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

SEA 209 2/4/6/8 MHz MF-SSB/HF-SSB marine transceiver - note the band switch + channel selector + clarifier or clarify (fine tune) combination with frequency display, similar to how export CB radios operate

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

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

See also:

• VHF marine band
• Maritime Fax Transmissions
• Maritime Weather Transmissions
• Pescadores or Peskies (Peskys) - marine users operating out of band
• 27 MHz Marine CB - 27MHz or 27 Meg Australia marine band
• 29 MHz CB - South African marine mobile 29MHz frequencies
• Japanese 1 watt DSB (AM) double side band fishery radio service Japan 26-27 MHz
• Japanese 25 watt SSB single side band fishery radio service Japan 27 MHz
• 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