HF Simplex Channels
Exclusive Maritime Channels
These frequencies are shared and are not available for the exclusive use of any station.
| 4 MHz Band kHz | 6 MHz Band kHz | 8 MHz Band kHz | 12 MHz Band kHz |
| 4146 | 6224 | 8294 | 12,353 |
| 4149 | 6227 | 8297 | 12,356 |
| 4417 | 6230 | 12,359 | |
| 6516 (daytime only) | 12,362 | ||
| 12,365 | |||
|
4065,4089,4116,4408 |
6209,6212,6510,6513 |
8201,8213,8725,8737 |
12,362 12,365 |
| 16 MHz kHz | 18/19 MHz Band kHz | 22 MHz Band kHz | 25/26 MHz Band kHz |
| 16,528 | 18,825 | 22,159 | 25,100 |
| 16,531 | 18,828 | 22,162 | 25,103 |
| 16,534 | 18,831 | 22,165 | 25,106 |
| 16,537 | 18,834 | 22,168 | 25,109 |
| 16,540 | 18,837 | 22,171 | 25,112 |
|
16,543
for Mississippi River |
18,840 | 22,174 | 25,115 |
|
16,546
for Mississippi River |
18,843 | 22,177 | 25,118 |
Maritime Channels Shared with the Fixed Service
The following channels in the band 4000-4063 kHz and 8100-8195 kHz may be used:
- for supplementing ship-to-shore channels for duplex operation;
- for Intership simplex (single-frequency) and cross-band operation;
- for cross-band working with coast stations;
- for duplex operation with coast stations working in the band 4438-4650 kHz or with Channels 834, 835, 836 and 837;
- for ship-to-shore or shore-to-ship simplex operations (8100-8195 kHz only).
| Channel No. | 4 MHz Carrier Frequency kHz | 8 MHz Carrier Frequency kHz |
| 1 | 4000 | 8101 |
| 2 | 4003 | 8104 |
| 3 | 4006 | 8107 |
| 4 | 4009 | 8110 |
| 5 | 4012 | 8113 |
| 6 | 4015 | 8116 |
| 7 | 4018 | 8119 |
| 8 | 4021 | 8122 |
| 9 | 4024 | 8125 |
| 10 | 4027 | 8128 |
| 11 | 4030 | 8131 |
| 12 | 4033 | 8134 |
| 13 | 4036 | 8137 |
| 14 | 4039 | 8140 |
| 15 | 4042 | 8143 |
| 16 | 4045 | 8146 |
| 17 | 4048 | 8149 |
| 18 | 4051 | 8152 |
| 19 | 4054 | 8155 |
| 20 | 4057 | 8158 |
| 21 | 4060 | 8161 |
| 22 | -- | 8164 |
| 23 | -- | 8167 |
| 24 | -- | 8170 |
| 25 | -- | 8173 |
| 26 | -- | 8176 |
| 27 | -- | 8179 |
| 28 | -- | 8182 |
| 29 | -- | 8185 |
| 30 | -- | 8188 |
| 31 | -- | 8191 |
Global Maritime Distress & Safety System DSC & Radiotelephone Channels
The simplex DSC frequencies are guarded and are used for digital alerting and calling for distress, urgency and safety. Once the DSC call has been sent, the corresponding radiotelephone frequency is used for voice communications.
These simplex voice frequencies are used for distress and safety communications, and (except for 2182 kHz) are not normally guarded.
| DSC | VOICE | DSC | VOICE |
| 2187.5 | 2182 | 8414.5 | 8291 |
| 4207.5 | 4125 | 12,577 | 12,290 |
| 6312.0 | 6215 | 16,804.5 | 16,420 |