Marine Radio FAQ's

Can I use a handheld VHF/DSC radio for ATIS?

The answer to this is not straightforward, and there are several important things to consider.

Firstly, ATIS identification numbers relate to a vessel...

Could you tell me what the A is shown on the screen of my marine VHF radio?

Many marine VHF channels are duplex (TX and RX on two different frequencies). Duplex channels can only communicate with a shore base station that is configured...

The collision alarm on my IC-M94DE sounds whilst I am sailing on a river. Can this be stopped or deselected?.

Yes, you can turn off the alarm or reduce the range at which it is triggered. If your own AIS transponder is triggering this, you can also add your MMSI to an I...

Where can I extend the warranty on my Icom marine VHF radio to 3 years?

If you are a leisure user and have just purchased a new Icom marine VHF radio from any of our dealers in the UK and Southern Ireland, you can extend the warrant...

My new Marine VHF radio doesn’t appear to have 37A in its channel listing?

Due to the increased need for marine VHF channels for commercial use, the ITU World Radio Conference authorised and developed a new channel plan for some VHF ma...

Adjusting Squelch on a Marine VHF Radio

Here are some simple instructions on how to adjust the squelch on your marine VHF radio.

1. Turn your VHF radio on.
2. Turn squelch all the way down ...

I am getting feedback on my Marine VHF radio from my hailer horn?

This is caused by your microphone picking up the output of your hailer horn (feedback). This can be mitigated by one or all of the following:

1. Ins...

I have a hard time getting my IC-M37E radio out of the battery charger.

The charger is designed to keep the battery in the charger if the boat is rolling. As stated in the Instruction Manual, if you cannot easily remove the radio fr...

Icom Marine VHF Radio Checklist

A simple set of tips to make sure that you use your marine radio is more efficient and enjoyable.

• Check that your VHF radio is turned on.
• Check ...

What types of information do AIS transponders transmit?

AIS transponders typically transmit the following information, depending on class.

• Vessel name, MMSI number and call sign
• Type of vessel (such a...

Is the GPS Antenna an optional accessory with the MA-510TR?

A GPS antenna is supplied as standard with the MA-510TR. It is different to a normal antenna and supports the latest types of GPS Augmentation Systems available...

Which Icom VHF models can send DSC calls with the MA-510TR/MA-500TR?

IC-M330GE, IC-M424GE, IC-M400BBE, IC-M506GE, IC-M605EURO and the previous version of the IC-M323. Two earlier models called the IC-M505 and IC-M603 can also wo...

Is it possible to receive Class A AIS information on the MA-510TR like the MA-500TR?

Both MA-500TR and MA-510TR receive class A and B AIS but they only send out class B AIS information.

How should I store my Marine VHF Radio and batteries for the Winter?

If you are storing your marine VHF radios away for an extended period such as the Winter, you should wash them with tap water to reduce salt corrosion. Once dri...

What is the AquaQuake draining function on an Icom marine radio?

When water enters into the speaker grill of our marine radios, Icom's unique AquaQuake function emits a buzzing sound, shedding water from the speaker. This fu...

Marine VHF Radio Licence: How to go about getting qualified?

All marine VHF users should be suitably qualified/licenced and have passed the RYA Marine Radio Short Range Certificate (SRC) course which is run at many sailin...

Channel 16 - What do I do in an emergency?

Channel 16 (The Calling and Emergency Channel) should be monitored in an emergency and as much as possible the channel should be kept clear for emergency respon...

What are Marine Channels M, M1 & M2?

Channel M1 (37A) and M2 (P4) are the designated club and marina use channels for leisure users. M (80) is also recognised as a Marina Channel, but unlike its co...

I want to connect an external antenna to marine handheld VHF radio. How do I do this?

Even though for range, there is no substitute for a fixed marine set, we do realise that there are smaller boat owners that want a smaller solution for their co...

The display on my IC-M330GE says "The Transceiver cannot RX or TX. Contact Dealer." What should I do?

The radio has a problem within its circuits called 'VCO Out of lock'. You will need to have the radio serviced by a qualified radio engineer.

How do I turn on the VOX function for my headset when connected to the IC-M73EURO/PLUS?

This is relatively straightforward. We have produced a PDF guide which provides instructions on operating the VOX function on your IC-M73EURO/PLUS. This sheet i...

I am an RYA training instructor, do Icom provide VHF/SRC training units?

Yes. Icom UK offers both DSC capable handheld or mounted units to meet training instructors’/students’ needs. Units we can supply are the IC-M94DE, IC-M330GE, ...

