Standard Horizon Matrix GX2000 User manual

Page 1GX2000S/GX2100S
MATRIX GX2000/GX2100
25 Watt VHF/FM
Marine Transceiver
Owner's Manual

GX2000/GX2100Page 2
QUICK REFERENCE GUIDE I
You can do the basic operation in numerical order of the illustration below.
h
[PTT]S
WITCH
Speak into the
microphone in a
normal voice level
while pressing this
switch.
d
[TT
TT
T]/ [SS
SS
S]K EY
Selects the operating
channel.
f
[H/L]B
UTTON
When pressed,
toggles the transmit
power between High
(25W) and Low (1W).
e
[SQL]K
NOB
Move this control
clockwise to squelch
or counter clockwise
un-squelch the radio.
c
[PWR/VOL]K
NOB
Press and hold this knob until the LCD
turns on, and adjust the audio level.
d
[CH]K
NOB
Selects the operating channel.
g
[16/9]B
UTTON
yPress to recall chan-
nel 16.
yPress and hold to
recall channel 9.
g
[16/9]B
UTTON
yPress to recall
channel 16.
yPress and hold to
recall channel 9.
M ICROPHON

Page 3GX2000/GX2100
[DISTRESS]B
UTTON
Note: for this key to
operate a MMSI must
be programmed.
Lift the red cover,
press the Distress but-
ton once, then press
and hold until the ra-
dio alarms.
QUICK REFERENCE GUIDE II
[CALL/MENU]B
UTTON
yPress to access the
“DSC MENU”.
yPress and hold to
access the “SETUP
MENU”.
[CH]K
NOB
ySelect the operating
channel.
ySelect the item in
the “SETUP MENU”
and “DSC MENU”.
yWhen the “SETUP
MENU” or “DSC
MENU” is selected,
pressing this knob
saves a selection.
[CLR/WX]B
UTTON
yPress to cancel the
menu selection.
yPress and hold to
recall the last-used
NOAA Weather
Channel.
[P
ROGRAMMABLE
]K
EY
These three keys
functions can be cus-
tomized by the Setup
Menu mode.
The factory defaults
are [PA/FOG], [IC],
and [SCAN]key.
[AIS]B
UTTON
Press to change the
display to AIS (Auto-
matic Identification
System) mode

GX2000/GX2100Page 4
QUICK INSTALLATION GUIDE I
DESKTOP MOUNTING OVERHEAD MOUNTING
DESKTOP/OVERHEAD MOUNTING THE RADIO
The supplied universal mounting bracket allows desktop or overhead nounting.
Use a 13/64” (5.2-mm) bit to drill the holes to a surface which is more 0.4 inch
(10 mm) thick and can support more than 3.3 lbs (1.5 kg) and secure the
bracket with the supplied screws, spring washers, flat washers, and nuts.
ELECTRICAL CONNECTIONS
GPS Receiver
Plotter ConnectionRadio Wires
External Speaker
Green
Purple
Red Black
NMEA OUT
NMEA COMMON
NMEA IN
( )
( )
( )
Blue
Shield
White
12 V Battery

Page 5GX2000/GX2100
QUICK INSTALLATION GUIDE II
FLUSH MOUNTING
Bracket
Adjusting Screw
Lock-washer nut combination
FLUSH MOUNTING THE RADIO
The optional MMB-84 Flush-Mount Bracket allows flush mounting the radio to
your vessel.
1. To assist in flush mounting, a template has been included. Use this tem-
plate to assess the mounting location.
2. Use the template to mark the location where the rectangular hole is to be
cut. Confirm the space behind the dash or panel is deep enough to accom-
modate the transceiver (at least 6.7 inches or 17 cm deep).
There should be at least 1/2 inch (1.3 cm) between the transceiver’s heatsink
and any wiring, cables or structures.
3. Cut out the rectangular hole and insert the transceiver.
4. Fasten the brackets to the sides of the transceiver with the lock washer nut
combination; so that the mounting screw base faces the mounting surface.
5. Turn the adjusting screw to adjust the tension so that the transceiver is
tight against the mounting surface.

