INSTRUCTION MANUAL
VHF MARINE TRANSCEIVER
iM304
FOREWORD
Thank you for purchasing this Icom radio. The IC-M304 VHF MARINE TRANSCEIVER is designed and built with Icom’s state of the art technology and craftsmanship. With proper care, this radio should provide you with years of trouble-free operation.
We hope you agree with Icom’s philosophy of “technology first.” Many hours of research and development went into the design of your IC-M304.
D FEATURES
Large 2-digit Channel with scrolling comment
New Force5Audio speaker
Built-in DSC meets RTCM SC101 requirement
Submersible construction
Favorite channel function
AquaQuake water draining function
Icom, Icom Inc. and the 
logo are registered trademarks of Icom Incorporated (Japan) in the United States, the United Kingdom, Germany, France, Spain, Russia and/or other countries.
FORCE5AUDIO logo is a registered trademark of Icom Incorporated (Japan) in the United States.
IMPORTANT
READ ALL INSTRUCTIONS carefully and completely before using the transceiver.
SAVE THIS INSTRUCTION MANUAL — This instruction manual contains important operating instructions for the IC-M304.
EXPLICIT DEFINITIONS
WORD |
DEFINITION |
Personal injury, fire hazard or electric shock R WARNING! may occur.
CAUTION Equipment damage may occur.
NOTE
Recommended for optimum use. No risk of personal injury, fire or electric shock.
CLEAN THE TRANSCEIVER AND MICROPHONE THOROUGHLY WITH FRESH WATER after exposure to water including salt water, otherwise, the keys and switches may become inoperable due to salt crystallization.
i
IN CASE OF EMERGENCY
If your vessel requires assistance, contact other vessels and the Coast Guard by sending a distress call on Channel 16.
USING CHANNEL 16
DISTRESS CALL PROCEDURE
1.“MAYDAY MAYDAY MAYDAY.”
2.“THIS IS ...............” (name of vessel)
3.Your call sign or other indication of the vessel (AND 9- digit DSC ID if you have one).
4.“LOCATED AT ...............” (your position)
5.The nature of the distress and assistance required.
6.Any other information which might facilitate the rescue.
Or, transmit your distress call using digital selective calling on Channel 70.
USING DIGITAL SELECTIVE CALLING (Ch 70)
DISTRESS CALL PROCEDURE
1.While opening the key cover, push and hold [DISTRESS] for 5 sec. until you hear 5 short beeps change to one long beep.
2.Wait for an acknowledgment from a coast station.
• Channel 16 is automatically selected.
3.Push and hold [PTT], then transmit the appropriate information as listed above.
NOTE
A WARNING STICKER is supplied with the transceiver.
To comply with FCC regulations, this sticker must be affixed in such a location as to be readily seen from the operating controls of the radio as in the diagram below. Make sure the chosen location is clean and dry before applying the sticker. (p. 32)
EXAMPLE
WARNING
STICKER
ii
RADIO OPERATOR WARNING
Icom requires the radio operator to meet the FCC Requirements for Radio Frequency Exposure. An omnidirectional antenna with gain not greater than 9 dBi must be mounted a minimum of 5 meters (measured from the lowest point of the antenna) vertically above the main deck and
all possible personnel. This is the minimum safe separation distance estimated to meet all RF exposure compliance requirements. This 5 meter distance is based on the FCC Safe Maximum Permissible Exposure (MPE) distance of 3 meters added to the height of an adult (2 meters) and is appropriate for all vessels.
For watercraft without suitable structures, the antenna must be mounted so as to maintain a minimum of 1 meter vertically between the antenna, (measured from the lowest point of the antenna), to the heads of all persons AND all persons must stay outside of the 3 meter MPE radius.
Do not transmit with radio and antenna when persons are within the MPE radius of the antenna, unless such persons (such as driver or radio operator) are shielded from antenna field by a grounded metallic barrier. The MPE Radius is the minimum distance from the antenna axis that person should maintain in order to avoid RF exposure higher than the allowable MPE level set by FCC.
FAILURE TO OBSERVE THESE LIMITS MAY ALLOW THOSE WITHIN THE MPE RADIUS TO EXPERIENCE RF RADIATION ABSORPTION WHICH EXCEEDS THE FCC MAXIMUM PERMISSIBLE EXPOSURE (MPE) LIMIT.
IT IS THE RESPONSIBILITY OF THE RADIO OPERATOR TO ENSURE THAT THE MAXIMUM PERMISSIBLE EXPOSURE LIMITS ARE OBSERVED AT ALL TIMES DURING RADIO TRANSMISSION. THE RADIO OPERATOR IS TO ENSURE THAT NO BYSTANDERS COME WITHIN THE RADIUS OF THE MAXIMUM PERMISSIBLE EXPOSURE LIMITS.
