I've a questions to those with class B ais and vhf, do you use splitter to share single antenna at mast top? If yes do the splitter really works? Is it active/powered splitter or passive?
If you use separate antenna for ais and vhf, where did you mount both?
Thanks.
Ken,
As I understand it, if you have a separate AIS receiver and VHF radio, you should not attempt to share a single antenna with a passive splitter. The problem is when you attempt to transmit with a passive splitter, the high power signal will be delivered back into the AIS device and ruin it. The alternative is a second VHF antenna that should be a reasonable distance away from the radio antenna, or the same problem will occur...too much power received by the AIS antenna. Leaving the VHF radio antenna on the mast head and mounting the AIS antenna on the stern rail should be ok. The range of detected signals will be less, but its not the ships that are 25 miles away that you need to worry about. Its the ship traffic within a couple of miles that can get you and that lower antenna will give you enough advance notice.
An active splitter works because it switches the signal fast enough, but you need to analyze the cost difference between a second antenna and that device which will also need a continuous source of power.
I would probably go for a second antenna as it is a backup if the masthead one fails for any reason.
