HF marine

From HFUnderground

HF-SSB marine bands - these are standardized maritime mobile MF and HF communications bands - note that many maritime mobile users operate outside of these bands and there are dozens of country- or region-specific additional bands/frequencies. These bands are used for USB voice transmissions, various data modes including FAX used for Maritime Fax Transmissions, FSK, modes for various purposes as well as USB voice and RTTY weather and emergency broadcasts to ships at sea.

Fisheries, fishing boats, and other commercial marine users will often use frequencies in the HF aeronautical or aircraft bands (including the 6525 kHz to 6685 kHz and 6685 kHz to 6765 kHz military aircraft 6 MHz subbands 6525 kHz to 6765 kHz), other HF aircraft bands, fixed/mobile band (including 43 meters - 6765-7000 kHz) clear frequencies in the shortwave broadcast bands or even amateur frequencies for "out of band" communications to reduce the chance of radio interception by their competition. Out of band frequencies are also used in other ITU regions for marine fax transmissions.

See also: VHF marine band

MF-SSB and HF-SSB marine traffic (usually in the bands above 4 MHz) can be in simplex or semi-duplex for voice and/or data. Cross-band operation is also allowed per ITU regulations. Often you will hear ship-to-ship communications in simplex mode on the "ship transmit" frequency of a duplex pair.

MF SSB and HF SSB marine bands

Note, many online sources use the MHz frequency notation instead of the kHz. Both are correct from a technical point of view and for all practical purposes it boils down to personal preference. To convert MHz to kHz or kHz to MHz simply move the decimal point. For example, 4003 kHz is 4.003 MHz. 6212 kHz is 6.212 MHz, 16420 kHz is 16.420 MHz, 27.555 MHz is 27555 kHz, 14.313 MHz is 14313 kHz, 7.200 MHz is 7200 kHz, and so on. Once you get into the VHF/UHF spectrum, MHz frequency notation is basically universally used, including for the VHF marine band.

SSB Voice and DSC Distress Safety Calling Frequencies

DSC should not be confused with DCS, digital coded squelch, a selective calling squelch system used on VHF/UHF land mobile radio systems.

• 2182 kHz Voice - no longer monitored by USCG, still monitored by private and commercial vessels and shore stations worldwide
• 2187.5 kHz DSC
• 4125 kHz Voice SSB
• 4207.5 kHz DSC
• 6215 kHz Voice
• 6312 kHz DSC
• 8291 kHz Voice
• 8414 kHz DSC
• 12290 kHz Voice
• 12577 kHz DSC
• 16420 kHz Voice
• 16804.5 kHz DSC

DSC calls should be made, then the vessel should switch to the voice frequency. Monitoring 2182 kHz is strongly recommended, along with VHF Channel 16 and standard VHF DSC watch. If possible, ships operating on the high seas should monitor 2182 kHz and 4125 kHz as well as VHF 16 and VHF DSC.

Search and rescue (SAR) operations may use the voice frequencies listed above, plus the following as well as various VHF/UHF aircraft band frequencies, VHF marine band frequencies and other frequencies depending on local circumstances.

• 3023 kHz USB - Voice SAR on-scene coordination / communications
• 5680 kHz USB - Voice SAR on-scene coordination / communications
• 8364 kHz USB - Voice SAR on-scene coordination / communications
• 10003 kHz USB - Voice SAR on-scene coordination / communications
• 14993 kHz USB - Voice SAR on-scene coordination / communications

SSB Sailing Net Frequencies

• 6215 kHz USB - Caribbean Net 10:00 UTC - 12:00 UTC
• 4045 kHz USB - Caribbean Weather Center Net 10:40 UTC
• 8137 kHz USB - Caribbean Weather Center Net 10:40 UTC
• 4036 kHz USB - Ocean Cruising Club Net Primary 11:00 UTC - July - mid September
• 6227 kHz USB - Ocean Cruising Club Net Secondary 11:00 UTC - July - mid September
• 8137 kHz USB - Caribbean Weather Center Net 11:30 UTC
• 12350 kHz USB - Caribbean Weather Center Net 11:30 UTC
• 8170 kHz USB - Coconut Telegraph Net Primary 12:00 UTC
• 8146 kHz USB - Coconut Telegraph Net Secondary 12:00 UTC
• 8164 kHz USB - Coconut Telegraph Net Alternate 12:00 UTC
• 8104 kHz USB - Seven Seas Cruising Association SSCA Net - "KPA" - 12:15 UTC
• 8170 kHz USB - Cruiseheimers Net Primary 12:30 UTC
• 8146 kHz USB - Cruiseheimers Net Secondary 12:30 UTC
• 8164 kHz USB - Cruiseheimers Net Secondary 12:30 UTC
• 8137 kHz USB - Caribbean Weather Center Net 12:30 UTC
• 12350 kHz USB - Caribbean Weather Center Net 12:30 UTC
• 6209 kHz USB - Southwest Caribbean Net SW Caribbean Net Primary 13:15 UTC
• 6212 kHz USB - Southwest Caribbean Net SW Caribbean Net Secondary 13:15 UTC
• 6516 kHz USB - Southwest Caribbean Net SW Caribbean Net Secondary 13:15 UTC
• 2582 kHz USB - Bermuda Harbor Control Net 13:30 UTC
• 8107 kHz USB - Panama Connection Net Primary 13:30 UTC
• 8167 kHz USB - Panama Connection Net Secondary 13:30 UTC
• 6209 kHz USB - Northwest Caribbean Net NW Caribbean Net Primary 14:00 UTC
• 6212 kHz USB - Northwest Caribbean Net NW Caribbean Net Secondary 14:00 UTC
• 6516 kHz USB - Northwest Caribbean Net NW Caribbean Net Secondary 14:00 UTC

