Overview

The Simrad 000-13612-001 is an NSPL-500 antenna splitter that lets one marine VHF antenna feed a VHF voice radio and an AIS Class B transceiver or receiver, with an optional FM output for a stereo. It supports 12 V or 24 V DC systems with a 9.6 to 31.2 V input range, draws less than 150 mA on average at 12 V DC, weighs 260 g, and is rated IPX7 for water ingress.

Once installed, switching is automatic. Receive signals are shared, and transmit is routed to the antenna when either the VHF radio or AIS transmits. VHF transmit has priority if both try to transmit at the same time, so AIS position reports pause while you are on the mic.

Key features

• Shares a single VHF antenna between a VHF radio and an AIS Class B transceiver or receiver, with an optional FM output for a stereo
• 12/24 V system support with 9.6 to 31.2 V DC input range
• Less than 150 mA average current draw at 12 V DC
• Rated IPX7 for water ingress and suited to a below-decks mounting location
• No insertion loss on AIS and VHF receive, with low insertion loss on AIS and VHF transmit
• SO-239 antenna connector that mates with a PL-259 on a typical marine VHF antenna lead

Installation and setup

Mount the unit below decks where the indicator lights stay visible and you have room to route coax and power. Keep it at least 0.3 m from a compass, avoid spaces with fuel vapors, and keep the local ambient temperature between -15°C and +55°C.

The VHF antenna, VHF radio, and AIS transceiver or receiver all need to be connected for the splitter to operate correctly. Power it from the vessel battery through a circuit breaker or a 1 A fuse. The supplied power lead is 2 m long, and longer runs should be sized to comfortably carry around 200 mA.

Compatibility and fit

The antenna side uses an SO-239 connector, so a standard marine band 50 ohm VHF antenna lead with a PL-259 will connect directly. The AIS side is intended for AIS Class B units such as the NAIS-500, and it works with DSC-capable marine VHF radios.

The FM connection is optional and works with SonicHub 2 and other stereos that accept an external FM antenna feed.

What’s included

• NSPL-500 antenna splitter unit
• 2 m power cable
• VHF radio accessory cable
• AIS transceiver accessory cable

Use on board

This splitter makes sense for refits where you want AIS and VHF on a single masthead antenna, or for boats where adding a second VHF antenna is not practical. It also helps keep the install straightforward when you are adding AIS to an existing VHF setup and want an FM feed for the stereo without adding more antennas.