Interphase iScan V90 Operation Manual page 20

STC ADJUSTMENT
The STC Adjustment can be used to help minimize surface
clutter problems. Typically, most depthsounders show a
band of noise near the surface caused by ringing in the
transducer, surface turbulence in the water and other
factors. Where there is severe surface clutter, the digital
depth display can get confused between showing the true
bottom or the surface clutter. In addition, severe surface
clutter can cause the alarms to sound.
To minimize these types of problems, the iScan V90
includes an STC Adjustment. STC stands for Surface
Time Constant and you can use it to force the iScan V90 to
ignore surface clutter. By default, the STC is set to 5 feet -
meaning that the digital depth and alarms will ignore
anything closer than 5' to the transducer. The clutter will
still be displayed, just not used to calculate the digital depth
or sound an alarm.
If you are having problems with the digital depth or alarms
because of excessive surface clutter, you can increase or
decrease the exclusion range as shown at right.
From the SET-UP menu, choose MORE and from that
menu choose MORE again. Then press the button below
the STC Symbol as shown at right. That will bring up a
display showing the STC adjustment line as shown. Use
the NAV key to adjust up or down to ignore the clutter area
and then press the EXIT symbol to save and return to a
normal display.
After making this adjustment, the surface clutter will still
remain on the display but will be ignored by the alarm and
digital depth functions.
Version 2.00
200KHz
EXIT LANGUAGE MORE
UNITS
FORWARD LOOKING SONAR
RANGE DEFAU
LT
100 FT 11
200 12
400 14
STC ADJUSTMENT LINE
13.2 Ft
12.5
25
20
CURSR
VERT
iSCAN V90
DOWN
RANGE
DEMO TRANSDUCER
MAX G
11
12
14
MORE
18
37
FORWARD LOOKING SONAR
PWR
VIDEO
DATA
GAIN
CURSR PWR
VERT VIDEO
DATA
DOWN
RANGE GAIN