Comar AST300 AIS Class B Antenna Splitter

£244.98 £214.98 (incl. VAT £257.98)



Shares an existing antenna between a VHF Radio Telephone and an AIS Transponder

SKU: 119-AST300 Categories: , , ,


Comar AST300 AIS Class B Antenna Splitter

The Comar AST200 splitter is a new product that allows VHF radios, AIS Class B transponders, and FM radios to be connected to one VHF antenna.

The AST100 is designed for operation with marine VHF radios and AIS transponders.  The great advantage of this splitter is that the radio operates normally when the splitter is switched off which means that it can be conveniently operated on the same circuit and the CSB200.  When the CSB200 and AST100 are switched on the splitter suppresses transmission from the CSB200 if it detects a voice transmission on the VHF radio – therefore in an emergency voice transmission takes precedence.

Designed to operate with the majority of AIS transponders we have carried out trials and found the unit gives excellent operation with the Comar CSB200 transponder and a marine VHF antenna.  This option allows the advantage of having the AIS antenna at the masthead giving significantly extra transmission and receiving range.

  • Simple and quick to install, using a single VHF antenna for both AIS and VHF operation saves installation cost and time.
  • Failsafe operation ensures priority to VHF voice and DSC even if the splitter power supply fails.
  • Minimal in circuit insertion loss
  • Additional output available for FM radio antenna connection
  • Simple LED indicators show when VHF voice radio or AIS is transmitting or receiving.
  • Includes RF leads for connection with AIS transponder, VHF radio, and a power lead.
  • Operation from 12/24 VDC



The AST300 Antenna Splitter from Comar Systems is designed to allow an AIS Class ‘B’ Transponder or an AIS Receiver to share the main VHF Antenna used by the VHF Radiotelephone, which removes the need and expense of installing an additional VHF antenna. Comar Antenna Splitters are built to the highest standards to ensure that the performance of the connected AIS and VHF Radio equipment is not compromised.


Automatic signal routing to a single VHF antenna  Works with an AIS Transponder (Class ‘B’) or AIS Receiver VHF transmissions have priority over AIS  Equipped with an FM Antenna Connection for receiving Public Radio Broadcasts


Enables AIS to be used with an existing antenna installed on a vessel. Removes the need and expense of installing a second antenna


Weight: 600 g  Dimensions: L 140 x W 120 x H 50 mm Mounting: To flat surface with case brackets  Connections: Power: 1 m 2-core captive cable Antenna: SO239 UHF Connector VHF Radiotelephone: SO239 UHF Connector AIS Transponder / Receiver: BNC Connector FM Radio: RCA Phono Socket  Finish: Grey aluminium housing; black end plates


Power Supply: 12 / 24 V dc  Operating Current: AIS / VHF Transmit: 135 mA (typical) AIS / VHF Receive: 65 mA (typical)  Antenna Impedance: AIS / VHF / Antenna: 50 Ω; FM Radio: 75 Ω


Frequency Range: 156.025 MHz to 162.025 MHz  Sensitivity: < -112 dBm  Display: 3 Indicator LEDs (ON; AIS TX; VHF TX) Switching Time: From Receive to AIS TX or VHF TX: 20 microseconds


IP rating: IP40  Operating temp: -15°C to +55°C  Storage temp: -20°C to +70°C  Operating Humidity: Up to 93%  Compass: Safe Distance 50 cm



Supplied: AST300 Splitter with Bracket Mount, VHF Patch lead; 1 m; with 2x PL259 male connectors AIS Patch lead; 1 m; with 2x BNC male connectors FM Radio: RCA Phono Plug (no cable)

Required: 4x M4 mounting screws


Shares an existing antenna between a VHF Radio Telephone and an AIS Transponder


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