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Maritime Telecommunications
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Maritime Information:

Effective 01 August, 2013, the U. S. Coast Guard terminated its radio guard of the international voice distress, safety and calling frequency 2182 kHz and the international digital selective calling (DSC) distress and safety frequency 2187.5 kHz. Additionally, marine information and weather broadcasts transmitted on 2670 kHz will terminate concurrently. See the safety alert. Note that these frequencies are still available and in use, notwithstanding the Coast Guard's termination of the radio guard. Please contact us if you have any questions.

This section provides information on middle and high frequency marine radiotelephone channels. The links below and to the left provide tables which show the various channels and their assigned frequencies. Clicking on the links below will open a new browser window.

Duplex Channels

These single sideband radiotelephone channels are used for communications between coast and ship stations. Frequencies listed are carrier frequencies. Channels used for calling, and channels guarded by the U.S. Coast Guard are indicated.

2 MHz Simplex Frequencies

These 2 Mhz single sideband radiotelephone frequencies are available for ships in or near U.S. waters.

HF Simplex Frequencies

HF Simplex single sideband radiotelephone frequencies are provided for worldwide common use by ships of all categories, for communications with coast stations or other ships. Global Maritime Distress and Safety System distress and safety working frequencies are also listed.

Channels in the band 4000 - 4063 kHz and 8100 - 8195 kHz are now included here as well.

Note: all duplex and simplex frequencies are upper sideband (USB), with assigned frequency 1.4 kHz above the listed carrier frequency.

This HF radiotelephone channel and frequency information was obtained from Appendix 16 of the International Telecommunications Union (ITU) Radio Regulations, including revisions made by the 1987 Mobile World Administrative Radio Conference (Mob-87).