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Subelement N
Marine
Section 85
VHF
What is the channel spacing used for VHF marine radio?
  • 10 kHz.
  • 12.5 kHz.
  • 20 kHz.
  • Correct Answer
    25 kHz.

What is the channel spacing used for VHF marine radio?

(D). 25 kHz.

Reference from International Telecommunications Union, pdf of Rec. ITU-R M.489-2 TECHNICAL CHARACTERISTICS OF VHF RADIOTELEPHONE EQUIPMENT OPERATING IN THE MARITIME MOBILE SERVICE IN CHANNELS SPACED BY 25 kHz

For details, please see Wikipedia's article on Marine VHF radio

Also, comprehensive info on Continuous Wave site, article VHF Marine Band Channels


Reference: VHF specifications and use are listed in the Code of Federal Regulations, Title 47 Chapter I Subchapter D
Part 80 - STATIONS IN THE MARITIME SERVICES

Since applicable regulations are in a number of places, please use CTRL-F and search on the word "VHF" to look up applicable regulations.

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What VHF channel is assigned for distress and calling?
  • 70
  • Correct Answer
    16
  • 21A
  • 68

What VHF channel is assigned for distress and calling?

(B). 16

From wp2ahg:

Channel 16 is reserved as the distress and calling channel.

Channel 70 - - Digital Selective Calling (DSC).
Channel 21A -US Coast Guard use only.
Channel 68 - -for non-commercial use.


For practical info regarding VHF radio use, please see Madden Marine Time site, pdf called Marine VHF Radio Use.

For detailed info, please see US Coast Guard site, article U.S. VHF Channel Information


Reference: VHF specifications and use are listed in the Code of Federal Regulations, Title 47 Chapter I Subchapter D
Part 80 - STATIONS IN THE MARITIME SERVICES

Since applicable regulations are in a number of places, please use CTRL-F and search on the word "VHF" to look up applicable regulations.

Last edited by markadlerdallas. Register to edit

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What VHF Channel is used for Digital Selective Calling and acknowledgement?
  • 16
  • 21A
  • Correct Answer
    70
  • 68

What VHF Channel is used for Digital Selective Calling and acknowledgement?

(C). 70

From wp2ahg:

Channel 70 - - Digital Selective Calling (DSC).
Channel 16 -- Distress and calling channel.
Channel 21A -US Coast Guard use only.
Channel 68 - -for non-commercial use.


For practical info regarding VHF radio use, please see Madden Marine Time site, pdf called Marine VHF Radio Use.

For detailed info, please see US Coast Guard site, article U.S. VHF Channel Information


Reference: VHF specifications and use are listed in the Code of Federal Regulations, Title 47 Chapter I Subchapter D
Part 80 - STATIONS IN THE MARITIME SERVICES

Since applicable regulations are in a number of places, please use CTRL-F and search on the word "VHF" to look up applicable regulations.

Last edited by markadlerdallas. Register to edit

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Maximum allowable frequency deviation for VHF marine radios is:
  • Correct Answer
    +/- 5 kHz.
  • +/- 15 kHz.
  • +/- 2.5 kHz.
  • +/- 25 kHz.

Maximum allowable frequency deviation for VHF marine radios is:

(A). +/- 5 kHz.

See the regulation that covers this on Code of Federal Regulations, Title 47 Chapter I Subchapter C Part 74 Subpart D
§ 74.462 Authorized bandwidth and emissions.

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What is the reason for the USA-INT control or function?
  • It changes channels that are normally simplex channels into duplex channels.
  • Correct Answer
    It changes some channels that are normally duplex channels into simplex channels.
  • When the control is set to “INT” the range is increased.
  • None of the above.

What is the reason for the USA-INT control or function?

(B). It changes some channels that are normally duplex channels into simplex channels.

For detailed info, please see The Coastal Passage site for the article on What every VHF user should already know

The goal is to inform all vessels to be able to receive maneuvering orders.

In US waters, change all VHF channels from Duplex to Simplex while in U.S. waters.

In International waters, reverse. Change all VTS frequencies to Duplex so all vessels can hear the orders.

See Wikipedia's article on Marine VHF radio

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

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How might an installer verify correct GPS sentence to marine DSC VHF radio?
  • Correct Answer
    Look for latitude and longitude, plus speed, on VHF display.
  • Press and hold the red distress button.
  • Look for GPS confirmation readout.
  • Ask for VHF radio check position report.

How might an installer verify correct GPS sentence to marine DSC VHF radio?

(A). Look for latitude and longitude, plus speed, on VHF display.

For practical info on installation, please see
West Marine pdf called VHF 580 DSC Marine Manual.

From wp2ahg:

If the latitude/longitude is correctly displayed on a marine DSC VHF radio, then the radio is interpreting the GPS sentence correctly.

As for (B): You would not press and hold the red distress button as that would initiate a distress signal.

As for (C): Unsure of what a 'GPS confirmation readout' is.

As for (D): A VHF radio check position report would confirm a VHF radio's transmit/receive capabilities, but would not confirm the GPS system is working.

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