Range Control - Raymarine H6 Owner's Manual

81238_1.book Page 142 Thursday, September 16, 2004 2:49 PM
142
Radar
R max = radar horizon of antenna (
The following table shows typical maximum radar ranges for various radar
antenna and target heights. Remember that although the radar horizon is greater
than the optical horizon, the radar can only detect targets if a large enough target
is above the radar horizon.
Antenna height (m)

Range control

The radar picture can be viewed at various scales. The shortest range scale gives a
maximum range of 1/8 nm, measured from the default center to the top of the
radar picture. The longest range scale gives a maximum range of between 24 and
72 nm depending on the scanner.
• Long range scales provide the best overview of the boats relationship to land
masses, weather fronts and large ship targets in or beyond view.
• Short range scales provide greater detail of the radar echoes close to the boat,
and should be used as the coastline, harbors or other boats in the area are
approached.
Concentric range rings are included to help in the judging of distances on
the radar picture. Their number and spacing are adjusted automatically if
the range scale is changed. Range rings can also be turned off.
R max
a
1
Earth
R max = 2.23 ( h + H )
R max maximum radar range
h radar antenna height
H target height
a
) + radar horizon of target (
1
Target height (m)
3
3 10
5
5 10
Raymarine H6 - Owner's Manual
a
2
in nautical miles
in metres
in metres
a
)
2
D7005_1
Maximum range (nm)
3 10
10.9
3 8.9
12.0
Cliff