NavCom SF-2040 Rev.F - Manual (Page 44)

SF-2040 User Guide – Rev. F
9
Antenna placement is critical to good system
performance. Avoid antenna shading by buildings,
rooftop structures, foliage, hills/mountains, etc.
9 Locate the antenna where it has a clear view of
the sky, to an elevation angle of 7º if possible.
Obstructions below 15º elevation generally are
not a problem, though this is dependent on
satellite availability for the local region.
9 Avoid placing the antenna where more than 90º
azimuth of the sky is obstructed. When more than
90º of azimuth is shaded, it is often still possible
for the receiver to navigate, however, poor
satellite geometry (due to satellite shading) will
provide poor positioning results. Even 10º of
shading can have a negative effect on
performance, though this generally is not the
case.
9 Avoid placing the antenna on or near metal or
other electrically reflective surfaces.
9 Do not paint the antenna enclosure with a
metallic-based paint.
9 Avoid placing the antenna near electrical motors
(elevator, air conditioner, compressor, etc.)
9 Do not place the antenna too close to other active
antennas. The wavelength of L2 is 0.244m and L1
is 0.19m. The minimum acceptable separation
between antennas is 1m (39 in), which provides
6dB of isolation. For 10dB of isolation, separate
the GPS antennas by 2.5m, and for 13dB of
isolation (recommended) separate the antennas
by 5m.
9 Active antennas (those with LNA’s or amplifiers)
create an electrical field around the antenna.
These radiated emissions can interfere with other
nearby antennas. Multiple GPS antennas in close
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