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Subelement C
Equipment Operations
Section 14
VHF Channel Selection
What channel must VHF-FM-equipped vessels monitor at all times when the vessel is at sea?
  • Channel 8.
  • Correct Answer
    Channel 16.
  • Channel 5A.
  • Channel 1A.

What channel must VHF-FM-equipped vessels monitor at all times when the vessel is at sea?

(B). Channel 16.

Code of Federal Regulations, Title 47 Chapter I Subchapter D Part 80 Subpart G - Safety Watch Requirements and Procedures

§ 80.305 Watch requirements of the Communications Act and the Safety Convention.

47 CFR 80.305(a)(2) Keep a continuous and efficient watch on the VHF distress frequency 156.800 MHz (VHF Ch. 16) from the room from which the vessel is normally steered while in the open sea outside a harbor or port.

The watch must be maintained by a designated member of the crew who may perform other duties, relating to the operation or navigation of the vessel, provided such other duties do not interfere with the effectiveness of the watch.


YouTube Video: The Emily & Clark's Adventure channel has a good overall video worth watching called How to use a Marine VHF RADIO

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What is the aircraft frequency and emission used for distress communications?
  • 243.000 MHz - F3E.
  • 121.500 MHz - F3E.
  • 156.525 MHz - F1B.
  • Correct Answer
    121.500 MHz - A3E.

What is the aircraft frequency and emission used for distress communications?

(D). 121.500 MHz - A3E.

Aircraft ELTs and distress calls are put out on the universal air band distress frequency, 121.500 MHz.

Aircraft emissions almost always use AM, so A3E is the emission mode.


Code of Federal Regulations, Title 47 Chapter I Subchapter D Part 80 Subpart H - Frequencies

§ 80.355 Distress, urgency, safety, call and reply Morse code frequencies.

47 CFR 80.355(c) Frequencies in the VHF bands.

47 CFR 80.355(c)(1) Survival craft stations using 121.500 MHz may be assigned A3N emission for radiobeacon purposes.

47 CFR 80.355(c)(2) EPIRB stations may be assigned 121.500 MHz and 243 MHz using A3E, A3X and NON emission or 406.0-406.1 MHz using G1D emission to aid search and rescue operations. See subpart V of this part.

§ 80.369 Distress, urgency, safety, call and reply frequencies.

47 CFR 80.369(e)(1) The frequencies 121.500 MHz and 123.100 MHz using A3E emission are available for scene of action search and rescue operations to ship, coast and aircraft stations.

Communications in support of search and rescue operations must employ the frequency 121.500 MHz only when communications on 123.100 MHz or other VHF frequencies is not practicable.

Ship, coast and aircraft stations engaged in such communications on 121.500 MHz must shift to 123.100 MHz as soon as possible.

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Which VHF channel is used only for digital selective calling?
  • Correct Answer
    Channel 70.
  • Channel 16.
  • Channel 22A.
  • Channel 6.

Which VHF channel is used only for digital selective calling?

(A). Channel 70.

Ch-70 - Digital Selective Calling (voice communications not allowed)

For more info, see BlueSeas site article U.S. VHF Frequency and Usage Table

For comprehensive list of channels, please see Wikipedia's article on Marine VHF radio "Channels and Frequencies" section table.


Title 47 Chapter I Subchapter D Part 80 Subpart
C - Operating Requirements and Procedures

§ 80.148 Watch on 156.8 MHz (Channel 16).

... For GMDSS ships, 156.525 MHz {Channel 70} is the calling frequency for distress, safety, and general communications using digital selective calling ...


Code of Federal Regulations, Title 47 Chapter I Subchapter D Part 80 Subpart H Radiotelephony

§ 80.369 Distress, urgency, safety, call and reply frequencies.

47 CFR 80.369(e)(4) The frequency 156.450 MHz (channel 9) is available for intership, ship and coast station general purpose calling by noncommercial vessels, such as recreational boats. Distress, urgency and safety calls should initially be made on 156.800 MHz (channel 16) or, if equipped with DSC, on 156.525 MHz (channel 70).

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Which channel is utilized for the required bridge-to-bridge watch?
  • DSC on Ch-70.
  • VHF-FM on Ch-16.
  • Correct Answer
    VHF-FM on Ch-13 in most areas of the continental United States.
  • The vessel’s VHF working frequency.

Which channel is utilized for the required bridge-to-bridge watch?

(C). VHF-FM on Ch-13 in most areas of the continental United States.

§ 80.373 Private communications frequencies.

