Digital Yacht GV30 VHF/AIS/GPS Combo Antenna [ZDIGGV30]GV30 Combo GPS & AIS Antenna A Class B AIS transponder requires a dedicated GPS antenna (all Class B units must have their own internal GPS and can't use an external feed for regulatory purposes) as well as a VHF antenna or suitable VHF AIS antenna splitter. The GV30 is a combination VHF AIS and GPS antenna with twin coax feeds (10m). It is fitted with a standard 1" threaded base so will mount onto a variety of deck, pole and rail attachments