Measuring Range By The Variable Range Marker (Vrm) - Furuno FA Manual

1.20.2

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.
By keyboard
1. Press the [VRM ON] key to display either of the VRMs. Successively
pressing the [VRM ON] key toggles the active VRM between No. 1 and No. 2.
The currently active marker is enclosed with >.....<.
2. Operate the VRM rotary control 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 or the RANGE box. This means that the
apparent radius of the VRM ring changes in proportion to the selected range
scale.
3. Press the [VRM OFF] key to erase each VRM.
By trackball
1. Roll the trackball to place the arrow in the VRM1 or VRM2 box, whichever
VRM you want to use.
2. The guidance box reads "VRM ON/." Push the left button to turn on the VRM.
The guidance box now reads "VRM SET L = DELETE /."
3. Push the left button again and the cursor jumps to inside the effective display
area. The guidance box now reads "VRM FIX / EXIT."
000
350 010
340
330
No. 1
320
VRM
310
300
290
280
270
260
250
240
230
220
210
200
190
170
180
Measuring range with VRMs
VRM1
VRM2
VRM boxes
020
030
Target
040
blip
050
060
070
080
090
100
No. 2
110
VRM
120
130
140
150
160 >0.66NM<
VRM1
1.18NM
VRM2
1. RADAR OPERATION
1-35