BoatBanter.com - View Single Post

wrote:

Recreational boat, height say 12 feet ... would making a change in the
angle of the radome be wise? In other words, would it make sense it to
have a unit that
could be maneuvered up and down (up being level, down being a degree or
two difference from ideal)?

For that matter, would "up" increase range (obviously losing minimum
read)?

Up will not increase range. At 12 feet, your horizon is about 4 miles
away. At ranges beyond that, object are "falling" below the horizon, so
nothing is gained by aiming up.

The formula for the radar horizon is almost the same as visual, about
1.2 times the square root of the height in feet yields the distance in
nautical miles. The total distance is the sum of the horizons for the
two objects, so a twelve foot radar can see a twelve foot object about 8
miles away.

When your using the radar for navigating, remember that low objects,
like a beach, may not be visible over the horizon. What you think is
the edge of land may be a hill set back a mile from the beach.

FWIW, I set my radar halfway up the mast, at about 23 feet. This gives
me all the range I need, and still lets me see objects in to about 50
yards. I have a slight downward tilt to compensate for squatting under
power. The only reason to have the radar "runtime adjustable" would be
if the boat has an extreme squat at speed. And of course tender
sailboats can benefit from leveling mounts.