GX2000/GX2100Page 6
1 GENERAL INFORMATION
1.1 INTRODUCTION
The STANDARD HORIZON GX2000/2100 is a VHF/FM Marine Transceiver
designed for use in the frequency range of 156.025 to 163.275 MHz. The
GX2000/2100 can be operated from 11 to 16 VDC and has a switchable RF
output power of 1 watt or 25 watts.
The GX2100 is equipped with the AIS (Automatic Identification System) re-
ceiver and its display program which enables to identify and avoid other large
vessels nearby your vessel. The GX2100 is equipped with the display pro-
gram of the AIS too. Threrfore, the GX2000 also enables to identify and avoid
other large vessels nearby your vessel, if the AIS receiver (not supply) is
commected.
The GX2000/GX2100 is capable of DSC (Digital Selective Calling) Class D
operation and an Enhanced second station RAM+ mic (CMP30 remote-con-
trol speaker/microphone with display) or VH-310 Handset. Class D operation
allows continuous receiving of Digital Selective Calling functions on channel
70 even if the radio is receiving a call.
The GX2000/GX2100 operates on all currently-allocated marine channels
which are switchable for use with USA, International, or Canadian regulations.
It has an emergency channel 16 which can be immediately selected from any
channel by pressing the red [16/9]key. NOAA Weather channels can also be
accessed immediately by Press and holding the [CLR(WX)] key with channel
selection.
Other features of the GX2000/GX2100 include: 30W PA/Fog, multi-station
intercom, scanning, priority scanning, submersible speaker mic, high and low
voltage warning, and GPS repeatability.
2 PACKING LIST
When the package containing the transceiver is first opened, please check it
for the following contents:
yGX2000 or GX2100 Transceiver
yMounting Bracket and attaching hardware
yOwner’s Manual
yWarning Sticker
yPower Cord

Page 7GX2000/GX2100
3 OPTIONS
MMB-84 .........................................................................Flush-Mount Bracket
CMP30B/W ............... Remote-Access Microphone (RAM+ Mic, Black/White)
VH-310 .................................................. Remote Handset (available in Black)
CT-100 ............................................... 23-foot Extension Cable for RAM+ Mic
CVS2500 ...............................................................................Voice Scrambler
MLS-310 .............. 10W amplified External Speaker with on/off Volum control
MLS-300 ...................................................................... External Loudspeaker
101W ............................................................... Mini White Extension Speaker
220SW ..................................................................... 4.5” Round Hail/PA Horn
240SW ........................................................ 5” x 8” Rectangular Hail/PA Horn
MEK-4 .... Microphone Extension Kit (to remote front panel mic to rear panel)
4 SAFETY / WARNING INFORMATION
This radio is restricted to occupational use, work related operations only where
the radio operator must have the knowledge to control the exposure condi-
tions of its passengers and bystanders by maintaining the minimum separa-
tion distance of 0.89 m (2.92 feet). Failure to observe these restrictions will
result in exceeding the FCC RF exposure limits.
Antenna Installation:
The antenna must be located at least 0.89 m (2.92 feet) away from passen-
gers in order to comply with the FCC RF exposure requirements.
Lithium Battery Included:
This radio contains a Lithium Battery. At the end of radio’s useful life, under
various state and lows, it may be illegal to dispose of Lithium Battery into the
municipal waste stream. Check with your local solid waste officials for details
in your area for recycling options or proper disposal.
ON-LINE WARRANTY REGISTRATION
Please visit www.standardhorizon.com to register the GX2000/
GX2100 Marine VHF. It should be noted that visiting the Web site from
time to time may be beneficial to you, as new products are released
they will appear on the STANDARD HORIZON Web site.
PRODUCT SUPPORT INQUIRIES
If you have any questions or comments regarding the use of the
GX2000/GX2100, you can visit the STANDARD HORIZON Web site
to send an E-Mail or contact the Product Support team at 800-767-2450
M-F 7:00-5:00PST.

