Shakespeare 4 Phase III AIS Antenna - 3dB The Shakespeare Phase III AIS Antenna enables reliable communication over marine AIS frequencies. This antenna has been specially engineered and tuned to match AIS transceivers and is backed by Shakespeares 8 year warranty. Ethafoam spacers, thick radome, and silver-plated elements enhance the antennas technical performance and longevity. Designed to look good on any vessel, the Phase III Antenna has a durable, high-gloss, white polyurethane finish to pr