Marine SSB frequencies

The frequencies used for marine communications are internationally agreed by the International Telecommunication Union (ITU).

There are a number of frequencies allocated for for ship to ship, ship to shore and frequencies allocated just for distress messaging.

A number of frequencies are duplex (split frequency) for ship to shore use, and where used for making telephone calls via shore stations.

Although these duplex channels still exist for making telephone calls, today there are very few if any shore stations providing such a service.
There are a number of HF simplex channels which can be used for either ship to shore or ship to ship communications.

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HF radio propagation

Low frequencies follow the curvature of the earth and this type of propagation is called Ground Wave, while higher frequency radio wave can also refract off the Ionosphere this type of propagation is called Sky Wave. On higher frequencies where Sky Wave propagation dead zones (where no signal is received) may occur when close to a transmitting station.

A good rule for daytime is 100 miles per MHz:-

MF/HF Range Freq.	Day-light	Darkness
2 MHz	200 NM	500NM
4 MHz	400 NM	800NM
6 MHz	600 MN	1200 NM
8 MHz	800 NM	1600NM
12 MHz	1200NM	2400NM
16 MHz	1600 NM	fade-out

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Marine Distress Frequencies (Radio Telephone (R/T) & DSC)

There are internationally agreed distress frequencies for both voice and Digital Selective Calling (DSC) communications.

The voice frequencies should ONLY be used for distress messaging, although the voice frequencies can be used for other types of calls, once communications is established all other types of messaging should be passed on a work channel.

Band	R/T Frequency	DSC Frequency	Day Time Range	Night Time Range
MF	2182 kHz	2187.5 kHz	150 NM	500 NM
HF4	4125 kHz	4207.5 kHz	300 NM	1000 NM
HF6	6215 kHz	6312 kHz	600 NM	1500 NM
HF8	8291 kHz	8414.5 kHz	1000 NM	2000 NM
HF12	12290 kHz	12577 kHz	2500 NM
HF16	16420 kHz	16804.5 kHz
VHF	156.800 MHz (Channel 16)	156.525 MHz (Channel 70)	30 NM	30 NM

NOTE: Range is for guidance only and will depend on your operating conditions and HF radio propagation conditions.

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Primary HF ship to ship work channels

Within each frequency band there are a number of primary simplex ship to ship working channels, some frequency bands have more than others.

Primary simplex frequencies

Channel	4 MHz	6 MHz	8 MHz	12 MHz	16 MHz	18 MHz	22 MHz	25 MHz
A	4146 kHz	6224 kHz	8294 kHz	12353 kHz	16528 kHz	18825 kHz	22159 kHz	25100 kHz
B	4149 kHz	6227 kHz	8297 kHz	12356 kHz	16531 kHz	18828 kHz	22162 kHz	25103 kHz
C		6230 kHz		12359 kHz	16534 kHz	18831 kHz	22165 kHz	25106 kHz
D				12362 kHz	16537 kHz	18834 kHz	22168 kHz	25109 kHz
E				12365 kHz	16540 kHz	18837 kHz	22171 kHz	25112 kHz
F					16543 kHz	18840 kHz	22174 kHz	25115 kHz
G					16546 kHz	18843 kHz	22177 kHz	25118 kHz

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C1 and C2 simplex frequencies

The following C1 and C2 channels in the band 4000-4063 kHz and 8100-8195 kHz are shared between ships and shore stations.

There are 21 C1 4 MHz frequencies and 31 C2 8 MHz frequencies.

