Shakespeare Phase III 4-Foot AIS Antenna - 3dB Gain

The Shakespeare Phase III 4-Foot AIS Antenna delivers 3dB of gain, purpose-engineered for the wider bandwidth AIS transceivers actually need to operate reliably, rather than being a standard VHF antenna pressed into AIS duty. That extra bandwidth matters because AIS operates on specific channels adjacent to standard VHF, and an antenna not properly matched for it can mean weaker target reception and less reliable position reporting to nearby vessels.

Construction runs a silver-plated outer layer over a copper core, a pairing chosen specifically to keep signal loss low across the antenna's length, important given how much AIS performance depends on picking up comparatively weak signals from vessels at real distance. A stainless mounting sleeve handles the physical install, and the antenna wraps up in a standard SO-239/PL-259 termination, matching most AIS transceivers and existing coax runs without needing an adapter.

The omnidirectional radiation pattern ensures AIS targets are picked up and broadcast equally in every direction around the boat, which is exactly what collision-avoidance and vessel-tracking systems depend on, rather than a directional pattern that could leave blind spots.

Look through the rest of our marine antennas.

• 3DB gain, VHF AIS marine band, vertical polarization
• Omnidirectional radiation pattern
• 5 MHz bandwidth within 2.0:1 VSWR, SWR under 1.5:1 at 162 MHz
• 50W maximum power input
• Silver-plated shielding over a copper core to keep loss low
• DC grounded