Determining MPE Radius
THE MAXIMUM PERMISSIBLE EXPOSURE (MPE) RADIUS HAS BEEN ESTIMATED TO BE A RADIUS OF ABOUT 3M PER OET BULLETIN 65 OF THE FCC.
THIS ESTIMATE IS MADE ASSUMING THE MAXIMUM POWER OF THE RADIO AND ANTENNAS WITH A MAXIMUM GAIN OF 9dBi ARE USED FOR A SHIP MOUNTED SYSTEM.
iii
TABLE OF CONTENTS
FOREWORD …………………………………………………………… i IMPORTANT …………………………………………………………… i EXPLICIT DEFINITIONS ……………………………………………… i IN CASE OF EMERGENCY…………………………………………… ii NOTE …………………………………………………………………… ii RADIO OPERATOR WARNING ……………………………………… iii TABLE OF CONTENTS ……………………………………………… iv
PRECAUTIONS ………………………………………………………… v
1OPERATING RULES ……………………………………………… 1
2PANEL DESCRIPTION ………………………………………… 2–4
■Front panel ……………………………………………………… 2
■Microphone ……………………………………………………… 3
■Function display ………………………………………………… 4
3BASIC OPERATION …………………………………………… 5–9
■Channel selection ……………………………………………… 5
■Receiving and transmitting……………………………………… 7
■Call channel programming ……………………………………… 8
■Channel comments ……………………………………………… 8
■Microphone lock function ……………………………………… 9
■Display backlighting……………………………………………… 9
■AquaQuake water draining function …………………………… 9
4SCAN OPERATION ………………………………………… 10–11
■Scan types ……………………………………………………… 10
■Setting TAG channels ………………………………………… 11
■Starting a scan ………………………………………………… 11
5DUALWATCH/TRI-WATCH ……………………………………… 12
■Description ……………………………………………………… 12
■Operation ……………………………………………………… 12
6DSC OPERATION …………………………………………… 13–27
■MMSI code programming……………………………………… 13
■MMSI code check ……………………………………………… 13
■DSC address ID………………………………………………… 14
■Position indication ……………………………………………… 15
■Distress call …………………………………………………… 16
■Transmitting DSC calls ………………………………………… 17
■Receiving DSC calls …………………………………………… 24
7SET MODE …………………………………………………… 28–30
■Set mode programming ……………………………………… 28
■Set mode items ………………………………………………… 29
8CONNECTIONS AND MAINTENANCE …………………… 31–34
■Connections …………………………………………………… 31
■Supplied accessories ………………………………………… 32
■Antenna ………………………………………………………… 32
■Fuse replacement ……………………………………………… 32
■Cleaning ………………………………………………………… 32
■Mounting the transceiver ……………………………………… 33
■Optional MB-92 attachment …………………………………… 33
■Optional MB-69 installation …………………………………… 34
9TROUBLESHOOTING …………………………………………… 35
10CHANNEL LIST…………………………………………………… 36
11 SPECIFICATIONS AND OPTIONS ……………………… 37–38
■Specifications …………………………………………………… 37
■Options ………………………………………………………… 38
12 TEMPLATE ……………………………………………………… 39
iv
PRECAUTIONS
RWARNING! NEVER connect the transceiver to an AC outlet. This may pose a fire hazard or result in an electric shock.
CAUTION: Changes or modifications to this device, not expressly approved by Icom Inc., could void your authority to operate this device under FCC regulations.
NEVER connect the transceiver to a power source of more than 16 V DC or use reverse polarity. This will ruin the transceiver.
NEVER cut the DC power cable between the DC plug and fuse holder. If an incorrect connection is made after cutting, the transceiver may be damaged.
NEVER place the transceiver where normal operation of the vessel may be hindered or where it could cause bodily injury.
KEEP the transceiver at least 3.3 ft (1 m) away from the ship’s navigation compass.
DO NOT use or place the transceiver in areas with temperatures below –4°F (–20°C) or above +140°F (+60°C) or, in areas subject to direct sunlight, such as the dashboard.
AVOID the use of chemical agents such as benzine or alcohol when cleaning, as they may damage the transceiver surfaces.
BE CAREFUL! The transceiver rear panel will become hot when operating continuously for long periods.
Place the transceiver in a secure place to avoid inadvertent use by children.