ITU Designated Simplex Frequencies

These frequencies are specifically designated for simplex use (ship-to-ship and/or ship-to-shore comms). Any frequency in the MF and HF marine bands may be used for simplex purposes, including the duplex channelized frequencies. Often the "ship TX" or "ship transmit" frequency is used for ship-to-ship communications. However, either frequency may be used for simplex communications. Frequencies in-between the ITU channels may be used for voice or data communications as well. USB mode is normally used, with some LSB. AM is rarely used, although ship to ship use of AM mode is found in the 2-4 MHz region in some parts of the world, especially Russia.

• 2 MHz (2000 kHz - 2850 kHz) marine band:

• 2003.0 kHz
• 2065.0 kHz
• 2079.0 kHz
• 2082.5 kHz
• 2086.0 kHz
• 2093.0 kHz
• 2096.5 kHz
• 2142.0 kHz
• 2203.0 kHz
• 2214.0 kHz
• 2635.0 kHz
• 2638.0 kHz
• 2670.0 kHz - this frequency is also used for maritime weather forecasts
• 2738.0 kHz
• 2782.0 kHz
• 2830.0 kHz

• 4 MHz (4000 kHz - 4438 kHz) marine band:

• 4146.0 kHz
• 4149.0 kHz
• 4417.0 kHz

• 4000 kHz to 4060 kHz are also designed for simplex maritime radio use, in 3 kHz steps (4000 kHz, 4003 kHz, 4006 kHz, etc.), shared with fixed/mobile service

• 6 MHz (6200 kHz - 6525 kHz) marine band:

• 6224.0 kHz
• 6227.0 kHz
• 6230.0 kHz
• 6516.0 kHz

• 8 MHz (8000 kHz - 8815 kHz) marine band:

• 8294.0 kHz - Channel 8A / Channel A
• 8297.0 kHz - Channel 8B / Channel B

• 8101 kHz to 8191 kHz are also designed for simplex maritime radio use, in 3 kHz steps (8101 kHz, 8104 kHz, 8107 kHz, etc.), shared with fixed/mobile service

• 12 MHz / 13 MHz (12330 kHz - 13200 kHz) marine band:

• 12353.0 kHz
• 12356.0 kHz
• 12359.0 kHz
• 12362.0 kHz
• 12365.0 kHz

• 16 MHz / 17 MHz (16460 kHz - 17360 kHz) marine band:

• 16528.0 kHz
• 16531.0 kHz
• 16534.0 kHz
• 16537.0 kHz
• 16540.0 kHz
• 16543.0 kHz
• 16546.0 kHz

• 18 MHz (18780 kHz - 18900 kHz) marine band:

• 18825.0 kHz
• 18828.0 kHz
• 18831.0 kHz
• 18834.0 kHz
• 18837.0 kHz
• 18840.0 kHz
• 18843.0 kHz

• 22 MHz (22000 kHz - 22855 kHz) marine band:

• 22159.0 kHz
• 22162.0 kHz
• 22165.0 kHz
• 22168.0 kHz
• 22171.0 kHz
• 22174.0 kHz
• 22177.0 kHz

• 25 MHz (25070 kHz - 25121 kHz) marine band:

• 25100.0 kHz - Channel 25A
• 25103.0 kHz - Channel 25B
• 25106.0 kHz - Channel 25C
• 25109.0 kHz - Channel 25D
• 25112.0 kHz - Channel 25E
• 25115.0 kHz - Channel 25F
• 25118.0 kHz - Channel 25G

Simplex Frequencies - Additional

These frequencies are used for ship to ship communications and are shared with fixed/mobile services worldwide. Due to the nature of the HF spectrum allocation system, the shared frequencies are only available on the 4 MHz and 8 MHz bands

• 4 MHz band - 4000 kHz - 4060 kHz, 3 kHz spacing, USB voice

• 4000.0 kHz
• 4003.0 kHz
• 4006.0 kHz
• 4009.0 kHz
• 4012.0 kHz
• 4015.0 kHz
• 4018.0 kHz
• 4021.0 kHz
• 4024.0 kHz
• 4027.0 kHz
• 4030.0 kHz
• 4033.0 kHz
• 4036.0 kHz
• 4039.0 kHz
• 4042.0 kHz
• 4045.0 kHz
• 4048.0 kHz
• 4051.0 kHz
• 4054.0 kHz
• 4057.0 kHz
• 4057.0 kHz
• 4060.0 kHz

• 8 MHz band - 8101 kHz to 8191 kHz 3 kHz spacing, USB voice

The 7450 kHz to 8100 kHz portion of the fixed/mobile band is not included in this shared spectrum...however, many marine users use these frequencies anyway, especially the lower portion of the 8 MHz band and the higher portion of the 7 MHz band.

