1. OPERATION
1-22
1.17
FTC (Fast Time Constant)
If you can not effectively suppress rain
clutter with the rain clutter control, use the
FTC function. In adverse weather, clouds,
rain or snow produce spray-like spurious
echoes which impair target detection over
a long distance. These echoes can be
suppressed by turning on the FTC circuit. There are two FTC settings, [FTC1] and
[FTC2]. [FTC2] provides increased rain clutter suppression.
Click the [FTC] icon at the bottom right corner on the screen to select an appropriate
FTC setting.
FTC PRESET
The [FTC PRESET] function, when active, applies the FTC a little stronger than nor-
mal. The combination effect of the [FTC PRESET] and [FTC] functions is shown as
below.
Set the [FTC PRESET] function as follows.
1. Open [MAIN MENU], click [ECHO].
2. Click [FTC PRESET].
3. Click [ON] to activate the [FTC PRESET] function.
1.18
How to Measure the Range to a Target (VRM)
You can measure the range to a target by two methods: fixed range rings and the VRM
(Variable Range Marker).
How to measure the range with the fixed range rings
Use the fixed range rings to get a rough estimate of the range to a target. The fixed
range rings are the concentric solid circles about your ship. The number of rings
changes with the selected range scale. The interval of the range ring is displayed at
the upper-left corner of the screen. Count the number of rings between the center of
the display and the target. Check the range ring interval and measure the distance of
the echo from the nearest ring.
How to measure the range with a VRM
There are two VRMs, VRM1 and VRM2. The VRMs are dashed so that you can iden-
tify them from the fixed range rings. You can identify VRM1 from VRM2 by the lengths
of their dashes. The dashes of the VRM1 are shorter than those of the VRM2.
1. Click the [VRM] icon to display the VRM. If the VRM already appears, go to step 2.
Effect
[FTC PRESET]
[OFF]
[ON]
[FTC]
[OFF]
–
low
[FTC1]
mid-low
mid-high
[FTC2]
mid-high
high
CAUTION
Switch off FTC if your objective is to
receive a radar beacon.