GX2000/GX2100Page 8
5 FCC RADIO LICENSE INFORMATION
Standard Horizon radios comply with the Federal Communication Commis-
sion (FCC) requirements that regulate the Maritime Radio Service.
5.1 STATION LICENSE
An FCC ship station license is no longer required for any vessel traveling in
U.S. waters (except Hawaii) which is under 20 meters in length. However, any
vessel required to carry a marine radio on an international voyage, carrying a
HF single side band radiotelephone or marine satellite terminal is required to
have a ship station license. FCC license forms, including applications for ship
(605) and land station licenses can be downloaded via the Internet at http://
www.fcc.gov/Forms/Form605/605.html. To obtain a form from the FCC, call
[phone].
5.2 RADIO CALL SIGN
Currently the FCC does not require recreational boaters to have a Ship Radio
Station License. The USCG recommends the boats registration number and
the state to be used.
5.3 CANADIAN SHIP STATION LICENSING
You may need a license when traveling in Canada. If you do need a license
contact their nearest field office or regional office or write:
Industry Canada
Radio Regulatory Branch
Attn: DOSP
300 Slater Street
Ottawa, Ontario
Canada, KIA 0C8
5.4 FCC / INDUSTRY CANADA INFORMATION
The following data pertaining to the transceiver is necessary to fill out the li-
cense application.
Type Acceptance ......................................................................... FCC Part 80
Output Power ...............................................1 Watt (low) and 25 Watts (high)
Emission ......................................................................... 16K0G3E, 16K0G2B
Frequency Range .................................................... 156.025 to 163.275 MHz
FCC Type Number ................................................................... K6630443X3D
Industry Canada Type Approval ............................................ 511B-30443X3S

Page 9GX2000/GX2100
6 FCC NOTICE
NOTICE
Unauthorized changes or modifications to this equipment may void com-
pliance with FCC Rules. Any change or modification must be approved
in writing by STANDARD HORIZON.
NOTICE
This equipment has been tested and found to comply with the limits for
a Class B digital device, pursuant to Part 15 of the FCC Rules. These
limits are designed to provide reasonable protection against harmful
interference in a residential installation. This equipment generates, uses
and can radiate radio frequency energy and, if not installed and used in
accordance with the instructions, may cause harmful interference to ra-
dio communications. However, there is no guarantee that interference
will not occur in a particular installation. If this equipment does cause
harmful interference to radio or television reception, which can be de-
termined by turning the equipment off and on, the user is encouraged to
try to correct the interference by one or more of the following measures:
- Reorient or relocate the receiving antenna.
- Increase the separation between the equipment and receiver.
- Connect the equpmet into an outlet on a circuit different from that to
which the receiver is connected.
- Consult the dealer or an experienced radio/TV technician for help.

GX2000/GX2100Page 10
7 GETTING STARTED
7.1 ABOUT VHF RADIO
The radio frequencies used in the VHF marine band lie between 156 and 158
MHz with some shore stations available between 161 and 163 MHz. The ma-
rine VHF band provides communications over distances that are essentially
“line of sight” (VHF signals do not travel well through objects such as buildings,
hills or trees). Actual transmission range depends much more on antenna type,
gain and height than on the power output of the transmitter. On a fixed mount
25W radio transmission expected distances can be greater than 15 miles, for
a portable 5W radio transmission the expected distance can be greater than 5
miles in “line of sight”.
7.2 SELECTING AN ANTENNA
Marine antennas are made to radiate signals equally in all horizontal direc-
tions, but not straight up. The objective of a marine antenna is to enhance the
signal toward the horizon. The degree to which this is accomplished is called
the antenna’s gain. It is measured in decibels (dB) and is one of the major
factors in choosing an antenna. In terms of effective radiated power (ERP),
antennas are rated on the basis of how much gain they have over a theoretical
antenna with zero gain. A 3 foot, 3dB gain antenna represents twice as much
gain over the imaginary antenna.
Typically a 3 foot 3dB gain stainless steel whip is used on a sailboat mast. The
longer 8 foot 6dB fiberglass whip is primarily used on power boats that require
the additional gain.

Page 11GX2000/GX2100
7.3 COAXIAL CABLE
VHF antennas are connected to the transceiver by means of a coaxial cable –
a shielded transmission line. Coaxial cable is specified by it’s diameter and
construction.
For runs less than 20 feet, RG-58/U, about 1/4 inch in diameter is a good
choice. For runs over 20 feet but less than 50 feet, the larger RG-8X or RG-
213/U should be used for cable runs over 50 feet RG-8X should be used. For
installation of the connector onto the coaxial cable refer to the figure below.
1/16''
3/4''
3/4''
1 1/8''
1/8''
5/8''3/8''
Adapter
To get your coax cable through a fitting and into your boat’s interior, you
may have to cut off the end plug and reattach it later. You can do this if
you follow the directions that come with the connector. Be sure to make
good soldered connections.

