directly connect the transceiver to an AC outlet.
• Use the optional DC Power Adapter (MBXRPA) to connect
the transceiver to a regulated power supply.
• Do not substitute a cable with smaller gauge wires.
BASE STATION OPERATION
In order to use this transceiver for fixed base station operation,
you will need an optional SS-30DV DC power supply and optional
Base Station Enclosure (not included). Please contact your local
dealer for these items.
Before connecting the DC power to the transceiver, be sure to
switch the transceiver and the DC Power Supply OFF.
Do not plug the DC Power Supply into an AC outlet until you
make all connections.
Power Supply (SS-30DV)
DC Power Adapter
(MBXRPA)
Power Supply
(SS-30DV)
1. Connect the optional DC Power Adapter (MBXRPA) to the
regulated DC Power Supply and ensure that the polarities are
correct. (Red: positive, Black: negative).
2. Connect the transceiver's DC power connector to
the connector on the DC Power Adapter (MBXRPA).
Press the connectors rmly together until the locking tab clicks.
NOTE
Red
Black
Base Station Radio
Enclosure (MBXCOVR)
Includes Power Adapter (MBXRPA)
LOWV/MHMSCN
SET
TV/SOL
V/MHMSCN
LOW

6
DB-750X
If the fuse blows, determine the cause, then correct the problem.
After the problem is resolved, replace the fuse. If newly installed
fuses continue to blow, disconnect the power cable and contact your
authorized dealer or an authorized service center for assistance.
Only use fuses of the specified type and rating, otherwise the
transceiver could be damaged.
Before operating, install an efcient, well-tuned antenna. The success
of your installation will depend largely on the type of antenna and its
correct installation. The transceiver can give excellent results if the
antenna system and its installation are given careful attention.
Use a 50 Ω impedance antenna and low-loss coaxial feed-line that
has a characteristic impedance of 50 Ω, to match the transceiver input
impedance. Coupling the antenna to the transceiver via feed-lines having
The possible locations of an antenna on a car are shown as follows:
3
Initial Installation
REPLACING FUSES
If you use the transceiver for a long period when the vehicle battery is
not fully charged, or when the engine is OFF, the battery may become
discharged, and will not have sufcient reserves to start the vehicle. Avoid
using the transceiver in these conditions.
• Transmitting without first connecting an antenna or other
matched load may damage the transceiver. Always connect
the antenna to the transceiver before transmitting.
• All xed stations should be equipped with a lightning arrester to
reduce the risk of re, electric shock, and transceiver damage.
Fuse Location Fuse Current Rating
Transceiver 15 A
Supplied accessory DC
Power Cable 20 A
ANTENNA CONNECTION
an impedance other than 50 Ω reduces the efficiency of the antenna
system and can cause interference to nearby broadcast television
receivers, radio receivers, and other electronic equipment.
NOTE
NOTE

7
3
If you plan to use the optional external speaker/s (MBXSPK), there
are two options. For a single speaker, plug into the upper 3.5 mm
SP jack on the rear of the radio to hear both bands through one
speaker. To use dual speakers, use the optional Y cable (MBXYCBL)
and plug it into the lower 3.5 mm ST jack on the rear of the radio to
split the left and right bands between the two speakers. See page 29
for programming this function.
For voice communications, connect a microphone equipped with
an 8-pin modular plug into the modular socket on the right side of
the control head. Press rmly on the plug until the locking tab clicks.
Attach the supplied microphone hanger in an appropriate location
using the screws included in the screw set.
When programming this radio for the first time with the optional
PC Programming Kit, RPS-DB750X-USB, it is recommended you rst
READ this radio with the software and then save the le for future
reference. In addition, after you READ this radio with the software,
make your programming and frequency changes, then send this
program back to your mobile radio.
Initial Installation
EXTERNAL SPEAKER
MICROPHONE
PC SOFTWARE PROGRAMMING
Ask your dealer about purchasing a Programming Kit: RPS-DB750X-USB.
ACCESSORIES CONNECTIONS
External Dual Speakers
(Use optional audio Y cable)
Microphone (MBXDTMF)
Antenna (MBXGAIN)
NOTE
Microphone
connector
�
V
/
M
H
M
S
C
N
L
O
W
1
4
789
0#
56
23PA
MIC
PB
AB
A
A/BB
PC
PD
MAIN
Speaker (MBXSPK) Audio Y Cable
(MBXYCBL)
External
Single
Speaker
External Speaker
(MBXSPK)