BE CAREFUL! The transceiver (except cables) and hand microphone employ waterproof construction, which corresponds to IPX7 of the international standard IEC 60529 (2001). However, once the transceiver has been dropped, waterproofing cannot be guaranteed due to the fact that the case may be cracked, or the waterproof seal damaged, etc.
v
DPRIORITIES
•Read all rules and regulations pertaining to priorities and keep an up-to-date copy handy. Safety and distress calls take priority over all others.
•You must monitor Channel 16 when you are not operating on another channel.
•False or fraudulent distress signals are prohibited and punishable by law.
DPRIVACY
•Information overheard but not intended for you cannot lawfully be used in any way.
•Indecent or profane language is prohibited.
DRADIO LICENSES
(1) SHIP STATION LICENSE
You must have a current radio station license before using the transceiver. It is unlawful to operate a ship station which is not licensed.
Inquire through your dealer or the appropriate government agency for a Ship-Radiotelephone license application. This government-issued license states the call sign which is your craft’s identification for radio purposes.
OPERATING RULES |
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(2) OPERATOR’S LICENSE |
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A Restricted Radiotelephone Operator Permit is the license |
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The Restricted Radiotelephone Operator Permit must be posted or kept with the operator. Only a licensed radio operator may operate a transceiver.
However, non-licensed individuals may talk over a transceiver if a licensed operator starts, supervises, ends the call and makes the necessary log entries.
Keep a copy of the current government rules and regulations handy.
Radio license for boaters (U.S.A. only)
The Telecommunications Act of 1996 permits recreational boaters to have and use a VHF marine radio, EPIRB, and marine radar without having an FCC ship station license. Boaters traveling on international voyages, having an HF single sideband radiotelephone or marine satellite terminal, or required to carry a marine radio under any other regulation must still carry an FCC ship station license. For further information, see the FCC Ship Radio Stations Fact Sheet.
1
2 PANEL DESCRIPTION
■ Front panel
Speaker |
q Function display (p. 4) w |
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i u y t r e
qCHANNEL UP/DOWN KEYS [Y]/[Z]•[U/I/C]
Selects the operating channels, Set mode settings, etc. (pgs. 5, 6, 28)
While pushing and holding [SCAN], push to adjust the brightness of the LCD and key backlight. (p. 9)
Selects one of three channel groups in sequence when both keys are pushed. (p. 6)
• U.S.A., International and Canadian channels are available.
While turning power ON, push and hold both keys to activate the AquaQuake function. (p. 9)
w POWER/VOLUME CONTROL [VOL] (p. 7)
Rotate to turn the transceiver power ON and OFF and adjusts the audio level.
e SQUELCH CONTROL [SQL] (p. 7) Rotate to set the squelch threshold level.
r CHANNEL 16/CALL CHANNEL KEY [!6•9]
Push to select Channel 16. (p. 5)
Push and hold for 1 sec. to select call channel. (p. 5)
• “CALL” appears when the call channel is selected.
Push and hold for 3 sec. to enter call channel programming condition when the call channel is selected. (p. 8)
While pushing and holding [CH/WX], push to enter the channel comments programming condition. (p. 8)
Push to move the cursor forward. (p. 8)
While turning power ON, push to enter Set mode. (p. 28)
t CHANNEL/WEATHER CHANNEL KEY [CH/WX•DUAL]
Selects and toggles the regular channel and weather channel when pushed momentarily. (p. 6)
Push and hold for 1 sec. to start Dualwatch or Tri-watch. (p. 12)
Push to stop Dualwatch or Tri-watch when either is activated. (p. 12)
Push to move the cursor backward. (p. 8)
2
y SCAN KEY [SCAN•TAG] (p. 11)
Push to start or stop the Normal or Priority scan.
Push and hold for 1 sec. to set or clear the displayed channel as a TAG (scanned) channel.
•The favorite channels are set by the TAG channel setting.
While pushing and holding [HI/LO] on the microphone, push for 3 sec. to clear all TAG channels in the selected channel group.
•Repeat above procedure to set all TAG channels.
u DISTRESS KEY [DISTRESS] (p. 16)
Push and hold for 5 sec. to transmit a Distress call.
i DSC/POSITION KEY [DSC•POS]
Push to enter DSC menu. (p. 13)
Push and hold for 1 sec. to show the current position from a GPS receiver. (p. 15)
PANEL DESCRIPTION 2
■ Microphone
2
q
Microphone
w
e
q PTT SWITCH [PTT]
Push and hold to transmit; release to receive. (p. 7)
wCHANNEL UP/DOWN KEYS [Y]/[Z]
Push either key to change the operating channel, Set mode settings, etc. (pgs. 5, 6, 28)
When the Favorite channel function is turned ON, push either key to select the favorite channels in the selected channel group in sequence. (p. 30)
e TRANSMIT POWER KEY [HI/LO]
Push to toggle the power high and low. (p. 7)
•Some channels are set to low power only.