GX2000/GX2100Page 12
8 INSTALLATION
8.1 LOCATION
The radio can be mounted at any angle. Choose a mounting location that:
• is far enough from any compass to avoid any deviation in compass read-
ing due to the speaker magnet
• provides accessibility to the front panel controls
• allows connection to a power source and an antenna
• has nearby space for installation of a microphone hanger
• the antenna must be mounted at least 3 feet from radio
Note: To insure the radio does not affect the compass or radios performance is
not affected by the antenna location, temporarily connect the radio in the de-
sired location and:
a. Examine the compass to see if the radio causes any deviation
b. Connect the antenna and key the radio. Check to ensure the radio is
operating correctly by requesting a radio check.
8.2 MOUNTING THE RADIO
8.2.1 Supplied Universal Mounting Bracket
The supplied universal mounting bracket allows overhead or desktop mount-
ing.
Use a 13/64” (5.2-mm) bit to drill the holes to a surface which is more 0.4 inch
(10 mm) thick and can support more than 3.3 lbs (1.5 kg) and secure the
bracket with the supplied screws, spring washers, flat washers, and nuts.

Page 13GX2000/GX2100
8.2.2 Optional MMB-84 Flush Mount Bracket
1. Make a rectangular template for the flush mount measuring 2.9” H x
8.1” W (72 x 205 mm).
2. Use the template to mark the location where the rectangular hole is to be
cut. Confirm the space behind the dash or panel is deep enough to accom-
modate the transceiver (at least 6 inches deep).
There should be at least 1/2 inch between the transceiver’s heatsink and
any wiring, cables or structures.
3. Cut out the rectangular hole and insert the transceiver.
4. Fasten the brackets to the sides of the transceiver with the lock washer nut
combination; so that the mounting screw base faces the mounting surface
(see illustration below).
5. Turn the adjusting screw to adjust the tension so that the transceiver is
tight against the mounting surface.
Bracket Adjusting Screw
Lock-washer nut combination

GX2000/GX2100Page 14
8.3 ELECTRICAL CONNECTIONS
CAUTION
Reverse polarity connections will damage the radio!
Connect the power cord and antenna to the radio. Antenna and Power Supply
connections are as follows:
1. Mount the antenna at least 3 feet away from the radio. At the rear of the
radio, connect the antenna cable. It must have a PL259 connector. RG-8/
U coaxial cable must be used if the antenna is 25 feet or more from the
radio. RG58 cable can be used for distances less than 25 feet.
2. Connect the red power wire to a 13.8 VDC ±20% power source. Connect
the black power wire to a negative ground.
3. If an optional remote extension speaker is to be used, refer to section 3.3
for connections.
4. It is advisable to have a Certified Marine Technician check the power out-
put and the standing wave ratio of the antenna after installation.
GPS Navigation Receiver
Accessory Cable
Optional Speaker
Antenna
Fuse
Red
Power Source
Black
Water proof
Deck Outlet
Optional HAIL/PA Horn
Fuse Replacement
To take out the Fuse from the Fuse Holder, hold
the both ends of the Fuse Holder and pull the Fuse
Holder apart, do not bend the Fuse Holder. When
you replace the Fuse, please confirm that the Fuse
is tightly fixed on the metal contact located inside
the Fuse Holder. If the metal contact holding the
fuse is loose, the Fuse holder may heat up.

Page 15GX2000/GX2100
Wire Color/Description
WHITE - External Speaker (+)
SHIELD - External Speaker (–)
RED - PA Speaker (+)
SHIELD - PA Speaker (–)
GREEN - NMEA Ground
BLUE- NMEA Input (+)
GRAY-NMEA Output (+)
Connection Examples
Connect to external 4 Ohm audio speaker
Connect to external 4 Ohm audio speaker
Connect to external 4 Ohm PA speaker
Connect to external 4 Ohm PA speaker
Connect to NMEA (–) connection of GPS
Connect to NMEA (+)output of GPS
Connect to NMEA (+)input of GPS
8.4 ACCESSORY CABLE
External Speaker
GPS Receiver
PA Speaker
Green
Blue NMEA OUT
NMEA OUT
NMEA IN
( )
( )
( )
Gray
Shield
Shield
Red
White
DISTRESS
PULL OPEN
VOL/PWR
SQL
CALL CLR
PA/
FOG
SCAN
ENT
DW
IC NAV
MENU
WX
16/9
QUANTUM GX5000S
H/L
When connecting the external speaker or GPS navigation receiver, strip off
about 1 inch (2.5 cm) of the specified wire’s insulation, then splice the ends
together.
• The GPS must have the NMEAut turned on and set to 4800 Baud in
the setup menu. If there is a selection for parity select none.
• For further information on interfacing /setting up your GPS. Please contact
the manufacturer of the GPS receiver.
•GX2000/GX2100 can read NMEA-0183 version 2.0 or higher.
• The NMEA supported sentences are:
Input: GLL, GGA, RMC and GNS (RMC sentence is recommended)
Output:DSC and DSE
(DSC sentences to Standard Horizon Plotter for Position Polling)
If you have further inquires, please feel free to contact Product Support at:
Phone: [phone]
Email: [e-mail]

