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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.


4 MHz Duplex Channels

ITU Channel No. Coast Transmit kHz Ship Transmit kHz
401  4357 4065
402 4360  4068
403 4363 4071
404  4366 4074
405   4369 4077
406 4372  4080
407  4375 4083
408   4378 4086
409   4381 4089
410   4384 4092
411   4387 4095
412   4390 4098
413 4393  4101
414   4396 4104
415 4399 4107
416   4402 4110
417  4405 4113
418   4408 4116
419 4411 4119
420   4414 4122
421  4417

4125

(USCG Calling
(See Note below)

422   4420 4128
423   4423 4131
424   4426 4134
425   4429 4137
426  4432 4140
427 4435  4143
428  4351 (varies)
429  4354 (varies)

Note regarding channel 421: 4125 kHz is used for calling, and is for GMDSS distress and safety communications, in the simplex mode. Distress and safety communications have priority over all other communications. The USCG urges that channel 421 not be used in the duplex mode.