47 CFR 80.373(f) Frequencies in the 156-162 MHz band. The following tables describe the carrier frequencies available in the 156-162 MHz band for radiotelephone communications between ship and private coast stations. Navigational (Bridge-to-Bridge)5 Table

Channel 13 / Ship Transmit 156.650 /
Coast Transmit 156.650

5 156.375 MHz and 156.650 MHz are available primarily for intership navigational communications. These frequencies are available between coast and ship on a secondary basis when used on or in the vicinity of locks or drawbridges.

Normal output power must not exceed 1 watt. Maximum output power must not exceed 10 watts for coast stations or 25 watts for ship stations.

6 On the Great Lakes, in addition to bridge-to-bridge communications, 156.650 MHz is available for vessel control purposes in established vessel traffic systems.


VHF-FM on Ch-13 is for Intership Navigation Safety (Bridge-to-bridge). The vessel's VHF working frequency is for mutually agreed frequency with another ship.

DSC on Ch-70 is a digital communication with external entities.

Ch-16 - International Distress, Safety and Calling. Ships required to carry radio, USCG, and most coast stations maintain a listening watch on this channel. VHF-FM on Ch-16 is only used as a distress channel.

Ch-70 - Digital Selective Calling (voice communications not allowed)

Ch-06 - Internship Safety

For more info, see BlueSeas site article U.S. VHF Frequency and Usage Table

For comprehensive list of channels, please see Wikipedia's article on Marine VHF radio "Channels and Frequencies" section table.

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Which channel would most likely be used for routine ship-to-ship voice traffic?
  • Ch-16.
  • Correct Answer
    Ch-08.
  • Ch-70.
  • Ch-22A.

Which channel would most likely be used for routine ship-to-ship voice traffic?

(B). Ch-08.

Channel 8 has the ship-to-coast assignment of 156.4 kHz frequency, per Code of Federal Regulations, Title 47, Chapter I, Subchapter D, Part 80, Subpart H - Frequencies


Ch-08: Commercial internship traffic

Other Marine Radio Channels:

Ch-16: International Distress, Safety and Calling.

Ch-70: Digital Selective Calling (no voice comms)

Ch-22A: Coast Guard Liaison and Maritime Safety Information Broadcasts

For more info, please see Wikipedia's article on Marine VHF radio "Channels and Frequencies" section table.


Additional references:

From NTIA a Dept of Commerce site Assessment of Compatibility Between 25 and 12.5 kHz Channelized Marine VHF Radios and in the pdf report format the assessment.

See additional info in the Federal Register for the report on Maritime Communications from FCC

Well organized and clearly presented info from Continuous Wave site in article on VHF Marine Band Channels

Also, please see very useful info from Starpath site article on Radio Information for Boaters

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What channel would you use to place a call to a shore telephone?
  • Ch-16.
  • Ch-70.
  • Correct Answer
    Ch-28.
  • Ch-06.

What channel would you use to place a call to a shore telephone?

(C). Ch-28.

Channel 28 has the ship assignment of 157.4 kHz and coast assignment of 162.0 kHz, per per Code of Federal Regulations, Title 47, Chapter I, Subchapter D, Part 80, Subpart H - Frequencies

Ch-28 - Public Correspondence (Marine Operator)

Ch-16 - International Distress, Safety and Calling. Ships required to carry radio, USCG, and most coast stations maintain a listening watch on this channel.

Ch-70 - Digital Selective Calling (voice communications not allowed)

Ch-06 - Internship Safety

For more info, see Blue Seas site article U.S. VHF Frequency and Usage Table

For comprehensive list of channels, please see Wikipedia's article on Marine VHF radio "Channels and Frequencies" section table.


Code of Federal Regulations, Title 47 Chapter I Subchapter D Part 80 Subpart H - Frequencies, Radiotelephony

§ 80.369 Distress, urgency, safety, call and reply frequencies.

47 CFR 80.369(e)(4) The frequency 156.450 MHz (channel 9) is available for intership, ship and coast station general purpose calling by noncommercial vessels, such as recreational boats.

Distress, urgency and safety calls should initially be made on 156.800 MHz (channel 16) or, if equipped with DSC, on 156.525 MHz (channel 70).


Additional references:

From NTIA a Dept of Commerce site Assessment of Compatibility Between 25 and 12.5 kHz Channelized Marine VHF Radios and in the pdf report format the assessment.

See additional info in the Federal Register for the report on Maritime Communications from FCC

Well organized and clearly presented info from Continuous Wave site in article on VHF Marine Band Channels

Also, please see very useful info from Starpath site article on Radio Information for Boaters

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