Raymarine hsb2 PLUS Owner's Handbook Manual page 83

Chapter 3: Getting Started & Adjusting the Display
➤ To adjust the range and shift values:
1. Press RANGE, this sets adjustment to manual and the range soft keys are
displayed. The range adjusts up or down depending on the direction
RANGE
pressed.
2. Use the RANGE key to adjust the range: press the up arrow to select a shal-
lower range, press the down arrow to select a deeper range.
3. If necessary, press the RANGE AUTO MAN soft key to select AUTO range.
RANGE
AUTO MAN
AUTO range is indicated by the letter R in the status bar.
4. To adjust the shift, press the appropriate SHIFT soft key: use the up soft key
to select a shallower shift, use the down soft key to select a deeper shift.
The image window is shifted up by the selected amount
5. Press ENTER to return to the default display.
When AUTO POWER has been selected, and you manually adjust the RANGE to
30 ft (10 m) or greater, the Fishfinder switches to HI power, regardless of what
the digital depth is calculated to be.
Manually Adjusting RANGE to Ignore Surface Clutter
There may be a time when clutter near the water's surface is so thick it returns
an echo that is stronger than the return from the bottom. In this a case, it is
possible the fishfinder may determine the clutter to be the seabed rather than
the bottom itself. You can use the RANGE setting to force the fishfinder to
ignore any interference in the upper boundaries of the water that may be giving
false bottom readings.
If you manually adjust the RANGE to 400 ft (150 m) or greater, the Fishfinder
ignores the first 25% of the range for the purpose of determining the digital
depth. If the RANGE is set to 400 ft (150 m), the first 100 ft (37.5 m) is ignored
for determining the depth. If the RANGE is set to 3000 ft (1000 m), the first 750
ft (250 m) is ignored, etc.
As an example, let's say the RANGE is set to 400 ft but there is some clutter at
126 ft that is returning a stronger signal than the bottom. Because its return is
stronger, the fishfinder determines the clutter to be bottom and displays it as
the bottom depth (126 ft). See Figure 3-8.
The upper 25% (400 x 0.25 = 100 ft) of the range is ignored but because the
clutter is deeper than this (126 > 100 ft), the clutter is still detected as bottom.
If you then manually adjust the RANGE to 600 ft, the value that is ignored now
increases to 150 ft (600 x 0.25 = 150). The clutter is now within the excluded
range (126 < 150) and so is ignored. The correct bottom of 302 ft is now
displayed.
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