GX2000/GX2100Page 16
OFFSET TIME TABLE
8.5 CHECKING GPS CONNECTIONS
After connections have been made between the
GX2000/GX2100 and the GPS, a small satellite icon
will appear on the top right corner of the LCD displayand
displays your current location (Latitude/Longitude) on
the display.
NOTE
If there is a problem with the NMEA input from a GPS, the GPS icon will
blink continuously until the connection is corrected.
8.6 CHANGING THE GPS TIME
From the Factory the GX2000/GX2100 shows GPS satellite time or UTC
time when a optional GPS is connected. A time offset is needed to show the
local time in your area.
1. Press and hold down the [CALL(MENU)] key until
“SETUP MENUSETUP MENU
SETUP MENUSETUP MENU
SETUP MENU” appears, then select “GENERALGENERAL
GENERALGENERAL
GENERAL
SETUPSETUP
SETUPSETUP
SETUP” with the CH knob.
2. Press the CH knob, then select “TIME OFFSETTIME OFFSET
TIME OFFSETTIME OFFSET
TIME OFFSET” with
the CH knob.
3. Press the CH knob, then turn the CH knob to select
time offset from UTC. See illustration below to find
your offset time from UTC. If “00:0000:00
00:0000:00
00:00” is assigned,
the time is the same as UTC (Universal Time Coor-
dinated or GMT Greenwich Mean Time).
4. Press the CH knob to store the time offset.
5. Press the [CLR(WX)] key several times to return to
radio operation.

Page 17GX2000/GX2100
8.7 CHANGING THE TIME LOCATION
Set the radio show UTC time or local time with the offset inputted in section 8.6
CHANGING THE GPS TIME.
1. Press and hold down the [CALL(MENU)] key until
“SETUP MENUSETUP MENU
SETUP MENUSETUP MENU
SETUP MENU” appears, then select “GENERALGENERAL
GENERALGENERAL
GENERAL
SETUPSETUP
SETUPSETUP
SETUP” with the CH knob.
2. Press the CH knob, then select “TIME DISPLAYTIME DISPLAY
TIME DISPLAYTIME DISPLAY
TIME DISPLAY” with
the CH knob.
3. Press the CH knob.
4. Turn the CH knob to select “UTCUTC
UTCUTC
UTC” or “LOCALLOCAL
LOCALLOCAL
LOCAL”.
5. Press the CH knob to store the selected setting.
6. Press the [CLR(WX)] key several times to return to
radio operation.
8.8 CHANGING COG TO TRUE OR MAGNETIC
Allows the GPS Course Over Ground to be selected to show in True or Mag-
netic. Factory default is True however following the steps below the COG can
be changed to Magnetic.
1. Press and hold down the [CALL(MENU)] key until
“SETUP MENUSETUP MENU
SETUP MENUSETUP MENU
SETUP MENU” appears, then select “GENERALGENERAL
GENERALGENERAL
GENERAL
SETUPSETUP
SETUPSETUP
SETUP” with the CH knob.
2. Press the CH knob, then select “MAGNETICMAGNETIC
MAGNETICMAGNETIC
MAGNETIC” with
the CH knob.
3. Press the CH knob.
4. Turn the CH knob to select “MAGNETICMAGNETIC
MAGNETICMAGNETIC
MAGNETIC” or “TRUETRUE
TRUETRUE
TRUE”.
5. Press the CH knob to store the selected setting.
6. Press the [CLR(WX)] key several times to return to
radio operation.