8
DB-750X
4
• Basic Functions
NO. KEY FUNCTION
1 Left Dial Knob
Rotate it to choose frequency /channel. Press
it to set the left band as "Main Band"; In VFO
mode, press it to choose the frequency band;
In function setup as conrm key; in scan mode,
rotate it to change scan direction
2 Right Dial Knob
Rotate it to choose frequency /channel. Press
it to set the right band as "Main Band"; In VFO
mode, press it to choose the frequency band;
In function setup as conrm key; in scan mode,
rotate it to change scan direction
3 Left Volume Knob Adjust left band volume level.
4 Right Volume Knob Adjust right band volume level.
5 Squelch Press this key and hold to adjust squelch while
either turning left dial knob or right dial knob
Getting Acquainted
FRONT PANEL
6 Function set Key In standby, press this key to enter function menu
7Press it to power On /Off the transceiver
8 Bottom
[ LOW ] Key
In standby press it to change H/L power for
left band channel. Long press it to turn On/Off
Frequency Reverse Function
9 Bottom
[ V/M] Key
In standby, press it to switch left band channel
mode and VFO mode. Long press it to set Wide/
Narrow band.
10 Bottom
[ HM ] Key
In standby, press it to switch left band HOME
channel and normal channel. Long press it to
enter dual watch of VFO channel and current
channel.
11 Bottom
[ SCAN ] Key
In standby, press it to start left band channel or
frequency scan.In channel mode, hold it to set
current channel scan skip.
12 Top
[ LOW ] Key
In standby press it to change H/L power for
right band channel. Long press it to turn On/Off
Frequency Reverse Function
13 Top
[ V/M ] Key
In standby, press it to switch right band channel
mode and VFO mode. Long press it to set Wide/
Narrow band.
14 Top [ HM ] Key
In standby, press it to switch right band HOME
channel and normal channel. Long press it to
enter dual watch of VFO channel and current
channel.
15 Top [ SCAN ] Key
In standby, press it to start right band channel or
frequency scan.In channel mode, hold it to set
current channel scan skip.
16 LCD
For channel, frequency and function display
setup.
12 13 14 15
LOW
VOLVOL
V/MHM SCN
SET
MHzREF TONE SUB

9
4
NO. KEY FUNCTION
1Ext. Power Jack Not available in US model.
2Ext. Dual Spkr Port Terminal for optional dual external speakers.
3Ext. Single Spkr Port Terminal for optional single external speaker.
4 Heat-Sink Fan Runs Automatically when radio temperature rises.
5Antenna Connector Connect a 50 Ω antenna.
NO. INDICATOR FUNCTION
1Displays the channel number and Menu number.
2Appears when current channel is priority channel.
3Appears when current channel is set Scan Skip.
4Appears when current channel has CTCSS Encode
5Appears when current channel has CTCSS Decode
6Appears when the Offset function is ON.
7Appears while transmitting.
8Displays the Main channel.
9Displays the operating frequency,channel name.
10 Displays when receiving a signal or Monitor is ON.
11 Signal strength for receiving and power level for
transmitting.
12 Appears while in Narrow band.
13 Appears when mute has been turned ON.
14 Appears when the DCS function is ON.
15 Appears while in AM mode.
16 Appears when the Scrambler function is ON.
17 Appears when the Compander function is ON.
18 Appears while using Low output power.
19 Appears while using Middle output power.
20 Appears while Auto power off function is ON.
21 Appears when the Key Lock function is ON.
22 Appears when press SET key.
23 Appears when in KEY2 mode.
24 Appears when cross band repeat function is ON.
Getting Acquainted
REAR PANEL
DISPLAY
4 132
1 1
10
11
11
12 1213 1314 1415 1616
21
22
17 1718 1819 19
20
23
24
9
8
2 534 6 7 8 2 534 6 7
99
.
.
ST SP ACC

