Owner's Manual
Table Of Contents
- Introduction
- Getting Started
- Basic Operation
- Turning the Radio On and Off
- Adjusting the Volume
- Adjusting the Squelch
- Selecting Channels
- Transmitting with the Radio
- Bypassing the LO (1 W) Transmission Power Setting
- Scanning and Saving Channels
- Repeating the Last Received Communication
- Monitoring Multiple Channels
- Reprogramming the Second-Priority Channel
- Using 16/9 Mode
- Switching Between 1 W and 25 W Transmitting Modes
- Adjusting the Local/Distant Receiving Sensitivity
- Using the Intercom
- Using the Hailer
- Using the Foghorn
- Listening to NOAA Weather Broadcasts and Enabling Weather Alerts
- Automatic Transmitter Identification System
- Digital Selective Calling
- Advanced Operation
- Appendix
- Index

VHF 300 Series Owner’s Manual 35
Appendix
Appendix
Alarms and Messages
The radio may generate the following alarms or system messages.
Battery Alarm
If the radio detects a voltage greater than 15.8 Vdc or less than 10 Vdc, “HIGH VOLTAGE”
or “LOW VOLTAGE” is displayed on the screen. Check the wiring if any of these
conditions occur.
Main in Use
When the primary VHF 300 series radio unit is being used, “MAIN IN USE” is displayed
on the screen of all remote Garmin GHS series handsets. The screen returns to normal three
seconds after the last input on the primary station.
Remote handset stations cannot interrupt the primary radio unit. However, remote handset
stations can interrupt the operation of other handset stations.
WX (Weather Alert)
If you set the WX alarm and an incoming weather alert is detected, the radio automatically
tunes to the WX channel that is broadcasting the alert. See page 11 for more information on
weather alerts.
GPS Data Alarm
When GPS data from a NMEA network or position data you entered manually is over four
hours old, the alarm tone beeps and “DATA IS OVER 4 HOURS OLD” is displayed on the
screen.
• Select IGNORE to disregard the alarm and to turn off the alarm beeping. When you take
no action after three minutes, IGNORE is selected automatically.
• Select SET to enter a new position. See page 26 for more information on manually
entering position data.
Invalid GPS Data Alarm
When GPS data from a NMEA network or position data you entered manually is over 23.5
hours old, “DATA IS INVALID” is displayed on the screen. The radio will not transmit
position data that is more than 23.5 hours old.
• Select IGNORE to discard the old position data. The screen displays “NO GPS INFO”
on the Home screen. When you take no action after three minutes, IGNORE is selected
automatically.










