6.2 VHF Channel Selection (Key Topic 14)

6.2 VHF Channel Selection (Key Topic 14)

Quick Answer: Monitor Channel 16 whenever a VHF-FM ship is at sea and the radio is not already working another channel. Aircraft distress voice is 121.500 MHz A3E. Channel 70 is DSC only. The bridge-to-bridge watch is Channel 13 in most U.S. continental waters. Routine ship-to-ship voice is often Channel 08. A shore-telephone (public correspondence) example is Channel 28. Keep the working frequencies for Channels 16, 13, 70, 22A, 6, and 9 in the same mental rack.

Channels are the rest of the VHF skill

Key Topic 13 taught the knobs. Key Topic 14 teaches which channel those knobs must sit on. A Dual Watch radio set to the wrong memory, a 1-watt carrier on a duplex marine-operator pair when you meant to call the Coast Guard, or a voice transmission on Channel 70 will fail the live item and can fail a real distress. Independent OpenExamPrep study material covering Element 1 channel selection uses the 2009 pool facts first and the U.S. Coast Guard Navigation Center U.S. VHF channel table as current operating context. The FCC does not publish a separate public Element 1 channel chart; NavCen does publish the U.S. table boaters and commercial operators actually use.

The six tested facts are: Channel 16 as the at-sea VHF-FM watch, 121.500 MHz A3E as aircraft distress, Channel 70 as DSC-only, Channel 13 as the bridge-to-bridge watch in most of the continental United States, Channel 08 as the likely routine ship-to-ship working channel, and Channel 28 as the example for a call to a shore telephone. Around those six, you still need the megahertz numbers and the neighboring channels you will actually key: Channel 16 at 156.800 MHz, Channel 13 at 156.650 MHz, Channel 70 at 156.525 MHz, Channel 22A at 157.100 MHz, Channel 6 intership safety, and Channel 9 recreational calling.

Frequencies and uses you should be able to state without the plate on the radio

NavCen modulation for these voice channels is 16KF3E or 16KG3E (FM/PM marine voice). Channel 70 is not a voice channel. Channel 28 is duplex: the ship transmits on 157.400 MHz and receives the coast marine operator on 162.000 MHz. Do not confuse that duplex pair with Channel 22A simplex 157.100 MHz.

Channel 16 at sea: 156.800 MHz

VHF-FM equipped vessels must monitor Channel 16 at all times when the vessel is at sea. Channel 16 is 156.800 MHz, the international distress, safety, and calling frequency. Ships required to carry radio, the U.S. Coast Guard, and most coast stations keep a listening watch there. Establish contact on 16, then move to a working channel. Do not pass routine cargo, weather chat, or a long radio check on 16.

Wrong at-sea answers in this topic are Channel 8 (a working intership channel), Channel 5A (a U.S. port-operations / VTS simplex channel in listed ports), and Channel 1A (another U.S. simplex port channel in listed areas). Those channels have jobs. None of them is the open-sea VHF-FM distress and calling watch. Key Topic 3 already covered the compulsory Channel 16 watch and the Bridge-to-Bridge-plus-VTS exception. Key Topic 14 asks the equipment-operations version: if the ship has VHF-FM and is at sea, the monitor is Channel 16.

47 CFR 80.148 and the Navigation Center watchkeeping page state the same operating habit for a radio that is turned on: when you are not exchanging traffic, you are listening on 16 (voluntary non-commercial vessels may use Channel 9 instead under 80.310, but the Coast Guard still recommends 16 because storm warnings are announced there). Element 1's Key Topic 14 item is the at-sea Channel 16 fact, not the Channel 9 option.

Aircraft distress: 121.500 MHz A3E

The aircraft frequency and emission used for distress communications is 121.500 MHz, emission A3E. A3E is amplitude-modulated double-sideband radiotelephony — the aeronautical AM voice that air traffic control and aircraft guard receivers use. It is not marine F3E (FM voice). An aircraft in distress that needs a maritime station, or a ship that is assisting an aircraft, is looking for 121.5 AM, not for Channel 16 FM, unless the aircraft also carries marine VHF.

Memorize the distractors so they cannot steal the item:

• 243.000 MHz F3E is not the tested aircraft distress pair. 243.0 MHz is the military UHF guard; F3E is the wrong emission class for the aeronautical AM distress channel.
• 121.500 MHz F3E has the right frequency and the wrong emission. Putting marine FM on 121.5 does not make an aircraft AM receiver hear you clearly, and it is not the tested designator.
• 156.525 MHz F1B is Channel 70 DSC, a digital maritime emission, not aircraft voice distress.

Some GMDSS and SAR procedures also mention VHF Channel 6 (156.300 MHz) for ship-to-aircraft communication at the scene. That is on-scene marine VHF, not the 121.5 A3E distress frequency. Keep 121.5 A3E on the aviation shelf and Channel 6 on the marine intership-safety shelf.

Channel 70: DSC only, 156.525 MHz

Channel 70 is used only for digital selective calling. Voice is not permitted. The frequency is 156.525 MHz. The Navigation Center states that Channel 70 is authorized exclusively for distress, safety, and calling using DSC techniques, that no other uses are permitted, and that the channel must be protected. GMDSS ships keep an automatic DSC watch here (Key Topic 3). After a DSC distress alert on Channel 70, voice distress traffic moves to Channel 16, not onto Channel 70 audio.

