Digital Antenna 4 VHF/AIS White Antenna w/15 Cable [594-MW]4' VHF AIS White Antenna with 15' Cable The 594 MW is one antenna designed for the best performance on VHF and AIS signals. To ensure the most incredible AIS and VHF range, Digital Antennas new 4. 5dB gain AIS VHF antenna features a less than 1: 5: 1 SWR on both the VHF (156MHz) and AIS (162MHz) frequencies. Digital VHF radio based transponder systems need antennas designed for digital signals. Digital Antenna is the only manufacturer to design all