Symmetricom TimeSource 500, User Manual

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TimeSource 3500
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Engineering & Ordering
097-72050-01 Issue 7: August 2003
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S S S S S S S S S S S S S S S S S S S S S S S S S S S S S
Figure 9. Antenna Field of View
Due to the geometry of the GPS satellite orbits, more satellites are
visible in the direction of the equator than the poles. If possible, place
the antenna so that the antenna has a clear view toward the equator
(toward the south in the northern hemisphere, or toward the north in
the southern hemisphere). Up to 60 degrees of arc, centered at the
pole, may be blocked with little effect in the temperate latitudes. This
note is less applicable in latitudes nearer the equator.
The total of obstructions above the mask angle should not obscure
more than 25 percent of the total field of view (90 degrees of
azimuth) (Figure 10).
Horizon
Antenna position
10°
Equator
10°
Mask angle*
Mask angle*
Pole
Antenna
field of view
* An angle of 10° masks objects up to about 3.5 ft above the
horizon at 20 ft from the antenna (illustration at right.)
10°
3.5 ft
20 ft
Obstructions
if possible
toward the pole