Do not voice-hail on 70. Do not run a radio check on 70. Do not program 70 into a voice scan list expecting to hear MAYDAY by ear. The DSC controller (Key Topic 1) is the device that uses Channel 70. Channel 16 remains the voice distress channel. Channel 22A remains the U.S. Coast Guard liaison voice channel after a 16 call.

Bridge-to-bridge: Channel 13 in most U.S. continental waters

The required bridge-to-bridge watch is VHF-FM on Channel 13 in most areas of the continental United States. Channel 13 is 156.650 MHz, simplex, intership navigation safety. NavCen: ships more than 20 meters in length maintain a listening watch on Channel 13 in U.S. waters, in addition to Channel 16, and Channel 13 is the channel to use to contact a ship when there is danger of collision. Sequential scanners alone cannot meet that Channel 13 requirement; two radios or a dual-receiver radio are required for ships that must guard both 13 and 16.

The lower Mississippi River is the well-known exception: bridge-to-bridge there uses Channel 67 (156.375 MHz), intership only. Element 1 still tests Channel 13 as the answer for most of the continental United States. Do not replace Channel 13 with DSC on Channel 70, with Channel 16 (a different watch), or with the ship's ordinary working frequency. Channel 13 is navigational communications only (Key Topic 7). Routine cargo chatter belongs somewhere else, often Channel 08.

Routine ship-to-ship: Channel 08

The channel most likely used for routine ship-to-ship voice traffic is Channel 08. NavCen lists Channel 08 as 156.400 MHz, commercial, intership only. That is a working simplex channel, not a distress channel and not a coast-station liaison channel.

Why the other choices fail:

• Channel 16 is for distress, safety, and calling. After contact, you leave 16.
• Channel 70 is DSC; no voice.
• Channel 22A is Coast Guard liaison and marine-safety broadcasts, not a ship-to-ship working channel for routine traffic.

Other commercial intership channels exist (for example Channel 07A, Channel 18A). Element 1's tested likely choice is Channel 08. Use it at 1 watt when the other ship is nearby.

Shore telephone: Channel 28 as the public-correspondence example

To place a call to a shore telephone, Element 1's example channel is Channel 28. NavCen lists Channel 28 as 157.400 MHz ship / 162.000 MHz coast, public correspondence (marine operator), a duplex pair. The marine operator patches the radio circuit into the public switched telephone network. You do not make that call on Channel 16, on Channel 70, or on Channel 06.

Public-correspondence Channels 24, 25, 26, 27, and 28 are the traditional marine-operator set. NavCen's current table notes that those public-correspondence channels cannot be used effective 2030 as VHF data-system changes take effect. That is a current operating note for voyage planning. It does not change the Element 1 example: when the item asks which channel you would use to place a call to a shore telephone, the tested answer is Channel 28, not 16, 70, or 06. Because Channel 28 is duplex, nearby ships will not hear the land-side talker; that is acceptable for a private telephone patch and is exactly why distress and VTS must not use a duplex pair.

Channel 6, Channel 9, and Channel 22A as operating context

Channel 6 (156.300 MHz) is intership safety. NavCen labels it Intership Safety. Ships and aircraft at a SAR scene use it for on-scene coordination on marine VHF. It is not the at-sea calling watch, not DSC, and not the shore-telephone channel.

Channel 9 (156.450 MHz) is the FCC supplementary boater calling channel for non-commercial vessels, requested by the Coast Guard to relieve congestion on Channel 16. A ship or shore unit calling a recreational boat may use 9; anyone calling a commercial ship or a commercial shore activity still uses 16. Recreational boaters still call the Coast Guard on 16. NavCen recommends that boaters normally keep tuned to Channel 16 unless the Coast Guard has directed otherwise, because the Coast Guard generally cannot announce urgent marine information on Channel 9. 47 CFR 80.310 allows voluntary non-commercial vessels to watch 9 in lieu of 16; compulsory commercial watches do not migrate to 9.

Channel 22A (ITU 1022) is 157.100 MHz simplex, Coast Guard liaison and maritime safety information broadcasts. Broadcasts are announced on Channel 16, then sent on 22A. Storm warnings follow the same pattern: announced on 16, broadcast on 22A (and on 2670 kHz for the MF version). All ships in U.S. waters over 20 meters must have radios capable of tuning this simplex channel. If INT-USA is left in INT, you may not have 22A at all — that is why Topic 13's switch matters to Topic 14's Coast Guard channel.

Choosing a VHF channel in order

1. If the radio is idle at sea, it is on Channel 16 (156.800 MHz).
2. If the message is a DSC alert, it is Channel 70 (156.525 MHz), never voice.
3. If you are hailing for navigation in most U.S. continental waters, it is Channel 13 (156.650 MHz), usually at 1 watt.
4. If the Coast Guard just told you to switch for a broadcast or a working liaison, it is Channel 22A (157.100 MHz).
5. If two ships need routine working voice, Channel 08 (156.400 MHz) is the tested likely choice.
6. If you need a marine-operator telephone patch, Channel 28 is the tested example.
7. If you are coordinating intership safety or on-scene SAR on marine VHF, Channel 6. If you are a recreational boat using the supplementary hailing channel, Channel 9 — then still listen to 16 for Coast Guard announcements.
8. If an aircraft is in distress on the aeronautical voice distress frequency, that is 121.500 MHz A3E, not a marine channel number.

Work that list from the top on every watch. Channel 16 is the default ear. Everything else is a working or specialized assignment you return from.