C1 4 MHz & C2 8 MHz simplex frequencies

4000 kHz	4024 kHz	4048 kHz		8101 kHz	8125 kHz	8149 kHz	8173 kHz
4003 kHz	4027 kHz	4051 kHz		8104 kHz	8128 kHz	8152 kHz	8176 kHz
4006 kHz	4030 kHz	4054 kHz		8107 kHz	8131 kHz	8155 kHz	8179 kHz
4009 kHz	4033 kHz	4057 kHz		8110 kHz	8134 kHz	8158 kHz	8182 kHz
4012 kHz	4036 kHz	4060 kHz		8113 kHz	8137 kHz	8161 kHz	8185 kHz
4015 kHz	4039 kHz			8116 kHz	8140 kHz	8164 kHz	8188 kHz
4018 kHz	4042 kHz			8119 kHz	8143 kHz	8167 kHz	8191 kHz
4021 kHz	4045 kHz			8122 kHz	8146 kHz	8170 kHz

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Yachtsmen's Nets

An open community of sailors keep in touch on a daily basis over the SSB radio, calls are totally free.

The best time to listen is early morning 0600 to 0930 and in the evenings 1800 to 2100 local time, this is when radio conditions are ideal.

You should hear a number of yachtsmen talking to each other, although in Northern Europe it is not so popular compared to the Mediterranean and Caribbean.

Net Areas	frequency	Times
Mediterranean Net	6516 kHz	0530 GMT
Caribbean calling frequency and safety net	8104 kHz	1215 (0815 AST)
Atlantic Net (Herb)	12359 kHz	2000
Bahamas weather net	4003 kHz	7:00 am AST
Caribbean weather net	4045 kHz 8104 kHz 8137 kHz	from 07:00 AST
Cruiseheimer's net (East coast and Bahamas)	8152 kHz	08:30 AST
Northwest Caribbean	8188 kHz	08:00 AST

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HF SSB Coastradio Stations

A network of coast-radio all for ship to shore communications. Below is a list of stations and the channels they use.

NOTE: ITU channel are duplex (split frequency)
e.g. coast station transmits on one frequency and the ship transmit on a different (lower) frequency.
Where (Tx in kHz) this is the coast station transit frequency, the frequency you may wish to monitor.
Frequency split; the number of kHz that has to be deducted to get the ships transmit frequency

Station (Station transmit frequency in kHz)	Callsign	4MHz	6MHz	8MHz	12MHz	16MHz	18MHz	22MHz
ITU duplex channels		401 to 429	601 to 608	801 to 837	1201 to 1241	1601 to 1656	1801 to 1815	2201 to 2253
Frequency split		-292kHz	-301kHz	-524kHz	-847kHz	-882kHz	-978kHz	-696kHz
DISTRESS		421 (4417)	606 (6516)	821 (8779)	1221 (13137)	1621 (17302)	1806 (19770)	2221 (22756)
Olympia, Greece	SVN	424 (4426)		806 (8734)	1232 (13170)	1640 (17359)		2217 (22744)
Oostende Radio, Belgium	OST	411 (4387)		815 (8761)	1207 (13095)	1630 (17329)
Monaco Radio	3AC	403 (4363)		804 (8728)	1224 (13146)	1607 (17260)		2225 (22768)
USA coastguard working channels		424 (4426)	601 (6501)	816 (8764)	1205 (13089)	1625 (17314)

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Australian HF weather frequencies

Australia Coastguard Weather Transmissions
Station and Callsign	Frequencies	Times (CST)
Wiluna W. Australia (VMW)	2056 kHz, 4149 kHz, 6230 kHz, 8113 kHz, 12362 kHz, 16528 kHz	0300, 0700, 1100, 1500, 1900, 2300
Charleville S. Australia (VMC)	2201 kHz, 4426 kHz, 6507 kHz, 8176 kHz, 12365 kHz, 16546 kHz	0200, 0600, 1000, 1400, 1800, 2200

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Safety and Rescue (SAR) communications

Frequency	Comments
2182kHz	MF International distress frequency for ship, aircraft and survival craft.
3023kHz	Intercommunications between mobile stations engaged in co-ordination of search and rescue.
4125kHz	Distress and safety traffic by radio-telephone
5680kHz	Intercommunications between mobile stations engaged in co-ordination of search and rescue.
6215kHz	Distress and safety traffic by radio-telephone
8364kHz	Designated for use by survival craft stations.