What is ITU-RM493-14 and how will it affect DSC marine radios?

As of November 30th 2018, DSC marine radios must comply with a new specification, EN301 025 V2.2.1 (ITU-RM493-14) which mandates an integrated GNSS Receiver and...

I am looking for a replacement battery for my IC-M33 Marine VHF handheld.

The BP-252 is the replacement battery for the IC-M33 as well as the IC-M31 and IC-M35. As of June 2018, this battery is still available for purchase. If you are...

What is the LEN (Load Equiv. Number) or mA draw for IC-M506 (NMEA 2000 version only) on an NMEA 2000 Bus?

The LEN (Load Equiv. Number) or mA draw for IC-M506 (NMEA 2000 version only) on an NMEA 2000 Bus is 1 (50mA).

Can I connect my IC-M323G to the NMEA 2000 network on my boat?

Not directly. The IC-M323G is capable of NMEA 0183, not NMEA 2000. An NMEA converter device can be used to make it compatible with a NMEA 2000 network, such as ...

Will the UT-98 scrambler board work on my IC-M506 Marine VHF/DSC radio?

No, it is not compatible. You need to use the UT-112.

What GPS format does Icom use to display GPS coordinates on its marine radios?

It is shown in the Degrees/Decimal Minutes format: e.g. 47.42.2147N 123.8.7456W.

What is the difference between an external speaker, a hailer/foghorn/PA?

External speakers are designed to be a second speaker for the radio; it can be mounted in a more advantageous position for the radio operator. It works the same...

How do I eliminate "noise" from my marine radio?

First, disconnect the antenna and see if the receive noise is still present (do not transmit when the antenna is disconnected). If the noise is still present, i...

Does the IC-M93D show magnetic north or true north?

It shows true north.

Does the IC-M506 send AIS data using NMEA 0183?

No. Only NMEA 2000 is used on AIS capable models.

My new IC-M506 does not work with my GPS antenna, which has NMEA 0183 version 2.0 (or older).

Your IC-M506 needs to have firmware v1.002 or greater loaded in it.

My IC-M506 does not show the correct AIS information on the plotter: the boats are always pointed in one direction. Sometimes the IC-M506 won't pass AIS information to other devices on the same MNEA 2000 network.

Upgrade the IC-M506 firmware to v1.004 or greater. The UX-232 firmware should also be upgraded to v1.007 or greater.

I'm not sure if my IC-M506 is putting out data. Is there a way I can check?

Yes, you can view all the data on the NMEA-2000 port by hooking it up to an aftermarket NMEA2000 to PC USB adapter such as the "Actisense NGT-1" (not an endorse...

Will the IC-M506 with AIS and NMEA 2000 capabilities send AIS data from the NMEA 2000 port to an NMEA 0183 device?

No, it only passes that data to an NMEA 2000 network. You can use an aftermarket NMEA 0183 to NMEA 2000 converter such as Actisense NGW-1 (not an endorsement) t...

On my IC-M506 with NMEA 2000, if I connect my GPS with NMEA 0183 to the radio, can the radio then relay the received GPS data to the NMEA2000 network?

Yes. The M506 can convert that data and send it over to NMEA 2000 network.

Who is affected by the latest IMO regulation for ATEX for fire fighters onboard vessels?

The latest amendments to SOLAS Regulation II-2/10 adds a minimum requirement of two ATEX two-way portable radio for each fire party for fire-fighters’ communica...

Where can I use a DSC handheld radio?

As it is licensed under a Ship Portable Radio Licence, you can use the handheld DSC on any ship within UK territorial sea…this means within 12 nautical miles of...

Do I need to register my DSC Handheld radio, like an EPIRB?

No. OFCOM share MMSI details with the MCA to assist their search and rescue operations. We shall share MMSIs for individual handheld VHF DSC radios with the MCA...

What should I do if I sell my DSC handheld radio?

You must surrender your Ship Portable Radio Licence. Until you do, we cannot transfer the MMSI to the new owner. If the new owner makes a DSC distress call, the...

What operator certificate do I need for a DSC Handheld radio?

You must hold at least the Short-Range Certificate to use a handheld VHF/DSC radio, just like any VHF/DSC radio.

Can I use a Handheld DSC radio on inland waters in the UK?

Handheld VHF DSC marine radios may be used in UK inland waterways. However, they must not be used overseas such as on the inland waterways of continental Europe...

