Brian Whatcott inscribed in red ink for all to know:
On Mon, 25 Sep 2006 13:00:13 GMT, "bushman" wrote:


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.



Rough estimate:
mast 2/3 ft. distance 22ft that's 1 in 33 or less than
2 degrees masking.

Mast mount - not enough data, but lets suppose an
equivalent scanner width of 2 ft at a distance of 2 ft:
inv cos 0.5 about 60 degrees
mast 2/3 masking 2 ft so 1/3 reduction in signal.

Roughly (You bet!)
a 1/3 reduction in echo strength in a 60 degree segment
(hardly noticeable) but watch out for detector overload

Brian Whatcott Altus OK

My radar is mounted on a mount on the front of my mizzen. There is a
small, permanent artifact directly in front, but there is a huge swath
of missing sensitivity behind me... I once missed a ferry (until I
heard its horm) behind me - completely invisible until it got to one side...

bob

On Mon, 25 Sep 2006 10:52:50 -0700, RW Salnick
wrote:

Brian Whatcott inscribed in red ink for all to know:
On Mon, 25 Sep 2006 13:00:13 GMT, "bushman" wrote:


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.



Rough estimate:
mast 2/3 ft. distance 22ft that's 1 in 33 or less than
2 degrees masking.

Mast mount - not enough data, but lets suppose an
equivalent scanner width of 2 ft at a distance of 2 ft:
inv cos 0.5 about 60 degrees
mast 2/3 masking 2 ft so 1/3 reduction in signal.

Roughly (You bet!)
a 1/3 reduction in echo strength in a 60 degree segment
(hardly noticeable) but watch out for detector overload

Brian Whatcott Altus OK

My radar is mounted on a mount on the front of my mizzen. There is a
small, permanent artifact directly in front, but there is a huge swath
of missing sensitivity behind me... I once missed a ferry (until I
heard its horm) behind me - completely invisible until it got to one side...

bob

A small effective scanner aperture and/or a big close mast diameter
could do that to you, no doubt! Ouch....

Brian Whatcott Altus OK