NorthStar Navigation Multi-Function Unit M84 - Manual (Page 78)

Northstar M121/M84 Installation and Operation Manual 77
There are four choices:
• Off. Interference rejection is off.
• Low operates the interference rejection at
minimum strength.
• Medium operates the interference rejection
at medium strength.
• High operates the interference rejection at
maximum strength. This setting can make
it more difficult to detect some targets and
radar beacons. Use this setting only when
necessary.
Palette
Select the color scheme for the radar window.
Digit size
The range of the radar is shown on the radar
window; for example 1/16. You can show this
information in small, medium or large digits.
Range ring
The range rings and compass ring help you to
quickly estimate the range and bearing of a
target from your boat.
The range ring and compass ring are shown.
The number of range rings and the spacing
interval between them is set automatically
according to the range setting. The current
spacing interval is shown in the top left corner
of the radar window.
Range ring and compass ring are hidden.
North line
Whatever the radar windorotation, you can
always show the blue North line.
If the bearing mode is set to:
• magnetic, the North line always points to
magnetic North.
• true, the North line always points to true
North.
Show the North line.
Hide the North line.
• Course up works only when COG data or
heading data from a heading sensor is
available and there is an active route. It
means that your desired heading is always
pointing to the top of the radar screen so
that you can compare the leg bearing of the
active route with the radar screen. (If you’re
in Course up rotation but don’t have an
active route, the radar uses Head up rotation
until a route is made active.)
Motion mode
True motion mode is not available if there is
no position data, and no heading or COG data.
However, you are strongly recommended to
use a good quality product (such as a Northstar
HS02, HS03 or Autopilot) to provide heading
data.
There are two choices:
• Relative (RM). Your boat remains in a fixed
location on the radar screen and all other
objects move relative to your position.
(You can choose the position of the fixed
location, see Section 18-10). RM is the
default.
• True (TM). Your boat, and moving targets,
move across the radar screen as you travel.
All stationary objects remain in a fixed
position. You must have position data, and
heading or COG data for this option to be
available.
Interference filter
If the radar on another boat is operating at
the same frequency as your radar, it can cause
interference patterns on the radar window.
Interference patterns always appear in a
different place with each sweep. They can be
randomly scattered bright dots or dotted lines
that extend from the centre to the edge of the
radar window, often producing a spiral pattern.
Generally, the stronger the interference, the
wider the interference lines.
Use the interference rejection option to reduce
both the interference patterns and the width of
the interference lines.