10
DB-750X
4
MIC Connector Diagram (in the front view of connector)
Getting Acquainted
MICROPHONE
Key Pad Serial Data
+5V
DOWN
UP / SPKR AUDIO OUT
MIC GND
MIC
PTT
GND
NO. KEY FUNCTION
1 UP Increase frequency, channel number or
setting value.
2DOWN Decrease frequency, channel number or
setting value.
3 PTT Press the PTT (Push-To-Talk) key to transmit.
4Number Key Input VFO frequency or DTMF dial out etc.
5A/B band Choose left band or right band as Main band
6 Band indicator The indicator light on for Main band.
7 TX/RX indicator Light green while receiving, Light red while
transmitting.
8 MIC Speak here during transmission.
9Speaker Option to hear speaker thru microphone.
1
2
3
5
6
7
8
4
DN UP
1
4
789
0#
56
23PA
MIC
PB
AB
A
A/BB
PC
PD
MAIN
9

11
In frequency (VFO) mode, turn the selector
knob clockwise to increase frequency;
counterclockwise to decrease frequency. Every
click will increase or decrease frequency by
one step. To adjust the Main band frequency,
press corresponding selector knob, the left
side of decimal point will ash. In this status,
turn the selector knob to increase or decrease
frequency quickly by 1 MHz steps.
ADJUSTING FREQUENCY THROUGH SELECTOR KNOB
INPUT FREQUENCY THROUGH MICROPHONE NUMBER KEY
In standby, press corresponding key to
switch between frequency and channel mode;
when the transceiver is in channel mode, the
LCD will display current channel.
5Basic Operations
POWER ON
Press key to switch the transceiver ON,
the LCD displays "WELCOME DB-750X", then
displays current frequency or channel.
POWER OFF
Press key for 1 second to switch the transceiver OFF.
Rotate the [VOLUME] knob of selected
band clockwise to increase the volume,
counterclockwise to decrease the volume.
SWITCHING THE POWER ON/OFF
ADJUSTING THE VOLUME
SWITCH BETWEEN VFO AND CHANNEL MODE
ADJUSTING FREQUENCY
To adjust the volume when no signal is present hold , keep pressing it
and adjust the [VOLUME] knob to desired level and release when done.
The microphone [ UP/DOWN ]key is also able to adjust frequency.
Pressing [ UP/DOWN ]key will increase(decrease) the frequency by one
step size. Hold [ UP/DOWN ]key to adjust the frequency continuously.
When the band lockout function is on, the input or adjusting of frequency
is limited to within the current VFO band. The right band is limited to
136-174 MHz and 400-490 MHz.
In VFO mode, you can input the frequency from the microphone
numeric keys. It is invalid to input frequency out of the frequency band.
For example:
to input 150.125 MHz, press 1, 5, 0, 1, 2, 5.
to input 152 MHz, press1, 5, 2, .
ADJUSTING CHANNEL
ADJUSTING CHANNEL THROUGH SELECTOR KNOB
In channel mode, you can adjust the channel directly by the channel
knob. Turn clockwise to increase one channel; turn counterclockwise
to decrease one channel.To adjust the main band channel, press
NOTE
NOTE
NOTE
Decrease frequency Increase frequency
VOL
HM SCN
VOL
HM SCN
Min
Volume
Max
Volume
VOL
HM SCN
Power