Do I need a special licence for my handheld DSC radio? Will my existing Ship Radio Licence cover it?

You must have a separate Ship Portable Radio Licence for each handheld VHF DSC radio. This is because each individual radio is given a separate identity. The ra...

Why distress messages are mandatory in DSC (Digital Selective Calling)?

All distress communications whether radio, DSC, or satellite must be conducted according to GMDSS (Global Maritime Distress and Safety System) guidelines. GMDSS...

I am looking for a battery replacement for the Icom BP-224, BP-225 & BP-241 batteries?

Due to a ban on the importation of Ni-cad batteries into the EU, the BP-224 and BP-225 Ni-cad batteries are now unavailable. These batteries can be replaced by ...

How should I charge the Lithium Ion battery from my Marine VHF radio?

Li-Ion batteries do not suffer with memory effect like the Ni-Cad's of the past. There is no problem with topping up the charge of a partly discharged battery ...

Can I use Channel 74 as my main VHF communication channel on inland waterways?

Channel 74 is a port operations channel allocated to the Canal and River Trust’s locks and bridges which is also allocated to various other port operators in th...

My IC-M323/IC-M423 does not send position and polling call requests?

In keeping with ETSI (European Telecommunication Standards Institute) standards, a Class D VHF does not have position/polling calls set as standard. To enable t...

Considerations to make when choosing a Multi-Functional Display (MFD)?

One of the major developments in marine electronics over recent years has been the integration of multiple equipment such as radar, chart plotters, fish-finders...

Why does my IC-M91D VHF/DSC Handheld buzz?

Your IC-M91D is buzzing because your 'Inactivity Timer' has gone off. If you look in the manual under the heading 'Inactivity Timer' you will find that if you l...

My Float and Flash Icom radio is flashing. Are my contacts wet?

If your radio flashes a red light, it is indicating that the radio is wet and the rear moisture sensing contacts need to be dried. It is normal for it to contin...

I’ve tried to enter my MMSI number twice and now my radio won’t accept another attempt. What do I do?

OFCOM requires that all Marine DSC radios are allowed only two attempts at programming the MMSI number (The MMSI number can only be programmed correctly once an...

I have an Icom VHF marine radio, and I'm attempting to contact another VHF operator. But, even though we are very close, we can't seem to be able to communicate. Stranger still, some channels seem to be working, and others do not!

Most marine channels can be used for direct ship-to-ship communication. They are called simplex channels. Some marine channels are duplex, and can only be used ...

When should I operate my Marine VHF radio on low power?

In general it depends on how far away the radio is that you are trying to communicate with. There are some channels that automatically require the high or low p...

What is RAINWAT?

RAINWAT is the "Regional Arrangement Concerning the Radiotelephone Service on Inland Waterways" which, through the Basel Arrangement has introduced and Automati...

What is ATIS?

ATIS, not to be confused with AIS, stands for automatic transmitter identification system. This system is used in inland waterways in various countries in mainl...

What can I do to prolong the life of my marine VHF radio?

To prolong the life of your marine handheld or fixed VHF, thoroughly clean your radio after every use. It is important because the radio's keys, switches and co...

Why can’t American marine radios be used/fitted in the UK?

All European electronic & electrical equipment must meet stringent technical and legislative standards including Electro Magnetic Compatibility (EMC) Directive ...

How long can the IC-M33 float in the water?

The IC-M33 marine VHF radio is not designed to be left submersed underwater and should be retrieved immediately.

How do I wire up my GPS?

This can be found in the manual of your radio. To view the manual on line visit http://www.icom.co.jp/world/support/download/manual/.

Alternatively you...

I have an IC-M421 and I cannot find any reference to a back-up battery or micro-chip. If I disconnect the unit, will it lose any programmed channels/tag channels I have inputted?

No, the channels you have programmed will remain in the radio even when disconnected.

I have bought an Icom Marine Handheld. I note that it has channel P4. Is this the same as M2? Is channel 37A the same as channel 37?

P4 is the same as M2. M1 or Channel 37A is the simplex version of channel 37.

Some marinas will use channel 80 – if this is the case they will let you k...

I recently purchased a boat that included an Icom radio. I have my own MMSI Number, can I add it myself?

Unfortunately not, the radio will need to go back to either your local Icom dealer or Icom UK service department.

For further information about this subje...

My Icom DSC/VHF radio will now not transmit on 25w. In addition the screen goes blank at the start of the transmission for a few seconds. It transmits clearly on 1w with no loss of screen data.

