Motorola SC 4812ET RF Hardware Installation Manual page 125

RGPS Mounting
Considerations
Apr 2001
SC
TM
V0A.03
The RGPS Head requires specific mounting considerations in order to
properly observe the GPS satellites.
– The mounting pipe for the RGPS Head should be mounted
vertically with less than five degrees (5°) of tilt.
– The RGPS Head needs to have a clear view of the sky, preferably to
within ten degrees (10°) of the horizon in all directions. The less
sky that can be observed the fewer the number of potential satellites
that can be tracked and hence the poorer the RGPS performance.
– For general operation, the RGPS Head needs to be able to
continuously track signals from at least four (4) GPS satellites. It is
theoretically possible to operate the BTS with only one GPS
satellite visible, however, operating in this mode it is not
recommended and requires an accurate site survey.
– Place the RGPS Head where RF obstructions of the sky are
minimized. The "sky" includes everything to within ten degrees
(10°) of the horizon in all directions. RF obstructions includes
buildings, towers, snow, foliage and debris.
– Separate the RGPS head from radiating sources. Excessive RF
energy can degrade the RGPS head's ability to observe the GPS
satellites. The RGPS head receives on the GPS L1 frequency of
1575.42 MHz and has filters incorporated within to minimize the
effects of potential RF interference, however, strong radiaters can
overwhelm the filters, thus degrading the units reception capability.
– The RGPS Head is rated for ambient air temperatures from –40° C
to +50° C, and has ratings for Humidity, Shock, Waterproof, UV
Light Resistance, Vibrations, Salt, Fog, ESD, EMI, and Altitude.
– The RGPS system will support up to 2000 feet (2609 m) of overall
cable length from the RGPS Head to the last connected base station.
If a long cable run needs to be broken into pieces, minimize the
number of breaks in the cable.
4812ET RF and Power Cabinet Hardware Installation Manual
DRAFT
Installing RGPS
– continued
125
A