Raymarine hsb2 PLUS Series - Changing the Range; Determining Actual Radar Range

Chapter 3: Standard Radar Operations 3-3
Changing the Range
Changing the Range
Figure 3-1: Changing the Radar Range
➤ Each time you press the RANGE key, the range changesto the next available
setting.The system will beep three times if no further range scale is available.
➤ To changethe rangequickly,pressandholdthe requiredarrow on the RANGE
key.
The rangescale and range ring intervalindicators, at the left-hand end of the
statusbar, are updated whenever you change the range.
Determining Actual Radar Range
Theactual maximum radar range isessentiallyline-of-sight, and is limitedby
the height of the scannerand the height of the targetas shown in Figure 3-1.
Table 3-2 lists some range examples:
Figure 3-2: Determining Radar Range
Note:The ranges shown in the table are theoreticalmaximum ranges. The ra-
dar horizon is greater than the optical horizon, but the radar can only detect
targets if a large enough target is above the radar horizon.
Table 3-2: Radar Range
Antenna Height (m) Target Height (m) Maximum Range (nm)
3 3 7.8
3 10 10.9
5 3 8.9
5 10 12.0
RANGE
D3939_1
Increases
the range scale
Decreases
the range scale
Selected
range scale
Range ring
spacing
Status Bar
6nm
RR
1nm
343°T
RANGE
AUTO MAN
a
1
a
2
Earth
h
H
Cliff
Radar
D1643-2
R
max
R
max
= 2.23 ( h + H )
R
max
h
H
maximum radar range
radar antenna height
target height
in nautical miles
in metres
in metres
R
max
= radar horizon of antenna (
a
1
) + radar horizon of target (a
2
)
81186_3.book Page 3 Thursday, August 22, 2002 8:23 AM