I don't believe there is much added benefit to mounting an AIS
B antenna higher that 14' to 18' off the water
: a handheld VHF has more than twice the power and is limited to less than a dozen miles with
line of sight. Vessels with short AIS antennas mounted on the pushpit report receiving AIS positions at 26 miles, or almost an hour warning in a worst-case head-on scenario.
antenna should be mounted as low as possible with a relatively clear sky view on a sailboat. The cabin
roof is the best bet. The motion of the antenna when mounted higher causes problems. Note that it should have a clear view down to the horizon, as more widely separated satellites yield better triangulation. It you also mount a satellite radio
antenna, it needs a clear view at low angles too.
I, too am pleased that a whip is a good ssb
antenna, even though I have an insulated backstay. The verticality issue is of less relevance with an SSB
, because it is not line of site, strictly speaking.
I have an omni-directional wifi
antenna with exceptional range, but that's still no more than 5 miles. The only reason to raise it would be to see over another boat or over a breakwater. The added height only exacerbates the problem of powering the antenna. Mine is on the same (fiberglass) pole as my AIS antenna.