Measuring The Range; Measuring Range By Range Rings; Measuring Range By Cursor; Measuring Range By Vrm - Furuno FR-7041R-MARK-2 Operator's Manual

1. OPERATION
1.17

Measuring the Range

In the basic radar system your ship is in the center of the display, and any target
received appears in a map-like projection throughout 360 degrees. This allows
the range and bearing from your vessel to a target appearing on the display to be
measured.
You can measure the range to a target three ways: by the range rings, by the
cursor and by the VRM (Variable Range Marker).
1.17.1

Measuring range by range rings

To get a rough measurement of the range to a target, use the range rings, which
you may show as follows:
1. Press the [MENU] key to show the main menu.
2. Use the trackball to select RINGS.
3. Press the [ENTER] key to show desired level in the message window.
4. Press the [MENU] key to close the menu.
To measure range by the range rings, count the number of rings between the
center of the display and the target. Check the range ring interval and judge the
distance of the echo from the inner edge of the nearest ring.
1.17.2

Measuring range by cursor

To measure the range by the cursor, rotate the trackball to place the cursor
intersection on the inside edge of the target. The range to the cursor intersection
appears at the bottom of the display.
1.17.3

Measuring range by VRM

Use the VRMs for accurate measurement of the range to a target. There are two
VRMs, VRM1 and VRM2, which appear as dashed rings to as to distinguish them
from the range rings. The two VRMs can be distinguished from each other by
different lengths of dashes.
1. Press the [VRM 1] or [VRM 2] key, whichever VRM you want to use. The
readout of the active marker is circumscribed.
2. Operate the trackball within five seconds of completing step 1 to place the
VRM on the inside edge of the target.
3. Check the VRM readout at the bottom right-hand corner of the display to find
the range to the target.
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