While pushing and holding [HI/LO], turn power ON to toggle the Microphone Lock function ON and OFF. (p. 9)
3
2 PANEL DESCRIPTION
■ Function display
q |
w |
e r |
t !0
y
!1
u !2 i
o
q CHANNEL GROUP INDICATOR (p. 6)
Indicates whether a U.S.A. “U,” International “ 
” or Canadian “C” channel is in use.
w CHANNEL NUMBER READOUT
Indicates the selected operating channel number.
• Refer to CHANNEL LIST. (p. 36)
In Set mode, indicates the selected condition. (p. 28)
e TRANSMIT INDICATOR (p. 7)
Appears while transmitting.
r BUSY INDICATOR (p. 7)
Appears when receiving a signal or when the squelch opens.
t CALL CHANNEL INDICATOR (p. 5) Appears when the call channel is selected.
y LOW POWER INDICATOR (p. 7) Appears when low power is selected.
u WEATHER CHANNEL INDICATOR (pgs. 6, 29)
“WX” appears when a weather channel is selected.
“WX ALT” appears when the Weather alert function is in use; blinks when an alert tone is received.
iDSC INDICATORS
“DSC” appears when a DSC call is received. (p. 24)
“POS REPLY” appears when a Position Reply call or Position Report Reply call is received. (p. 27)
o CHANNEL COMMENT INDICATOR
Channel comment appears if programmed. (p. 8)
“ 
” scrolls when the battery voltage drops to approx. 10.8 V DC or below.
“ 
” blinks during Priority scan; “ 
” blinks during Normal scan. (p. 11)
“ 
” blinks during Dualwatch; “ 
” blinks during Triwatch. (p. 12)
!0TAG CHANNEL INDICATOR (p. 11) Appears when a TAG channel is selected.
!1DUPLEX INDICATOR (p. 6)
Appears when a duplex channel is selected.
!2GPS INDICATOR
Appears while valid position data is received.
Blinks when invalid position data is received.
Disappears when no GPS receiver is connected.
4
■ Channel selection
ï Channel 16
Channel 16 is the distress and safety channel. It is used for establishing initial contact with a station and for emergency communications. Channel 16 is monitored during both Dualwatch and Tri-watch. While standing by, you must monitor Channel 16.
Push [!6] momentarily to select Channel 16.
Push [CH/WX] to return to the condition before selecting Channel 16, or push [Y] or [Z] to select operating channel.
Push 
Scrolls
Convenient!
When the Favorite channel function is turned ON (p. 30), [Y]/[Z] keys on the microphone select the favorite channels in the selected channel group in sequence when pushed.
• The favorite channels are set by the TAG channel setting. (p. 11)
BASIC OPERATION |
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ï Channel 9 (Call channel) |
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Each regular channel group has a separate leisure-use call |
channel. The call channel is monitored during Tri-watch. The call channels can be programmed (p. 8) and are used to store your most often used channels in each channel group for quick recall.
Push and hold [9] (!6) for 1 sec. to select the call channel of the selected channel group.
•“CALL” and call channel number appear.
•Each channel group may have an independent call channel after programming a call channel. (p. 8)
Push [CH/WX] to return to the condition before selecting call channel, or push [Y] or [Z] to select a channel.
Push 
for 1 sec.
Scrolls
5
3 BASIC OPERATION
ï U.S.A.,Canadian and international channels
The IC-M304 is pre-programmed with 59 U.S.A., 59 international and 63 Canadian channels. These channel groups may be specified for the operating area.
qPush [CH/WX] to select a regular channel.
• If a weather channel appears, push [CH/WX] again.
wPush [U/I/C] (both [Y] and [Z]) on the transceiver to change the channel group, if necessary.
•U.S.A., International and Canadian channel groups can be selected in sequence.
ePush [Y] or [Z] to select a channel.
• “ 
” appears for duplex channels.
Push [U/I/C] (both 
and 
)
ï Weather channels
The IC-M304 has 10 pre-programmed weather channels. These are used for monitoring broadcasts from NOAA (National Oceanic and Atmospheric Administration.)
The transceiver can automatically detect a weather alert tone on the selected weather channel while receiving the channel or during scanning. (p. 29)
qPush [CH/WX] once or twice to select a weather channel.
•“WX” appears when a weather channel is selected.
•“WX ALT” appears when the Weather alert function is in use. (p. 29)
w Push [Y] or [Z] to select a channel.
