Raymarine Chartplotter RL70CRC PLUS manual Gain Control and Sea Control, Change the range scale

Adjusting Gain, Sea Clutter, Rain Clutter and Tune

3-8 hsb2 PLUS Series Color LCD Display

4.Use the trackpad to move the slider up or down. You can press and hold the control to move the slider quickly rather than in single steps.

The image on the screen changes as you move the slider, so that you can see the effect of your adjustment.

If you select MANUAL TUNE adjustment, an 8-step signal-strength indicator bar is displayed above the slider. Adjust the slider to obtain the maximum reading on the indicator.

Note: Because the changes to the settings are made immediately, you cannot revert to the previous setting by pressing CLEAR.

5.When you have set all the controls to the levels you require, press ENTER, or CLEAR to clear the slider display. The status bar is updated to indicate which controls are switched to Auto or On.

Gain Control and Sea Control

The GAIN control can be set to either Auto or Manual. In Auto mode, the Pathfinder Plus radar optimizes the setting. The SEA control can be set to Auto- Harbour (default), Auto-Offshore or Manual mode. In Auto-Offshore mode, the Pathfinder Plus Radar optimizes its settings to account for the effects of sea clutter. In harbours or close proximity to land different auto settings may be necessary to cater for the effects of land clutter. To avoid losing small targets it is therefore advisable to set the Sea control to Auto-Harbour mode. Alternatively, set both Sea and Gain to Manual mode then adjust the settings to ensure that all close small targets are visible.

The GAIN control adjusts the level of the display of signals received from the scanner; it is equivalent to a volume control on a radio.

Because the SEA control affects the gain, you may need to manually readjust it if you manually change the Gain setting.

Gain Control

When the GAIN control is set to Manual, you should check it every time you

MANUAL	change the range scale.
50%	On long range settings, the gain should be set to give a slight speckle in the
GAIN	background of the radar picture. Do not set the gain too low, or you may miss
	small or weak targets.
	On shorter ranges, you may wish to reduce the gain slightly to reduce the
MANUAL	speckle and therefore improve target definition.
75%	Sea Clutter Control
	Radar returns from waves around your vessel can clutter the centre of the radar
SEA	picture (see Figure 3-7, making it difficult to detect real targets. Such sea
	clutter usually appears as multiple echoes on the display at short range scales,