Module 2 - VHF Radio Basics
A Simple Pre-Call Check
What you will learn
Complete a short channel, set, message and priority check before a routine call, then troubleshoot no reply without making a longer, less controlled transmission.
A five-second pre-call check prevents many confused calls: confirm the intended station and channel, the radio state, the message priority and the essential words you need to send.
Before pressing PTT, identify whom you are calling, verify the published channel and listen. Confirm usable volume and squelch, the intended transmit power and the vessel identity. Put the request, position or other critical information in a short order that can be spoken clearly.
After transmitting, release PTT and listen. If there is no reply, do not fill the channel with a continuous or increasingly long call. Recheck the channel and radio state, wait for a reasonable interval, repeat briefly, or use the appropriate alternative procedure for the priority and risk.
A no-reply result is evidence, not a diagnosis. The other station may be busy or not listening; the channel may be wrong; your receiver, antenna or power may be mis-set; terrain may block the path. If the situation becomes urgent or distressing, change to the correct priority procedure rather than repeatedly treating it as routine.
| No-reply check | Question | Unsafe shortcut |
|---|---|---|
| Channel and watch | Is this the current channel, and is either station listening? | Calling continuously |
| Receive controls | Can weak traffic pass the volume and squelch settings? | Adding transmit power |
| Antenna and range | Is the path screened or the installation damaged? | Assuming a fixed mileage |
| Priority | Is this still routine, or have conditions genuinely changed? | Inventing urgency |
Prepare a marina call before PTT
You are approaching a harbour and need a berth instruction while also monitoring traffic and steering.
1. Set
Confirm the harbour's current published channel, radio controls and low-power routine setting.
2. Script
Prepare the called station, your vessel identity and one clear request before transmitting.
3. Receive
Release PTT, listen and write down or read back critical instructions when needed.
Sense check: If you cannot state the station, your vessel and the request in one short outline, you are not ready to press PTT.
Common mistake or limitation
- Using an old or assumed working channel without checking current harbour information.
- Transmitting first and deciding the message while occupying the channel.
- Treating no reply as permission to transmit continuously or to declare a higher priority without the real conditions.
Recap
- Check station, channel, controls, priority, identity and request.
- Listen before transmitting and release PTT to receive.
- Troubleshoot no reply across the whole communication chain.
- Escalate because the situation warrants it, not merely because a routine call failed.
Optional quick check
Section 7 of 9
Which is the strongest routine pre-call outline?
Sources and factual review
Reviewed 20 August 2026 - Compass Revision editorial review.
Continue studying VHF Radio Basics
This public lesson is part of Revision Module 2. Full revision access adds the guided Learn, Practise and Test flow, flashcards and revision progress.