AIS antenna: masthead or rail mount

[MYTraveler]

Originally Posted by monte

I think it's hard to argue that seeing a target 40 miles out with a CPA of over an hour isn't safer than seeing it at 15 miles with a CPA around 30 minutes.

You won't get an argument from me, but around here, a lead-in like that is comparable to a red flag is front of a bull. It so predictable, its comical.

[capitangiorg]

IMHO the higher the better, BUT depending on how high you should start consider the coax loss. In our boat we installed a second VHF antenna on the mast head, (85'), we can see Class A AIS ship very far, but usually we are not able to be seen further than 15 to 20 miles, due to the fact that our Class B transponder has an nominal output of only 2 Watts. So if you put the antenna very high use the best low loss coax and the best connector to bring most of the power to the antenna.
Andrea

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