Radar: how high up does it need to be?

[chrisD]

I am about to instal radar and would be interested in opinions on how high up the mast the radome needs to be. The head sail tends to brush the mast quite a bit, and I am inclined to fit the Raymarine 18" radome inside the inner forestay, about ten feet above the coachroof, a few feet below the cross trees. That's already a good bit higher than it would be on a stern pole or on a stinkie's roof. Any views?

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[sailorman]

i have mine on a pole but a friend has his fitted beside the mast on the cross-tree
tottally out of the way

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[Talbot]

reasonable place for it is inside that inner forestay, but not too close to the stay (at least a couple of feet clearance) otherwise a lot of the power will end up in the forestay to the detriment of your performance.

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[Vara]

Up in the frozen wastes of Norway recently I saw a couple of boats with radars mounted well above the cross trees but with the fitting angled at 90 degrees to the fore and aft line,thus minimising fouling of the fore sails.
At first sight looked sensible as it allowed higher mounting(good?) without associated problems.

<hr width=100% size=1>If it can't be fixed with a lump hammer dont fit it!

 

[johnsomerhausen]

The height of the radome depends of what you want to see. If you put it high up, you´ll be able to see smaller buoys in a seaway but you´ll get more sea clutter, if you put it lower, you´ll be able to see buoys at a shorter distance (very useful for navigating a channel in thick fog) and you´ll get less sea clutter. I´ve got my Furuno 1621 radome on a poile 10 ft above the water and I can see ships getting out of the screen at 16 miles (I can´t see them entering at that distance because the blip is too small for my bad eyesight but the radar alarm will sound)
john

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[brianhumber]

Radome should be high enough to avoid beams hitting people and low enough to avoid adverse effects of weight on mast. Your position seems to be a good compromise. You might loose a bit of scan from the innner forestay but unless you can steer a constant course to within half a degree I would not be too concerned.

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[Piers]

Considerations would be,

Height - the higher, the further you see. And with a good radar clutter can be tuned out. The height you indicate should be good for around a useful 6 mile range.

Fore/aft etc? Bear in mind the potential blind spot caused by the mast being in the way and ask yourself if it's acceptable.

Angle - there are some mounts that gimbal, keeping the aerial level with the sea without heeling. That means a better picture.

Which radar do you have in mind?

<hr width=100% size=1>Piers du Pré
http://www.dupre.co.uk