12
DB-750X
SWITCH BETWEEN MAIN BAND AND SUB BAND
SELECTING THE FREQUENCY BAND
If there is any empty channel, the adjustment will ignore it and jump to
next channel.
This transceiver can be set to RX/TX on 2 UHF bands or 2 VHF bands.
INPUT CHANNEL THROUGH MICROPHONE NUMBER KEY
In channel mode, you can switch to desired channel by pressing three
of the microphone numeric keys (001-758). For example, input 001 for
channel 1; input 030 for channel 30; input 512 for channel 512. If the
input channel is not programmed with frequency, the transceiver will emit
a warning beep and return to last channel.
This transceiver by default shows dual
receive. A "MAIN" icon will display in the top
right of the working frequency. Transmitting is
only available on the main band. When the left
band is main band, pressing the right selector
knob will switch the right band to main band. Pressing the left selector
knob will switch the left band to main band.
1. Left band VFO: press the bottom key to switch it to VFO mode,
press the left selector knob over one second, then repeat above
operation to switch the left band between 108~180 MHz (RX:
108-174 MHz, TX: 136-174 MHz), 220~260 MHz (RX only),
350~399.995 MHz (RX only) or 400~490 MHz.
2. Right band VFO: press the top key to switch it to VFO mode; press
the right selector knob over one second, then repeat above operation
to switch the right band between 136-174MHz, 400~490MHz.
5
Basic Operations
RECEIVING
If the transceiver has been set at a higher squelch level, it may fail to
hear the weaker stations. If the “BUSY” and signal strength icon display
in left band or right band, but no station is heard, read just the squelch
level to above threshold.
In standby, both left band and right band are
able to receive. When they receive any signal,
the “BUSY” icon and signal strength icon will appear in the corresponding
area of the LCD, and you will hear the audio.
SQUELCH OFF/SQUELCH OFF MOMENTARY
Long press of key can be programmed as Squelch Off or Squelch
Off Momentary to monitor the weak signal.
1. Squelch Off: Hold key until you hear a beep; the squelch is off.
Repeat the above operation to resume squelch.
2. Squelch Off Momentary: Hold key to disable squelch; release the
key to resume squelch.
TRANSMITTING
Hold “PTT” key; the transceiver will transmit. Hold the microphone
approximately 2~5 inches from your mouth, and then speak into the
microphone in your normal voice to get best results.
Transmitting is only available on the main band, the “TX” icon will display
in the top right corner of the main band frequency.
In standby, press the microphone to cancel squelch; press it again to
turn on the squelch.
corresponding selector knob. The channel number flashes in this
situation; the channel number will increase 10 channels by each click
of selector knob. Press microphone [UP/DOWN ] key also to adjust the
channel.
NOTE
NOTE
NOTE
NOTE
NOTE

13
6Shortcut Operations
SQUELCH LEVEL SETUP
This function is used to setup the level of receiving signals. When the
signal strength reaches a certain level, it will unmute the transceiver.
In standby, press and hold key; meanwhile turn the selector knob
to adjust the squelch level of Main band.
1-20: 20 squelch levels are available.
OFF: turn off squelch. The background noise will remain on.
The squelch level setup is for right band and left band separately.
TRANSMIT DTMF/2 TONE/5 TONE SIGNALING
If the current channel is programmed with DTMF / 2-Tone / 5-Tone
signaling, hold PTT and [ UP ] key will transmit selected preprogrammed
signaling.
HIGH/MID/LOW TRANSMIT POWER SWITCH
In standby, repeatedly press key to choose power levels as follows:
When LCD displays HIGH, the power for current channel is high.
When LCD displays MID1, the power for current channel is middle 1
When LCD displays MID2, the power for current channel is middle 2.
When LCD displays LOW, the power for current channel is low.
Output power for each level:
HIGH MID1 MID2 LOW
VHF (50 W) VHF (20 W) VHF (10 W) VHF (5 W)
UHF (40 W) UHF (25 W) UHF (10 W) UHF (5 W)
In channel mode, this operation is for temporary use only
This function is valid only when current channel is programmed with
repeater offset frequency and offset direction
In standby, press key to switch to HOME
channel, and communicate on HOME channel.
Repeatedly press it to return to last channel.
In standby, hold key for one second to turn On/Off frequency
reverse function. When reverse function is on, the TX frequency will
change to RX frequency and RX frequency will change to TX frequency.
The signaling will also be reversed for CTCSS/DCS signaling set in this
channel.
HOME CHANNEL
FREQUENCY REVERSE
This transceiver has three bandwidths. Select suitable bandwidth in
accordance with different local conditions.
In standby, hold key for one second to choose the three bandwidths.
When LCD displays WIDE, current channel is working on wide band
25 kHz. When LCD displays MIDDLE, current channel is working on middle
band 20 kHz. When LCD displays NARROW, current channel is working
on narrow band 12.5 kHz. Per FCC Rules, in North America wide band
and narrow band is used. See top of page 36 for band plan.
BANDWIDTH SELECTION
NOTE
NOTE
NOTE
HYPER MEMORY CHANNEL
In standby, press the left or right volume knob to switch the radio to work
on hyper channel 1 or hyper channel 2.