GX2000/GX2100Page 18
8.9 OPTIONAL CMP30 ENHANCED RAM+ SECOND STATION MIC
OR VH-310 HANDSET INSTALLATION
The GX2000/GX2100 is capable of using a CMP30 Enhanced RAM+ mic
or VH-310 Handset to remotely control the Radio, DSC and PA/Fog functions.
In addition the GX2000/GX2100 can operate as a full function intercom
system.
1. Connect the Extension Cable to the Remote Mic eight pin connector on
the rear panel, then tighten the Cable Nut (see illustration below).
2. Referring to illustration below, make a 1.2” (30 mm) hole in the wall, then
insert the Extension Cable into this hole. Connect the Gasket and Mount
Base to the Extension Cable Connector using the Nut.
3. Drill the four Screw holes (approx. 2 mm) on the wall, then install the Mount-
ing Base to the wall using four screws.
4. Put the Rubber Cap on to the Nut. The installation is now complete.
NOTE
The routing cable can be cut and spliced, however care needs to be
taken when reconnecting the wires to ensure water integrity.
Before cutting the cable make sur it is not plugged into the radio. After
cutting you will notice there are the following wires:
Yellow, Green, Brown, Purple, Blue, Green, RedÚ, ShieldÚ
ÚThe red and shield wires arewrapped in foil. Remove the foil, and
seperate the Red and shield wires.
Figure 3. Enhanced RAM+ MIC Installation
Wall
Gasket
Mounting Bracket
Routing Cable
Cap
Nut
External Speaker Connections

Page 19GX2000/GX2100
Remote Mic or External Speaker Selection
By default the RAM+ or VH-310 Handset internal speaker is turned on, how-
ever using the RAM+ mic (or VH-310 Handset) this speaker can be turned off
so the external speaker can be used.
RAM+ mic procedure
1. Press and hold the [CALL(ENT)] key.
2. Press the [S]or [T]key to select “RADIO SETUPRADIO SETUP
RADIO SETUPRADIO SETUP
RADIO SETUP.”
3. Press the [CALL(ENT)] key.
4. Press the [T]key to until “EXT SPKEXT SPK
EXT SPKEXT SPK
EXT SPK” is shown and press the
[CALL(ENT)] key.
5. Press the [S]or [T]key to select “oFoF
oFoF
oF” (External speaker
off) or “onon
onon
on” (External speaker on).
6. Press the [CALL(ENT)] key to save the selection.
7. Press the [16/9]key to exit this mode.
VH-310 Procedure
1. Press and hold the [CALL(MENU)] key.
2. Press the [S]or [T]key to select “RADIO SETUPRADIO SETUP
RADIO SETUPRADIO SETUP
RADIO SETUP.”
3. Press the [ENT]key
4. Press the [T]key to until “EXT SPKEXT SPK
EXT SPKEXT SPK
EXT SPK” is shown and press the
[ENT]key.
5. Press the [S]or [T]key to select “oFoF
oFoF
oF” (External speaker
off) or “onon
onon
on” (External speaker on).
6. Press the [ENT]key to save the selection.
7. Press the [16/9]key to exit this mode.

GX2000/GX2100Page 20
9 CONTROLS AND INDICATORS
NOTE
This section defines each control of the transceiver. See illustration at
the next page for location of controls. For detailed operating instructions
refer to chapter 10 of this manual.
9.1 CONTROLS AND CONNECTIONS
CH Knob
Rotary knob used to select channels and to choose menu items (such as
the DSC menu, Radio Setup and DSC Setup menu). The [UP(S)] /
[DOWN(T)] keys on the microphone can also be used to select channels
and menu items.
SECONDARY USE
yPress this knob to enter a selection the “SETUP MENU” or “DSC MENU”.
yWhile holding down the [SCAN]key and turning this knob, you can con-
firm memory channels for scanning.
yAdjust the PA output level while in PA/FOG mode.
PWR/VOL Knob (Power Switch / Volume Control)
Turns the transceiver on and off as well as adjusts the audio volume.
To turn the transceiver on, press and hold this knob until the LCD turns on.
When the power is turned on, the transceiver is set to the last selected
channel. Clockwise rotation of this knob increases the audio volume level.
To turn the transceiver off, press and hold this knob until the LCD turns off.
SECONDARY USE
When in PA or Fog mode, controls the listen back volume.
SQL Knob (Squelch Control)
Adjusting this control clockwise, sets the point at which random noise on
the channel does not activate the audio circuits but a received signal does.
This point is called the squelch threshold. Further adjustment of the squelch
control will degrade reception of wanted transmissions.