What would happen if your VHF is set to...

Question 1 / 27070BZiM9l59DT81gdq73YsO

Question 1 of 27070BZiM9l59DT81gdq73YsO

What would happen if your VHF is set to "INT" and you called a VTS that operates on an "alpha" channel?

Question 1 of 27070

What would happen if your VHF is set to "INT" and you called a VTS that operates on an "alpha" channel?

🔍 Key Concepts

• Difference between INT (International) and US (USA) channel sets on a VHF radio • How alpha channels work (simplex vs. duplex, ship vs. coast frequencies) • Which side (ship or coast station) changes frequency when switching between INT and US modes

💭 Think About

• Think about whether your transmit frequency changes when you switch the radio from INT to US, or only the channel label on the display. • Ask yourself: on an alpha channel, are the ship and coast station using the same frequency or different ones? How does that interact with INT vs US mode? • Consider in which situation one party could transmit and the other could not hear—who is actually off‑frequency in this scenario?

✅ Before You Answer

• Verify which channels become 'alpha' channels only in the US set (e.g. 13/67 vs 13A/67A) and what that means for the ship frequency. • Check whether in INT mode, your radio is transmitting on the same ship frequency that the VTS expects on an alpha channel. • Confirm which side of the link (your ship or the VTS) would end up transmitting on a different frequency if your set is on INT instead of US.

Question 1 of 27070

What would happen if your VHF is set to "INT" and you called a VTS that operates on an "alpha" channel?

The coast station should hear your call and respond and you will be able to receive VTS instructions.

The coast station will not hear your call but you will hear their responses to other vessels in the VTS area.

You will be able to hear the coast station calling you but will not be able to hear other vessels in the VTS area.

The coast station should hear your call and respond but you will not hear their response.

Question 1 / 27070BZiM9l59DT81gdq73YsO

Question 1 of 27070BZiM9l59DT81gdq73YsO

What would happen if your VHF is set to "INT" and you called a VTS that operates on an "alpha" channel?

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Question 1 of 27070

What would happen if your VHF is set to "INT" and you called a VTS that operates on an "alpha" channel?