Module 2 - VHF Radio Basics
Listening Before Transmitting on VHF Radio
What you will learn
Use the listen–think–press–speak–release cycle so a routine call does not mask existing or higher-priority traffic.
Marine VHF is a shared, one-speaker-at-a-time system. Listen before transmitting, prepare the short message, hold push-to-talk only while speaking, then release it promptly to hear the reply.
The MCA advises operators to listen before transmitting, keep transmissions brief and avoid unnecessary conversation. A clear-looking display does not prove the channel is free: turn the volume up, use a workable squelch setting and listen long enough to recognise an exchange already in progress.
Voice marine VHF is effectively one speaker at a time. If two stations transmit together, neither message may be understood. Push-to-talk, or PTT, switches the set from receiving to transmitting; while PTT is held, that radio cannot receive the reply.
Distress, urgency and safety traffic take priority over routine traffic. If you hear higher-priority traffic, stop routine calling and keep the channel available. VHF is a communication aid: an agreement made by radio does not replace the collision-avoidance duties in the COLREGs or the need to navigate the vessel safely.
Join a shared channel without talking over another vessel
You want to call a marina on its published working channel. When you listen, you hear the marina answering another yacht.
1. Listen
Keep the volume audible and wait for the existing exchange to finish; do not press PTT merely to reserve a turn.
2. Prepare
Have the called station, your vessel identity and the reason for the call ready before transmitting.
3. Transmit and release
Make the brief call, release PTT immediately and listen for the reply.
Sense check: If your radio remains silent because PTT is still pressed, you are transmitting—not listening.
Common mistake or limitation
- Treating a short pause as proof that an exchange has ended; listen for the stations' closing words or a clear break.
- Holding PTT while waiting for the answer, which blocks reception and may block the channel.
- Using a VHF conversation as a substitute for maintaining a proper lookout or applying the COLREGs.
Recap
- Listen before every routine transmission.
- Prepare the essential message before pressing PTT.
- Release PTT as soon as you finish speaking.
- Stop routine traffic for distress, urgency or safety communications.
Optional quick check
Section 1 of 9
You hear a weak exchange already in progress on the marina's working channel. What should you do before making a routine call?
Sources and factual review
Reviewed 20 August 2026 - Compass Revision editorial review.
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