"bushman" wrote in
:

How much does the mast effect the picture when the radar is mounted on
the stern?
How big of a slice does the mast block when the radar is mounted to
the mast?
Dang that's two questions.
- Allen
Endeavour 37 sloop
about 22' to mast 8" cross section
budget radar unit undetermined.


The mast and rigging might reduce range a bit looking forward, but it
doesn't "BLOCK" the view because the antenna, unlike your eye, is not a
point source and receptor of RF energy...it has width.

Hold a pencil 6" in front of your nose. Look at something behind the
pencil. Can you see it? Is your view blocked so at some point you can't
see it? No. When one eye is blocked, the other eye can see around the
pencil to the object. Radar antennas, even the little cheap ones rotting
away inside the leaky radome, are like your eyes. When one side of the
antenna can't see through the mast, the other side can see around the
side of it. A weak target, one way off, might not get enough RF bouncing
off it around the mast to "see" it, but on a sailboat, any target over 5
miles away might as well be on the Moon it takes so long to get to it.
Worrying about targets at 16 miles is hilarious...(c; You need more to
see the bouy 400' ahead in the FOG.

My captain's old boat, now belonging to another friend of mine, is an
Endeavour 35 B plan. When it had a radar on it, I mounted it on a
tiltable platform mount on the port side where that rear handrail stacion
is just forward of the stern. The mast wasn't dead ahead of it, which is
why I put it as far to port as I could get it, looking around the
shrouds, a much less blocking target than the mast. Targets ahead were
visible from 22' off the water out 12 miles just fine.

His newer boat, an Amel Sharki 41 ketch, has a radar mount dead aft of
the roller furling main mast beast on the leading edge of the mizzen
mast. I can see a little dead zone from this arrangement, but with the
boat rolling around at sea, it just doesn't paint a target dead ahead all
the time. As soon as the yacht pitches port or starboard, the target
shows up fine until the autopilot has time to react and oversteer it past
the target once again...



--
There's amazing intelligence in the Universe.
You can tell because none of them ever called Earth.