I'm struggling with the AIS transmitter on my vessel. She is a 2003 Hunter 356. The masthead antenna whip was recently replaced and is a GAM SS-2. The cabling is original as far as I know. I hooked the AIS unit to a laptop and ran ProAIS2. After two transmits it throws a VSWR fault, with values seemingly all over the place but all very high. Some were around 6:1, some were 12:1, and a few were even higher (one read 47:1 and one result even showed 1635:1.) There is a splitter in place, but bypassing it didn't noticeably change VSWR numbers. Thoughts on where to start?