Site preparation
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Chapter 3: Installation
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Install
ation
Radar distance
The minimum acceptable separation (d min.) between a radar and the ADU is determined
by the radar wavelength/frequency and the power emitted by the radar. The tables below
show some “rule of thumb” minimum separation distances as a function of radar power at X
and S band. If the d min. separation listed below is applied, antenna damage is normally
avoided.
“d min.” is defined as the shortest distance between the radar antenna (in any position) and
the surface of the SAILOR 600 Viasat Ka ADU.
The separation distance for C-band (4-8 GHz) radars should generally be the same as for SX-
band radars.
Radar interference
Even at distances greater than “d min.” in the previous section the radar might still be able
to degrade the performance of the SAILOR 600 Viasat Ka system. The presence of one or
more S or X-band radars within a radius up to 100 m may cause a minor degradation of the
Ka-band connection. The degradation will be most significant at high radar pulse repetition
rates. As long as receiving conditions are favourable, this limited degradation is not
important. However, if receiving conditions are poor – e.g. due to objects blocking the
signal path, heavy rainfall or icing, low satellite elevation and violent ship movements – the
small extra degradation due to the radar(s) could cause poor connection quality.
The presence of S-band radar(s) is unlikely to cause any performance degradation – as long
as the minimum distances (d min.) listed in the previous section are applied.
X-band (~ 3 cm / 10 GHz) damage distance
Radar
power
SAILOR 600 Viasat Ka ADU
d min. at 15° vertical separation d min. at 60° vertical separation
0 – 10 kW
1.0 m (3.3 ft)
1.0 m (3.3 ft)
30 kW
2.0 m (6.6 ft)
1.0 m (3.3 ft)
50 kW
3.3 m (10.8 ft)
1.7 m (5.6 ft)
Table 3-2: Minimum radar separation, X-band
S-band (~ 10 cm / 3 GHz) damage distance
Radar
power
SAILOR 600 Viasat Ka ADU
d min. at 15° vertical separation d min. at 60° vertical separation
0 – 10 kW
2.0 m (6.6 ft)
1.0 m (3.3 ft)
30 kW
3.0 m (9.8 ft)
1.5 m (4.9 ft)
50 kW
5.0 m (16.4 ft)
2.5 m (8.2 ft)
Table 3-3: Minimum radar separation, S-band
