T-
900 series Chapter 5 Equipment
0093142132-00
5-2
How to shift the antenna from an obstacle
1. How to shift the antenna from the keel line
By shifting the antenna from keel line to the starboard, the blind moves to the port and the visibility in
the heading can be secured. According to a distance to an obstacle, the distance to be shifted can be
derived from the formula below.
Ls
R
D
Antenna
Obstacle
Keel line
Distance to be shifted from the keel line
Distance to an obstacle
Diameter of an obstacle over the keel line
How to shift the antenna from the keel line
2. How to keep an angle of depression
To keep enough angle of depression
θ
that is an angle between the horizontal and the observer’s line of
sight (In this case, it is not the observer but an antenna), elevate the antenna height. By making
θ
more
than 5°, the blind at the middle and long distances can be avoided.
An object below the line of sight cannot be detected.
Horizon
Line of sight
How to keep an angle of depression