Push 
once or twice
When Weather alert is OFF. |
When Weather alert is ON. |
6
■ Receiving and transmitting
CAUTION: Transmitting without an antenna will damage 
the transceiver.
q Rotate [VOL] to turn power ON.
wSet the audio and squelch levels.
Rotate [SQL] fully counterclockwise in advance.
Rotate [VOL] to adjust the audio output level.
Rotate [SQL] clockwise until the noise disappears.
e Push [U/I/C] (both [Y] and [Z]) on the transceiver several times to select the desired channel group. (p. 6)
r Push [Y] or [Z] to select a channel. (p. 5)
• When receiving a signal, “ 
” appears and audio is emitted from the speaker.
• Further adjustment of [VOL] may be necessary.
t Push [HI/LO] on the microphone to select the output power if necessary.
• “LOW” appears when low power is selected.
• Choose low power for short range communications, choose high power for longer distance communications.
• Some channels are for low power only.
y Push and hold [PTT] to transmit, then speak into the microphone.
• “ 
” appears.
• Channel 70 cannot be used for transmission other than DSC. u Release [PTT] to receive.
BASIC OPERATION 3
Simplex channels, 3, 21, 23, 61, 64, 81, 82 and 83 CAN-
NOT be lawfully used by the general public in U.S.A. wa- 3
ters.
IMPORTANT: To maximize the readability of your trans-
mitted signal, pause a few sec. after pushing [PTT], hold
the microphone 2 to 4 inches (5 to 10 cm) from your mouth 
and speak into the microphone at a normal voice level.
e r |
q y u Microphone |
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w r t
NOTE for TOT (Time-out Timer) function
The TOT function inhibits continuous transmission over a preset time period after the transmission starts.
7
3 BASIC OPERATION
■ Call channel programming
Call channel is used to select Channel 9 (default), however, you can program the call channel with your most often-used channel in each channel group for quick recall.
q Push [U/I/C] (both [Y] and [Z]) on the transceiver several times to select the desired channel group (U.S.A., International or Canada) to be programmed.
wPush and hold [9] (!6) for 1 sec. to select the call channel of the selected channel group.
• “CALL” and call channel number appear.
e Push and hold [9] (!6) again for 3 sec. (until a long beep changes to 2 short beeps) to enter call channel programming condition.
• Channel number starts blinking.
r Push [Y] or [Z] to select the desired channel.
t Push [!6] to program the displayed channel as the call channel.
• Push [CH/WX] to cancel.
•The channel number stops blinking.
■ Channel comments
Memory channels can be labeled with a unique alphanumeric ID of up to 10 characters each.
More than 6 characters comment scrolls automatically at the channel comment indicator after the channel selection.
Capital letters, small letters (except f, j, k, p, s, v, x, z), 0 to 9, some symbols (= + – . /) and space can be used.
qSelect the desired channel.
• Cancel Dualwatch, Tri-watch or Scan in advance.
w While pushing [CH/WX], push [!6] to edit the channel comment.
• A cursor and the first character start blinking alter-
nately.
ePushing [Y] or [Z] to select the desired character.
•Push [!6] or [CH/WX] to move the cursor forward or backward, respectively.
r Repeat step e to input all characters.
tPush [DSC] to input and set the comment.
•Push [SCAN] to cancel.
•The cursor and the character stop blinking.
yRepeat steps q to t to program other channel comments, if desired.
8
■ Microphone lock function
The microphone lock function electrically locks [Y] and [Z] keys on the supplied microphone. This prevents accidental channel changes and function access.
While pushing and holding [HI/LO] on the microphone, turn power ON to toggle the Microphone lock function ON and OFF.
[Y]/[Z] 
[HI/LO]
BASIC OPERATION 3
■AquaQuake water draining function
The IC-M304 uses a new technology to clear water away 3 from the speaker grill: AquaQuake. AquaQuake helps drain
water away from the speaker housing (water that might otherwise muffle the sound coming from the speaker). The ICM304 emits a vibrating noise when this function is being used.
While pushing and holding [Y] and [Z], turn power ON.
•A low beep tone sounds while [Y] or [Z] keys are held to drain water, regardless of [VOL] control setting.
•The transceiver never accepts a key operation while the AquaQuake function is activated.
•“ 
” scrolls at the channel comment indicator.
■ Display backlighting
Scrolls
The function display and keys can be backlit for better visibility under low light conditions.
While pushing and holding [SCAN], push [Y] or [Z] to adjust the brightness of the LCD and key backlight.
•The backlight is selectable in 3 levels and OFF.
9
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