Motorola SC 4812ET RF Hardware Installation Manual page 184

Installing RF GPS
– continued
RF GPS Mounting
Considerations
n
1 The mounting pipe for the RF GSP Head should be mounted vertically with less than five (5)
degrees of tilt.
2 The RF GPS Head requires a clear view of the sky, preferably to within ten (10) degrees of the
horizon in all directions. The less sky that can be observed the fewer the number of potential
satellites that can be tracked resulting in poorer RF GPS performance.
3 For general operation, the RF GPS 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 (1) GPS
satellite visible, however, operating in this mode is not recommended and requires an accurate site
survey.
4 Place the RF GPS Head where RF obstructions of the sky are minized. The "sky" includes
everything to within ten (10) degrees of the horizon in all directions. RF obstructions include
buildings, towers, snow, foliage and debris.
5 Separate the RF GPS Head from other radiating sources. Excessive RF energy can degrade the RF
GPS Head's ability to observe the GPS satellites. The RF GPS 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 radiants can overwhelm the filters, thus degrading the units
reception capability.
6 The RF GPS Head is rated for ambient air temperatures from –40 degrees C to + 50 degrees C,
and has ratings for humidity, shock, waterproof, UV light resistance, vibrations, salt, fog, ESD,
EMI, and altitude.
7 If the overall length from the RF GPS Head to the BTS is greater than 50 feet, the cable style and
length should be determined by the site configurations. The maximum loss should be less than
4.5 dBm @ 1575 MHz for all cabling and connections between the GPS Head and the RF cabinet.
H
184
The RF GPS Head requires specific mounting considerations in order to
properly observe the GPS satellites.
Table H-2: Mounting Considerations
SC 4812ET RF and Power Cabinet Hardware Installation Manual
TM
Consideration
NOTE
A 1/2" cable "pigtail" should always be used to exit the
cabinet before transitioning to a larger cable. This will
ensure a proper seal on the rubber I/O boot. It is suggested
that the supplier cable be cut to the desired length to
achieve this.
DRAFT
Apr 2001
V0H.01