Kongsberg Simrad RA83 Instruction Manual page 46

RA83/84/85/93/94/95 Series
Operation Manual
sheet (GAIN/SEA/HEIGHT sheet, hereafter).
(8) Repeat the above procedure for all range scales, if required.
4.7.3.2 STC (Height) setting
The STC characteristic is more less subject to vary depending on the height of the
antenna from the sea surface. Resetting the STC may be needed according to the
circumstances of the respective vessels. To achieve the best result, this setting should
be carried out off shore. Use the following procedure to do.
(1) Set SEA, GAIN and RAIN control to manual mode.
(2) Set GAIN to 8, SEA to 0 and RAIN to 0, respectively. Make sure that the sea
clutter speckle is appropriately shown on the screen. If the speckle is too much
or too short on the display, adjust the GAIN control as appropriate.
(3) Select an appropriate range scale to permit the clutter speckle is shown within
the screen.
(4) Adjust the SEA control to reduce the sea clutter until some residual clutter
speckle is shown.
(5) Turn the SEA control either clockwise or counterclockwise to see the effect of the
STC. If the effect is uniform in both long and short ranges, the STC Height
selection is considered appropriate. In such a case when the short range sea
return is suppressed earlier that that of the long range or vice versa, use the
following procedure to correct.
(6) Go SYSTEM>SYSTEM SETUP>HEIGHT and display the HEIGHT index entry
window.
(7) Adjust the SEA control to see the tendency of the control. If the short-range
clutter return is suppressed in advance to the long range one, reduce the
HEIGHT value by pressing the Joystick downwards, and vice versa.
(8) Adjust the SEA control to confirm the effect. If the result is not satisfactory, repeat
the above procedure.
(9) Press the ENT key to fix the setting.
(10) The HEIGHT index is irrelevant to the range. If this setting cannot be performed
offshore, the HEIGHT index should be selected with reference to the actual
antenna height from the sea surface. Use the following criteria as reference.
93142105-02
Antenna height
3 m
5 m
10 m
Recommended
HEIGHT index
8
5
2
Chapter 4
Installation
4-17