Radar antenna installation

[Chester]

On a C-Dory 22-Cruiser is the Radar antenna installed parallel to the roof or does it need a wedge to achieve best performance?
Thank you, Steve.

[matt_unique]

[thataway]

If you are going dead slow (which you may be in very limited visability), then the beam will be close to parallel with the lines of the cabin top. If you are going at displacement speeds--up to semi displacement speeds, you may be up 5 to 8 degrees--and at a plane you are often at a bit of an up angle. However, I have always installed my radars parallel to the cabin top, and found that I had good radar visabilty at all speeds. Theoretically the down angle of 5 degrees could be justified.

[Les Lampman]

I'll further add (to what Bob said) that your "need" for what the radar does often changes with speed.

When it's absolutely horrible and you're dead slow you really want the radar to "see" closer in (and regardless of the angle it will still see targets worth knowing about further out).

If it's not quite so bad and you can run at just over displacement speeds the nose will lift a bit and in these conditions (since you can physically see close in) you want the radar to "look" a little further out.

If you're using radar at cruise speed it usually means you're using it to pick up distant targets (primarily for navigation as opposed to collision avoidance) and you want the radar to "see" way out yonder.

If the radar is parallel with the resting waterline of the boat all these things happen automatically on planning hulls.

[Chester]

Very good, thank you for the responses.

[Chester]

We looked at some photos of Chester sitting in the water and the roofline is very close to being parallel with the waterline.
Todd at Portland Marine Electronics said the Seaview(?) radar riser has a little wedge built in so I told him not to install an additional wedge.