The Garmin Signal™ VHF 400 (010-02951-00) is a premium fixed-mount marine VHF radio that combines a 25-watt VHF transceiver, integrated Class D Digital Selective Calling (DSC), and a built-in 5-watt Class B SOTDMA AIS transponder into a single compact unit. Featuring edge-to-edge glass and a 3.5-inch color IPS touchscreen display, it offers intuitive navigation, target tracking, and direct DSC target calling. Built-in adaptive noise cancellation ensures clear audio in harsh offshore conditions, while a 3-minute continuous audio recording buffer allows users to replay recent transmissions. The system operates on 12 V and 24 V electrical systems, utilizes a single SO-239 marine antenna connection for both VHF and AIS duties, and features dual NMEA 2000 and Garmin BlueNet networking capabilities. Designed for versatile helm installations, it carries IPX6 and IPX7 water ingress ratings, supports up to 25 W hailer output with automatic fog signals, and allows expansion for up to five full-function remote handsets.

In the Box

Garmin Signal^™ VHF 400 head unit
Fist mic
Sun cover
Head unit power and external audio cable with fuse (2 m)
Fist mic power cable with fuse (2 m)
Drop cable for NMEA 2000^® network (2 m)
Mounting hardware
Mounting template
Documentation

Technical Specification

General
Unit size	Head Unit: 75 x 160 x 104 mm (3.0″ x 6.3″ x 4.1″) Fist Mic: 100 x 60 x 31 mm (3.9″ x 2.4″ x 1.2″)
Weight	Head Unit: 655 g (1.45 lbs) Fist Mic: 245 g (0.54 lbs)
Operating voltage	9.6 – 32 VDC
Water rating	IPX7
Display Type	color IPS LCD, capacitive touch
Display Size	3.5″ (89 mm)
Display resolution	640 x 480 pixels
Operating temperature	–20° to 55° C (–4° to 131° F)
Inland waterways (ATIS)	✓
Backlight	1,000 nits
Multi-language interface	✓

VHF Features
Adaptive noise cancellation	✓
Audio record and playback	✓
Auto squelch	✓
Dual/Tri watch	✓
Presets watch	✓
NOAA weather alert	✓
NOAA weather watch	✓
Loud hailer	✓
Loudhailer listen back	✓
Intercom support	✓
AIS target display	✓
AIS collision and MOB alarms	✓
Integrated AIS transponder	✓

VHF Radio
Region	All U.S., Canadian and International marine channels; NOAA weather channels
VHF frequency range Tx	156.025–162.025 MHz
VHF frequency range Rx	156.025–163.275 MHz
VHF transmit power (max)	25 W, 1 W (high, low)
Transmitter frequency tolerance	+/0.3 kHz
Adjacent channel power	more than 70 dB
Spurious emissions	Less than –80 dBc (at 25 W)
Sensitivity (12 dB SINAD)	-118 dBm (-11 dBu/0.28 uV)
Adjacent channel selectivity	80 dB
Spurious response	more than 75 dB
VHF intermodulation	more than 75 dB
Max antenna gain	6 dBi

DSC
Class	Class D
Sensitivity (1% BER)	-117 dBm (-10 dBu/0.32 uV)
Adjacent channel selectivity	80 dB
Spurious response	more than 75 dB
Intermodulation	more than 75 dB

AIS Transponder Features
Remote station support	RM 100 (x5)

AIS
Class	SOTDMA Class B
Long range position reports (Msg 27)	✓
Frequency range	156.025 – 162.025 MHz
AIS power output	5 W
AIS Sensitivity (20% PER)	-115 dBm (-8 dBu/0.4 uV)
Adjacent channel selectivity	80 dB
Spurious response	more than 75 dB
Intermodulation	more than 65 dB

GNSS
Integrated GNSS receiver	✓
Integrated GNSS antenna	✓
Constellations	GPS, GLONASS, BeiDou, Galilleo
Differential support	SBAS, AIS Msg 17
Navigation rate	10 Hz

Sensors
NMEA 2000 Compatible	✓
Battery voltage	✓

Audio
Max speaker output power	Fist Mic: 5 W RMS, < 1% THD
Max external speaker output power	15 W RMS, < 1% THD, 4 Ω
Max hailer loudspeaker output power	25 W RMS, < 1% THD, 4 Ω

Tactical Features
Night vision mode	✓
Stealth mode	✓

Electrical Features
Typical current draw at 12 Vdc	Head Unit: 700 mA, 6 A max Fist Mic: 90 mA, 0.9 A max
Compass-safe distance	Head Unit: 70 cm (27.6″) Fist Mic: 40 cm (15.8″)

Networking & Connections
Garmin Marine Network	GMN 1.0/2.0
Wireless Connectivity	Access point for mobile phones, 802.11b/g/n, integrated antenna
Wireless security	WPA2 Personal
External GNSS antenna connector	SMA
ANT connector	SO-239 (50 Ω)