Table 9
Recommended GPS / GLONASS Antenna Specifications (Cont.)
Requirement / Recommendations
Operating Temperature
0°C to +40°C (Recommended)
Cable length requirements
The limit on the length of the GPS cable depends on multiple factors:
•
Location of the GPS antenna.
•
Type of the RF GPS cable used.
•
Splitters and connectors used.
Lengths vary based on the above parameters. The parameter, defining proper cable
length, is the signal strength at the inputs of the Pico GPS receiver. The signal strength
must meet the sensivity requirements as shown in the table below.
Table 10
GPS sensitivity requirements
Parameter
Action type
Sensitivity
GPS Sensitivity
Tracking
-161 dBm
Hot Acquisition
-161 dBm
Cold Acquisition
-147 dBm
Reacquisition
-161 dBm
* - Values are valid at room temperature 25
o
C [77
o
F]
External GPS Antennas
Many different GPS antenna options are available for an outdoor GPS antenna. The
guidelines in
Table 9: Recommended GPS / GLONASS Antenna Specifications
apply to an external GPS/GLONASS receiver. The FlexiZone Micro GPS antenna
(473100A) can suit this purpose. This antenna is designed to mount directly to the
female N connector on the FZM so does not include a cable or mounting feature. A
mounting bracket would be needed with a bulkhead female N connector then a long run
of cable. If a deployment of a large number of FZPs is needed with remote GPS then the
best solution would be a single GPS antenna and a distribution network. Care must be
taken to insure the DC block is in place. This DC block can be a separate item or
included in the distribution network.
Distribution networks
In the case of large indoor deployments of FZP units utilizing GPS/GLONASS it is better
to use a single GPS antenna with a distribution network. This equipment is not supplied
by Nokia as it is site specific, but can be used to overcome the losses incurred with long
cable runs and multiple splits to accommodate separate feeds into each FZP. Care must
be taken when selecting the proper distribution amplifier. The key requirements are as
follows:
•
Active GPS/GLONASS antenna bias: The amplifier must provide 5 VDC for the
active antenna.
•
Port Impedance: All ports (IN/OUT) must be 50 ohms.
Synchronization
Flexi Zone Indoor Pico BTS Product Description
22
DN09210454
Issue: 01
