Spectracom VelaSync 1232 User Manual page 248

APPENDIX
Regarding the selection of a suitable
generally apply:
A
for the most optimal satellite reception. The mounting location of the external
GNSS antenna should be free of objects that could obstruct satellite visibility
from straight overhead to within 20 degrees of the horizon in all directions.
To optimize timing accuracy, the GNSS receiver attempts to track satellites that
are spread out as far as possible across the sky. The GNSS receiver must track at
least four satellites in order to obtain time synchronization. Obstructions that
block a significant portion of the sky result in degraded performance.
GPS antennas need to be separated from surrounding
metal in the area changes the shape of the reception pattern of the antenna. Any
buildings or metallic materials close to the antenna can create shadows which can
shield the antenna from receiving in that particular direction.
Separation between multiple
together there could potentially be interaction between the antennas and a res-
ulting loss of sensitivity. This could also adversely affect the search pattern of the
antennas, resulting in fewer satellites being tracked.
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clear view of the sky down to the horizon
Ideally, antennas should be separated as much as physically possible, so as
to help isolate them from being simultaneously affected by the same anom-
aly (such as a nearby lightning strike or a falling object, for example). The
minimum GNSS antenna-to-antenna distance is 39 inches (1 meter).
GPS antennas are receive-only antennas which do not intentionally trans-
mit any signals. Even though this reduces the amount of separation needed
between multiple antennas, a few meters of separation are recommended
to isolate the antennas from each other, in order to limit any possible EMI
interference caused by the active components inside the antennas.
antenna location, the following recommendations
in all directions is recommended
metallic
antennas: If the antennas are installed too close
materials. Any
VelaSync User's Manual