Satellite Signal At Low Elevation Angles - Thrane&Thrane EXPLORER 110 User Manual

OPERATION '
CONT D

Satellite signal at low elevation angles

Angles below 10°
Inmarsat satellites are geostationary and are located
in fi xed positions in the sky above equator. A fi xed
antenna installation is therefore possible. However, a
geostationary satellite moves slightly (3° in azimuth +
1° in elevation) during a 24 hrs cycle.
At low elevations (< 10 degrees), variations in the sat-
ellite signal must be expected. This normally does not
affect the communication. Only if the surface in front
of the antenna is completely fl at, e.g. roof or calm
water, can it cause reduction in signal strength and/or
data rate.
The solution is to change the height above ground
30 cm up/down. On a fl at roof the antenna should be
installed close to the edge or horizontally on the roof,
26 26
especially for a permanent installation. This is not an
issue if the terrain in front of the antenna is uneven.
MULTIPATH FADING
AVOID REFLECTIONS AT 10 DEGREE ELEVATION OR LESS.
To find the best possible satellite signal when pointing
the antenna, adjust the terminal height above the surface
up or down in steps of 30cm.
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