Module 2 of 10
Radio Basics
Core fixed and handheld VHF controls, listening watch, power, squelch, and range limits.
Listening Before Transmitting
A marine VHF is a shared safety channel system. Before transmitting, listen first. If another station is using the channel, wait unless you have distress traffic.
Press-to-talk means only one station can speak at once. Think, press, speak clearly, release, and listen.
Key Points
- Listen before transmitting
- Hold PTT only while speaking
- Keep routine calls short
Power, Squelch, and Volume
High power increases range but can create unnecessary congestion. Low power is usually enough for close routine traffic such as marina or nearby vessel calls.
Squelch suppresses background noise. Too much squelch can hide weak signals; too little can make the set noisy and tiring to monitor.
Key Points
- Use low power when it is enough
- Set squelch just above background noise
- Keep volume audible for watchkeeping
Antenna and Range
VHF range is largely line-of-sight. A masthead antenna normally reaches further than a handheld at cockpit height.
Range also depends on power, antenna condition, obstructions, weather, and the height of the receiving station.
Key Points
- VHF is line-of-sight
- Antenna height matters
- Handheld range is usually shorter