Measuring The Range To A Target - Furuno FR-8062 Operator's Manual

1.16

Measuring the Range to a Target

The range to a target may be measured three ways: with the fixed range rings, with the cursor (if
set to measure range and bearing), or with the VRM.
Use the fixed range rings to obtain a rough estimate of the range to a target. They are the concen-
tric solid circles about own ship, or the sweep origin. The number of rings is automatically deter-
mined by the selected range scale and their interval is displayed at the upper-left position of the
screen. 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.
1.16.1 Adjusting range ring brilliance
1. Press the MENU key to open the menu.
2. Choose the Brill/Color menu and then press the ENTER key.
3. Choose Range Rings Brill and then press the ENTER key.
Off
Low
Medium
High
4. Choose appropriate brilliance and then press the ENTER key.
5. Press the MENU key to close the menu.
1.16.2 Measuring range by the variable range marker (VRM)
There are two VRMs, No. 1 and No. 2, which appear as dashed rings so that you can discriminate
them from the fixed range rings. The two VRMs can be distinguished from each other by different
lengths of dashes.
1. Press the VRM key to display either
of the VRMs. Successively pressing
the VRM key toggles the active
VRM between No. 1 and No. 2. The
currently active marker is enclosed
with >.....<.
2. Operate the Trackball to align the
active variable range marker with
the inner edge of the target of
interest and read its distance at the
lower-right corner of the screen.
Each VRM remains at the same
geographical distance when you
operate the RANGE key. This
means that the apparent radius of
the VRM ring changes in proportion
to the selected range scale.
3. Press the VRM key to erase each
VRM.
VRM1
+ 96.8°R 0.338 NM
How to measure range with VRMs
1. OPERATIONAL OVERVIEW
Target
VRM2
+
VRM1>0.007 <
NM VRM1, VRM2
VRM2 0.140
NM
range
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