Typically this fault is caused by high resistance on the DC leads to the transceiver. This could be caused by old or poorly insulated power leads. Please call o...

Can I send my marine radio back to any Icom around the world?

Icom UK offer a 3 year warranty on marine products, this is within the UK only. If you are outside UK waters in a UK flagged vessel please contact us and we wil...

I own an Icom DSC Radio and have purchased a Raymarine C120 system. There are no spare NMEA outputs available. Can I cut into a NMEA cable and join all the wires to form a branch for the radio?

Yes is possible to connect up to 4 NMEA devices in parallel. If you are unsure about how to do this please contact our service department who will be able to ad...

I have your IC-M401 and DS-100 units. Do I need to connect the DS-100 to a separate antenna?

Yes. To correctly install the DS-100 you need two separate aerials as this is a dual antenna system.

Can anyone use a VHF radio?

To operate a ships VHF radio you must hold a valid operator certificate or be monitored by someone who does. The only exception is in a distress situation. All ...

What are marine VHF channels used for?

Some of the marine channels have designated functions. The important numbers are as follows:

Ch 16 is the Distress, Safety and Calling channel. ...

Common features on a marine VHF/DSC radio

The main features that should be on any unit are as follows:

Channel Selector
This will either be a rotary knob or a pair of buttons marked u...

VHF Ship Licences To Be Free and Last Indefinitely

OFCOM (The UK Office of Communications) have decided that from 1st October 2006, marine radio ship licences will be available free of charge, and will remain va...

I’m using your optional hailer horn with my Icom marine radio and all I get is feedback!

This is caused by close proximity of the hailer horn to the location of the radio. The hailer horn is very loud, and it should be mounted a safe distance away f...

Why shouldn't I use mobile phones aboard boats?

Modern marine electronic equipment fitted to a craft, regardless of size, is designed to operate normally when in close proximity to other items of marine elect...

The Ships Wheel or Wheelmark explained

The “Ships Wheel”, or “Wheelmark” as it is officially called, is an accreditation that is required for equipment placed on board ships for which safety certific...

What is a DSC controller?

A DSC controller is a unit that encodes and interprets DSC messages. In some radios this is built-in and in others it is an external ‘add-on’. DSC controllers h...

What is an MMSI number?

MMSI (Maritime Mobile Service Identity) numbers are a series of nine digits, which are used to uniquely identify a radio station or group of radio stations. Whe...

Are your waterproof marine radios really waterproof?

They are conditionally waterproof. For example, the IC-M31 can withstand being submerged in one metre of water (about 3ft) for 30 minutes with no water intrusio...

My mounted VHF radio, or SSB radio, seems to have a problem. The display lights dim when I transmit

This behaviour is caused by an insufficient power supply, or a bad electrical connection somewhere between the battery (or a power supply) and the transceiver. ...

What do I do if I accidentally press my DSC distress button?

The DSC button on an ICOM marine radio is covered by a red flip-up cover. This cover must first be lifted before the button can be pressed (so accidental depres...

What is GMDSS?

The GMDSS (Global Maritime Distress and Safety System) is an integral part of SOLAS and is a radio-based communications system designed to support the implement...

What is HF Email?

HF email is the method of using HF frequencies to send data transmissions. One of the most obvious benefits is that, being a wireless system, it is possible to ...

What is DSC?

DSC uses digital data, rather than voice, to transfer information between radios. Using this mechanism provides several important benefits including increased v...

The Case for DSC

There is no question that GMDSS has a big part to play in improving safety at sea. Firstly a vessel’s position and the time are automatically included in distre...

Can I use my Icom mounted VHF radio, or an SSB radio, on a vessel with a 24V electrical system?

Only if you purchase a separate power converter that will convert 24V DC into 12 Volt DC. All Icom mounted VHF and SSB marine radios are designed to operate wit...

Will other electronics interfere with my VHF unit?

Yes that is possible. Many electronic devices are capable of generating RF energy which might interfere with radio reception. This can take the form of wideband...

How DSC will affect you?

From 1 February 1999 SOLAS vessels are no longer required to monitor the 2182kHz MF distress frequency. From 1 February 2005 they will no longer need to monitor...

How do I get a Marine VHF Licence?

All marine VHF, MF and HF radios require the user and the vessel to hold a relevant licence.

The vessel’s licence is like a car tax disc, but it is als...

How should I look after my rechargeable radio batteries?

The failure to manage rechargeable batteries correctly can result in a gradual decline in performance. This decline very often goes unnoticed by the user and ca...