• 8101.0 kHz
• 8104.0 kHz
• 8107.0 kHz
• 8110.0 kHz
• 8113.0 kHz
• 8116.0 kHz
• 8119.0 kHz
• 8122.0 kHz
• 8125.0 kHz
• 8128.0 kHz
• 8131.0 kHz
• 8134.0 kHz
• 8137.0 kHz
• 8140.0 kHz
• 8143.0 kHz
• 8146.0 kHz
• 8149.0 kHz
• 8152.0 kHz
• 8155.0 kHz
• 8158.0 kHz
• 8161.0 kHz
• 8164.0 kHz
• 8167.0 kHz
• 8170.0 kHz
• 8173.0 kHz
• 8176.0 kHz
• 8179.0 kHz
• 8182.0 kHz
• 8185.0 kHz
• 8188.0 kHz
• 8191.0 kHz

ITU Designated Duplex Frequencies

These frequencies are specifically designated for duplex use (generally ship-to-shore or shore-to-ship comms). Simplex operations are very common, often using the ship frequency, but simplex ship to ship comms are found on the shore frequencies as well.

Any frequency in the MF and HF marine bands may be used for simplex purposes, including the duplex channelized frequencies. Often the "ship TX" or "ship transmit" frequency is used for ship-to-ship communications in regular single-frequency simplex mode. However, either frequency may be used for simplex communications. Frequencies in-between the ITU channels may be used for voice or data communications as well. USB mode is normally used, with some LSB.

• 4 MHz (4000 kHz - 4438 kHz) marine band:

• 6 MHz (6200 kHz - 6525 kHz) marine band:

• 8 MHz (8000 kHz - 8815 kHz) marine band:

Note that "channel 833" is programmed in SSB marine radios in simplex mode only. It is the 8 MHz distress/calling frequency, 8291 kHz.

• 12 MHz / 13 MHz (12330 kHz - 13200 kHz) marine band:

• 16 MHz / 17 MHz (16360 kHz - 17460 kHz) marine band:

• 18 MHz (18780 kHz - 18900 kHz) / 19 MHz (19680 kHz - 19800 kHz) marine band:

• 22 MHz (22000 kHz - 22855 kHz) marine band:

• 25 MHz (25070 kHz - 25121 kHz) and 26 MHz (26145 kHz - 26175 kHz) marine band:

See also:

• VHF marine band
• Maritime Fax Transmissions
• Maritime Weather Transmissions
• Pescadores or Peskies (Peskys) - marine users operating out of band
• Land Mobile Allocations 25 MHz - 30 MHz
• 27 MHz Marine CB - 27MHz or 27 Meg Australia marine band
• 29 MHz CB - South African marine mobile 29MHz frequencies
• Chinese 480 channel HF/VHF low band 480 Channel FM fishery radiotelephone 27.500 MHz - 39.475 MHz
• Thai 10 watt / 25 watt AM FM SSB fishery marine CB radiocommunications service 168 channel 26 MHz 27 MHz
• Japanese 1 watt DSB (AM) double side band fishery radio service Japan 26-27 MHz 1W DSB 27MHz
• Japanese 25 watt SSB single side band fishery radio service Japan 27 MHz 25W SSB 27MHz
• Japanese 5 watt DSB (AM) double side band fishery radio service Japan 35.5 MHz-36 MHz and 39-40 MHz 5W DSB 40MHz
• South Korean - Republic of Korea 27MHz fishery radio service AM 27 MHz
• HF fixed/mobile allocations, often heavily used by marine stations, i.e. pescadores
• Fishnet beacons, radiobuoy, 1.6-4 MHz and 26-30 MHz, slowly being replaced by SATCOM/GPS based systems

• [1] HF marine distress and calling frequencies
• [2] US Coast Guard MF and HF SSB marine radiotelephone frequency channel list (duplex and simplex)
• [3] US Coast Guard MF & HF 2-26 MHz marine SSB channel information
• [4] Marine Safety Broadcasts MF, HF, VHF and SATCOM broadcasts and services

SEA 209 2/4/6/8 MHz MF-SSB/HF-SSB marine transceiver - note the band switch + channel selector + clarifier or clarify (fine tune) control (labelled as clarity on this radio) combination with frequency display, similar to how export CB radios operate. This particular radio only covers the lower MF/HF SSB marine bands, 2 MHz, 4 MHz, 6 MHz and 8 MHz marine bands

SEA 235 2-30 MHz MF-SSB/HF-SSB marine transceiver

ICOM IC-M802 2-30 MHz MF-SSB/HF-SSB marine transceiver