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DB-750X
Shortcut Operations
In standby, hold key for one second to enter Dual Watch mode.
The radio will scan the channel every 5 seconds. When the radio receives
a matching signal, it pauses scanning until the signal disappears. Repeat
above operation to exit dual watch.
DUAL WATCH
FREQUENCY SCAN
MEMORY CHANNEL/FREQUENCY SCAN
In VFO mode, this function is designed to monitor signals at every
"step size" you have set.
1. In VFO mode, press the main band key to enter channel scan.
2. During the scanning, adjust the main band selector knob or press the
microphone [ UP/DOWN ] key to change the scan direction.
3. Press key to exit scan.
MEMORY CHANNEL SCAN
1. In channel mode, press the main band key to enter channel scan.
2. During the scanning, adjust the main band selector knob or press
microphone [ UP/DOWN ] key to change the scan direction.
3. Press key to exit scan.
In channel mode, switch selector knob to choose the channel, then
1. In VFO mode, turn selector knob to select the desired frequency or
input frequency by microphone numeric
keypad. Set offset and CTCSS/DCS
tones.
2. Hold key until the transceiver beeps and the channel number
ashes.
3. Turn selector knob to select the channel number to store. (If the
storage has data, the LCD will display the
frequency, otherwise will display "----------")
4. Press key. The LCD will display MEN- IN, and channel edit is
completed.
1. In channel mode, turn the selector knob to choose the channel.
2. Hold key until the transceiver beeps and channel number
ashes.
3. Turn selector knob to choose channel number for storage. (If the
MEMORY CHANNEL SCAN SKIP
MEMORY CHANNEL ADD
MEMORY CHANNEL COPY
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EMERGENCY ALARM
To start emergency alarm, hold the right volume knob until the trans
-ceiver displays ALARM and emits an alarm. Re-power on the transceiver
to exit alarm. This transceiver has four kinds of alarm which can be setup
by programming software.
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hold for one second. The radio will beep
twice and the LCD will display "SKIP"; now the
current channel will be skipped during scan.
SCAN RANGE LIMIT
1. Choose upper limit and lower limit frequency. Five pairs (L1 / U1 -
L5 / U5) may be selected. L stands for lower the limit and U stands
for the upper limit. the upper limit must be higher than the lower limit
frequency. Please refer to the Channel
Edit to setup the limit frequency.
2. In VFO mode, set the VFO frequency in
the range between upper and lower limit.
3. Press key to start scan in lmited range.
You can set the VFO scan frequency range with this function:

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Shortcut Operations
1. In standby, hold key until the
transceiver beeps, and channel number
ashes.
2. Turn selector knob to choose channel number for delete. (If the
storage has data, the LCD will display the frequency, otherwise will
display"----------")
3. Hold main band volume knob until the transceiver beeps twice and
LCD displays MEN-OUT. Channel delete was completed.
MEMORY CHANNEL DELETE
storage has data , the LCD will display the frequency, otherwise will
display"----------")
4. Press key. The LCD will display MEN-IN, and channel copy was
completed.
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