INT-USA control settings primarily affect which aspect of VHF channel usage?

INT-USA control settings primarily affect which aspect of VHF channel usage?

• A. To encrypt VHF traffic
• B. To switch between VHF and MF bands
• C. To change Duplex to simplex in the U.S. for VTS
• D. To adjust antenna tuning

Answer: (C)

INT-USA control settings determine how VHF channels used for Vessel Traffic Service are treated in the United States, specifically whether those channels operate in duplex (with a repeater) or in simplex (direct, on the same frequency). In US VTS operations, simplex is typically used so you can communicate directly with the VTS center on the same frequency. Switching to international mode can enable duplex on channels where that practice is expected abroad. So this setting primarily changes whether VTS channels are used in simplex within the US, rather than encrypting traffic, switching bands, or tuning the antenna.

INT-USA control settings determine how VHF channels used for Vessel Traffic Service are treated in the United States, specifically whether those channels operate in duplex (with a repeater) or in simplex (direct, on the same frequency). In US VTS operations, simplex is typically used so you can communicate directly with the VTS center on the same frequency. Switching to international mode can enable duplex on channels where that practice is expected abroad. So this setting primarily changes whether VTS channels are used in simplex within the US, rather than encrypting traffic, switching bands, or tuning the antenna.